Dry land farming pertains to high-yield and high-efficient agricultural production on areas without irrigation and largely depending upon natural rainfall through the adoption of different dry land farming technologies. Given the severe shortage of water resources, irrigation alone cannot satisfy the water demand in agricultural production and it is necessary to make efforts to promote dry land farming development. Of the total cultivated area of 22.91 million hectares, about 18 million hectares are irrigated. Thus dry land farming is spread over an area of around 4.91 million hectares in different agro-ecological zones of the four provinces.Dry land farming faces problems including shortage of precipitation, surface water, ground water and soil erosion. Precipitation is distributed unevenly in time and space. Usually, rainfall occurs during spring and early summer. At the same time, water losses and waste in farm land irrigation are serious.
About 25 per cent water is lost from canals in the form of seepage, percolation and evaporation during conveyance and distribution. Similarly, about 24 per cent water losses occur from major and minor water courses. Moreover, 25 per cent water is lost during field application owing to defective irrigation methods. Resultantly, irrigation efficiency of our canal system dubbed as one of the largest canal networks in the world remains very poor.Soil infertility in dry land farming due to monotonous crop structure that includes mainly cereals and less legume crops also affects crop production adversely. Moreover, desertification and erosion are other problems in dry land farming area. All these factors contribute to low and unstable agricultural yield. Yield of crops in dry land farming is considerably low compared to that of irrigated farming. Poor level of skills, lack of education and poor socio-economic conditions are also the reasons of low agricultural yields in dry land farming. Farmers largely practice extensive farming with poor harvest. In most of the places, farmers still solely depend on climatic conditions in their farming activities.
Keeping in view the importance of dry land farming in sustainable agricultural growth, it is essential to develop dry land farming on modern lines. Enhancing moisture retention capacity of the soils, retaining rainfall by using agronomic, biological and engineering measures in an integrated way to improve soil fertility, changing farming practices and making full use of resources like light, heat, soil, fertiliser, water and improved seeds to increase agricultural productivity in dry land should be the objectives for the development of dry land agriculture.Terracing is an important practice to be adopted in dry land area. It aims at building slope land with an angle less than 25 degrees into contour terrace. It is because slope land with an angle of 10-25 degrees is susceptible to soil erosion due to large angle, steep slope, frequent farming activities and high cultivation coefficient, particularly improper farming practices. It has been found that farming activities on such slopes land have led to soil erosion of 0.43 cm of soil layer and loss of 48 tons of surface soil per hectare per annum. Changing such slope land into contour terrace plus other measures like small catchments improvement and biological and agronomic practices would help improve production conditions, prevent water and soil erosion and raises soil fertility, grain yield and sustainable development.
Using farming practices like moisture retention mulched furrow, machine furrow drilling and large furrow help to increase active soil layer, improve moisture retention capacity and soil fertility, reduce soil evaporation and improve eco-system. Furrow drilling is suitable for any slope land with annual rainfall over 400 mm or for terrace land. When it is used for small-angle slope land and terrace land, machines or animals can be employed to reduce labour intensity and speed up engineering progress.Building water cisterns to collect rainfall as supplementary irrigation water for agriculture is practicable in slope land and terrace land. In case of serious drought, such water could be used for drip irrigation to increase soil moisture. Due to limited volume of water, such technology is usually used together with other water-saving measures such as wet sowing, plastic mulching, root-zone drip irrigation, hole irrigation with mulching so as to enhance crop resistance to drought and enhance stable high yield. It is applicable to places with annual rainfall less than 350 mm.
Mulching with plastic film and crop residue could reduce moisture evaporation, increase moisture retention capacity of soil, alleviate the threat of drought and improve water use efficiency. Plastic film could be used for hole-sown wheat, rice, film-side sowing, multiple crops using the same mulching. Wheat farming with plastic film could bring major breakthrough in increasing wheat yield in these areas. Mulching with crop residues features easily accessible material, low cost, high efficiency, water saving, moisture retention, fertility enhancement, yield increase and no contamination to soil. Seed coating with drought-resistant chemical agents developed in recent years like water-retention agent, evaporation suppressant and soil regulator could bring very good results at low cost when used at a time of drought. For instance, seed coated with water retention agent could improve moisture use efficiency by 0.05-0.17 kg/mm compared with the control group and wheat seed coated with drought-resistant agent could increase yield by 20 per cent.Fertilisation aims at application of chemical fertiliser, organic fertilizer and green fertilizer to improve soil fertility and yield to improve soil resistance to drought through the improvement of soil fertility. To establish rational and effective dry land farming, it is essential to increase percentage of legume and green fertiliser crops, increase fertiliser input by combining organic fertiliser with chemical fertiliser and improve scientific fertilisation level and combine farming with fertility improvement. Increased use of chemical fertiliser on dry land farming could bring about twice as much yield as on irrigated land.Mechanised deep ploughing technology could break the sub-arable layer without disturbing surface soil layer so as to improve soil ventilation and rainfall retention capacity. This technology could be equally effective both for dry land as well as irrigated farming.Using drought-enduring varieties is the most cost-effective yield increasing technology. At present, most dry areas have their own varieties with good drought resistance. However after a long time, most varieties have experienced degradation in their performance. And the breeding of new varieties is still lagging behind. It is an urgent need to develop drought ?resistant varieties and accelerate the purification and rejuvenation process in order to improve yield.Last but not the least, reforming the farming system in accordance with prevailing local conditions in a bid to readjust crop structure, avoid flooding and drought and improve income is imperative. Suitable cost-effective farming systems recommended in dry land farming include grain-gram, grain-cotton, grain-oilseed, grain-vegetable, grain-herb intercropping and rotation of multiple crops.
Moreover, research on and improvement of drought-enduring and drought-resistant varieties and matching technology, setting up demonstration bases for protective farming technology to develop technical capacity in this field, conducing technical exchange in order to train a backbone team of professional equipped with advanced dry land farming technology, developing a group of farm tools and machines suited for dry land farming and promoting financial resources to support the extension of advanced dry land farming technology in the poor areas would help to achieve sustainable agricultural production on dry land farms.