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Presentasi berjudul: "Foto: smno.kampus.ub.febr2013. Bahan Kajian MK Dasar Ilmu Tanah Febr 2013."— Transcript presentasi:

1 Foto: smno.kampus.ub.febr2013. Bahan Kajian MK Dasar Ilmu Tanah Febr 2013

2 KUALITAS TANAH Soil quality is defined by the interactions of a particular soil’s measurable chemical, physical, and microbiological properties. These properties can be managed and adjusted by farmers. Soil quality, therefore, should be distinguished from a soil’s inherent properties, which cannot be managed or adjusted by farmers. Inherent properties are determined by factors such as climate, topography, vegetation, parent material, and time. From a productivity standpoint, each soil has an innate capacity to function, and some soils will be inherently more productive than others. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

3 INDIKATOR KUALITAS TANAH Kualitas tanah dapat diukur dengan parameter atau indikator tertentu. Examples of such indicators are soil water- holding capacity, organic carbon content, and microbial respiration. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

4 KUALITAS TANAH Indikator Biologis Some biological indicators of soil quality that are commonly measured include : 1.Bahan organik tanah, 2.Respirasi, 3.Biomasa mikroba (total, bacterial, fungal, or all of these), 4.C dan N dalam biomassa mikroba, 5.N dapat dimineralisasi. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

5 KUALITAS TANAH BAHAN ORGANIK TANAH - BOT Soil organic matter is that fraction of the soil composed of anything that was once alive. It includes plant and animal remains in various stages of decomposition, cells and tissues of soil organisms, and other organic substances. When the organic substances within the soil and any organic matter that has been added to it, such as compost, decompose, they produce humus—organic matter that is stable or relatively resistant to further decay. BOT Sangat penting dalam menentukan sifat dan perilaku fisika, kimia dan biologi tanah. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

6 FUNGSI BAHAN ORGANIK DALAM TANAH Organic matter contributes to plant growth through its effect on the physical, chemical, and biological properties of the soil. Fungsi BOT : 1.Fungsi hara, in that it serves as a source of N, P for plant growth 2.Fungsi Biologis, in that it profoundly affects the activities of microflora and microfaunal organisms 3.Fungsi Fisika dan Fisko-kimia, that it promotes good soil structure, thereby improving tilth, aeration and retention of moisture and increasing buffering and exchange capacity of soils.

7 KUALITAS TANAH Respirasi Tanah Soil respiration is the creation of carbon dioxide (CO 2 ) as organic matter decomposes in the soil. It provides a gauge of the activity of living organisms in the soil. Microbial respiration and activity are influenced by such elements as moisture, temperature, availability and degradability of organic residues, and toxic effects of various agricultural chemicals. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

8 KUALITAS TANAH C - Organik. Soil organic carbon, in particular labile (easily decomposed) organic carbon, has an overwhelming effect on soil microbial activity. Labile organic carbon makes up approximately 10 to 14 percent of total soil carbon. It is the heterogeneous mix of living and dead organic materials that are readily circulated through soil biological pools, groups of interacting organisms. C-organik ini merupakan cadangan hara dalam tanah. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

9 KUALITAS TANAH Aktivitas Mikroba Microbial activity in the soil can be assessed in a number of ways. Farmers can measure the status of either the total community of micro organisms or specific members of that community. Of these two assessments, the latter is perhaps the most useful. For example, populations of predatory nematodes are good indicators of soil quality. These microscopic worm-like organisms play numerous important roles in the soil, with both negative and positive effects. Some act as primary consumers of plants—in other words, they are pests. Others act as secondary predators of bacterial and fungal feeders—they serve as beneficials in the soil. Analisis komunitas nematode merupakan salah satu cara menentukan kesehatan dan keseimbangan suatu tanah. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

10 KUALITAS TANAH Earthworms. Earthworms are also good bioindicators of soil quality. Earthworm populations can tell a researcher a great deal about the structural, microclimatic, nutritive, and toxic status of soils. Large, vertically-burrowing earthworms play an important role in conserving and improving soil structure, recycling soil nutrients, pro-moting the gradual mixing of the soil layers, and creating an aeration and drain-age system in the soil. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

