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Presentasi berjudul: "REKAYASA BIOLOGIS SUMBERDAYA HAYATI"— Transcript presentasi:


Manipulating and engineering genetic material in the lab may represent the best hope for increasing agricultural production further without destroying more natural lands. But many people remain uneasy about genetically engineering crop plants and other organisms. Diunduh dari: …… 20/12/2012 Genetically modified foods (GM foods, or biotech foods) are foods derived from genetically modified organisms (GMOs), specifically, genetically modified crops. GMOs have had specific changes introduced into their DNA by genetic engineering techniques. These techniques are much more precise than mutagenesis (mutation breeding) where an organism is exposed to radiation or chemicals to create a non-specific but stable change. Other techniques by which humans modify food organisms include selective breeding; plant breeding, and animal breeding, and somaclonal variation. Diunduh dari: 22/12/2012

3 REKAYASA GENETIK MENGGUNAKAN What is transgenic food?
DNA - REKOMBINAN Genetic engineering (GE) = directly manipulating an organism’s genetic material in the lab by adding, deleting, or changing segments of its DNA Genetically modified (GM) organisms = genetically engineered using recombinant DNA technology Recombinant DNA = DNA patched together from DNA of multiple organisms (e.g., adding disease-resistance genes from one plant to the genes of another) Diunduh dari: …… 20/12/2012 What is transgenic food? Transgenic food are those directly made from or processed from the species (animals, plants and microorganisms, etc.) which can produce substances possessing highly effective expressions, such as polypeptide and protein, after one or several types of exogenous genes are transferred into it through the means of genetic engineering. The first category----transgenic plant food product There are various kinds of transgenic plant foods, such as high protein wheat used to bake breads. To reverse the situation that wheat in the current market contains low rate of protein, protein genes possessing highly effective expressions are transferred into wheat, so that bread made from the wheat can be of more nutritious value. Diunduh dari: …… 22/12/2012

Genes moved between organisms are transgenes, and the organisms are transgenic. These efforts are one type of biotechnology, the material application of biological science to create products derived from organisms. Diunduh dari: …… 20/12/2012 Transgenosis technology is a kind of modern technology in molecular biology, which is used to transfer genes from one species into another so as to reconstruct the genetic materials of the receiving species for the improvement of its properties, quality of nutrition in line with the need of human beings. The transgenic species as immediate food and food processed from transgenic species are called transgenic food. Diunduh dari: 22/12/2012

REKAYASA GENETIK vs. PEMULIAAN TRADISIONAL They are similar: We have been altering crop genes (by artificial selection) for thousands of years. There is no fundamental difference: both approaches modify organisms genetically. They are different: GE can mix genes of very different species. GE is in vitro lab work, not with whole organisms. GE uses novel gene combinations that didn’t come together on their own. Diunduh dari: …… 20/12/2012

6 Some GM foods Golden rice: Enriched with vitamin A. But too much hype?
FlavrSavr tomato: Better taste? But pulled from market. Ice-minus strawberries: Frost-resistant bacteria sprayed on. Images alarmed public. Bt crops: Widely used on U.S. crops. But ecological concerns? Diunduh dari: …… 20/12/2012

7 Some GM foods Bt sunflowers: Insect resistant.
But could hybridize with wild relatives to create “superweeds”? StarLink corn: Bt corn variety. Genes spread to non-GM corn; pulled from market. Roundup-Ready crops: Resistant to Monsanto’s herbicide. But encourages more herbicide use? Terminator seeds: Plants kill their own seeds. Farmers forced to buy seeds each year. Diunduh dari: …… 20/12/2012

Although many early GM crops ran into bad publicity or other problems, biotechnology is already transforming the U.S. food supply. Two-thirds of U.S. soybeans, corn, and cotton are now genetically modified strains. Diunduh dari: …… 20/12/2012 Health concerns and potential food hazards Health risks associated with genetically modified foods are concerned with toxins, allergens, or genetic hazards. The mechanisms of food hazards fall into three main categories (Conner et al., 1999): Inserted genes and their expression products Secondary and pleiotropic effects of gene expression Insertional mutagenesis resulting from gene integration For example, bean plants that were genetically modified to increase cysteine and methionine content were discarded after the discovery that the expressed protein of the transgene was highly allergenic. (Butler et al., 1999) Diunduh dari: 22/12/2012

9 ORGANISME TRANSGENIK Are there health risks for people?
Can transgenes escape into wild plants, pollute ecosystems, harm organisms? Can pests evolve resistance to GM crops just as they can to pesticides? Can transgenes jump from crops to weeds and make them into “superweeds”? Can transgenes get into traditional native crop races and ruin their integrity? Diunduh dari: …… 20/12/2012 The potential risks accompanied by disease resistant plants deal mostly with viral resistance. It is possible that viral resistance can lead to the formation of new viruses, and therefore new diseases. It has been reported that naturally occurring viruses can recombine with viral fragments that are introduced to create transgenic plants, forming new viruses. Additionally, there can be many variations of this newly formed virus. (Steinbrecher, 1996) Diunduh dari: 22/12/2012

10 ORGANISME TRANSGENIK These questions are not fully answered yet. In the meantime… Should we not worry, because so many U.S. crops are already GM and little drastic harm is apparent? Or should we adopt the precautionary principle, the idea that one should take no new action until its ramifications are understood? Diunduh dari: …… 20/12/2012

Should scientists and corporations be “tinkering with” our food supply? Are biotech corporations testing their products adequately, and is outside oversight adequate? Should large multinational corporations exercise power over global agriculture and small farmers? Diunduh dari: …… 20/12/2012 RISKS AND CONTROVERSY With all this new technology comes question and fear. What are the risks of "tampering with Mother Nature"? What effects will this have on the environment? Are there health concerns consumers should be aware of? Is recombinant technology really beneficial? The following section will address some major concerns about the risks involved with genetically modified foods and recombinant technology, touching up environmental risks as well as health risks. Diunduh dari: …… 20/12/2012

12 Genetically Modified Food and Crops
Projected Disadvantages Need less fertilizer Need less water More resistant to insects, plant disease, frost, and drought Faster growth Can grow in slightly salty soils Less spoilage Better flavor Less use of conventional pesticides Tolerate higher levels of pesticide use Higher yields Advantages Trade-Offs Genetically Modified Food and Crops Irreversible and unpredictable genetic and ecological effects Harmful toxins in food From possible plant cell Mutations New allergens in food Lower nutrition Increased evolution of Pesticide-resistant Insects and plant disease Creation of herbicide- Resistant weeds Harm beneficial insects Lower genetic diversity Diunduh dari: …… 20/12/2012

13 Viewpoints: Genetically modified foods
Indra Vasil Ignacio Chapela “Biotech crops are already helping to conserve valuable natural resources, reduce the use of harmful agro-chemicals, produce more nutritious foods, and promote economic development.” “We should expect fundamental alterations in ecosystems with the release of transgenic crops… We are experiencing a global experiment without controls.” Diunduh dari: …… 20/12/2012

MELESTARIKAN KEANEKA-RAGAMAN TANAMAN Native cultivars of crops are important to preserve, in case we need their genes to overcome future pests or pathogens. Diversity of cultivars has been rapidly disappearing from all crops throughout the world. Diunduh dari: …… 20/12/2012 Crop diversity is the variance in genetic and phenotypic characteristics of plants used in agriculture. Crops may vary in seed size, branching pattern, in height, flower color, fruiting time, or flavor. They may also vary in less obvious characteristics such as their response to heat, cold or drought, or their ability to resist specific diseases and pests. It is possible to discover variation in almost every conceivable trait, including nutritional qualities, preparation and cooking techniques, and of course how a crop tastes. And if a trait cannot be found in the crop itself, it can often be found in a wild relative of the crop; a plant that has similar species that have not been farmed or used in agriculture, but exist in the wild. Diunduh dari: …… 22/12/2012

15 Seed banks preserve seeds, crop varieties
Seed banks are living museums of crop diversity, saving collections of seeds and growing them into plants every few years to renew the collection. Careful hand pollination helps ensure plants of one type do not interbreed with plants of another. Diunduh dari: …… 20/12/2012

16 Animal agriculture: Livestock and poultry
Consumption of meat has risen faster than population over the past several decades. Diunduh dari: …… 20/12/2012

Increased meat consumption has led to animals being raised in feedlots (factory farms), huge pens that deliver energy-rich food to animals housed at extremely high densities. Diunduh dari: …… 20/12/2012

18 Immense amount of waste produced, polluting air and water nearby
PERTANIAN-TERNAK DAMPAK LINGKUNGANNYA Immense amount of waste produced, polluting air and water nearby Intense usage of chemicals (antibiotics, steroids, hormones), some of which persist in environment However, if all these animals were grazing on rangeland, how much more natural land would be converted for agriculture? Diunduh dari: …… 20/12/2012 Diunduh dari: ……..…… 22/12/2012

19 The FOOD PYRAMID is a nutrition guide that is shaped like a pyramid.
PILIHAN PANGAN = PILIHAN ENERGI Energy is lost at each trophic level. When we eat meat from a cow fed on grain, most of the grain’s energy has already been spent on the cow’s metabolism. Eating meat is therefore very energy inefficient. Diunduh dari: …… 20/12/2012 The FOOD PYRAMID is a nutrition guide that is shaped like a pyramid. It is separated in parts, with each segment depicting the suggested intake of a particular food group. Diunduh dari: …..…… 22/12/2012

20 Grain feed input for animal output
Some animal food products can be produced with less input of grain feed than others. Diunduh dari: …… 20/12/2012

Some animal food products can be produced with less input of land and water than others. Diunduh dari: …… 20/12/2012

22 AQUACULTURE Aquaculture
The raising of aquatic organisms for food in controlled environments Provides 1/3 of world’s fish for consumption 220 species being farmed The fastest growing type of food production Diunduh dari: …… 20/12/2012 Aquaculture The cultivation of aquatic organisms. Some of the most common organisms that are cultivated are salmon, trout, oysters, and clams. Diunduh dari: …… 22/12/2012

