Experiment and Extension of Water-Saving Irrigation and Techniques in Paddy Field in the Wind-Sand Areas Around the Great Wall of Loess Plateau

The potential to develop agricultural production is very large in the wind sand areas around the Great Wall of Loess Plateau. Because of the limitations such as drought and barren land, etc., the sustainable development of agriculture in these regions is restricted and the ecological environment is failed. In order to further develop agricultural production in this area, a set of practical water saving systems should be established and gradually improved in practice to meet the development of intensive and modern agriculture. From 1983, the experiments of water saving irrigation and associated techniques in paddy field have been carried out in this area. The results were obtained. Deep water irrigation method during the whole growth stage of paddy was reformed by the improved method, it could save water of 10440～14745 m³/hm², and increase output by 11.1 %～24.2 %. The maintained proper water levels in the panicle differentiation stage, heading and flowering stage, earlier filling stage were considered and the replacable way of the shallow water, slight water and no water alternately was taken in the other stage. 3 improved japonica varieties including Tiegeng 4 and Qidao 1 and Liaoyou 73 were introduced. The sowing date was in the former of middle ten days of April and the sowing amount was kept within 150～200g/m², the basic seeding was about 1500～2250 thousand per hectare and the efficient panicle maintained 5250～6750 thousand per hectare. Application amounts of pure N and P per hectare were 264 kg respectively. The mass ratio of N to P was 1∶(0.4～0.5), meanwhile some special Zn fertilizer was utilized as supplement. This project was extended 5.8×10³hm² in 1996 and the average yield reached 8356.5 kg/hm², the total yield increased 11.1 %.