11 KUALITAS TANAH Indikator Kimiawi Petani yang mengharapkan mendapatkan hasil tanaman secara maksimal maka ia harus menyediakan hara dalam jumlah besar. Petani mengubah dan meningkatkan cadangan hara dalam tanah dengan jalan pemupukan, membenamkan pupuk hijau, dan aplikasi bahan organik lainnya seperti kompos dan rabuk kandang. The types and proportions of amendments—and how they contribute to soil quality—largely depend on each farmer’s management principles and philosophy. In any case, soil chemistry, with its influence on the availability of nutrients to plants, plays a key role in soil quality. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

12 KUALITAS TANAH Kemasaman = Acidity. Kemasaman tanah (pH) merupakan salah satu faktor utama yang mempengaruhi ketersediaan hara bagi tanaman. The major nutrients (nitrogen, potassium and phosphorous) can’t effectively promote high crop yields if the soil pH is not correct. Decreasing soil pH increases the solubility of elements such as aluminum, zinc, copper, and iron. At pH values less than approximately 5.5, toxic levels of these elements may even be present in the soil. Applying lime will help to increase soil pH and thus decrease the solubility of these elements in the soil. Liming has other benefits as well. It tends to produce favorable conditions for microbial activity in soil, with such related benefits as enhanced nitrogen fixation and, in some cases, improved soil structure. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

13 KUALITAS TANAH Indikator Fisika Sifat-sifat fisika tanah memperngaruhi pertumbuhan tanaman melalui berbagai cara. Plant health and growth are heavily influenced by the soil’s texture, bulk density (a measure of compaction), porosity, water-holding capacity, and the presence or absence of hard pans. These properties are all improved through additions of organic matter to soils. Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System.

14 Qualitative Soil Quality Indicators Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System. IndikatorBuruk (Jelek)SedangBaik Earthworms0-1 worms in shovelful of top foot of soil. No casts or holes in shovelful. Few casts, holes, or worms. 10+ in top foot of soil. Lots of casts and holes in tilled clods. Birds behind tillage. Organic matter (OM) color Topsoil color similar to subsoil color. Surface color closer to subsoil color Topsoil clearly defined, darker than subsoil Roots/resid ue/(OM) No visible residue or roots. Some residue, few roots. Noticeable roots and residue

15 Qualitative Soil Quality Indicators Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System. IndikatorBuruk (Jelek)SedangBaik Subsurface compaction Wire breaks or bends when inserting surveyor’s flag. Have to push hard, need fist to push flag in. Flag goes in easily with fingers to twice the depth of plow layer. Soil tilth, mellowness, and friability Looks dead. Like brick or concrete, cloddy. Either blows apart or hard to pull drill through. Somewhat cloddy, balls up, rough pulling seedbed. Soil crumbles well, can slice through, like cutting butter. Spongy when you walk on it. ErosionLarge gullies over 2 inches deep joined to others, thin or no topsoil, rapid run-off the color of the soil. Few rills or gullies, gullies up to two inches deep. Some swift runoff, colored water No gullies or rills. Clear or no runoff

16 Qualitative Soil Quality Indicators Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System. IndikatorBuruk (Jelek)SedangBaik Water holding capacity Plant stress two days after a good rain. Water stress after a week Holds water for a long period of time without puddling. Drainage, infiltration Water lays for a long time, evaporates more than drains, always very wet ground Water lays for short period of time, eventually drains No ponding, no runoff, water moves through soil steadily. Soil not too wet, not too dry. Crop condition Problem growing throughout season, poor growth, yellow or purple color. Fair growth, spots in field different, medium green color. Normal, healthy dark green color, excellent growth all season, across field.

17 Qualitative Soil Quality Indicators Soil Quality Considerations for Organic Farmers. Sumber: Soil Quality Considerations for Organic Farmers. by Keith R. Baldwin. CEFS. Center for Environmental Farming System. IndikatorBuruk (Jelek)SedangBaik pHHard to correct for desired crop. Proper pH for crop. Nutrient holding capacity Soil test values dropping with more fertilizer applied than crops use. Little or slow change Soil tests trending up in relation to fertilizer applied and crop harvested. Source: Maryland Quality Assessment Book, Natural Resource Conservation Service

18 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Kunci atribut tanah Tanah menyediakan kebutuhan tanaman berupa: 1.Udara 2.Air 3.Unsur hara 4.Stabilitas/ tempat berpijak DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf Bagaimana tanaman tumbuh? Sumber: do-plants-grow.html