23 Global aquaculture has been doubling about every 7 years.
Fish make up half of aquacultural production. Molluscs and plants each make up nearly 1/4. Global aquaculture has been doubling about every 7 years. Diunduh dari: …… 20/12/2012

24 Budidaya Ikan Lele di Gemolong Sragen
MANFAAT AKUAKULUR Provides reliable protein source for people, increases food security Can be small-scale, local, and sustainable Reduces fishing pressure on wild stocks, and eliminates bycatch Uses fewer fossil fuels than fishing Can be very energy efficient Diunduh dari: …… 20/12/2012 Budidaya Ikan Lele di Gemolong Sragen Lele merupakan jenis ikan yang digemari masyarakat, dengan rasa yang lezat, daging empuk, duri teratur dan dapat disajikan dalam berbagai macam menu masakan. PT. NATURAL NUSANTARA dengan prinsip K-3 (Kuantitas, Kualitas dan Kesehatan) membantu petani lele dengan paket produk dan teknologi. Diunduh dari: …… 20/12/2012

Density of animals leads to disease, antibiotic use, risks to food security. It can generate large amounts of waste. Often animals are fed grain, which is not energy efficient. Sometimes animals are fed fish meal from wild-caught fish. Farmed animals may escape into the wild and interbreed with, compete with, or spread disease to wild animals. Diunduh dari: …… 20/12/2012 Aquaculture is the fastest growing food production sector in the World with annual growth in excess of 10 percent over the last two decades. Much of this development has occurred in Asia, which also has the greatest variety of cultured species and systems. Asia is also perceived as the ‘home’ of aquaculture, as aquaculture has a long history in several areas of the region and knowledge of traditional systems is most widespread. Diunduh dari: …… 22/12/2012

Transgenic salmon (top) can compete with or spread disease to wild salmon (bottom) when they escape from fish farms. Diunduh dari: …… 20/12/2012

27 Trade-Offs Aquaculture
Highly efficient High yield in small volume of water Increased yields through cross- breeding and genetic engineering Can reduce over- harvesting of conventional fisheries Little use of fuel Profit not tied to price of oil High profits Advantages Large inputs of land, feed, And water needed Produces large and concentrated outputs of waste Destroys mangrove forests Increased grain production needed to feed some species Fish can be killed by pesticide runoff from nearby cropland Dense populations vulnerable to disease Tanks too contaminated to use after about 5 years Disadvantages Trade-Offs Aquaculture Diunduh dari: …… 20/12/2012

28 More Sustainable Aquaculture
Reduce use of fishmeal as a feed to reduce depletion of other fish Improve pollution management of aquaculture wastes Reduce escape of aquaculture species into the wild Restrict location of fish farms to reduce loss of mangrove forests and other threatened areas Farm some aquaculture species (such as salmon and cobia) in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean Set up a system for certifying sustainable forms of aquaculture Solutions More Sustainable Aquaculture Diunduh dari: …… 20/12/2012

Agriculture that can practiced the same way far into the future Does not deplete soils faster than they form Does not reduce healthy soil, clean water, and genetic diversity essential for long-term crop and livestock production Low-input agriculture = small amounts of pesticides, fertilizers, water, growth hormones, fossil fuel energy, etc. Organic agriculture = no synthetic chemicals used. Instead, biocontrol, composting, etc. Diunduh dari: …… 20/12/2012 Components of a Sustainable Soil Management System Diunduh dari: …… 23/12/2012

30 Principles in Organic Farming
PERTANIAN ORGANIK Small percent of market, but is growing fast 1% of U.S. market, but growing 20%/yr 3–5% of European market, but growing 30%/yr Organic produce: Advantages for consumers: healthier; environmentally better Disadvantages for consumers: less uniform and appealing-looking; more expensive Diunduh dari: …… 20/12/2012 Principles in Organic Farming Diunduh dari: …… 23/12/2012

Organic Agriculture should sustain and enhance the health of soil, plant, animal, human and planet as one and indivisible. This principle points out that the health of individuals and communities cannot be separated from the health of ecosystems - healthy soils produce healthy crops that foster the health of animals and people. Health is the wholeness and integrity of living systems. It is not simply the absence of illness, but the maintenance of physical, mental, social and ecological well-being. Immunity, resilience and regeneration are key characteristics of health. The role of organic agriculture, whether in farming, processing, distribution, or consumption, is to sustain and enhance the health of ecosystems and organisms from the smallest in the soil to human beings. In particular, organic agriculture is intended to produce high quality, nutritious food that contributes to preventive health care and well-being. In view of this it should avoid the use of fertilizers, pesticides, animal drugs and food additives that may have adverse health effects. Diunduh dari: …… 23/12/2012

Organic Agriculture should be based on living ecological systems and cycles, work with them, emulate them and help sustain them. This principle roots organic agriculture within living ecological systems. It states that production is to be based on ecological processes, and recycling. Nourishment and well-being are achieved through the ecology of the specific production environment. For example, in the case of crops this is the living soil; for animals it is the farm ecosystem; for fish and marine organisms, the aquatic environment. Organic farming, pastoral and wild harvest systems should fit the cycles and ecological balances in nature. These cycles are universal but their operation is site-specific. Organic management must be adapted to local conditions, ecology, culture and scale. Inputs should be reduced by reuse, recycling and efficient management of materials and energy in order to maintain and improve environmental quality and conserve resources. Organic agriculture should attain ecological balance through the design of farming systems, establishment of habitats and maintenance of genetic and agricultural diversity. Those who produce, process, trade, or consume organic products should protect and benefit the common environment including landscapes, climate, habitats, biodiversity, air and water. Diunduh dari: …… 23/12/2012

Organic Agriculture should build on relationships that ensure fairness with regard to the common environment and life opportunities. Fairness is characterized by equity, respect, justice and stewardship of the shared world, both among people and in their relations to other living beings. This principle emphasizes that those involved in organic agriculture should conduct human relationships in a manner that ensures fairness at all levels and to all parties - farmers, workers, processors, distributors, traders and consumers. Organic agriculture should provide everyone involved with a good quality of life, and contribute to food sovereignty and reduction of poverty. It aims to produce a sufficient supply of good quality food and other products. This principle insists that animals should be provided with the conditions and opportunities of life that accord with their physiology, natural behavior and well-being. Natural and environmental resources that are used for production and consumption should be managed in a way that is socially and ecologically just and should be held in trust for future generations. Fairness requires systems of production, distribution and trade that are open and equitable and account for real environmental and social costs. Diunduh dari: …… 23/12/2012

Organic Agriculture should be managed in a precautionary and responsible manner to protect the health and well-being of current and future generations and the environment. Organic agriculture is a living and dynamic system that responds to internal and external demands and conditions. Practitioners of organic agriculture can enhance efficiency and increase productivity, but this should not be at the risk of jeopardizing health and well-being. Consequently, new technologies need to be assessed and existing methods reviewed. Given the incomplete understanding of ecosystems and agriculture, care must be taken. This principle states that precaution and responsibility are the key concerns in management, development and technology choices in organic agriculture. Science is necessary to ensure that organic agriculture is healthy, safe and ecologically sound. However, scientific knowledge alone is not sufficient. Practical experience, accumulated wisdom and traditional and indigenous knowledge offer valid solutions, tested by time. Organic agriculture should prevent significant risks by adopting appropriate technologies and rejecting unpredictable ones, such as genetic engineering. Decisions should reflect the values and needs of all who might be affected, through transparent and participatory processes. Diunduh dari: …… 23/12/2012

Chemical pesticides pollute, and kill pollinators, and pests evolve resistance. GM crops show promise for social and environmental benefits, but questions linger about their impacts. Much of the world’s crop diversity has vanished. Feedlot agriculture and aquaculture pose benefits and harm for the environment and human health. Diunduh dari: …… 20/12/2012 Pesticide Action Network (PAN) is a global network working to eliminate the human and environmental harm caused by pesticides and to promote biodiversity based ecological agriculture. We are dedicated to protect the safety and health of people, and the environment from pesticide use and genetic engineering. Diunduh dari: …… 23/12/2012

Organic farming remains a small portion of agriculture. Human population continues to grow, requiring more food production. Soil erosion is a problem worldwide. Salinization, waterlogging, and other soil degradation problems are leading to desertification. Grazing and logging, as well as cropland agriculture, contribute to soil degradation. Diunduh dari: …… 20/12/2012 SUSTAINABLE CROP MANAGEMENT One of the most significant challenges facing Mankind is the adequate provision of food from sustainable and profitable production systems within a context of high energy costs. Diunduh dari: …… 23/12/2012

Biocontrol and IPM offer alternatives to pesticides. Further research and experience with GM crops may eventually resolve questions about impacts, and allow us to maximize benefits while minimizing harm. More funding for seed banks can rebuild crop diversity. Ways are being developed to make feedlot agriculture and aquaculture safer and cleaner. Diunduh dari: …… 20/12/2012

38 An Assets-Based Model for Sustainability
SOLUSI PERTANIAN MASA DEPAN Organic farming is popular and growing fast. Green revolution advances have kept up with food demand so far. Improved distribution and slowed population growth would help further. Farming strategies like no-till farming, contour farming, terracing, etc., help control erosion. Government laws, and government extension agents working with farmers, have helped improve farming practices and control soil degradation. Better grazing and logging practices exist that have far less impact on soils. Diunduh dari: …… 20/12/2012 An Assets-Based Model for Sustainability Agricultural systems at all levels rely for their success on the value of services flowing from the total stock of assets that they control. Five types of capital, natural, social, human, physical and financial, are now being addressed in the literature : Natural capital Social capital Human capital Physical capital Financial capital. Diunduh dari: …… 23/12/2012

