Theory And Practice Of Micro-water Harvesting Technique On Potato Field In Semi-arid Area Agroecological System

Potato is one of the main dry land field crops of north China(especially in inner Mogolia,Shanxi Province, NingXia Hui Autonomous Region). The climate of these region is semi-arid, and is benefic it for potato to grow. The raining season coincides with growth stages for potato in these areas. However, water stress is a crucial factor limiting potato production, when the growing season's precipitation doesn't satisfy the requirement of potato in relative dry years, moreover it is very difficulty to fulfill limited supplement irritation in these regions because of the shortage of water. It may improve Micro-ecology environment of potato, and resolve the problem of moisture deficits at its critical growth stage, then increase the yield of potato and water use efficiency to use the planting technique of Micro-water harvesting (Plastic-covered ridges serve as rainfall harvesting zones and furrows serve as planting zones). These have many reports about the planting technique of Micro-water harvesting, but how the availability of nutrient varies, and how dry-matter and nutrient distribute in different stages on potatoes, and what the nutrient use efficiency is have no significant experimental evidences when using this planting method at present. In this research (Potato as an indicator crop), we carry out rigid field experiments to resolve these problem. The main result and new opinion are as follows:1. The influence of the technique of Micro-water harvesting to soil moisture relates to growing stages of potato, hi seedling it my increase soil moisture because the soil water through evaporating was little after the soil surface was covered with plastic film. In anthesis it has little effect on soil moisture because the precipitation was little and the severe drought lead to the different at different treatment vanish, hi mature the precipitation was profusion and the speed of potato reduce slowly .so the micro-water harvesting show Water-harvesting effect.2. The technique of Micro-water harvesting significantly influence the content of nitrate nitrogen. Plastic-covered ridges water harvesting treatment may improve soil moisture and soil temperature and therefore influence the content of nitrate nitrogen, but in mature the content of nitrate nitrogen of plastic-covered ridges water harvesting treatment was lower than other treatment because potato use a large amount of nitrate nitrogen.3.Plastic-covered ridges water harvesting treatment may significantly increase soil water supply and crop water use. Plastic-covered ridges may prevent water under ridges from evaporating and force it diffuse from furrow and on the other hand it has the role of water harvesting. In mature, potato water use is large, but the effect of Plastic-covered ridges water harvesting treatment makes potato grow rapidly.4. Plastic-covered ridge water harvesting treatment may increase potato leaf areas .Crop water use is the main factor that influence its leaf area index.5. Plastic-covered ridge water harvesting may increase potato dry-matter accumulating, yield and water use efficiency. The 45:60cm ridge and furrow ratio had significant effect on potato yield and potato water use efficiency.