19 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf Sifat TanahRelevansi bagi pertumbuhan tanaman KebasahanWater supply, exclusion of air and, consequently, exclusion of oxygen Barier AkarControls the depth of soil available for roots to extract water and nutrients, and to anchor the plant StoninessStones and rocks dilute the volume of soil within the root depth that is available for water storage and nutrients PorositasPromotes stability by allowing deep rooting. Drains excess water, and circulates air to roots Status hara alamiah Controls nutrient supply and reserves KekeringanAn interaction between climate and soil attributes

20 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Kebasahan - Wetness When a soil is very wet for a prolonged time the supply of air to roots may be limited. This level of wetness may be observed directly, but regular episodes of wetness can be indicated by soil colour when it is not currently wet. Deskripsi sifat-sifat dalam setiap lapisan: 1.Becak-becak berwarna karat 2.Warna kelabu dominan 3.Kedalaman posisi becak-becak 4.Topsoil bergambut DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

21 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Barier Akar - Root barrier Root barriers control the depth of soil that is available for roots to extract water and nutrients, and to anchor the plant. Deskripsi siofat-sifat setiap lapisan: 1.Lapisan berbatu sangat kompak 2.Lapisan berbatu yang berpasir longgar 3.Batuan 4.Cadas keras 5.Lapisan tanah yang kompak 6.Kebasahan akibat muka air tanah sangat dangkal. DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

22 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Berbatu - Stoniness Stones and rocks dilute the volume of soil within the root depth that is available for water storage and nutrients. They have an especially important effect on water storage in soils in seasonally dry climates. Deskripsi sifat dalam setiap lapisan Batu atau batuan Observasi sifat : Batu atau batuan Stones range in size from boulders to fine gravel (down to 2 mm diameter). A large number of stones in the soil restricts the volume of soil that is available for roots to explore for water and nutrients. DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

23 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Porosity Soil pores are cracks or tubular holes in the soil filled with water or air. They can store water or circulate air to roots, and larger pores drain excess water. Sifat-sifat yang harus dideskripsikan dalam setiap lapisan: 1.Tekstur berpasir 2.Bidang batas - Weak soil strength 3.Pola retakan 4.Perakaran - Roots DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

24 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Status Hara Alamiah The natural nutrient status includes both the ability of soil to make nutrients readily available to plant roots and to store nutrients in reserves that will become available in the future as the soil matures. It is an expression of the fertility in the absence of fertilisers. Analisis tanah diperlukan untuk menentukan status hara tanah pada saat sekarang. Beberapa kunci penting bagi status hara alamiah (sebelum dilakukan pemupukan) dapat diperoleh dari observasi tanah di lapangan. The concepts of weathering and leaching: Weathering is the amount of change in the soil material from the original parent material. Over long periods of time (thousands of years) the original parent material decays, sand and silt particles break down into clay, iron in minerals turns to rust, percolating rain water leaches out nutrients, and acidity increases. These and many other processes lead to the formation of distinct soil layers (or horizons). These alterations are indicated by a combination of clay content, colour, and the extent of decay of any stones that may be present. DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

25 SIFAT TANAH UNTUK PERTUMBUHAN TANAMAN Ketahanan Kekeringan Ancaman kekeringan biasanya merupakan faktor iklim, tetapi di daerah kering musiman, sifat-sifat tanah mempengaruhi keparahan kekeringan yang dialami tanaman. Drought is related to the amount of water stored in the soil and available for plant survival or growth. The water available to plants can be predicted by inputs from rainfall, losses by evapotranspiration and drainage, and the water storage in the soil. The focus here is only on the soil water storage in the soil. Deskripsi Sifat-sifat pada setiap lapisan Potensi kekeringan pada suatu lokasi dinyatakan dengan : 1.Kedalaman barrier 2.Batu-batu 3.Tekstur berpasir DIUNDUH DARI : 16/2/2013http://www.mwpress.co.nz/store/downloads/LRSciSeries26_4web.pdf

26 Tanah dan Pertanian Berlanjut Menjaga produktivitas dnegan jalan mereduksi input eksternal Menghasilkan jasa-jasa ekosistem – Mendukung pertumbuhan tanaman – Daur ulang hara – Menahan dan menyimpan air tersedia – Pertukaran gas – Konservasi musuh alami hama dan mengendalikan hama – Menyimpan karbon. Diunduh dari: 12/2/2013