Natural capital produces nature’s goods and services, and comprises food (both farmed and harvested or caught from the wild), wood and fibre; water supply and regulation; treatment, assimilation and decomposition of wastes; nutrient cycling and fixation; soil formation; biological control of pests; climate regulation; wildlife habitats; storm protection and flood control; carbon sequestration; pollination; and recreation and leisure. Social capital yields a flow of mutually beneficial collective action, contributing to the cohesiveness of people in their societies. The social assets comprising social capital include norms, values and attitudes that predispose people to cooperate; relations of trust, reciprocity and obligations; and common rules and sanctions mutually-agreed or handed-down. These are connected and structured in networks and groups. Human capital is the total capability residing in individuals, based on their stock of knowledge skills, health and nutrition. It is enhanced by their access to services that provide these, such as schools, medical services, and adult training. People’s productivity is increased by their capacity to interact with productive technologies and with other people. Leadership and organisational skills are particularly important in making other resources more valuable. Physical capital is the store of human-made material resources, and comprises buildings (housing, factories), market infrastructure, irrigation works, roads and bridges, tools and tractors, communications, and energy and transportation systems, that make labour more productive. Financial capital is accumulated claims on goods and services, built up through financial systems that gather savings and issue credit, such as pensions, remittances, welfare payments, grants and subsidies. Diunduh dari: …… 23/12/2012

The basic premise is that sustainable systems, whether farms, firms, communities, or economies, accumulate stocks of these five assets, thereby increasing the per capita endowments of all forms of capital over time. But unsustainable systems deplete or run down these various forms, spending assets as if they were income, and so leaving less for future generations. Diunduh dari: …… 23/12/2012

41 The inputs are shown as:
AN ASSETS-BASED MODEL FOR SUSTAINABILITY The assets-based model shows how farms and rural livelihoods take inputs of various types, including renewable assets, and transform these to produce food and other desirable outputs. These can be processed for home consumption, transformed through value-added processes for sale, or sold directly as raw product. The inputs are shown as: Renewable natural capital – soil, water, air, biodiversity etc; Social and participatory processes – including both locally embedded and externally-induced social capital, and partnerships and linkages between external organisations; New technologies, knowledge and skills – both regenerative (eg legumes, natural enemies) and non-renewable (eg hybrid seeds, machinery); Non-renewable or fossil-fuel derived inputs (eg fertilizers, pesticides, antibiotics); Finance – credit, remittances, income from sales and grants. Availability and access to these five inputs is shaped by a wide range of contextual factors (on the far left). These include unchanging ones (at least over the short-term), such as climate, agro-ecology, soils, culture; and dynamic economic, social, political and legal factors shaped by external institutions and policies. These contextual factors are an important entry point for shaping and influencing agricultural systems (such as national policies, markets, trade). Diunduh dari: …… 23/12/2012

42 The Modernisation of Agriculture
AN ASSETS-BASED MODEL FOR SUSTAINABILITY The Modernisation of Agriculture The process of agricultural modernisation during the 20th century has produced three distinct types of agriculture: industrialised, `Green Revolution’, and all that remains - the pre-modern, `traditional’ or `unimproved'. The first two types have been able to respond to modern technological packages, producing highly productive systems of agriculture. Diunduh dari: …… 23/12/2012

43 Sustainable Agriculture
AN ASSETS-BASED MODEL FOR SUSTAINABILITY Sustainable Agriculture A more sustainable farming seeks to make the best use of nature’s goods and services whilst not damaging the environment. It does this by integrating natural processes such as nutrient cycling, nitrogen fixation, soil regeneration and natural enemies of pests into food production processes. It also minimises the use of non-renewable inputs (pesticides and fertilizers) that damage the environment or harm the health of farmers and consumers. It makes better use of the knowledge and skills of farmers, so improving their self-reliance. And it seeks to make productive use of social capital - people’s capacities to work together to solve common management problems, such as pest, watershed, irrigation, forest and credit management Diunduh dari: …… 23/12/2012

44 Sustainable Agriculture
High-yield polyculture Organic fertilizers Biological pest control Integrated pest management Irrigation efficiency Perennial crops Crop rotation Use of more water- efficient crops Soil conservation Subsidies for more sustainable farming and fishing Increase Soil erosion Soil salinization Aquifer depletion Overgrazing Overfishing Loss of biodiversity Loss of prime cropland Food waste Subsidies for unsustainable farming and fishing Population growth Poverty Decrease Sustainable Agriculture Diunduh dari: …… 20/12/2012

45 Pangan minim limbah Sustainable Agriculture Mengurangi konsumsi daging
Feed pets balanced grain foods instead of meat Use organic farming to grow some of your food Membeli bahan pangan organik Komposting limbah makanan Apa yang dapat dilakukan ? Sustainable Agriculture Diunduh dari: …… 20/12/2012



48 DEGRADASI LAHAN Degradasi lahan merupakan proses menurunnya kualitas dan kuantitas suatu lahan yang meliputi aspek fisika tanah, kimia tanah, biologi tanah, pada suatu bidang lahan tertentu. Dalam praktek budidaya pertanian sendiri sering akan menimbulkan dampak pada degradasi lahan. Dua faktor penting dalam usaha pertanian yang potensial menimbulkan dampak pada sumberdaya lahan, yaitu tanaman dan manusia (sosio kultural) yang menjalankan pertanian. Faktor AKTIVITAS manusia  dapat memberikan dampak positip atau negatip pada suatu lahan, tergantung pada aktivitas pengelolaan pertanian yang dilakukan. Apabila dalam menjalankan pertaniannya benar maka akan berdampak positip, namun apabila cara menjalankan pertaniannya salah maka akan berdampak negatif. Kegiatan budidaya pertanian yang  menimbulkan dampak antara lain meliputi kegiatan pengolahan tanah, penggunaan sarana produksi yang tidak ramah lingkungan (pupuk dan insektisida) serta sistem budidaya termasuk pola tanam yang mereka gunakan. Tiga faktor penyebab degradasi tanah akibat campur tangan manusia secara langsung, yaitu : pertanian intensif, pembukaan tambang, deforestasi. Faktor-faktor tersebut di Indonesia pada umumnya terjadi secara simultan, berikut adalah pembahasan dari ketiga degradasi pada tiga bidang. Diunduh dari: 24/12/2012

Aktivitas budidaya pertanian dapat menyebabkan dampak negatif pada sumberdaya lahan. Erosi dan pencemaran tanah terjadi akibat budi daya pertanian yang melampaui daya dukung tanah. Penggunaan bahan-bahan agrokimia yang berlebihan dapat mencemari lingkungan dan mengganggu kelestarian kualitas tanah. Cara-cara budi daya pertanian yang tidak mengindahkan kaidahkaidah konservasi lahan menyebabkan kualitas lahan menurun sejalan dengan hilangnya lapisan tanah subur akibat erosi dan pencucian hara. Kegiatan pembangunan yang berpotensi menimbulkan dampak terhadap degradasi lahan antara lain kegiatan deforesterisasi, industri, pertambangan, perumahan, dan kegiatan pertanian sendiri. Apabila kegiatan tersebut tidak dikelola dengan baik, maka akan mengakibatkan terjadinya degradasi lahan pertanian yang mengancam keberlanjutan uasaha tani dan ketahanan pangan. Oleh karenanya, dalam kegiatan pembangunan hendaknya harus dipikirkan keberlanjutannya dimasa mendatang (sustainabilitas). Praktek budidaya pertanian sering mengakibatkan degradasi lahan. Kegiatan budidaya pertanian yang menimbulkan dampak negatif antara lain meliputi kegiatan pengolahan tanah, penggunaan sarana produksi yang tidak ramah lingkungan (pupuk dan pestisida), serta sistem budidaya termasuk pola tanam yang tidak tepat. Diunduh dari: 24/12/2012

50 Barrow (1991) merinci faktor-faktor utama penyebab degradasi lahan :
1)        Bahaya alami 2)        Perubahan jumlah populasi manusia 3)        Marjinalisasi tanah 4)        Kemiskinan 5)        Status kepemilikan tanah 6)        Ketidakstabilan politik dan masalah administrasi 7)        Kondisi sosial ekonomi 8)        Masalah kesehatan 9)        Praktek pertanian yang tidak tepat, dan 10)    Aktifitas pertambangan dan industri. Degradasi lahan ada tiga aspek, yaitu : aspek fisik. kimia dan biologi. Degradasi fisik terdiri dari pemadatan, pengerakan, ketidakseimbangan air, terhalangnya aerasi, aliran permukaan, dan erosi. Degradasi kimiawi terdiri dari asidifikasi, pengurasan unsur hara, pencucian, ketidakseimbangan unsur hara dan keracunan, salinisasi, dan alkalinisasi. Degradasi biologis meliputi penurunan karbon organik tanah, penurunan keanekaragaman hayati tanah, dan penurunan karbon biomas. Diunduh dari: 24/12/2012

DEGRADASI LAHAN TYPES OF SOIL DEGRADATION Soil degradation is any type of problem that removes soil in an area or makes high-quality soil become poor. Careless agricultural practices, pollution and deforestation cause lots of soil degradation in the world. Several types of soil degradation exist and are a threat to natural forests and planted crops. Read more: Types of Soil Degradation | SOIL EROSION Erosion occurs when the topsoil that many plants need to grow gets blown or washed away. While some erosion is natural, the humans often remove plants that cover soil and, therefore, speed up erosion. Since topsoil takes so long to build back up through natural processes, erosion damage is almost irreversible. NUTRIENT LOSS Nutrient loss often occurs in conjunction with salinization. The nutrient loss occurs through a variety of mechanisms, including leaching, erosion, runoff, crop uptake and denitrification. The crops uptake too many soil nutrients that farmers do not always replace. Deforestation and careless agricultural processes lead to soil degradation in the form of nutrient loss. After soil becomes nutrient-poor, crops and naturally occurring plants have a hard time growing in the area. Diunduh dari: 24/12/2012

