| Temperature has a significant impact on the growth and development ofcrop, and the formation of soil texture, and it is a very important factor toagricultural production, irrigation and fertilization. Studies have shown that: in acertain range, with the increase of soil temperature, the growth of crop accelerate;when other condition is satisfied, low water temperature will have a inhibition inthe use of crop root system on soil moisture and nutrients.Water storage pit irrigation method is a new type of water-saving irrigationmethod. It can effectively solve the water deficit and play a role in soil andwater conservation. Temperature is a key factor of controlling soil microbialactivity. The temperature variation will affect the soil nutrient content, and thenitrogen plays an important role in plant growth. The accumulation of nitrogenin the soil will improve soil fertility and increase crop yields. The indoorexperiment was conducted with theoretical analysis. The goals of this study are:1) determining the nitrogen distribution in soil water at the different soiltemperature;2) determining the nitrogen distribution in soil water at different temperature of irrigation water3) designing a reasonable irrigation system basedon results of the first two points. Through the indoor soil box simulation test,studied at the single water storage pit irrigation, different soiltemperatures(20,25,30oC) and irrigation water temperature(15,20oC),corresponding to a single pit irrigation amount(7l) and different times(1,5,10，15d) after filling, effects on soil moisture and nitrogen migration rule.Main research results are:⑴Under the water single pit irrigation condition of different temperature,effects on soil moisture migration，included:①since the water bottom is madeof seal baffle, the simulated soil fertilizer solution poured into the tank, at thebeginning of fertilizer is mainly horizontal infiltration on liquid infiltration, soilwetting range increasing with time. With the increase of soil water storage of pitdepth and the radial distance, soil moisture showed a decreasing trend after thefirst increase; wetting front dynamic under the condition of differenttemperatures has little difference, moisture content of the spatial distribution ruleis almost the same.②Irrigation water temperature is constant, the higher thesoil temperature, the smaller the moisture migration area, the greater themoisture content.③Under the condition of a certain soil temperature，thehigher the irrigation water temperature, the greater the range of moisturemigration, the more hook the soil moisture distribution in the wet.⑵Under the water single pit irrigation condition of different soiltemperature, the law of nitrogen migration, mainly for:①On the vertical distribution of soil ammonium nitrogen content over time, showed a decreasingtrend after the first increase with the increase of soil temperature. The content ofammonium nitrogen reach maximum gradually shorten the time, thenammonium nitrogen content decreases gradually over time, nitrification is morenoticeable during20—30oC.②The content of nitrate nitrogen in different soiltemperature conditions increases over time，in the range of20—30oC, thenitrate content rise faster with the increase of soil temperature.⑶Under the water single pit irrigation condition of water temperature, thelaw of nitrogen migration, main show is:①On the vertical distribution of soilammonium nitrogen content show a trend of decrease after the first increase.Irrigation water temperature20oC when the corresponding ammonium nitrogenpeak is more than15oCunder ammonium nitrogen peak. Soil ammoniumnitrogen content decreases gradually with the increasing of radial distance.②The content of nitrate distribution has the characteristics of the high middlewhile the low around. The soil nitrate content gradually increased with the timecontinues. The content of nitrate decreases with the increasing of radial distance.In the soil wetting front edge, the content of nitrate reaches the maximum. In therange of15—20oC, with the increase of water temperature, the nitrateconcentration increases.⑷The main transport way of ammonium nitrogen is migration, most ofthe ammonium nitrogen concentrated in the inside of moist body. The migrationpatterns of nitrate nitrogen is mainly composed of convection, most of nitrate concentrated at the edges of the wet body. |