27 1.Kemampuan tanah untuk berfungsi di dalam batas- batas ekosistem untuk mendukung tanaman dan ternak yang sehat, menjaga dan memperbaiki kualitas air dan udara, dan mendukung kesehatan lingkungan / manusia dan habitation. 2.Kualitas tanah mengintegrasikan kondisi fisika, kimiawi dan biologis tanah. Soil Properties Diunduh dari: 12/2/2013 Kualitas Tanah

28 Dalam satu sendok tanah yang sehat mengandung:  Bacteria 100 million to 1 billion  Fungi 6-9 ft fungal strands put end to end  Protozoa Several thousand flagellates & amoeba One to several hundred ciliates  Nematodes 10 to 20 bacterial feeders and a few fungal feeders  ArthropodsHingga 100  Cacing tanah 5 Atau lebih Travis & Gugino - PSU Diunduh dari: 12/2/2013

29 Diunduh dari: 12/2/2013 Jaring-jaring makanan dalam tanah

30 Jasa-jasa ekosistem yg dihasilkan Organisme Tanah 1.Many beneficial effects by activities of soil organisms 2.Decomposition and mineralization 3.Menyumbang hara tanaman (Rhizobia, Mycorrhizae) 4.Agregasi tanah, Stabilitas agregat, dan porositas 5.Infect, compete with or antagonize pests Actinomycetes Predatory Mite Ground and rove beetles Insect-parasitic Fungus Earthworms and other ecosystem engineers Diunduh dari: 12/2/2013

31 Ruangan Air Udara Makanan Apa saja kebutuhan organisme tanah? Rose & Elliot Diunduh dari: 12/2/2013

32 Gangguan Tanah dalam Pertanian Tanah sawah pada musim kemarau diolah untuk menanam bibit tomat

33 Beberapa Efek Pengolahan Tanah Soil organisms more abundant and more diverse in systems that reduce soil disturbance Organisms vary in sensitivity Olah tanah meningkatkan fluktuasi: –Lengas tanah –Suhu tanah –Residu tanaman dan BOT Pencampuran tranah Kerusakan struktur tanah Risiko erosi Diunduh dari: 12/2/2013

34 PENGELOLAAN BOT 1.Akar tumbuhan 2.Dedaunan 3.Mulsa 4.Rabuk kandang 5.Kompos 6.Pupuk Hijau PanenPanen OksidasiOksidasi ErosiErosi Tingkat Kesetimbangan BOT tercapai Olah tanah Diunduh dari: 12/2/2013

35 Kualitas tanah: Pertanian Organik vs. Tanpa-olah Sustainable Agriculture Demonstration Project, USDA, Beltsville, MD Teasdale et al., Agron. J. 99: Diunduh dari: 12/2/2013

36 R. Weil, Univ. MD Rotasi Tanaman dan Pertanian berlanjut: Efek rotasi tanaman terhadap kualitas tanah dna produktivitasnya. Diunduh dari: 12/2/2013

37 Pengelolaan dan Konservasi Pengendalian Hayati Tujuan: Memperbaiki lingkungan yg sesuai untuk proses-proses dan organisme yang menguntungkan “Farmscaping”: menyediakan tanaman atau habitat, mis., –pollen and nectar resources required by many insect natural enemies and pollinators –refuge strips of flowering plants, hedgerows –beetle banks or grassy drive lanes –Tanaman tahunan –Tanaman penutup tanah Diunduh dari: 12/2/2013

38 Tanaman penutup tanah dan jasa ekosistem 1.Cover crops can enhance numbers of soil organisms 2.Add diversity to system 3.Add food resources for beneficial insects – pollen and nectar 4.Seresahnya menjadi habitat bagi predator 5.Bersaing dengan gulma 6.Melindungi tanah 7.Kesuburan tanah dan retensi hara Photos: T. Pisani Gareau Hairy Vetch Buckwheat Mustard Diunduh dari: 12/2/2013