52 Kehilangan kesuburan tanah Erosi Tanah Salinitas Pemadatan Tanah
DEGRADASI LAHAN SOIL DEGRADATION When plants (trees & shrubs) are cleared from a site, soil is exposed to sunlight and the eroding effects of wind and water. Soil aeration is increased and the rate of weathering increases. Apart from erosion, the proportion of organic matter in the soil gradually decreases, through the action of microbes in the soil which use it as a source of energy ‑ unless the new land use provides some replacement. TYPES OF SOIL DEGRADATION A number of major soil related problems occur in Australia these include: Kehilangan kesuburan tanah Erosi Tanah Salinitas Pemadatan Tanah Pengasaman Tanah Pencemaran tanah oleh bahan kimia berbahaya. Diunduh dari: 24/12/2012

KESUBURAN TANAH Land use, human nutrition and the carbon cycle form an intricate set of relationships. Healthy plants use carbon dioxide, give off oxygen and increase soil organic matter (OM), thereby enhancing soil fertility. Practices that increase organic matter can increase soil fertility while decreasing greenhouse gas emissions. Diunduh dari: ……… 24/12/2012

BASIC PLANT NUTRIENT CYCLE The basic nutrient cycle usually describes the outstanding role of soil organic matter. Cycling of many plant nutrients, especially N, P, S, and micronutrients, are similar to the Carbon Cycle. Plant residues, grain green manure, farmyard manure and other substances are returned to the soil. This organic matter pool of carbon compounds serve as food for bacteria, fungi, and other decomposers. As organic matter is decomposed to simpler compounds, plant nutrients are released in available forms for root uptake and the cycle begins again. Plant-available macronutrients such as N, P, K, Ca, Mg, S and micronutrients are also released when soil minerals dissolve. Diunduh dari: ……… 24/12/2012

POTENTIAL FOR N LOSSES Greater losses occur when soils enter the spring season with recharged subsoil moisture, when more N is in the nitrate form, and when soils are warm. Deciding if losses are substantial enough to warrant supplemental N application must therefore take into consideration the following factors: (1) amount of nitrate present, which is affected by time of N application, form of N applied, rate applied, and use of a nitrification inhibitor; (2) when and the length of time soils are saturated; (3) subsoil recharge, leaching rate, and drainage--water amount moved through the soil; and (4) loss of crop yield potential from water damage. Diunduh dari: ……… 24/12/2012

Integrated plant nutrient components in the Nepalese farming system An integrated nutrient model developed quite some time ago as shown below was a successful programme but it has not been popularized or has not been well adopted by large number of farmers. There should be a follow up study to see the impact on soil fertility management and to look on how best we can promote to wider areas. Diunduh dari: ……… 24/12/2012

There are several losses from soil nutrient pools caused by either unfavorable soil conditions or improper use of fertilizers. The main characteristics of these losses are the following: Losses will result in a decrease in the amounts of plant available soil nutrients Nutrient losses occur by: Releases from the soil - leaving the soil-plant system Transformation of soil nutrients into non-available forms (i.e. precipitation, chemical reactions resulting insoluble forms etc.) = „internal losses” PELEPASAN HARA DARI TANAH Crop removal by yields Erosion losses – nutrients in soil particles removed from soil by water Runoff – loss of dissolved nutrients moving across the soil profile Leaching– moving dissolved nutrient forms downward into the groundwater Gaseous losses to the atmosphere by volatilization and denitrification. Under various cropping systems, both internal and external losses of nutrients from soils may be rather diverse. „INTERNAL LOSSES” Transformation of soil nutrients into non-available forms (i.e. precipitation, chemical reactions resulting insoluble forms etc.) Transformation into insoluble forms – typical for P Strong fixation in interlayer sites of clay minerals – ammonium and K+ ions These forms do not leave the soil = therefore referred as „internal losses”

What happens if we lose soil fertility, we will eventually cease to exist as soil is alive and we require soil for almost all of the food that we grow today around the world. The healthy soil contains: It has sufficient concentrations of nitrogen, phosphorous, and potash (potassium) to support plant life. It also has sufficient levels of the trace minerals needed for plant nutrition, including boron, chlorine, cobalt, copper, iron, manganese, magnesium, molybdenum, sulfur, and zinc. Diunduh dari: ……… 24/12/2012

59 EROSI TANAH Soil erosion is a natural process characterized by the transport or displacement of particles (sediment) that are detached by rainfall, flowing water, or wind. Soil erosion can be caused by the improper use of lands for cultivation or grazing and by deforestation. The types of soil erosion associated with agricultural activities are : Splash erosion, which occurs when rain hits exposed soils. Sheet and rill erosion, which mainly moves soil particles from the surface or plough layer of the soil. Surface sediments typically contain higher pollution potential due to richer nutrient content, the presence of chemicals from past fertilizer and pesticide applications, and natural biological activities. Rill and gully erosion, severe erosion in which trenches are cut to a depth greater than 1 foot. Generally, trenches too deep to be crossed by farm equipment are considered gullies (USEPA, 1994). Stream and channel erosion, which occurs due to increased rates and volumes of runoff from agricultural land uses flowing through a stream or channel. Diunduh dari: 24/12/2012

60 EROSI TANAH Effect on soil erosion
Slope angle and length affects runoff generated when rain falls to the surface. Examine the diagram below showing the relationship between hill slope position, runoff, and erosion. The amount of water on a particular hill slope segment is dependent on what falls from precipitation and what runs into it from an upslope hill slope segment. The hill slope has been divided into several segments and the amount of precipitation falling on each segment is the same. As water runs down slope, the water that has accumulated in segment A runs off adding to what falls into segment B by precipitation. The water in B runs into C, and C into D, and so on. The amount of water increases in the down slope direction as water is contributed of water from upslope segments. The velocity of the water increases as well as it moves towards the base of the slope. As a result, the amount and velocity of water, and hence rate of erosion increases as you near the base of the slope. Diunduh dari: 24/12/2012

Soil erosion occurs naturally when rain falls. Runoff flows to the lowest point of the landscape. The velocity depends on the characteristics of the soils, the slope of the land and the vegetative cover.   Erosion can be a serious environmental problem when the land is disturbed by development, agriculture, or forestry. Surfaces like roads, roofs, driveways and hard-packed soils will not absorb water, and the runoff increases. Expanses of pavement like parking lots reduce the chances for ground water recharge. Exposed soils are lost and the land becomes less productive. Fertilizers and pesticides that may have been applied wash away, too, causing water quality problems for people living downstream. Diunduh dari: 24/12/2012

62 B. J. Andraski and B. Lowery
EROSI TANAH EROSION EFFECTS ON SOIL WATER STORAGE, PLANT WATER UPTAKE, AND CORN GROWTH B. J. Andraski and B. Lowery SSSAJ Vol. 56 No. 6, p.  Levels of past erosion were based on depth to red clay (2Bt horizon): slight, 0.95 m; moderate, 0.74 m; and severe, 0.45 m. The total quantity of plant-extractable water that could be stored in the upper 1 m of slightly eroded soil (181 mm) was 7% more than that for moderately eroded soil (169 mm) and 14% more than that for severely eroded soil (159 mm). For all erosion levels, water retained in the 0.5- to 1.0-m soil depth was utilized by corn. Erosion level had no negative effect on early-season plant growth. As plant-extractable water decreased to <55 to 60% of total, evapotranspiration (ET) and vegetative-growth rates decreased as erosion level increased. The greatest differences in ET rates among erosion levels were observed during a 35-d period in the drought year of 1988 when rates averaged 3.7 mm d−1 for slight erosion, 2.6 mm d−1 for moderate erosion, and 2.2 mm d−1 for severe erosion. For the 3 yr in which plant water stress was observed, maximum plant heights for the slight erosion level averaged 7% more than those for moderate erosion and 13% more than those for severe erosion. Although the soil's capacity to store and supply water decreased as erosion increased, the observed effects of erosion level on grain and stover yields, grain-yield components, and harvest populations typically were not significant. Diunduh dari: ……… 24/12/2012

63 EROSI TANAH . CROPPING AND TILLAGE SYSTEMS EFFECTS ON SOIL EROSION UNDER CLIMATE CHANGE IN OKLAHOMA X.-C.(John) Zhang  SSSAJ Vol. 76 No. 5, p.  Soil erosion under future climate change is very likely to increase because of increases in occurrence of heavy storms. The objective of this study is to quantify the effects of common cropping and tillage systems on soil erosion and surface runoff during 2010 to 2039 in central Oklahoma. A combination of 18 cropping and tillage systems is evaluated using the Water Erosion Prediction Project (WEPP) model for 12 climate change scenarios projected by four global climate models (GCMs) under three emissions scenarios. Tillage systems include conventional, reduced, delayedno tillage. Cropping systems include continuous monocultures of winter wheat, soybean, sorghumcotton and double crops of wheat and soybeans. Compared with the present climate, overall t tests show that the future mean precipitation will decrease by some 6% (>98.5% probability), daily precipitation variance increase by 12% (>99%), and mean temperature increase by 1.36°C (>99%). Despite the projected precipitation declines, the overall averaged runoff and soil loss will increase by 19.5 and 43.5% because of increased occurrence of large storms. Soil erosion is positively related to the degree of tillage disturbances in all cropping systems. Compared with the conventional till, reduced, delayedno tillage substantially reduce soil erosion, showing that adoption of conservation tillage will be effective in controlling soil erosion in the next 30 yr. Cropping systems decrease runoff and soil loss from continuous cotton to soybean to sorghum to wheat in all tillage systems under climate change, indicating a preference of winter wheat for controlling runoff and soil loss in the region. Diunduh dari:……… 24/12/2012

