Erosion Control

Erosion is the process by which soil and rock are removed from the Earth's surface by natural processes such as wind or water flow, often accelerated by human activities like deforestation or construction.

Principles of Erosion Control 

1. It is better to control the initiation of soil erosion than reclaim an eroded land. For this purpose, every piece of land in a watershed should be used properly in accordance with its capability. 

2. Land should be used in such a manner so that no erosion or deterioration of land takes place even after prolonged use.  

3. Suitable agronomical practiced should be followed to protect the land from the energy of the falling raindrop and surface flow.  

4. Different tillage and agronomical practices are required to be followed to achieve the desired effects.

Erosion control involves strategies to prevent or mitigate this loss of soil, which is vital for agriculture, ecosystem health, and infrastructure stability. Some erosion control methods include: 

Contour Cropping

1. Contour Cropping is a conservation farming method that is used on slopes to control soil losses due to water erosion. 

2. Contour cropping involves planting crops across the slope instead of up and down the slope. 

3. Use of contour cropping protects the valuable topsoil by reducing the velocity of runoff water and inducing more infiltration. 

4. Contour cropping is most effective on slopes between 2-10 %.

Strip Cropping

1. Strip Cropping is the practice of growing strip of crops having poor potential for erosion control, such as root crop, cereals, etc. alternated with strips of crops having good potentials for erosion control, such as fodder crops, grasses, etc., which are close growing crops. 

2.  Strip cropping is a more intensive farming practice than contour farming. 

3.  Strip cropping is laid out by using the three methods:

Contour Strip Cropping: In contour strip cropping, alternate strips of crop are sown more or less following the contours, similar to contouring. Suitable rotation of crops and tillage operations are followed during the farming operations.

Field Strip Cropping: In a field layout of strip cropping, strip of uniform width are laid out across the prevailing slope, while protecting the soil from erosion by water. To protect the soil from erosion by wind, strips are laid out across the prevailing direction of wind. Such practices are generally followed in areas where the topography is very irregular, and the contour lines are too curvy for strict contour farming.

Buffer Strip Cropping: Buffer strip cropping is practiced where uniform strip of crops are required to be laid out for smooth operations of the farm machinery, while farming on a contour strip cropping layout. Buffer strip of legumes, grasses and similar other crops are laid out between the contour strips as correction strips. Buffer strips provide very good protection and effective control of soil erosion. 

Mulching

1. Mulch is any material that is spread or laid over the surface of the soil as a covering. 

2. Mulches are used to minimise rain splash, reduce evaporation, control weeds, reduce temperature of soil in hot climates, and moderate the temperature to a level conducive to microbial activity.

3. It also helps in breaking the energy of raindrops, prevent splash and dissipation of soil structure, obstruct the flow of runoff to reduce their velocity and prevent sheet and rill erosion. 

4. They also help in improving the infiltration capacity by maintaining a conductive soil structure at the top surface of land. 1. Bunding 2. Terracing

Mechanical practices are engineering measures used to control erosion from slopping land surfaces and thus land surface modification is done for retention and safe disposal of runoff water. In the design of such practices, the basic approach is:

To increase the time of stay of runoff water in order to increase the infiltration time for water.

To decrease the effect of land slope on runoff velocity by intercepting the slope at several points so that the velocity is less than the critical velocity.  

To protect the soil from erosion caused by the runoff water. 

Bunding Methods 

Bund is an engineering measure of soil conservation, used for creating obstruction across the path of surface runoff to reduce the velocity of flowing water.  It retains the running off water in the watershed and thus to helps to control soil erosion. Bunds are simply embankment like structures, constructed across the land slope. 

Different Types of Bunds 

Contour bund:  When the bunds are constructed along the contours with some minor deviation to adapt to practical situation, they are known as contour bunds. Contour bunds are recommended for areas with low annual rainfall (< 600 mm) , permeable soils and land slope of less than 6%. The main functions of contour bunds are: 1. It reduces the length of slope which in turn reduces the soil erosion. 2. The water is impounded for some time and gets recharged into the soil which helps in crop cultivation.

