Soil Erosion and Conservation

Soil Erosion
Soil Conservation
Geological erosion
Deforestation
Accelerated erosion
Over grazing
Splash erosion
Sheet erosion
Rill erosion
Gully erosion
Coastal erosion
Effects of soil erosion
Agronomic practices
Dry farming
Agrostological methods
Strip farming
Contour farming
Terrace cropping
Pan breaking
mulching

1. Soil Erosion & Soil Conservation Dr. T. Annie Sheron Asst. Professor of Botany Kakatiya Govt. College, Hanamkonda Telangana

2. Learning Objectives What is soil ? What is soil erosion ? What are the causes of soil erosion? How does soil erosion takes place? What are effects of soil erosion? Why should we conserve soil? What are the different methods of soil conservation?

3. SOIL The upper layer of earth in which plants grow soil is the weathered surface of the earth crust which is mixed with organic material and in which plants grow Soil  is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life

4. Soil erosion Removal of top fertile layer of soil from its original place by agent of water, wind and glaciers. Soil erosion is a gradual process of movement and transport of the upper layer of soil (topsoil) by different agents – particularly water, wind, and mass movement – causing its deterioration in the long term. soil erosion is the removal of the most fertile top layer of soil through water, wind and tillage.

5. Types of soil erosion Geological erosion - caused by natural agencies such as wind, water, glaciers without interference of biotic factors Accelerated erosion - caused due to human interferences such as deforestation, construction activities etc

6. Causes of soil erosion Landslide Rain & Flood Cyclone Wind Tides & waves Water Forest fire Poor drainage system Deforestation Over grazing Conversion of hilly areas to crop lands Various cultivation practices

7. Landslide A landslide is defined as the movement of a mass of rock, debris, or earth down a slope.   Caused by rain, earthquakes, volcanoes, or other factors that make the slope unstable

8. Rain & Flood Splash erosion Sheet erosion Rill erosion & Gully erosion

9. Splash erosion/ Rain Drop Impact - detachment of soil particles by raindrop splash. Sheet erosion - Sheet erosion or sheet wash is the even erosion of substrate along a wide area. It occurs in a wide range of settings such as coastal plains, hillslopes, floodplains and beaches .

10. Rill erosion - removal of soil by concentrated water flow, and it occurs when the water forms small channels in the soil as it flows off site. Gully erosion - removal of soil along drainage lines by surface water runoff.

11. Soil erosion by cyclones & Floods   cyclones  remove forest canopy as well as change the landscape near coastal areas, by moving and reshaping sand dunes cause extensive erosion along the coast.

12. Soil erosion by Waves & Tides   Waves & Tides Coastal erosion  is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides etc.

13. Deforestation & Soil erosion   Deforestation, clear cutting or clearing is the removal of a forest or stand of trees from land which is then converted to a non-forest use Trees help the land to retain water  and  topsoil. Deforestation reduces soil cohesion and absence of vegetation causes the topsoil to erode more quickly.

14. Forest fire & Soil erosion   Fire changes forest ecosystems and interacts with geomorphic processes, climate, and landform. Intense heat from fire cause hydrophobicity in the soil which accelerate the rate of water runoff.

15. Wind & Soil erosion   can be transported over great distances, sometimes across continents and oceans. Wind erosion affects soil quality through the loss of topsoil rich in organic matter and can cause crop damage from abrasion. Wind erosion can occur when soil is dry and loose, the surface is bare and smooth, and the landscape has few physical barriers to wind.

16. Various cultivation practices & Soil erosion Tillage -  fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. Monoculture cropping - Long-term Monoculture deteriorates organic matter levels and soil physical properties and lead to accelerated erosion losses and impeded drainage. Slash and burn agriculture

17. Effects of soil erosion  Water Pollution and Clogging of Waterways Sedimentation and Threat to Aquatic Systems Loss of Arable Land Desertification Loss of nutrient in soil and also causes a reduction in land productivity. Loss of biodiversity Air Pollution Destruction of Infrastructure huge losses to the economy

18. Why Preventing and Stopping Soil Erosion is so Important Soil is the backbone of our food security Soils act as a pantry for plants, storing and cycling essential nutrients and minerals that plants need to grow Capture and store water for crops. Reduce surface evaporation Increase water use efficiency and productivity. Help fight and adapt to climate change by collecting and storing carbon and reducing GHGs in the atmosphere.