64 E. M. Craft , R. M. Cruse and G. A. Miller
DEGRADASI LAHAN . SOIL EROSION EFFECTS ON CORN YIELDS ASSESSED BY POTENTIAL YIELD INDEX MODEL E. M. Craft , R. M. Cruse and G. A. Miller SSSAJ Vol. 56 No. 3, p.  Soil erosion alters crop production via alteration of the soil chemical and physical environment. The objectives of this study were to: (i) develop a Potential Yield Index (PYI) model to index soil productivity based on simulated root growth, soil properties, and potential nutrient and water uptake of corn (Zea mays L.) through a growing season, (ii) utilize the PYI to estimate erosion effects on soil productivity by simulating the removal of 15 and 30 cm of soil, and (iii) simulate the impact of fertilizer additions to the eroded soil on the PYI. The PYI model independently estimates P, K, and water (W) uptake by corn. From these estimates, three separate yield indexes (PYIP, PYIK, and PYIW) are calculated. The lowest yield index is identified as the PYI for a given soil. The predicted PYIs for 45 soils in Iowa compared well to the yr average corn yield (R2 = 0.83) and corn suitability rating (R2 = 0.73) for each soil. Changes in the PYI were predicted for 15 and 30 cm of simulated erosion. After 15-cm soil loss, the PYI for all soils decreased, with all but three soils remaining within 15% of the uneroded PYI. The PYI decreased further after 30-cm soil loss, with only 12 soils remaining within 15% of the uneroded PYI. Fertilizer additions to the plow layer of the eroded soils were then simulated. The PYI returned to within 5% of the uneroded PYI for 38 soils with 15-cm soil loss and for 27 soils with 30-cm soil loss. The PYI indicated that the soil factor that most limited plant yield changed with the soil, amount of soil loss, and plow-layer soil fertility status. Diunduh dari: ……… 24/12/2012

65 EROSI TANAH PERKIRAAN TINGKAT EROSI TANAH DI SUB DAS BESAI, LAMPUNG BARAT Asep Mulyono Jurnal Riset Geologi dan Pertambangan, Vol 19, No 1 (2009) Tingkat erosi tanah di sub DAS Besai telah diperkirakan sebagai dasar kuantitatif dalam merekomendasikan upaya mempertahankan, memulihkan, meningkatkan kesuburan dan fungsi tanah sebagai pengatur tata air. Perkiraan tingkat erosi tanah dilakukan dengan metoda RUSLE yang dilakukan secara spasial dengan menggunakan perangkat lunak Sistem informasi geografis (SIG). Erosivitas, erodibilitas, kemiringan lereng, panjang lereng, sistem penanaman dan faktor konservasi merupakan 6 parameter data yang dimasukan dalam pendekatan RUSLE. Tingkat konversi lahan, khususnya hutan lindung menjadi lahan pertanian dan perkebunan, sangat pesat terjadi di Sub DAS Besai. Sub DAS Besai yang terletak di wilayah Kecamatan Sumber Jaya, Kabupaten Lampung Barat merupakan salah satu bagian hulu DAS Tulang Bawang Lampung. Selama rentang waktu 30 tahun (1970 – 2000) telah terjadi penurunan tutupan lahan hutan sebesar 48 %. Perubahan terjadi sebagai akibat tingginya aktivitas masyarakat dalam usaha tani kopi monokultur dan tanaman semusim.   Hasil studi menunjukkan 23.62% wilayah penelitian dikategorikan dalam tingkat erosi tanah yang normal, tingkat ringan seluas 42.98%, tingkat moderat seluas 14.57%, tingkat berat seluas 15.38% dan sangat berat seluas 3.45%. Seluas 45% wilayah dengan tutupan lahan perkebunan kopi mengalami tingkat erosi dalam kategori ringan sampai sangat berat pada semua rentang kelerengan dan jenis tanah. Perkebunan kopi sistem monokultur mengakibatkan lapisan tanah sangat mudah tergerus oleh adanya aliran permukaan dikarenakan tidak adanya tutupan tanah di bawah kanopi tanaman kopi tersebut. Diunduh dari: ……… 25/12/2012

CISANGGARUNG BAGIAN HULU DALAM MEMPERKIRAKAN SISA UMUR WADUK DARMA Muhammad Nursa’ban. Hasil Penelitian Dosen muda tahun 2006, Dosen Jurusan Pendidikan Geografi UNY. Hasil penelitian menunjukan bahwa tingkat erosi tanah permukaan yaitu ,74 ton/tahun, atau rata-rata 573,795 ton/ha/tahun, erosi total ,43 ton/tahun atau 717,244 ton/ha/tahun dan erosi tanah yang diperbolehkan yaitu 686,033 ton/tahun atau sekitar 12,473 ton/ha/tahun. Data-data tersebut menunjukkan bahwa tingkat erosi permukaan maupun erosi total berlangsung cukup tinggi dibandingkan dengan besar erosi yang diperbolehkan. Sediment Yield tahunan di Waduk Darma yaitu ,419 ton/tahun atau ,660 m3. Waduk Darma tidak dapat berfungsi lagi yaitu pada saat mencapai umur ± 84,25 tahun. Tahun 2006 Waduk Darma telah beroperasi selama 36 tahun sehingga sisa umur Waduk Darma sampai terpenuhinya tampungan mati oleh sedimen yaitu ± 48,25 tahun atau tampungan mati akan terisi penuh yaitu pada tahun ± 2054. Diunduh dari:  ……… 25/12/2012

67 Tuahta Tarigan dan Iwan Ridwansyah.
EROSI TANAH PREDIKSI BEBAN NUTRIEN DAN SEDIMEN DAS SUMPUR DANAU SINGKARAK MENGGUNAKAN MODEL AGNPS Tuahta Tarigan dan Iwan Ridwansyah. LIMNOTEK, 2005, Vol, XII, No, 2, p AGNPS merupakan sebuah program model untuk mensimulasikan kualitas air dan sedimen dari suatu catchment yang didominasi lahan pertanian. Model ini dikombinasikan dengan perangkat program GIS untuk memperkirakan kemungkinan penambahan fospor ke DAS Sumpur, Paket Program GIS (ArcView 3.1, 3D Analyst, Spatial Analyst) digunakan untuk mempersiapkan input data model dan proses penempatan dari hasil simulasi. Perkiraan dari loading nutrient dari Sungai Sumpur yang masuk ke Danau Singkarak memperlihatkan nilai ton tahun-1 sedimen, 52,5 ton tahun-1 Total N dan 37,5 ton tahun-1 Total P dan 195 ton tahun-1 COD. Diunduh dari: ……… 25/12/2012

68 EROSI TANAH MODIFIKASI FAKTOR C-USLE DALAM MODEL ANSWERS UNTUK MEMPREDIKSI EROSI DI DAERAH TROPIKA BASAH (STUDI KASUS: DAS NOPU HULU, SULAWESI TENGAH) Y. Hidayat, N. Sinukaban, H. Pawitan, dan K. Murtilaksono Jurnal Tanah dan Iklim. Vol.26 No.4 Th. 2004 Penelitian dilakukan untuk : a) mendefinisikan nilai faktor pengelolaan tanaman sebagai parameter input model ANSWERS, b) membangun model ANSWERS dalam PCRaster untuk mensimulasikan perubahan penggunaan lahan dan penerapan teknik konservasi tanah dan air, dan c) mengkaji dampak konversi hutan terhadap aliran permukaan, erosi dan kehilangan hara. Aliran permukaan dan erosi harian diukur pada lahan hutan primer, hutan sekunder, lahan terbuka, jagung, kakao muda, kakao sedang, kakao dewasa, dan tumpang sari antara kakao muda dengan jagung, pisang dan ketela pohon. Pada outlet daerah aliran sungai debit aliran ditentukan melalui pengukuran tinggi muka air dan kecepatan aliran, sedangkan volume sedimen diukur melalui  pengambilan sampel sedimen. Penggunaan faktor pengelolaan tanaman parsial pada model ANSWERS dan ANSWERS-PCRaster memberikan hasil prediksi erosi lebih baik dibandingkan dengan menggunakan faktor pengelolaan tanaman USLE (faktor C-USLE), khususnya pada curah hujan tinggi. Penghutanan kembali lahan berlereng curam (> 45%) yang diikuti oleh penerapan teras gulud pada lahan pertanian merupakan tindakan pengelolaan terbaik dalam mengendalikan aliran permukaan dan erosi untuk menjamin pertanian berkelanjutan dan keberlanjutan fungsi daerah aliran sungai. Konversi hutan ke lahan pertanian telah meningkatkan aliran permukaan, erosi dan kehilangan hara. Diunduh dari: ……… 25/12/2012

69 EROSI TANAH . DEGRADASI TANAH DI LAHAN KERING WILAYAH BARITO KALIMANTAN TENGAH M. A. Firmansyah, R.Y. Galingging dan Suparman (Balai Pengkajian Teknologi Pertanian Kalimantan Tengah) A. Krismawati (Balai Pengkajian Teknologi Pertanian Jawa Timur) Degradasi tanah di Indonesia umumnya terjadi di lahan kering yang dipicu oleh erosi tanah dan salah kelola tanah. Tujuan tulisan ini untuk menunjukkan besarnya erosi yang terjadi pada berbagai sistem usahatani eksisting antara lain: padi gogo, jagung, kacang tanah, ubi kayu, dan karet rakyat. Lokasi penelitian dilaksanakan di Lagan (kemiringan 6%) di Kabupaten Barito Timur dan Jingah (kemiringan 16%) di Kabupaten Barito Utara. Hasil analisis menunjukkan bahwa Jingah mengalami erosi lebih besar dibandingkan Lagan, hal ini disebabkan oleh tingginya faktor erosivitas hujan, kemiringan lereng, dan teknik konservasi tanah yang buruk. Erosi potensial di Jingah mencapai t/ha/th sedangkan di Lagan mencapai 431 t/ha/th. Kondisi tersebut menyebabkan kedua lokasi tergolong memiliki Indeks Bahaya Erosi (IBE) ekstrem, dengan nilai 47,4 untuk Jingah dan 11,2 untuk Lagan. Erosi aktual pada sistem usahatani di Jingah tertinggi pada karet rakyat mencapai 954 t/ha/th (91 mm/th), begitu juga di Lagan mencapai 183 t/ha/th (14 mm/th). Erosi aktual terendah pada sistem usahatani kacang tanah, di Jingah mencapai 505 t/ha/t (48 mm/th) dan di Lagan mencapai 97 t/ha/th (8 mm/th). Erosi yang terjadi dikedua lokasi jauh melampaui Eosi yang piperbolehkan (EDP) yang hanya mencapai 3 mm/th. Erosi yang terjadi berdampak terhadap kehilangan produktivitas cukup besar di Jingah yaitu 21% pada karet rakyat, dan terendah sebesar 2% di Lagan untuk padi gogo dan kacang tanah. Guna mencegah erosi yang besar, maka dikedua lokasi perlu dilakukan perbaikan terutama pada pengelolaan teknik konservasi tanah. Diunduh dari: ……… 25/12/2012

