FACTORS AFFECTING SOIL FERTILITY AND PRODUCTIVITY

FACTORS AFFECTING SOIL FERTILITY AND PRODUCTIVITY

1.   FACTORS AFFECTING SOIL FERTILITY AND PRODUCTIVITY BY SAID HUSSEIN MARZOUK [email protected]

2. Soil fertility Soil fertility . The capacity of soil to supply available nutrients to plants in an adequate amount and suitable proportions to maintain growth and development. It is a measure of nutrient status of soil which decides growth and yield of crops. Fertile soil can supply essential plant nutrients  and water in adequate amounts and proportions for plant growth and reproduction; and the absence of toxic substances which may inhibit plant growth. [email protected]

3. Soil productivity Soil productivity . The ability of a soil to support crop production or yields determined by the entire range of its physical , chemical , and biological attributes . Soil fertility is only one aspect of soil productivity but it is a very important one. For example, the soil may be very fertile , but produce only a little yield because of a lack of water or unfavorable climatic conditions . [email protected]

4. Factors affect soil fertility and productivity The factors affecting soil productivity includes those which affect the physical, chemical, and biological conditions of the soil in which plants grown. All factor that affect fertility also affects productivity Other factors like soil-water and air relationships, soil biology such as plant diseases , and microbial life all affects productivity. [email protected]

5. Factors affect soil fertility and productivity cont.. Soil pH, sodicity, and salinity on soil fertility Soil pH or soil reaction is an indication of the acidity or alkalinity of soil The pH scale goes from 0 to 14 with pH 7 as the neutral point. The ideal soil pH is close to neutral. pH of 6.5 to a slightly alkaline pH of 7.5 Most plant nutrients are optimally available to plants within this 6.5 to 7.5 pH range [email protected]

6. pH cont….. Below and above the range cause an effects on nutrients Eg. Phosphorous. At acidic pH values Al and Fe become dominant in the soil, phosphate ions react with Al and Fe to form less soluble compounds of either aluminum or iron hydroxide (Brady et al., 1974) At alkaline pH, phosphate ions tend to react quickly with Ca and Mg compounds to form less soluble compounds [email protected]

7. pH cont….. Nitrogen (N), Plants can take up N in the form (NH4+) or (NO3-) from pH near neutral (pH 7). At pH 7, The microbial conversion of NH 4 + to nitrate (nitrification) is rapid , and crops generally take up nitrate. In acid soils (pH < 6), nitrification is slow , and plants with the ability to take up NH 4 + may have an advantage (Nieder et al., 2011). Ammonia volatilization losses is pH dependent, higher pH more volatilization [email protected]

8. Factors affect soil fertility and productivity cont.. Soil structure and texture Good soil structure : high CEC , high water holding capacity and more pore space. Texture, clay more CEC , hold more nutrients, store more water. Sand soil leached easily and hold less nutrients [email protected]

9. Factors affect soil fertility and productivity cont.. III. Soil organic matter Includes : plants and animals residue , micro and macro fauna. acts as a storehouse of various nutrients Improves soil structure and permeability Improving water holding capacity (Lehmann et al., 2004) [email protected]

10. Factors affect soil fertility and productivity cont.. Adequate mineral nutrients All plants require 17 elements to complete their life cycle Some elements required in large amounts eg. N,P,K and S other required in trace amount eg. Fe, Mo, Cu, and Except for C, H, and O, which plants obtain from air and water, plants derive the remaining 14 elements from the Soil or through fertilizers, manures, and amendments (Parikh and James 2012). [email protected]

11. Factors affect soil fertility and productivity cont.. V. Parent rocks parent materials; is an important raw materials for the formation of any soil . If rich in plant nutrients , the soils formed from it are usually quite fertile and productive The property of soil depends on the property of the parent rock. Eg. Soils derived from calcareous rock contain more P than the soil derived from granite . [email protected]

12. Factors affect soil fertility and productivity cont.. VI. Topography and age of the soils Mountainous soils with steep slope are usually poor because of excessive leaching and erosion of the topsoil. The soils of low-lying areas are usually rich in nutrients because of the transportation and accumulation of soil and plant nutrients Old soils are less fertile due to excessive weathering, leaching, and continuous cultivation . [email protected]

13. Factors affect soil fertility and productivity cont.. VII. Climate and vegetation Influences fertility of the soils Tropical soils receive High rainfall and develop thick forest vegetation. More decomposition of organic matter Temperate soils are not very fertile compared to tropical soils because of the lesser decomposition of organic matter. Tropical soils more fertile due to constant high temperature which helps in a faster rate of disintegration and  decomposition of organic matter. [email protected]

14. Factors affect soil fertility and productivity cont.. All productive soils are fertile but not all fertile soil are productive. Apart from soil fertility as a factor of productivity there is other factors that affect soil productivity Climatic Factors Nearly 50 % of yield is attributed to the influence of climatic factors. Precipitation , Temperature , Atmospheric humidity , solar radiation , wind velocity, and Atmospheric gases [email protected]

15. Factors affects soil productivity cont.. ii. Biotic Factors Beneficial and harmful effects caused by other biological organisms (plants and animals) influences production. Plants Competitive and complementary nature among field crops when grown together. Eg crops and weeds When different crops of cereals and legumes are grown together, mutual benefit results in higher yield (synergistic effect) [email protected]

16. Factors affect soil productivity cont.. Animals Soil fauna like protozoa , nematode , and insects help in organic matter decomposition Insects and nematodes cause damage to crop yield and are considered harmful organisms. Honey bees and wasps help in cross-pollination Burrowing earthworm facilitates aeration and drainage of the soil Large animals cause damage to crop plants by grazing (cattle and goats [email protected]

17. Factors affects soil productivity cont.. iii. Socio-economic factors Appropriate choice of crops with environmental and soil type. Breeding varieties by the human invention for increased yield or pest & disease resistance The economic condition of the farmers greatly decides the input/ resource mobilizing ability (marginal, small, medium, and large farmers) [email protected]

18. Factors affects soil productivity cont.. v. Soil temperature It affects the physical and chemical processes going on in the soil. It influences the rate of absorption of water and solutes (nutrients) It affects the germination of seeds and the growth rate Soil temperature controls the microbial activity and processes involved in the nutrient availability [email protected]

19. Factors affects soil productivity cont.. vi. Soil moisture Water is a principal constituent of the growing plant which it extracts from soil Water is essential for photosynthesis Soil water helps in the chemical and biological activities of soil including mineralization Nutrient availability and mobility [email protected]

20. Fertility vs productivity Soil fertility Soil productivity It is an index of available nutrients to plants. It usually used to indicate the ability of soil for crop yields Influenced by physical, chemical, and biological factors of the soil. Depends on the physical condition and fertility, climate, and weather. The fertility of certain soils may be the same in the entire climate. Differ in response to variation in climate and location. Usually assessed in the laboratory. Assessed in the field concerning a particular climate. The function of available nutrients in the soil. The function of soil fertility, climate, and crop management. All fertile soils are not productive. All productive soils are fertile. [email protected]

21. THANK YOU [email protected]