Effect Of Fertigation Time On Distribution And Distribution Of Available Nitrogen In Soil Of Maize

The drip irrigation and fertilization technology can directly supply water and fertilizer to the soil near the root of the crop in a timely and appropriate manner,and can simultaneously achieve water and fertilizer manure,high-efficiency and high-yield,and reduce environmental pollution.In order to further explore the influence of fertilization period on fertilizer use efficiency in the process of water and fertilizer integration;this experiment explored the spatial and temporal distribution and distribution of available nutrients in soil wetted bodies by setting potted plant simulation tests and field application validation tests to control the test boundary conditions.In this study,the spring maize and Yangling early sowing summer corn in Ningxia Yanghuang Irrigation District were studied.In Yangling,fertilize potted plants with simulated point source(equivalent to “one pipe,one line” drip irrigation).In the Yellow River Irrigation District,“one tube,two rows” drip irrigation method was adopted to conduct field corn verification test.Each of the four fertilization stages was set to process(fat first,then first,then first,then first,later,and then)to observe the available nutrients temporal and spatial distribution changes(nitrate nitrogen and ammonium nitrogen)in the wetted soil profiles before and after irrigation and fertilization.Through the experiment,the following conclusions were obtained:(1)The distribution of nutrient content in the soil moisture body after irrigation is similar to the distribution of soil moisture content,and the two adapt to each other.After the irrigation of the soil wetted body is stable(about 48 hours after the irrigation),the high value area of ammonium nitrate in the humid area is close to the center of the wettest body with the highest moisture content,and the available nitrogen gradually decreases as the distance from the drip point increases.Because ammonium nitrogen is easily absorbed by soil colloids,it is basically distributed in the upper part of the wet area.(2)After irrigation and fertilization,the contents of nitrate nitrogen and ammonium nitrogen in the soil were significantly increased,and then the trend was to increase first and then decrease due to the effect of root absorption and volatilization.There is a tradeoff between nitrate nitrogen and ammonium nitrogen content.Nitrate nitrogen was affected by the root absorption and nutrient gradient of maize,and the redistribution of migration was more intense in the wet body,while the transfer and redistribution of ammonium nitrogen was limited under the adsorption of soil colloids.(3)The application of nitrogen fertilizer in different stages of drip irrigation of maize water and fertilizer,the distribution of nutrients in soil moisture body is different,and the high-efficient nitrogen high value area is different from the corn root zone,which will ultimately affect the absorption and utilization of nutrients and yield of maize root system.(4)Under a drip irrigation system with one pipe and one pipe,two lines of drip irrigation,a certain degree of first fertilization will make the fertilizer move outward with the water away from the center of the wet body,and further increase the high value area of fast-acting nitrogen and corn.Root zone overlap,promote root absorption,increase fertilizer use efficiency and corn yield.When the roots of crops are shallow,the layout of drip irrigation in one pipe and two lines is more practical and economic.Different fertility stages can reasonably formulate the order of irrigation and fertilization according to the root system distribution,which can not only ensure that the fertilizers are wrapped in the root zone with irrigation,but also promote absorption and utilization,and can also save Drip irrigation costs.(5)To determine a reasonable order of irrigation and fertilization,comprehensive consideration should be given to various factors,including the layout of drip irrigation,the distribution of crop roots,irrigation duration,and so on.When the drip point is farther away from the root zone,the fertilization time should be appropriately advanced,but at the same time,the time and irrigation amount of subsequent irrigation should also be controlled;otherwise,the irrigation time should be postponed.When the deeper range of crop roots is larger,the water requirement is larger and fertilization time should be appropriately advanced,but at the same time,the amount of irrigation and irrigation time should be controlled to avoid deep leaching of nutrients;when the crop root system is shallow(small),When the amount of water is small and the amount of water required for irrigation is small,the fertilization period should be appropriately delayed so that the nutrients can be concentrated in the root zone.