EROSI TANAH EROSI PADA BERBAGAI PENGGUNAAN LAHAN DI DAS CITARUM S. Sutono, S. H. Tala’ohu, O. Sopandi, dan F. Agus Balai Penelitian Tanah, Bogor Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian Lahan sawah mempunyai banyak fungsi, termasuk diantaranya fungsi produksi, dan lingkungan. Penelitian bertujuan untuk menduga besarnya erosi pada lahan pertanian di daerah aliran sungai Citarum serta menduga besarnya biaya pengganti (replacement cost method/RCM) pengamanan erosi jika luas lahan sawah berkurang. Pendugaan erosi menggunakan metode universal soil loss equation (USLE). Hasil penelitian menunjukkan bahwa erosi pada lahan sawah lebih rendah dibandingkan dengan tegalan, kebun campuran, kebun teh, kebun karet, dan hampir sama dengan tingkat erosi hutan. Erosi paling tinggi terjadi pada lahan tegalan. Lahan sawah erosinya berkisar antara 0,33 t/ha/tahun dan 1,45 t/ha/tahun. Seluruh replacement cost untuk Citarum pada tahun 2000 sebesar Rp. 18,6 milyar. Jumlah ini adalah perkiraan investasi yang harus dikorbankan untuk penanganan sedimen apabila sawah yang ada sekarang di Citarum mengalami konversi. Diunduh dari: ……… 25/12/2012

71 EROSI TANAH NERACA AIR, EROSI TANAH DAN TRANSPOR LATERAL HARA NPK PADA SISTEM PERSAWAHAN DI SUB DAS KALI BABON, SEMARANG Muhamad Kundarto 1, F. Agus 2, Azwar Maas 3, dan B. H. Sunarminto 3 Jurusan Ilmu Tanah UPN “Veteran” Yogyakarta, 2 Balai Penelitian Tanah Bogor, 3 Jurusan Tanah UGM Yogyakarta Prosiding Seminar Nasional Air, Erosi Tanah Konversi Lahan Pertanian Penelitian ini bertujuan untuk mengetahui neraca air, erosi tanah, dan transpor lateral hara NPK pada sistem persawahan. Penelitian dilaksanakan selama dua musim tanam dari Oktober 2001 sampai Juni 2002 di sub daerah aliran sungai Kali Babon, Semarang. Hasil penelitian pada musim ke dua menunjukkan total input air sebesar 4031,81 mm yang berasal dari air irigasi 3530,41 mm dan air hujan 501,40 mm. Total output air sebesar 3035,13 mm terdiri atas air drainase 153,22 mm, infiltrasi/perkolasi 94,74 mm, evapotranspirasi 85,87 mm, dan genangan 2701,30 mm. Selisih antara input dan output air sejumlah 996,68 mm diduga merupakan total air yang menyusup secara lateral melalui pematang (seepage dan lubang tikus/ketam) dan air yang tersimpan pada lapisan olah. Total tanah yang tererosi dari daerah atas (upland) dan masuk ke sawah pada musim sebesar 864,1 kg dan yang keluar (lewat outlet petak no. 18) sebesar 347,5 kg. Sehingga tanah yang mengendap di petak sawah sebesar 516,6 kg (2,05 t/ha). Pada musim kedua, total tanah masuk ke sawah sebesar 1567,1 kg dan yang keluar dari sawah (lewat outlet petak 18) sebesar 209,6 kg. Sehingga tanah yang mengendap di petak sawah sebesar 1357,5 kg (5,40 t/ha). Jumlah tanah yang mengendap pada musim kedua 2,5 kali lebih besar dibanding musim pertama. Total hara N, P, dan K dalam bentuk NH4+, NO3-PO43-, dan K+ yang terkandung dalam air irigasi dan masuk ke sawah masing-masing sebesar: 98; 478; 29; dan 237 g/ha/musim. Sedangkan total hara NH4+, NO3-, PO43-, dan K+ yang terkandung dalam air drainase dan keluar dari sawah masing-masing sebesar: 10; 161; 413; dan 35 g/ha/musim. Penambahan hara NH4+, NO3-, dan K+ pada sawah masing-masing sebesar: 88; 317; dan 203 g/ha/musim. Hara PO43- mengalami pengurangan sebesar 384 g/ha/musim. Diunduh dari:……… 25/12/2012

72 EROSI TANAH . APLIKASI SISTEM INFORMASI GEOGRAFIS (SIG) UNTUK IDENTIFIKASI LAHAN KRITIS dan ARAHAN FUNGSI LAHAN DAERAH ALIRAN SUNGAI SAMPEAN Runi Asmaranto, Ery Suhartanto dan Bias Angga Permana Jurusan Pengairan Fakultas Teknik Universitas Brawijaya DAS Sampean merupakan daerah aliran sungai yang kondisi topografinya rata-rata sangat curam. Kondisi tata guna lahan yang sebagian besar sawah irigasi ini cukup memungkinkan terjadinya erosi. Apalagi tataguna lahan lainnya berupa ladang, semak dan sawah tadah hujan yang tanamannya merupakan tanaman berkedalaman akar rendah dan berperan besar dalam proses penyebab terjadinya kerusakan tanah, mempercepat laju erosi dan meningkatkan volume limpasan permukaan. Metode yang digunakan dalam menghitung besarnya laju erosi adalah metode MUSLE dimana metode tersebut menggunakan pendekatan dari faktor limpasan permukaan. Pengolahan data-datanya menggunakan Sistem Informasi Geografis (SIG) karena memudahkan dalam penganalisaan dan pengelompokan data. Dari hasil analisa diperoleh debit limpasan permukaan yang terjadi sebesar 247,967 m3/ dt. Total Erosivitas Limpasan Permukaan yang terjadi adalah ,73 m2/jam, hal ini memicu terjadinya laju erosi yang rata-ratanya mencapai ,94 ton/ha/thn, atau identik dengan kehilangan tanah sebesar : 258,470 cm/thn. Besarnya laju erosi pada DAS Sampean ini mengakibatkan tingkat bahaya erosi sebesar 95,54% dari luas wilayahnya termasuk sangat berat. Sedangkan untuk tingkat bahaya erosi lainnya yaitu, berat : 2,72%, sedang : 1,02%, ringan : 0,72%. Analisa kemampuan lahan didominasi kemampuan kelas VII (75,39%), yang merupakan daerah Pengembalaan Terbatas. Sedangkan ARLKT di DAS Sampean terdiri dari 3 (tiga) kawasan, yaitu Kawasan lindung (10,53%), Kawasan Penyangga (52,23%), Kawasan Budidaya Tanaman Tahunan (37,23%). Diunduh dari: ……… 25/12/2012

73 EROSI TANAH TINGKAT EROSI PERMUKAAN PADA LAHAN PERTANIAN JAGUNG DI DAS ALO-POHU PROVINSI GORONTALO Fitryane Lihawa Pusat Studi Lingkungan Universitas Negeri Gorontalo PROSIDING KONFERENSI DAN SEMINAR NASIONAL PUSAT STUDI LINGKUNGAN HIDUP INDONESIA KE – 15 SEPTEMBER 2012 DI MATARAM Fenomena pemanfaatan lahan untuk pertanian semakin meningkat, terlebih lagi setelah dicanangkannya Program Agropolitan di Provinsi Gorontalo. Pada Tahun 2003 luas pertanian lahan kering adalah ha dan Tahun 2005 meningkat hingga ha, dan pada Tahun 2010 mencapai ha (Citra Landsat Tahun 2003, Tahun 2005 dan BPS Tahun 2011). Perubahan penggunaan lahan tersebut dapat mengakibatkan kerusakan DAS yang berdampak pada rusaknya fungsi hidroorologis DAS. Salah satu DAS penyumbang sedimen terbesar ke Danau Limboto adalah DAS Alo-Pohu. Pengukuran erosi permukaan dilakukan dengan menggunakan sistem plot dengan bentuk persegi panjang. Ukuran petak yaitu lebar 2 m dan panjang 5 m dan ketinggian 20 cm di atas permukaan tanah. Untuk mengkaji pengaruh curah hujan terhadap erosi permukaan pada lahan pertanian jagung digunakan analisis regresi. Hasil pengukuran erosi permukaan pada lahan pertanian jagung dengan kemiringan lereng datar (3,5%) menunjukkan bahwa tingkat erosi permukaan sebesar 1,04 ton/ha/tahun (sangat rendah), pada lereng landai tingkat erosi permukaan sebesar 9,88 ton/ha/tahun (sangat rendah), pada lereng agak curam tingkat erosi permukaan sebesar ton/ha/tahun (rendah), dan pada lereng curam tingkat erosi permukaan sebesar ton/ha/tahun (sedang). Hasil pengamatan selama satu tahun menunjukkan bahwa erosi permukaan akan berkurang seiring dengan umur pertumbuhan jagung. Hal ini disebabkan karena telah disertai dengan tumbuhnya tanaman bawah (rumput-rumputan) pada umur jagung memasuki bulan kedua dan ketiga. Pengaruh curah hujan terhadap erosi permukaan pada lahan pertanian jagung lereng datar adalah Log Y = -3,2 + 3,11 Log X; pada lereng landai Log Y = -3,02 + 2,93 Log X; pada lereng agak curam Log Y = -2,73 + 3,74 Log X; dan pada lereng curam Log Y = 0,28 + 1,71 Log X. Diunduh dari: ……… 25/12/2012

