Here is an essay on ‘Dry Farming’ for class 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Dry Farming’ especially written for school and college students.
Essay on Dry Farming
Essay # Introduction to Dry Farming:
Dry farming is a system of soil and crop management in regions of low and uncertain rainfall. Such regions are widely distributed all over the world. The term ‘rainfed farming’ is being increasingly used instead of ‘dry farming’ in order to include areas of high rainfall but with no assured irrigation facilities. The emphasis in rainfed agriculture is often on disposal of excess water, high levels of fertilizer inputs and water erosion constraints.
In dryland agriculture, emphasis is on water conservation, limited inputs of fertilizer, and both water and wind erosion constraints. Drylands generally receive less than 750 mm of annual rainfall, even though an absolute value cannot be stated for the reason that seasonal distribution of rainfall and temperature affect crop water requirements and thus the type of soil and water management practices.
For example – with an annual rainfall of 750 mm, a region in cool climate and rainfall well distributed will be requiring rainfed agriculture type management systems whereas in hot climate with not well distributed rainfall it may require dryland farming methods.
In general, each of the regions under dryland agriculture, have its own rainfall, soil conditions and cropping practices. Because of this reason the technology for crop production in these areas is location specific and its application is regional in nature. Venkateswarlu (1987) presented a detailed review of dryland agriculture in India.
Essay # Climatic Classification for Dry Farming:
Based on total annual precipitation, the world is divided into three major regions viz.:
(1) Humid region,
(2) Sub-humid region, and
(3) Arid region.
The limits of these regions are defined in terms of the relation between evaporation and precipitation in the regions. In the humid regions precipitation is in excess of evaporation.
In the sub-humid region, the precipitation is in excess of evaporation during the rainy season while evaporation is in excess of precipitation during the rest of the year. In the arid region evaporation is in excess of precipitation. Arid regions are further grouped as arid and semi-arid areas. In defining the arid and semi-arid areas where dry farming is important, Troll’s classification is widely accepted.
The emphasis in this classification is on the duration’ of dry and humid months rather than on an assignment of climatic boundaries based on annual values of precipitation, temperature and humidity. A humid month is defined as a month in which the mean rainfall exceeds the mean potential evaporation. Based on this definition, the classification as in Table 23.1 is suggested.
Essay # Components of Dry Farming Technology:
All the soil and water conservation measures outlined earlier can be considered as part of the dry farming technology. The most important factors in dry farming is the conservation of moisture for proper and timely utilization by the crops. In order to suggest suitable dry farming methods and practices for an area, a thorough study of the climatic conditions, adaptable crops, nature of the soil and topography of the area is essential.
The recommended practices may be broadly grouped as:
(1) Crop management practices, and
(2) Land management practices.
(1) Crop Management Practices:
Selection of crops, tillage practices, proper sowing method, control of plant population, weed control and application of the appropriate quantity of manures and fertilizers are the practices that are to be considered.
Selection of crops will involve not only the crop itself but also the particular strain of the crop suitable for dry farming conditions. Plant breeding has taken great strides and varieties of several crops have now been evolved that are drought resistant. The duration of the crop is another aspect and relatively short duration crops are more suited under dry farming conditions.
(2) Land Management Practices:
These include all the soil erosion control and water conservation practices. In addition, land management practices that are of significance in dryland agriculture are water harvesting and runoff recycling, tied ridging and sub-soiling.
Essay # Water Harvesting:
Water harvesting is the process of collecting and storing water from an area that has been modified or treated to increase runoff from precipitation. A water harvesting system usually consist of a catchment or water-collecting area, a water storage facility and auxiliary components like conveyance and sediment control structures.
Water harvesting systems are used not only for collecting water for plant growth but also for collecting water for domestic consumption. In some parts of the world, rain water from roof tops is collected in containers and later used for domestic purposes.
Essay # Catchment Area Treatments:
The catchment area treatments designed to increase runoff from rainfall can be grouped into three general categories –
(1) Topography modifications,
(2) Soil modifications, and
(3) Impermeable coverings or membranes.
Topographic modifications consists of practices like brush clearance, land grading, construction of diversion channels etc., which help in increasing the runoff from land areas. Soil modification treatments consist of chemicals applied to the soil surface by spraying or mixing to reduce infiltration.
One such chemical used is a sodium based salt (NaCl) which is mixed in the top 2 cm of soil and the area is wetted and compacted to a firm smooth surface. The sodium salt disperses the clay, plugs the soil pores and reduces the hydraulic conductivity. Bitumen or asphalt has also been tested as soil modification treatments. These are generally suited for use on fine sandy soils and have a projected effective life of 2 to 5 years.