39 Pengelolaan pertanian untuk Kualitas Tanah dan Jasa Ekosistem Continuous resources –mis. hay/pasture, tanaman tahunan, mulsa, penutup tanah, high root:shoot ratio, controlled grazing, kompos, rabuk kandang Tanaman dan ragam pengelolaannya –Mis. Rotasi tanaman, refuge strips, hedgerows, polycultures, cover crops Mengurangi Gangguan –Mis. woodlands/orchards, pasture, reduce or rotate tillage, refuges, tanaman tahunan atau penutup tanah, minim biosida Diunduh dari: 12/2/2013

40 Jasa Ekosistem Tanah: Mineralization dan Immobilization Organisme mengkonsumsi BOT dan organisme lainnya menghasilkan limbah anorganik Hara anorganik tersedia bagi tanaman dan bersifat mobil dalam tanah Hara Organik disimpan dalam organisme tanah dan dalam bahan organik Organisme mengambil dan menyimpan hara untuk pertumbuhannya Diunduh dari: 12/2/2013

41 Definisi Kualitas Tanah Soil Fertility Physical Properties Biological Activity “The ability of soil to function; to supply plants with adequate nutrients, have good drainage and aeration, promote root growth and biological activity.” Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

42 A Definition of Soil Quality Context: soil type, slope, climate……. Problems - Salinity -Low in nutrients -Erosion -Drainage Soil is OK Soil Quality - High OM - Tilth - Infiltration -Nutrient buffering Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

43 Uji tanah untuk kualitasnya: Fisika, Kimia, Biologis Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

44 Uji Fisika – Tekstur Tanah Fill a jar 2/3 with soil. Fill the same jar about 7/8 full of water. Add detergent (optional) to break up aggregates. Dikocok dengan baik. Measure height of settling at 30 seconds, 30 minutes, and 24 hours – or -- look at particle size differences – sand, silt, and clay layers. Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

45 Tekstur tanah ditentukan oleh bahan induk tanah, erosi masa lalu, dan deposit baru (mislanya penambahan topsoil) Tanah berpasir – good drainage, but doesn’t hold water or nutrients well. (particles 0.05 to 2 mm) Tanah Debu– moderate drainage, moderate nutrient and water holding capacity. (0.002 – 0.05 mm) Tanah Liat – poor drainage, can supply K mineral, shrink/swell with water (<0.002 mm) Semua karakteristik ini diperbaiki oleh penambahan bahan organik tanah, misalnya kompos. Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

46 Bahan Organik Tanah Humus stabil BO makro (mulch, residue, roots, large pieces of compost, etc.) BO terdekomposisi (Partikulat organik atau POM) Uji tanah untuk BO BO aktif BO stabil Uji Humus Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

47 Stabilitas agregat = Agregat yang stabil air Agregat yg mantap terbentuk oleh proses agregasi liat (partikel halus), yg diikuti dengan pengikatan bersama menjadi agregat makro dengan bantuan perekat hasil sekresi bakteri, hifa jamur dan akar-akar rambut. Fungsi bahan organik tanah Organic matter contributes to plant growth through its effect on the physical, chemical, and biological properties of the soil. It has a : 1.Fungsi per-hara-an, in that it serves as a source of N, P for plant growthNP 2.Fungsi biologis, in that it profoundly affects the activities of microflora and microfaunal organisms 3.Fungsi fisik dan fisiko-kimia, that it promotes good soil structure, thereby improving tilth, aeration and retention of moisture and increasing buffering and exchange capacity of soils.

48 Mengukur stabilitas agregat Metode ayakan basah. Demonstrate with a few aggregates in a shallow dish. Field soilPrairie soil Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

49 Soil biology: important, but difficult to measure. Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

50 Uji biologi tanah meliputi jumlah cacfing tanah (dengan tangan), ekstraksi serangga tanah dengan cahaya di atas dan di bawah cerobong menuju jaring. No accurate tests yet for microbial species diversity. Soil respiration rate tests also available, but difficult to interpret. Biologi Tanah……. Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

51 Pertumbuhan akar yang sehat memerlukan “tanah yang baik” Banyak tanaman “sakit” ternyata tidak ada penyakitnya, hanya memerrlukan perbaikan tanah/ perakarannya. Kondisi tanah yang baik juga dapat membantu melawan gangguan hama dan penyakit (seperti sistem mkekebalan pada manusia). Try to improve the subsoil and also the topsoil. Limit compaction, and keep adding organic matter over a period of years. Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