74 Tuti Herawati (Pusat Litbang Hutan dan Konservasi Alam)
EROSI TANAH ANALISIS SPASIAL TINGKAT BAHAYA EROSI DI WILAYAH DAS CISADANE KABUPATEN BOGOR Tuti Herawati (Pusat Litbang Hutan dan Konservasi Alam) Jurnal Penelitian Hutan dan Konservasi Alam. Vol. VII No. 4 : , 2010 Penelitian ini bertujuan untuk menghitung tingkat bahaya erosi di DAS Cisadane berdasarkan rumus USLE menggunakan analisis GIS. Berdasarkan rumus yang digunakan, maka diperlukan empat jenis peta sebagai dasar perhitungan tingkat bahaya erosi, yaitu peta curah hujan, peta jenis tanah, kemiringan, dan peta penutupan lahan. Pada setiap peta dilakukan klasifikasi menjadi empat atau lima kelas berdasarkan standar tertentu. Proses overlay dilakukan untuk mendapatkan hasil akhir berupa tingkat bahaya erosi yang dikategorikan menjadi lima kelas yaitu sangat ringan, ringan, sedang, berat, dan sangat berat. Hasil penelitian menunjukkan bahwa tingkat bahaya erosi di DAS Cisadane meliputi sangat ringan hingga sangat berat dengan persentase luas lahan berturut-turut dari yang sangat ringan hingga sangat berat 55,85%; 15,74%; 6,33%; 0,81%; dan 0,30%. Lahan dengan tingkat bahaya erosi sangat berat meliputi luas 316 ha dan tingkat berat meliputi 851 ha. Tamansari merupakan kecamatan yang memiliki luas wilayah dengan tingkat bahaya erosi sangat berat terluas yaitu 87 ha. Beberapa kecamatan lain yang memiliki luas lahan dengan tingkat bahaya erosi berat adalah Tenjolaya, Caringain, Cijeruk, dan Nanggung. Hasil penelitian ini dapat digunakan sebagai data dasar untuk membuat rencana pengeolaan DAS yang baik. Diunduh dari: 25/12/2012

PADA LAHAN USAHATANI BERBASIS TANAMAN SAYURAN DI SENTRA TEMBAKAU H. Suganda dan Ai Dariah Pengkajian Penerapan Teknik Konservasi Tanah BALITTANAH – LITBANG - DEPTAN. Studi ini bertujuan untuk mendapatkan informasi tentang penerapan teknik konservasi tanah dalam usahatani sayuran di daerah sentra tembakau, Kabupaten Temanggung. Penelitian dilaksanakan tepatnya di tengah lokasi demontrasi plot penerapan teknologi konservasi tanah dengan luas lahan 2,85 ha di Desa Batursari dengan 13 orang petani kooperator, dan 2,53 ha di Desa Kledung dengan 10 orang petani kooperator. Pengamatan berlangsung mulai musim hujan (MH) 2006/07 sampai dengan MH 2007/08. Tanah di dua lokasi tersebut tergolong Andisol. Teknik konservasi tanah yang diterapkan adalah cara mekanik dengan tambahan rumput penguat teras. Hasil penelitian menunjukkan bahwa dengan menerapkan teknik konservasi tanah ternyata erosi pada lahan sayuran di sentra tembakau dapat diturunkan sebanyak 38,4 % - 66,2 %, bahkan kehilangan tanah akibat erosi dapat ditekan menjadi < 6,0 t/ha. Rumput penguat teras (paspah) dengan luasan 1 m2, dapat menghasilkan hijauan 3,6-4,0 kg, cukup untuk kebutuhan sehari pakan domba yang bobotnya sekitar 20 kg. Penerapan konservasi tanah dapat mengurangi laju kehilangan hara akibat erosi dan mempertahankan kesuburan tanah. Petani kooperator di Desa Kledung yang sudah menerapkan teknik konservasi tanah, lahannya relatif lebih subur dibanding dengan lahan petani kooperator di Desa Batursari, sehingga rata-rata pendapatannya per tahun lebih tinggi dari Rp Diunduh dari:……… 25/12/2012

ANCAMAN KEKERINGAN SAWAH KERING, WARGA SHALAT ISTISQO’ Petani Nagari Canduang Koto Laweh was-was jika musim kemarau terus berlanjut hingga sebulan ke depan.  Irigasi yang berada di nagari itu tidak lagi mampu mengalirkan air ke lahan pertanian. Sebab debit air semakin berkurang sejak kemarau  bulan lalu. Menanggapi persoalan yang terjadi, pemerintah nagari menganjurkan masyarakat untuk melaksanakan shalat minta hujan (istisqo’). ”Semoga hujan yang turun bisa menjadikan tanaman kami bisa kembali tumbuh subur,” harap Wan saat berbincang dengan Padang Ekspres di salah satu warung kopi di Jorong Tigo Alua Nagari Koto Laweh. Diunduh dari: ……… 25/12/2012

Rabu, 8 Agustus :20 WIB, Lebak: Kekeringan sawah di Kabupaten Lebak, Provinsi Banten, hingga saat ini mencapai hektare akibat kemarau yang terjadi belakangan ini. "Kekeringan ini tentu berdampak terhadap berkurangnya produksi pangan“. Ia mengatakan pihaknya terus melakukan penyelamatan tanaman padi yang mengalami kekeringan dengan pengoptimalan pompanisasi terpadu. Diperkirakan dari hektare itu dipastikan seluas hektare bisa diselamatkan dengan pengairan menggunakan pompanisasi terpadu. Sedangkan hektare terancam gagal panen. Sebagian besar areal persawahan yang terjadi kekeringan itu di daerah sawah tadah hujan. Sawah tadah hujan itu disebabkan tidak memiliki saluran irigasi yang memadai. Akibat kekeringan ini, petani mengalami kerugian hingga miliaran rupiah apabila tanaman padi mereka gagal panen. Saat ini, biaya produksi rata-rata Rp5 juta per hektare. Diunduh dari: 25/12/2012

78 450 Ha sawah di Indramayu terancam kekeringan
ANCAMAN KEKERINGAN ANTARA. 20 Juni 2011 | 14:10 WIB 450 Ha sawah di Indramayu terancam kekeringan INDRAMAYU: Sekitar 450 hektare sawah di Desa Soge, Indramayu, Jawa Barat, terancam gagal panen akibat kekeringan. Pasokan air memasuki musim kemarau semakin sulit dan diperkirakan ratusan hektare sawah akan terancam gagal panen akibat kekeringan. Dua sungai pemasok air, yaitu kali Prawan dan Kali Persijat, debitnya semakin menurun. Jika hujan tidak turun, diperkirakan tanaman milik petani setempat yang baru berusia kurang dari dua bulan akan kering akibat pasokan air terhambat. Petani kurang memperhatikan cuaca. Mereka terlalu memaksakan tanam padi, padahal mulai memasuki kemarau. Musim tanam tahun sebelumnya pasokan air cukup melimpah, sehingga mereka terlena diperkirakan hujan masih panjang. Menurut dia, petani di daerah pantura Indramayu harus tanggap memperkirakan pasokan air hujan karena lahan pertanian masih mengandalkan tadah hujan. Lahan pertanian di sepanjang pantai pesisir utara Indramayu memasuki kemarau setiap tahun mengalami kekeringan, sementara musim hujan sawah sering terendam akibat banjir.. Diunduh dari: 25/12/2012

ANCAMAN KEKERINGAN ANTARA. 12 September 2011 | 19:51 WIB HEKTARE SAWAH DI KABUPATEN BEKASI KEKERINGAN BEKASI ( Dinas Pertanian Kota Bekasi, Jawa Barat, mencatat sekitar hektare persawahan di wilayahnya mengalami kekeringan akibat debit air yang terus menurun selama musim kemarau. Sumber air dari waduk Jatiluhur melalui kali Tarum Barat terus menyusut selama musim KEMARAU. Saluran irigasi sawah di 23 kecamatan di Kabupaten Bekasi, saat ini sudah kering seiring berkurangnya debit air tersebut. Wilayah paling parah di bagian selatan, seperti Kecamatan Cibarusah, Cikarang Selatan, Serang Baru, dan Kecamatan Setu. Pompanisasi dilakukan untuk menjaga target produksi beras di Kabupaten Bekasi sebanyak 631 ribu ton setiap kali panen tetap terjaga. Diunduh dari: ……… 25/12/2012

ANCAMAN KEKERINGAN PULUHAN HEKTARE SAWAH KEKERINGAN Puluhan hektare sawah di Dukuh Klampok, Desa Sendangsikucing, Kecamatan Rowosari mengalami kekeringan sejak satu pekan ini. Akibat kekeringan, tanaman padi berumur satu minggu terancam mati. Petani kesulitan mendapatkan pasokan air dari saluran irigasi karena lokasinya jauh. “Jika dalam jangka waktu tiga hari ke depan, pasokan air tidak ada, tanaman padi terancam mati,” (Menurut petani Sulaemi). Setiap musim kemarau tiba, puluhan hektare sawah di dukuhnya kekurangan air. Selain itu, puluhan hektare sawah di perbatasan Desa Bulak- Sendang si kucing juga kekurangan air. Pemerintah diharapkan dapat membuat saluran irigasi yang permanen agar air dapat mengairi lahan pertanian. Diunduh dari: ……… 25/12/2012

