Areas with 500-750 mm of rainfall, which account for 10 percent of the total land area, also require dry farming measures for successful crop production (Figure 1). Rainwater and soil losses in arid areas are also more due to runoff and erosion respectively due to the favorable physical and chemical properties of the soil. The basic operation of dry farming involves soil treatment that allows the maximum possible annual precipitation to be stored in the soil.
Mechanical measures of soil and water conservation
The watersheds were compacted and designed to create a slope to increase drainage to the built-up areas. In this method, holes of different sizes are dug at many places in the fields to collect the run-off water along with the silt. Damming is the most effective and widely practiced field measure for controlling runoff and reducing soil erosion.
The purpose of graded bonding is to allow runoff to flow rather than rushing out. A terrace is a ridge or bank of soil built across the slope to control runoff and minimize soil erosion. It is suitable for low rainfall conditions, for taking assured harvest on runoff receiver area.
The ratio of flow donor to flow receiving area can vary from 1 : 1 to 3 : 1. vi) Compartment separation:. Dead furrow: Instead of furrows, furrows are made across the slope to trap runoff and eroded soil.
Moisture conservation
Moisture conservation practices i) Mulches
The conservation bench terraces have been successfully applied to gently sloping lands in arid, semi-arid and sub-humid regions for erosion control, water conservation and improvement of crop productivity. The CBT system consists of a terrace ridge to store runoff on a level bank and a donor watershed, which is left in its natural slope and produces runoff that spreads on the level bank. This method is one of the cheapest rainwater conservation techniques, suitable for rainfed vertisols with a slope of less than 1%.
Through this method, the entire field is divided into small sections, which helps to store the initial rainfall and allows for increased infiltration rates. This method ensures rational moisture distribution as well as optimal moisture for better germination of seeds. vii).
Water harvesting and recycling
Monsoon runoff that causes soil erosion unchecked but can be useful for improving crop production in a rainwater agroecosystem. Rainwater harvesting is the collection, storage and recycling of runoff water for irrigation and other purposes. Harvesting of surface runoff water can be achieved with the help of earthen ponds, tanks, khadins, havelis, bypass embankments and roof-top rainwater tanks.
Harvesting of flow runoff is practiced through nala embankment, check dams, check dams, percolation tanks/ponds and nadi. In dryland agriculture, water harvesting usually refers to collecting excess runoff in farm ponds and using it to provide protective irrigation (pre-sowing irrigation or life-saving irrigation or irrigation at the most critical stage of the crop) and seepage ponds and silt-detention tanks for to recharge the groundwater. Haveli farming system is a traditional water harvesting practice in the black soil of Bundelkhand region, where rainwater is collected in bunded fields during the monsoon and the crop is absorbed on residual moisture during the rabi season.
The most common water retention structures are dike ponds for hilly and rugged terrains and excavated farm ponds for flat topography. To capture a larger amount of precipitation, in arid areas, runoff is induced by compacting the soil surface or using ground cover made of plastic films, rubber and metal sheets.
Factors influencing choice of soil moisture conservation practices i) Topography and slope of the land;
Mulches
- Types of mulches:-Based on the material used for mulching, mulches can be classified into following categories
- Mode of action of mulches
- Effects of mulches
- Limitations of mulches
After preliminary moisture loss, the soil cover effectively controls further evaporation from the subsoil by breaking capillary continuity. The amount of rainwater taken up by the soil depends on runoff and infiltration. Organic mulches also reduce the rate of evaporation by reducing the amount of energy absorbed by the soil and the movement of air immediately above the soil surface.
The effect of mulches on soil temperature depends on the albedo effect of the mulch material, its control of sky radiation, soil moisture content, evaporative cooling, and thermal conductivity. In general, the soil temperature is lower in summer and higher in winter due to mulch compared to the bare soil surface. i) Mulches improve soil water availability to plants by reducing evaporation and runoff, maintaining infiltration rates and controlling weeds. ii) Mulches reduce soil erosion by reducing runoff rates and increasing infiltration rates. iii). The change in soil temperature due to the use of mulches depends on the type of mulch material.
These temperature changes are used for early sowing of crops, to protect seedlings from extremely low and high temperatures and to control weeds during the summer. iv) Mulches reduce accumulation of salts on the soil surface by increasing infiltration and reducing evaporation. v) Organics contribute to the improvement of soil's organic carbon content and physical, chemical and biological properties of the soil. vi). Plastic mulch during the summer affects the viability of weed seeds by raising the soil temperature to lethal levels. i) Less availability of material (crop residues, straw and stover) for mulch processing especially under dry land conditions. ii) Inorganic mulch is very expensive and poor farmers from dry land areas cannot afford the purchase of synthetic mulch. iii) Organic mulches increase the incidence of insect pests and diseases. iv) Scarcity of crop residues due to their alternative uses.