19. Allow for water infiltration through the soil, filtering pollutants and preventing them from leaching into the groundwater. Soils provide fiber, fuel, medicinal products, and other ecosystem services. Soils are home to 1/4 of  biodiversity  and they are a key part of the global cycles that make all life possible. Continued …

20. Soil conservation Soil conservation  is the prevention of loss of the top most layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination. OECD – “Protection of soil from erosion and other types of deterioration, so as to maintain soil fertility and productivity, it generally includes watershed management and water use.”

21. Includes conservation achieved by use of plant vegetation cover and is differentiated into 1. Agronomic practices 2. Dry farming 3. Agrostological methods. Biological methods

22. Contour farming Strip Cropping Crop Rotataion Agronomic practices Mulching

23. Contour farming Oldest method of conservation used in areas of low rainfall fields are prepared with alternate ridges and furrows Ridges of same level are called Contours Water is collected in furrows

24. Mulching Mulch is a layer of material applied to the surface of soil. Mulches can either be organic -grass clippings, straw, bark chips, etc. or inorganic - stones, brick chips, and plastic.  Organic mulches improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil

25. Crop Rotation Practice of growing a series of different types of crops in the same area across a sequence of growing seasons.   Advantages : Better nitrogen management, Reduced land and water pollution, Improved soil structure , Water conservation, Prevention of soil erosion , Easier pest, weed control and resistance to diseases, Climate change mitigation , Production of green manure cover crops, Higher crop yields , Creates a healthier environment for life

26. Strip Cropping A method of farming which involves cultivating a field partitioned into long, narrow strips which are alternated in a crop rotation system. Types: Strip intercropping Contour stripcropping Strip cropping helps to stop soil erosion by creating natural dams for water, helping to preserve the strength of the soil.

27. Dry farming Employed in places where there is low to moderate rainfall . To check soil erosion farmer usually employ methods such as Crop production, animal husbandry and growing grazing fields. Benefits: limited  soil  moisture reduces weed growth, reduces usage of weedicide . Mulches check water evaporation, hinder runoff and prevent erosion.

28. Ley farming Reforestation Retiring the land Agrostological methods Afforestation

29. LEY farming  is a system in which grasses and legumes are cultivated in proper rotation for hay, silage and pasture to meet maximum livestock needs and improve and conserve soil fertility. Ley farming Advantages: Improves soil nitrogen content; Restores soil organic matter structure; Controls weed growth; Prevents deep drainage and erosion; Improves livestock efficiency; acts as Natural fertilizer.

30. Retiring the land Areas subjected to heavy soil erosion should necessarily be put under thick cover of grasses.  Dectylis glomerata, Eragrostis amabitis and E. cerbula are proved to be most effective in soil binding and in stabilizing the reserves of the bench terrace and sodding water channels .

31. Afforestation and reforestation Reforestation  - planting trees on land that was previously forest. Afforestation  - refers to planting trees on patches of land which were not previously covered in forest.

32. Basin listing Contour terracing Pan breaking Mechanical methods Sub soiling Contour trenching Terrace outlets Gully control Digging of ponds & reservoirs Stream bank protection

33. In this method of soil and water conservation basins are constructed using a special implement called basin-lister. These basins are constructed across the slope. Basin listing provides maximum time to rain water for infiltration into the soil. Basin listing

34. Pan breaking Used to improve soils which are impervious to water and are less productive Breaking hard clay pans by means of pan breaker on contour at a distance of about 5 feet. Improves drainage and percolation of rain water and soil is saved from residual run-off and erosion .

35. Sub soiling Hard subsoil is broken deeply by sub soiler. Essential in soils with hard pans to help provide soil aeration and improved soil drainage Promotes absorption of rain water in the soil and makes the soil more loose and fit to allow luxuriant growth of vegetation.

36. Stream bank protection Stream bank protection is the process of placing material along a bank of a watercourse for the purpose of erosion control to prevent the loss of bank material and property adjacent to the banks of the watercourse Provides bank protection and local site protection, reduces the input and movement of sediment,  reducing the risk of downstream sediment accumulation and flooding .

37. A channel is constructed along the slope to intercept and divert the runoff water. Channel terrace: digging channels at suitable intervals and the excavated soil deposited as a wide, low ridge along the lower edge of the channel. Broad based ridge terrace : A ridge constructed along both the sides of the channel. Bench terrace: A number of platforms are constructed along contours or suitable graded lines across the slope. contour terracing :

38. Gully control In  gully control , temporary structural measures such as woven-wire, brushwood, logs, loose stone and boulder check dams are used to facilitate the growth of permanent vegetative cover. Check dams are constructed across the  gully  bed to stop channel and lateral erosion