ANCAMAN KEKERINGAN Jum'at, 07 September 2012 | 00:51 WIB BELASAN RIBU HEKTARE SAWAH ALAMI KEKERINGAN   TEMPO.CO, Surabaya - Kepala Bidang Produksi Tanaman Pangan Dinas Pertanian Jawa Timur, Achmad Nurfalakhi, mengatakan 13,9 ribu hektare sawah bertanaman padi di Jawa Timur mengalami kekeringan. Sebagai dampak akibat kekeringan sawah, sejumlah tanaman padi mengalami puso (gagal panen). Dinas Pertanian Jawa Timur mencatat, kekeringan paling luas terjadi di Kabupaten Bojonegoro seluas hektare, Lamongan hektare, Tulungagung seluas hektare, Trenggalek hektare dan Ngawi 948 hektare. Gagal panen yang dialami petani, menurut dia, terbagi dalam berbagai kriteria. Seluas 2.977,49 hektare padi mengalami gagal panen 100 persen dan hektare gagal panen 75 persen. Selain itu, seluas hektare mengalami kekeringan sedang (gagal panen 50 persen) dan seluas hektare mengalami kekeringan ringan (gagal panen 25 persen). TEMPO/Marifka Wahyu Hidayat Diunduh dari: ……… 25/12/2012

82 ANCAMAN CEKAMAN AIR American-Eurasian J. Agric. & Environ. Sci., 5 (2): , 2009 EFFECTS OF DROUGHT STRESS ON GROWTH AND YIELD OF RICE (ORYZA SATIVA L.) CULTIVARS AND ACCUMULATION OF PROLINE AND SOLUBLE SUGARS IN SHEATH AND BLADES OF THEIR DIFFERENT AGES LEAVES A. Mostajeran and V. Rahimi-Eichi One of the main problems of rice cultivation and production is the lack of water resources, especially during periods of low rainfall which affect the vegetative growth rate and the amount of yield. In this study the effect of low water supply on the number of heading per hill, number of grain per hill, dry weight of vegetative tissues and panicle and 1000 grain weight in three new cultivars of rice including 216, 829 and Zayandeh-Rood were measured under submerged and non-submerged conditions in a randomize complete block design with three replicates. Simultaneously, the variation in proline and total sugars in sheaths and blades of leaves at different ages was determined. The data indicated that Zayandeh-Rood cultivar showed the lowest reduction in shoot dry weigh and the number of tillers per hill under non-submerged conditions. Furthermore, the panicle weight and the number of filled grains per spike were higher in Zayandeh-Rood cultivar than the other cultivars. In addition, the result of this study show that Zayandeh-Rood cultivar in which originated from local cultivars, have higher ability in solute accumulation such as proline and total carbohydrates than the other new lines. Due to correlation between drought tolerance of Zayandeh-Rood and solute accumulation, it may be suggested that the solute accumulation is one of the mechanisms for drought tolerance in rice. Diunduh dari: ……… 25/12/2012

83 ANCAMAN CEKAMAN AIR EFFECTS OF WATER STRESS ON RICE GRAIN YIELD AND QUALITY AFTER HEADING STAGE ZHENG Jia-guo; REN Guang-jun; LU Xian-jun; JIANG Xin-lu Chinese Journal of Rice Science 2003, 17(3): Pot experiment was conducted in Results showed that water stress reduced rice yield significantly within 25 days after 80% of full heading; the effects were very weak after 25 days due to water in soil could maintain rice physiological activity about 10 days. The grain quality interrelated to the grain filling degree. It was better to keep water in paddy until 25 days after 80% of full heading for rice quality cultivation. Diunduh dari: 25/12/2012

84 ANCAMAN CEKAMAN AIR . Ying Yong Sheng Tai Xue Bao Jul;17(7): EFFECTS OF WATER STRESS DURING GRAIN-FILLING PERIOD ON RICE GRAIN YIELD AND ITS QUALITY UNDER DIFFERENT NITROGEN LEVELS. Cai Y, Wang W, Zhu Z, Zhang Z, Lang Y, Zhu Q To examine the effects of nitrogen (N) supply and water stress on rice grain yield and its quality, a pot experiment was conducted at Yangzhou University. Three rice cultivars were grown under two N levels (high N and normal N) from initial heading, and two water conditions (well watering and water stress) were installed for each of the two N levels from flowering to maturity. The results showed that when the plants of test cultivars were grown under normal N level, water stress markedly reduced the grain-filling percentage and grain weight, resulting in a significant decrease of grain yield by 11.6% to approximately 14.7%. Though the head-milled rice had a slight increase, the percentage of chalkiness was significantly increased by 18.7% to approximately 33.1%, which resulted in an inferior performance in grain-apparent quality. In contrast, when the plants were grown under high N level, water stress increased the grain yield by 18. 8% to approximately 22.2% because of the increase of grain-filling percentage and grain weight. As compared with well watering, water stress decreased the percentages of chalky grain and chalkiness by 15.3% to approximately 37.2% and 13.7% to 29.9%, respectively, which improved the performance of grain-apparent quality. The pronounced effects of N application and water treatment were observed on the RVA profile and cooked quality. Under both two N levels, water stress decreased the peak viscosity and breakdown (except for Yangdao 6) while increased the setback. According to the performance in the indices of cooked quality, the palatability became poor when subjected to water stress under normal N level, as the result of the increase of hardness and cohesiveness. In contrast, under high N level, water stress availed the ascending of viscosity at the early stage when rice flours were pasting, peak viscosity and breakdown were increased, and setback was decreased, suggesting that the palpability got well. It was concluded that mild water stress during grain-filling period was benefit for the development of high quality grain when rice plants were grown under high N level. Diunduh dari: 25/12/2012

85 ANCAMAN CEKAMAN AIR BIOLOGIA PLANTARUM (PRAHA) 26 (4) : , 1984 EFFECT OF WATER STRESS AT DIFFERENT DEVELOPMENTAL STAGES OF FIELD-GROWN RICE AJoY K. BISWAS and M. A. CHOUDHVRI Water-stress for 10d at different developmental stages, affected relative water content and leaf water potential of plants. Subsequent rewatering removed these effects. Water stress lowered the contents of chlorophyll, protein, RNA and the activity of catalase, while it increased free proline accumulation and activities of protease, RNase and peroxidase. An overall improvement in biochemical parameters was achieved as soon as the stress was withdrawn by watering and this was reflected in subsequent developmental stages. Water-stress at the reproductive stages induced similar changes as in the vegetative stage but the removal of stress could not improve these parameters to the same extent as at the vegetative stage. In consequence, stress applied at the vegetative stage augmented yield parameters but when applied at the reproductive stage it significantly reduced the yield. Diunduh dari: 25/12/2012

86 Australian Agronomy Conference. 2004 12th AAC, 4th ICSC.
ANCAMAN CEKAMAN AIR Study of water stress effects in different growth stages on yield and yield components of different rice (Oryza sativa L.) cultivars Hemmatollah Pirdashti , Zinolabedin Tahmasebi Sarvestani , Ghorbanali Nematzadeh and A. Ismail. Australian Agronomy Conference th AAC, 4th ICSC. Water stress affects plant growth and development and ultimately, reduces grain yield of irrigated lowland rice. A field experiment was conducted during to evaluate the effect of water stress on the yield and yield components of four rice cultivars commonly grown in Mazandaran province, Iran. The cultivars used were Tarom, Khazar, Fajr and Nemat. The different water stress conditions were water stress during vegetative, flowering and grain filling stages and well-watered was the control. Water stress at vegetative stage significantly reduced plant height of all cultivars. Water stress at flowering stage had a greater grain yield reduction than water stress at other times. The reduction of grain yield largely resulted from the reduction in fertile panicle and filled grain percentage. Water deficit during vegetative, flowering and grain filling stages reduced mean grain yield by 21%, 50% and 21% on average in comparison to control respectively. The yield advantage of two semidwaf varieties, Fajr and Nemat, were not maintained under drought stress. Diunduh dari: 25/12/2012

ANCAMAN CEKAMAN AIR . Journal of Agricultural Biotechnology and Sustainable Development Vol. 2(6), pp , June 2010 EFFECT OF WATER DEFICIT AT GRAIN REPINING STAGE ON RICE GRAIN QUALITY M. Fofana, M. Cherif , B. Kone, K. Futakuchi and A. Audebert. Rice production is usually reduced by water stress that can evenly occur during rice cycle in West Africa under bimodal rainfall pattern. In order to determine the effects of water stress on rice grain quality, experiments were conducted on upland site (on ferralsol) at the main AfricaRice research center at M’be, 30 km North of Bouaké, Côte d’Ivoire. The rice varieties CG14 (Oryza glaberrima), WAB (Oryza sativa), and NERICA1 (cross WAB x CG14) were sown at 25 × 25 cm spacing during the dry season cropping period of 2000, 2001 and Irrigation line (Boon irrigation) was used to supply water until flowering stage. Water was then supply manually from the milky stage of each variety to its full ripening stage. Physical (husking yield, milling recovery, and head rice ratio), chemical (amylose and proteins contents) and cooking parameters (cooking time, volume expansion, rice flour gelatinization temperature, consistency and viscosity) of the harvested grains were determined in the laboratory. The results showed a significant difference (p < 0.05) between all the parameters in comparison with the checks samples and stressed crop. In general, NERICA 1 showed better physical and cooking quality traits than its parents. Rice samples from plots subject to lower water availability during repining stage showed higher protein content for all varieties studied. Increase in the average protein content of stressed samples were 31, 11.8 and 13.3% times, respectively for NERICA 1, CG14 and WAB , where (using the protein content of check plots as 100%) NERICA 1 showed higher husking yield, total mean milling recovery and head rice ratio for samples collected on stressed plots than the glaberrima and the sativa samples recorded on similar plots. Finding showed that cooking properties that meet West African rice consumers’ preferences for cooked rice were more improved for NERICA 1 than its parents in comparison with samples collected from stressed plots. It is concluded that moisture stress at ripening stage should be further investigated as potential indirect means of improving rice grain quality. Diunduh dari: 25/12/2012


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