SOILMETHODS FOR CONSERVATION OF RESOURCESMade By Keshav Priyadarshi– X-D Roll No. - 09
Index Topic Slide Topic Slide No. No. What is Soil? 4 Sustainable Agriculture 13 through Soil ConservationFactors of Soil formations 5 Irrigation Techniques 16 Classification Soils 6 Soil Nutrients 17 Alluvial Soil 7 Fertilizers 18 Black Soil 8 The Green Revolution and 19 its Environmental Impact Red & Yellow Soil 9 Appendix 22 Laterite Soil 10 Bibliography 23 Arid Soil 11 Assessment Sheet 24
What is soil? Top soil the upper soil layerTop most layer of earthcrust consisting of Subsoil weatheredorganic and inorganic rocks sand and silt claymatters is called soil.Soil is a renewableresource. Substratum weathered parent rock materialSoil is a living system.It is the medium of plantgrowth andsupports different types Unweatheredof living organisms on parent bed rockthe earth.
Factors of Soil formationsA. Relief,B. Parent rock or bed rock,C. Climate,D. Time are important factors in the formation of soil.E. Actions of running water, wind and glaciers,F. Activities of decomposers etc.G. Chemical and organic
Classification SoilsMajor types of Soilsfound in India.• Alluvial Soil• Black Soil•Red and YellowSoils• Laterite Soils• Arid Soils
Alluvial Soilsa. Most widely spread: The entire northern plains are made of alluvial soil.b. Deposited by Himalayan river systems– the Indus, the Ganga and the Brahmaputra.c. Alluvial soils as a whole are very fertile having potash, phosphoric acid and lime.d. Regions of alluvial soils are intensively cultivated.
Black Soilsa. These soils are also known as regur soils or black cotton soil.b. Climatic condition along with the parent rock material are the important factors for the formation of black soil.c. They are well-known for their capacity to hold moisture. In addition, they are rich in soil nutrients.d. These soils are generally poor in phosphoric contents.e. These soils are sticky when wet and difficult to work on unless tilled immediately after the first shower or
Red and Yellow Soilsa. Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan plateau.b. Yelllow and red soils are also found in parts of Orissa, Chhattisgarh middle Ganga plain.c. These soils develop a reddish colour due to diffusion of iron in crystalline and metamorphic rocks.d. It looks yellow when it occurs in a hydrated form.
Laterite Soilsa. Laterite has been derived from the Latin word ‘later’ which means brick.b. This is the result of intense leaching due to heavy rain. Humus content of the soil is low because most of the micro organisms, particularly the decomposers, like bacteria, get destroyed due to high temperature.c. These soils are mainly found in Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, and the hilly areas of Orissa and Assam.d. Red laterite soils in Tamil Nadu, Andhra Pradesh and Kerala are more suitable for crops like cashew nut.
Arid Soilsa. Arid soils range from red to brown in colour.b. They are generally sandy in texture and saline in nature.c. In some areas the salt content is very high and common salt is obtained by evaporating the water.d. Due to the dry climate, high temperature, evaporation is faster and the soil lacks humus and moisture.e. The lower horizons of the soil are occupied by Kankar because of the increasing calcium content downwards.f. The Kankar layer formations in the bottom horizons restrict the infiltration of water.g. After proper irrigation these soils become cultivable as has been in the case of western Rajasthan.
Forest Soilsa. These soils are found in the hilly and mountainous areas where sufficient rain forests are available.b. The soils texture varies according to the mountain environment where they are formed. They are loamy and silty in valley sides and coarse grained in the upper slopes.c. In the snow covered areas of Himalayas, these soils experience denudation and are acidic with low humus content.d. The soils found in the lower parts of the valleys particularly on the river terraces and alluvial fans are fertile.
SUSTAINABLE AGRICULTURETHROUGH SOIL CONSERVATION Terracing, contour planting, strip cropping, alley cropping, and windbreaks can reduce soil erosion.
Strip Cropping – a row crop such as corn alternates in strips with another crop that completely covers the soil, reducing erosion. It catches and reduces water runoff and helps prevent the spread of pests and plant
Cover Cropping (alley cropping) – severalcrops are planted together in strips or alleysbetween trees and shrubs that can provideshade (which reduces water loss byevaporation) and helps to retain and slowlyrelease soil moisture.
Irrigation Techniques Conventional center-pivot irrigation- allows 80% of the water input to reach crops Gravity-flow irrigation- Valves that send water down irrigation ditches. Drip irrigation- Can raise water efficiency to 90-95% and reduce water use by 37-70%. Floodplain irrigation- allowing the natural floods to irrigate the crops. Soils in flood zones tend to be nutrient rich and fertile.
Soil Nutrients Macronutrients are larger in atomic structure. Ex. Nitrogen, Phosphorus & Potassium. MicronutrientsThese are smaller in atomicstructure. Plants need them insmall amounts.
Fertilizers Organic Fertilizers – animal manure, crop residues, bone meal, and compostInorganic Fertilizers – man-made from chemicalcompounds Benefits – exact compositions are known; they are soluble & thus immediately available to the plant Costs – quickly leach away; this pollutes the water; doesn’t help the water holding capacity of the soil like organic fertilizers do.
THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT Since 1950, high-input agriculture has produced more crops per unit of land. In 1967, fast growing dwarf varieties of rice and wheat were developed for tropics and subtropics.
THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT Lack of water, high costs for small farmers, and physical limits to increasing crop yields hinder expansion of the green revolution. Since 1978 the amount of irrigated land per person has declined due to: Depletion of underground water supplies. Inefficient irrigation methods. Salt build-up. Cost of irrigating crops.
THE GREEN REVOLUTION AND ITSENVIRONMENTAL IMPACT Modern agriculture has a greater harmful environmental impact than any human activity. Loss of a variety of genetically different crop and livestock strains might limit raw material needed for future green and gene revolutions. In the U.S., 97% of the food plant varieties available in the 1940 no longer exist in large quantities.
Bibliography Birkeland, Peter W. Soils and Geomorphology, 3rd Edition. New York: Oxford University Press, 1999. Chesworth, Edited by Ward (2008), Encyclopedia of soil science, Dordrecht, Netherland: Springer, xxiv, ISBN 1- 4020-3994-8 Voroney, R. P., 2006. The Soil Habitat in Soil Microbiology, Ecology and Biochemistry, Eldor A. Paul ed. ISBN=0-12-546807-5 James A. Danoff-Burg, Columbia University. The Terrestrial Influence: Geology and Soils Janet Raloff. Dirt Is Not Soil. ScienceNews July 17th, 2008) Taylor, S. A., and G. L. Ashcroft. 1972. Physical Edaphology