52 LENGAS TANAH = SOIL MOISTURE Sumber: Air yang diberikan di permukaan tanah nakan menembus tanah memasuki zone perakaran, dan sebagian menembus ke lapisan yang lebih dalam hingga mencapai lapisan tanah jenuh air. the top of the saturated layer is called groundwater table or sometimes just water table

53 Pentingnya air bagi tanaman 1.Air merupakan hara 2.Air berfungsi sebagai pelarut bagi unsur hara Diunduh dari : 16/2/2013 Water have function for plant; constructor of plant body about 70 to 90%, solvent and biochemical reaction media, compound transportation media, for fission and dilation of cell, and basic compound for photosynthesis and maintain temperature plant body. Water in the plant is divided by capillary water and unavailable water. Capillary water is water between below (constant withered point) and top (field capacity). Air tidak tersedia dibagi menjadi air higroskopis dan air gravitasi (di atas kapasitas lapang)

54 54 What are the water requirements for plants? Crop use several hundred pounds of water for each pound of dry matter produced Diunduh dari : 16/2/2013 Crop Water Requirement (mm) Rice Wheat Sorghum Maize Sugarcane Groundnut Cotton Soybean Tobacco Tomato Potato Onion Chillies500 Sunflower Castor500 Bean Cabbage Pea Banana Citrus Pineapple Gingelly Ragi Grape

55 55 How does water enter the soil? through pores in the soil sandy soils have the largest pores, but are often filled with other material medium textured soils (loamy) have good water entry properties clays, pores swell shut when they get wet Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

56 56 Gaya Adhesi it is the attraction of two different molecules (water to soil) Water held by adhesion = not available to the plant Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu Gaya Kohesi Gaya tarik-menarik antara dua molekul yang sejenis (air dengan air) Air yang ditahan dengan gaya kohesi = tersedia bagi tanaman

57 57 Pentingnya Kohesi dan Adhesi dalam tanah 1.Molekul-molekul air diikat kuat oleh partikel mineral dan bahan organik tanah dnegan gaya adhesi 2.Molekul-molekul air juga saling berikatan satu sama lain dengan gaya Kohesi 3.soil holds a thin layer of water, that layer holds a thin layer of water etc., the farther away from the soil particle you get, the looser the water is held Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

58 58 Pentingnya Adhesion dan Kohesion dalam tanah 1.water then tends to move from wetter places to drier places. Roots remove water, then water is drawn from surrounding areas 2.Pada kondisi kering, air tanah bergerak lambat dan menempuh jarak pendek, sehingga akar tanaman harus terdistribusi secara baik dan luas. Diunduh dari : 16/2/2013 Pergerakan air tanah berhubungan langsung dengan ukuran pori tanah. Dalam tanah-tanah liat yang porinya kecil-kecil, air bergerak lambat ke semua arah, kapilaritas.

59 59 Klasifikasi air (lengas) tanah 1) Air Higroskopis ditahan sangat kuat oleh partikel tanah (adhesion), sehingga tidak tersedia bagi tanaman 2) Air Kapiler, ditahan dengan gaya kohesi yang lebih besar dari gravitasi dan tersedia bagi tanaman 3) Gravitational Water is that water which cannot be held against gravity – as water is pulled down through the soil, nutrients are"leached" out of the soil (nitrogen) Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

60 60 What is Field Capacity? Pada saat tanah mengandung air-tersedia paling maksimum; the greatest amount of water it can hold against gravity Diunduh dari : 16/2/2013 Determining Field Capacity and Permanent Wilting Point

61 61 Apakah Titik-Layu? Tanah mengandung terlalu sedikit air, sehingga tanaman tidak mampu pulih segar kembali Akar tidak mampu mnerap air dari tanah Diunduh dari : 16/2/2013 Permanent Wilting Point: The amount of water remaining in the soil when the plant wilts in a humid atmosphere. The water remaining in the soil is held tightly by soil particles and plant roots cannot absorb it.