Contour bunds are of two types: 1. Narrow base 2. Broad base 

Narrow Base 

a) Narrow base contour bunding system, there is an obstruction for crossing of farm implements; natural vegetations cover the sides and more height is allowed for same cross-section. 

b) It has limitations that, there is considerable area is lost in constructing the bund; the bund section is liable to get affected by erosion due to rain drop impact, hence requires a sincere maintenance. 

c) The narrow base contour bund also causes obstruction in farming operations. 

Broad base 

a) The broad base contour bunding is concerned, it does not create hindrance in farming operations; the entire area can be kept under cultivation. 

b)  It has some limitations, such as disturbance of bund’s section due to crossing of farm equipments, as result there is required an attentive care and maintenance.

c) Apart from above, the soil of bund is also loosened during movement of farm machineries, causing reduction in the size of bund in a very short period, unless some proper maintenance is adopted.

Graded bunds: If the bunds are constructed with some slope, they are known as graded bunds. The choice of the types of bund is dependent on land slope, rainfall, soil type and purpose of the bund in the area.

1) Graded bund system is designed to dispose of excess runoff safely from agricultural fields. 

2) A graded bund is laid out with a longitudinal slope gradient leading to outlet. 

3) Variations in the grade are provided at different sections of the bund to keep the runoff velocity within the desired limits so as not to cause any soil erosion. Graded bunds are laid out in areas where - The land is susceptible to water erosion - The area has water logging problems - High rainfall (>600 mm) and Relatively impervious soil.

Terracing 

1) Terrace is an earth-embankment, constructed across the slope, to control runoff and minimise soil erosion loss at highly slopping land (slope >10%).  

2) A terrace acts as an intercept to land slope, and divides the sloping land surface into strips. 

3) Terraces are classified into to two major types:

1. Broad-base terraces    2. Bench terraces

 Broad-base terraces are adapted where the main purpose is either to remove or retain water on sloping land suitable for cultivation. The purpose of bench terraces is mainly to reduce the land slope.

 Bench Terrace Components

The original bench terrace system consists of a series of flat shelf-like areas that convert a steep slope of 20 to 30% to a series of level, or nearly level benches. In other words, bench terracing consists of construction of series of platforms along contours cut into hill slope in a step like formation. These platforms are separated at regular intervals by vertical drop or by steep sided and protected by vegetation and sometimes packed by stone retaining walls. In hilly areas bench terraces is used for the purpose of converting hill slopes to suit agriculture.  In some areas where the climatic conditions favour the growing of certain cash crops like potato, coffee, the hill slopes are to be bench terraced before the area is put for cultivation of these crops. It also been adopted for converting sloping lands into irrigated fields or for orchard plantations.

Types of Bench

Terraces Depending on the purpose for which they are used, bench terraces are also classified as follows: 

1. Hill-type bench terraces: used for hilly areas with a grade reversely towards the hill. 

2. Irrigated bench terraces: level benches adopted under irrigated conditions. 

3. Orchard bench terraces: narrow width terraces for individual trees. 

Water Conservation

 Water conservation refers to the efficient use and management of water resources to reduce waste and ensure sustainability. This is particularly important in regions facing water scarcity or where demand exceeds the available supply. Water conservation practices include:

Efficient irrigation: Using drip irrigation systems or timed sprinklers to deliver water directly to plant roots, minimising evaporation and runoff.

Rainwater Harvesting: Collecting rainwater from rooftops or other surfaces for later use in irrigation or household activities.

Low Flow Fixtures: Installing low-flow toilets, shower heads, and faucets to reduce water usage in homes and buildings.

Xeriscaping: Landscaping with native plants that require minimal water, reducing the need for irrigation.

Water Recycling: Treating and reusing wastewater for non-potable purposes like irrigation or industrial processes.