Impermeable or waterproof sheeting or membranes are used when the areas to be covered are relatively small. These materials consist of concrete, sheet metal and rubber sheetings. Several types of plastic and other thin sheetings have been tried as soil coverings. Most of these thin film coverings were found to be susceptible to mechanical damage and deterioration due to sunlight. Their use therefore is limited to small areas as well as for relatively shorter durations.
Essay # Runoff-Farming Systems:
Runoff farming is a water harvesting system specifically designed to provide water for growing plants.
These could be broadly be grouped in two types. One is the direct water application system by which the runoff is stored in the soil profile of the crop growing area. The other is the supplemental water system by which runoff water is stored off-site and applied to the crop as needed.
Interplot water harvesting is used under very low rainfall conditions. The surface runoff from the upper area gets collected in the lower part and thus more water is available in the lower part.
In case enough rainfall is expected in the area, a crop like maize requiring good drainage may be grown in the contributing area and crops requiring more water can be put in the receiving area. Chemical sprays, compaction etc., are sometime used in the contributing area to increase runoff.
Microcatchments are land areas surrounded by small earth bunds with infiltration pit in the lowest corner. The diamond shaped basins are known as Negarim microcatchments and widely used in Israel.
Runoff is collected from within the basin and stored in the infiltration pit wherein suitable species of trees or bushes are planted. The layout and design depends on the local conditions.
Essay # Runoff Collection and Recycling:
Even in semi-arid regions, some runoff occurs from the agricultural lands, particularly during the rainy season. In the supplemental water system, the runoff is collected and stored in a pond at a convenient location. The stored water can be used for providing supplemental irrigation to crops located near the pond.
If the areas to be irrigated are upstream to the pond (in the donor catchment) water lifting devices are to be used to lift the water. In case of downstream areas, gravity flows from the pond are possible.
The stored water in the pond is usually limited and may not be enough to give full irrigation to the crops.
The following issues need to be considered:
1. Identification of critical periods of crops when the effects of moisture stress would be maximum.
2. Reducing percolation losses from the ponds through sealing or lining procedures.
3. Efficient use of the harvested runoff water.
The stored water may be used to give one or two irrigations to the crops at the critical periods so that the crop survives and produces maximum possible yield. Optimization procedures like linear programming and dynamic programming together with crop water production functions can be used for optimal irrigation schedules.
Efficient water application methods are also desirable. Instead of flooding, furrow irrigation and alternate furrows could help in better use of the water.
Essay # Tied Ridging:
Tied ridging consists of covering the land surface with closely spaced ridges in two directions at right angles so that a series of rectangular basins are formed. The purpose of such basins is to retain the rain water till it infiltrates into the soil.
Tied ridging can be successful when carefully designed and constructed. The system can be successful on level ground or when the amount of water which can be stored in the basins, plus the amount infiltrating during the storm, is more than the worst storm likely to occur. Failure of a ridge, particularly on sloping land, can cause a series of failures of other ridges.
In general tied ridging has been found to be successful on permeable soils rather than on shallow soils. To prevent failure of the ridges, they are constructed on grade with ties lower than the ridges so that the failure and runoff will be along each ridge and not down the slope. It is also advisable to back up the system with other measures like terraces or bunds.
Tied ridging is also referred to as basin listing. Special implements are used capable of forming the basins i.e., the ridges as well as the ties in one operation. Basin lister is such an implement.
A basin lister consists of one or two shovel like bodies mounted on a shaft and wheels. When the implement is drawn these shovels make interrupted basins on the land surface. Rain water gets collected in these basins and is slowly absorbed by the soil.
Essay # Subsoiling:
This practice consists of deep ploughing or chiselling using special equipment known as chisel plough or subsoiler.
The objectives in subsoiling are –
(1) Break and shatter plough soles or other impermeable layers in the soil profile,
(2) Loosen soil profile to considerable depths to permit deep leaching of accumulated salts in the upper layers,
(3) In some cases bring the clod-forming subsoil to the surface for wind erosion control, and
(4) To deepen the effective plough zone depth for crop growth.
The effectiveness of the subsoiling practice for achieving any of the objectives and ultimately helping crop production is dependent upon the particular site conditions. The effect of sub soiling does not last long and the operation has to be repeated after some years. To adopt this practice a study of the local condition and the results obtained under those conditions should be known.
Essay # Watershed-Based Soil and Water Conservation:
Water is the limiting natural factor in crop production in the arid and semi-arid areas. In most of these areas, the only water available is the ram that falls on a given area. The watershed (or catchment) being an independent hydrological unit, the rainwater management in relation to conservation and utilization should be planned on a watershed basis.
All the land treatment measures like contour cultivation, bunding, bed and furrow system are executed on an individual plot basis. The runoff from these areas is conveyed through grassed waterways to prevent erosion. The water at a convenient place is collected in farm ponds to be subsequently used for irrigation.
All the above outlined practices are location specific and the package of practices to suit the particular area taking into consideration the climate, soil and crops need to be developed.