62 62 APAKAH Air-tersedia? Jumlah dalam tanah di antara Kapasitas lapang dan Titik Layu Diunduh dari : 16/2/2013 Air tanah yang tersedia: Jumlah air dalam tanah antara kapasitas lapang dan titik layu permanen. Generally, overhead irrigation should start before soil reaches 50% of available soil water. Drip irrigation should start before soil reaches 80% of available soil water

63 63 Apakah “Water Table” ? 1.the level beneath the soil which the soil is saturated with water 2.marshes develop where the water table is just below the ground surface 3.Kalau posisi “water-table” tidak terlalu dalam, biasanya “kekeringan” dapat dikoreksi dengan sendirinya melalui pergerakan air kapiler menuju ke lapisan tanah permukaan Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

64 64 Apakah Kejenuhan air? Tanah jenuh air 1.Semua pori tanah terisi penuh dengan air 2.Kondisi tidak sehat bagi tanaman, kalau berlangsung lama, karena oksigen terlarut dalam air yang diperlukan untuk respirasi cepat habis. Diunduh dari : 16/2/2013 Zone jenuh - Saturated zone. The pore space in this zone is filled with water (saturated). Depending on the length of time elapsed from the initial application of water, this zone will generally extend only to a depth of a few millimeters..

65 65 Apa yang mempengaruhi kemampuan tanah menyimpan/ menahan air? 1.Semakin kecil ukuran partikel tanah, semakin besar luas- permukaannya, sehingga mampu menahan molekul air lebih banyak 2.consider a book compared to all of its pages Diunduh dari : minto=1……….. 16/2/2013 Kemampuan tanah menyimpan air (Water holding capacity, WHC) mencerminkan jumlah air yang disimpan di antara kapasitas lapang dan titik layu.

66 66 Faktor-faktor yang menentukan jumlah air dalam tanah 1.Jumlah air hujan, air irigasi 2.Laju infiltrasi, masuknya air di permukaan tanah 3.Kapasitas simpanan air tanah 4.Laju ervaporasi 5.height of water table 6.rate which water can move within the soil 7.amount and type of vegetation Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

67 67 Bagaimana meningkatkan air tanah yang tersedia bagi tanaman? Hujan : better utilize snow and rain by keeping the water on the soil surface. – windbreaks – keep snow in place (cover) – strip cropping – contour strips – grassland farming Irrigasi: may not be practical Infiltrasi air ke dalam tanah: reduce cultivation, green manures, correct alkaline soils Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

68 68 Bagaimana meningkatkan air-tersedia dalam tanah? 1.Kapasitas simpanan: Meningkatkan kandungan BOT 2.Evaporatsi: olah tanah konservasi, Jalur naungan, strip cropping 3.Pergerakan air dalam tanah: BOT 4.Penutup vegetatif: Menahan air Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu Simpanan Air Tanah The soil water storage or soil water content can be quantified on the basis of its volumetric or gravimetric water content. The volumetric water content is the volume of water per unit volume of soil, expressed as a percentage of the volume. The gravimetric water content is the mass of water per unit mass of dry (or wet) soil. The volumetric water content is equal to the gravimetric water content times the soil's bulk density (on a dry soil basis). Faktor simpanan air tanahg: 1.Porositas dan ruang pori 2.Ukuran pori, distribusi dan kontinyuitasnya 3.Potensial air tanah, status energi air tanah (sumber:

69 69 Kebutuhan air tanaman 1.Rasio Transpirasi: jumlah kg air yang diperlukan untuk menghasilkan satu kg bhahan kering tanaman. 1.Jagung = 350# Gandum = 500# 2.Kentang = 630# Grass & Alfalfa = 860# 2.It takes 4,533 gallons of water to produce enough food for one person for 3 meals. (That's 1,654,545 gallons per year) 3.It takes 10,000 gallons of water to make one bushel of wheat 4.It takes 7.35" of rain to make a 20 bushel per acre crop. Diunduh dari : ……….. 16/2/2013www.ffa.cccs.edu

70 (to get to all KSU publications, soil test lab info, etc.) (for “Citizens Guide to Soil and Water Testing”) (fact sheets and other info on soil quality) (copies of other soil quality publications, compost testing) or other book seller (for copies of “Soul of the Soil.”) Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU. Beberapa Web Sites yang terkait

71 Web Sites yang terkait (compost testing, respiration rate tests) (for nutrient and humus test kits) (for nitrate, pH, and ammonia test strips) (for E. coli plates, order #6484 EC plates, $70 for 50, also need pipets) Sumber: Soil Quality – Why it matters. Rhonda Janke. Assoc. Prof and Ext Specialist, KSU.

72 72...pengolahan tanah dilakukan untuk memperbaiki kualitas tanah sebagai media tanam bibit …. Sumber : smno.jursntnh.fpub.2013


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