Anti-transpirants
Scope of using anti-transpirants
Plastic mulch during the summer affects the viability of weed seeds by raising the soil temperature to lethal levels. i) Less availability of material (crop residues, straw and stover) for mulch processing especially under dry land conditions. ii) Inorganic mulch is very expensive and poor farmers from dry land areas cannot afford the purchase of synthetic mulch. iii) Organic mulches increase the incidence of insect pests and diseases. iv) Scarcity of crop residues due to their alternative uses. formed must have more resistance to the passage of water than to that of carbon dioxide. Film-type antiperspirants, which provide selective type permeability barriers for water vapor and carbon dioxide diffusion in the required directions, have not yet been found. iii). Increasing leaf reflectance type: White reflective materials such as whitewash or kaolinite spray form a coating on the leaves and increase the leaf reflectance (albedo).
By reflecting the large amount of radiation, they reduce leaf temperature and the vapor pressure gradient from leaf to atmosphere and thus reduce transpiration. Growth retardants: Foliar application of chemicals such as cycocel reduces shoot growth, increases root growth and causes the stomata to come closer together. Thus, the application of such a chemical helps in improving the water status in the plants and soil.
Effect of anti-transpirants on crop production
Limitations of anti-transpirants
Efficient Management of Rainfed Crops 1 Land preparation
- Seeding
- Plant population
- Choice of crops, varieties and cropping systems
- Alternate cropping and land use strategy
- Soil fertility management and fertilizers use
- Weed control
- Weed control measures
- Contingency crop planning for aberrant weather
In the post-rainy season, sowing should be done taking into account the moisture retention of the soil and the prevailing temperature. The ridge seeder can also be used to place fertilizer in the moist zone under seed and sowing of dry land crops along with making ridges and furrows. Under dry soil conditions, evaporation is affected more by the moisture supply at the soil surface than by radiation.
In the kharif grains, coarse grains (millet and sorghum) are a better choice than maize and rice. Some important crops and their varieties recommended for dry soil conditions are listed in Table 5. There is great potential to increase productivity under dry soil conditions through effective nutrient management practices.
By including legumes in the cultivation systems, the N fertilizer can be supplemented with an amount of 20 to 40 kg N/ha. The critical period for weed competition is the period from the time of sowing to the time when the crop must be kept in a weed-free environment to obtain the highest yield. Crop production in the rain-fed region is affected by the abnormal weather in the following ways.
Removing the basal three to four leaves of the crop in the later stages, in case of premature cessation of rain or terminal drought. iv) Mulching of the soil surface with agricultural waste and/or weeding in case of short break in monsoon. v).
Rainfed Hill Agriculture
Watershed Management
- Principles of watershed management:-The main principles of watershed management based on resource conservation, resource generation and resource utilization, are
- Components of watershed treatment plan
- Benefits of watershed management
- Watershed development experiences
It covers soil and water conservation measures in river basins, including appropriate land use, land protection against degradation, surface and groundwater management, flood protection and increasing land productivity. Ensuring the sustainability of the ecosystem, in line with the human-animal-plant-water complex; .. xiii) Maximizing the combined incomes from interconnected and dynamic complexes of crops, livestock, trees and labor over the years; Agronomic measures on agricultural lands (mixed farming, strip cropping, mixed cropping, run-off farming, contour farming, residue management, land management practices, etc.) . i) Mechanical measures on agricultural land (contour and sloping bunds, terraces, contour cultivation, etc.) . ii) Erosion control measures on non-agricultural lands (contour trenches, gully control measures, nalla dams etc.). iii) Water conservation and harvesting structures (farm ponds, earth embankments, etc.). iv) Groundwater recharge and management (percolation tanks, embankments etc.) v) Nursery and community planting of fuel, fodder, fruits and small timber species. vi) Grassland development. vii) Horticultural development. viii) Agro-forestry. ix) Protection, conservation and enrichment of degraded forests in watersheds through joint forest management.
Society benefits from flooding of downstream farmland and human settlement, reduced siltation of expensive irrigation structures, and protection of natural resources. In Indian conditions, several watershed development programs have been implemented or are being implemented in different parts of the country. As a result of the development activities undertaken in various watershed projects based on the principles and practices of watershed management, an average cultivated area increased from 12 to 53%, the water level in open wells increased from 1.0 to 7.0 meters and planting intensity increased from 115 to 157.
Increases in crop yield in watersheds range from 51% for mustard to 91% in pearl millet and to a maximum of 206% in sorghum. In the watershed areas, the percentage of irrigated area increased from 38.2 in non-watershed areas to 52.4 in watershed areas.
