Environment-friendly on-farm water-management technologies

The irrigated agriculture of Pakistan is faced with a number of problems, which include scarcity and quality of water, and traditional irrigation and agronomic practices. These practices are not only affecting the crop-yields but also creating Environmental problems, such as waterlogging, salinity and air pollution. In order to overcome these problems, resource-conservation technologies were introduced in Pakistan. These technologies are mainly concerned with the efficient use of water & fertilizer, and reduce CO2 emissions. Some of the technologies were tested and evaluated during 1999-2000 in rice-wheat system of the Punjab Province of Pakistan, by making comparisons with the traditional approach. These technologies included laser leveling, zero-tillage, and bed- and-furrow method of irrigation. Results showed that zero-tillage method for wheat cultivation in rice-harvested fields was most economical, followed by laser leveling and bed and furrow method. Time of sowing had significant impact on wheat yield By zero- tillage technology, the sowing of wheat was accomplished about two weeks earlier than with the conventional method of sowing. The water-use efficiency was 1.89 on bed and furrow, 1.67 on laser- leveled and 1.58 on zero-tillage farms. On zero-tillage, laser levelling, bed and furrow and conventional farms, fertilizer-use efficiency was 27.52, 26.91, 25.36 and 20.77 percent, respectively. Weed densities in bed-and- furrow, zero- tillage, laser levelled and conventional fields were 63, 67, 89 and 96 weeds/m2 respectively. A slight increase in soil salinity was observed on zero-tillage fields because of lower water-application. However, increase in salinity remained within safe limits. The wheat yield with laser levelled, zero-tillage, bed and furrow and conventional farms was 4764, 4623, 4312 and 4134 kg/ha, respectively. It was concluded that resource- conservation technologies, are environment-friendly and can be used to achieve self- sufficiency in agriculture on sustainable basis. The zero- tillage technology eliminates seedbed-preparation operations and hence emission of CO2 from tractors and dust pollution. The laser-levelled fields and bed and furrow methods of irrigation ensure high application-efficiency of irrigation. High-efficiency systems help to control deep- percolation of soil-nutrients, insecticides, pesticides and waterlogging and salinity.