Experimental Research On Soil Nitrogen Movement Rule Of Water Storage Pit Irrigation

Water shortage and poor fertility are two key factors of limiting the agricultural development in north of china. Water storage pit irrigation is a new orchard irrigation method that is suitable for northern hilly region. It can not only meet the need of water saving, water holding and drought resistance, but also make the best use of local rainfall runoff and efficiently reduce soil erosion. To better understand the movement of water and nutrients under this irrigation model will be helpful for reasonable management of water and fertilizer in order to save water and fertilizer. This will play an important role in properly using agricultural resources, avoiding destroy environment and ecosystem, improving the sustainable development of arid agriculture.In this paper, on the base of the theory of water storage pit irrigation, we do a research of indoor and field experiments on the problem of soil nitrogen movement rule set in water storage pit irrigation. Measuring the consistence of nitrate-n and NH4+-N in soil, the key research is soil nitrogen movement rule of water storage pit irrigation.The conclusions as follows:1.Under water storage pit irrigation, nitrate-n determined by the convection-dispersion mechanism shows the same rule to water, the major losses is nitrate-n denitrification together with nitrate-n leaching infiltration by excessively large irrigation guantity.The mainly principle is that soil colloid adsorption is weakly and nitrate-n is easily solubled in soil solution with the water movement. However, nitrate-n content of soil itself, there is room for variability, water transfer and nitrate migration may not be entirely synchronized to a certain extent, there is speed difference.2. Under water storage pit irrigation, ammonium-n drived by the diffusion mechanism moves slowly because of the ammonium-n sorption on the soil stuied. ammonium-n is fastly movement in the water.The majer losses is ammonium-n volatilization and nitrification.3. Under the different irrigation guantity (6,8,10L)condition, it proofs that soil moisture migration under water storage pit irrigation can hold water. Namely, deep soil with high moisture content, the corresponding increase in the regional irrigation water rate increases. Moist boundary relative concentration of ammonium nitrogen (c/c0) increased with irrigation water increased slightly, while easy to over water nitrate transport, irrigation increased the migration rate increased, but increased the amount of irrigation to the 10L, the Nitrate leaching has undergone an obvious trickle-down phenomenon.4. Under the conditions of different fertilizer concentration (800,1700,2600 mg / l) changes in soil moisture content was no significant difference, namely, fertilizer concentration on the distribution of soil moisture content had no significant effect. As the moisture migration is not affected, so that different fertilizer concentration of nitrate transport under the laws of little change, while the soil ammonium obvious adsorption, ammonium nitrogen with irrigation water to seep into the soil, the majority of is the soil fixed, not easy to downward and forward movement. Fertilizer concentration resulted in increased water potential measured in the vicinity of the relative concentration of ammonium nitrogen increased.5. A comparative analysis of field surface irrigation and water storage pit irrigation of soil moisture migration laws, highlights the water storage pit irrigation law as the benefits of irrigation in the deep three-dimensional, there is a strong water conservation drought resistance.6. A comparative analysis of field surface irrigation and water storage pit irrigation of soil nitrogen transport laws, ways of nitrogen loss from the start, water storage pit irrigation under the conditions of nitrogen dissolved in the full, nitrogen is more evenly distributed, while the more obvious the proliferation of surface irrigation nitrogen , particularly on nitrogen loss in the radial speed. Reflects the water storage pit irrigation is conducive to nitrogen dissolved, Paul fertilizer is good and so on.To sum up this experiment to understand and master the nitrogen in the soil of the migration laws, for the management of soil moisture and nutrients to provide a scientific basis for water storage pit irrigation laws lay the foundation for further research and extension, has an important scientific value.