Effect Of Water And Nitrogen Coupling On Physiological Regulation Of Drip Irrigation In Wheat

The experiment was conducted in the net room of Agricultural Experiment Station of Tarim University in2014~2015. Statistically Split-plot design was used in the experiment which had two factors: water and nitrogen. The main treatments were nitrogen treatment and the irrigation treatment. There were three levels of drip irrigation amounts: 2700 m3/hm2,4050 m3/hm2 and 5400m3/hm2(respectively, W1, W2, W3).Nitrogen treatment was set four kinds drip fertilization amounts: 0 kg/hm2,138kg/hm2,207 kg/hm2and276kg/hm2(respectively, N0, N1, N2,N3). This experiment observed and analyzed the agronomic traits,physiological indexes, leaf adversity enzymes and related compounds under different water and nitrogen treatments. And the experiment put forward the wheat drip irrigation system and the related indexes of integrated fertilization. It provided a theoretical basis for the implementation of water and fertilizer synchronization technology of southern Xinjing drip-irrigated wheat. This study shows that:(1)Under the different condition of water treatment,The increasing amount of fertilizer could improve leaf protective enzymatic activities of POD,SOD,CAT. While, the activity of MDA was decreased. Under the same condition of moderate moisture, too much or too small irrigation amount both could lead to increased the activity of MDA, thereby inhibit the activity and content of the other three kinds of enzymes.(2) Under different water content conditions, the proper increase of fertilizer nitrogen rate could improve the growth rate remarkably. Under the condition of moderate moisture applying nitrogen fertilizer can effectively increase the wheat plant height, stem diameter and dry matter weight. But when the nitrogen amount exceeded a certain threshold, the growth rate of wheat has slowed down,In the experiment nitrogen threshold of 207kg/hm2.With the three kinds of nitrogen fertilizer, the amount of water applied in prophase of wheat to plant height and stem diameter showed rapid growth,While in high nitrogen(N3), water(W2)under the treatment of wheat development optimization. In the existing conclusion, we found that applying nitrogen could regulate the action of water, irrigation also has regulating effect on nitrogen fertilizer.(3)It is considered that applying proper nitrogen fertilizer could improve the nitrogen accumulation of wheat stem and kernel effectively. At different growth stages, nitrogen fertilizer had different effects on the nitrogen accumulation.The nitrogen content of wheat stem reached their highest in the flowering period,and then dropped, in the mature period the nitrogen content of wheat kernel reached the highest. Under different water conditions, nitrogen application was proportional to the nitrogen content.It is showed that nitrogen application promoted the development of wheat kernel.While with the increasing of nitrogen fertilizer,t he nitrogen content of W1,W3 was significantly less than W2.Based on test observation.We know that too much or too little water prevented the wheat absorption of nitrogen.Under the same irrigated conditions, phosphorus content of plant decreased firstly and then increased as the increase of the nitrogen content. The phosphorus content of low water-low nitrogen treatment was significantly higher than the high water-high nitrogen. Results of the trial indicated that nitrogen application and irrigation both had effect on the phosphorus content of wheat stem and kernel.(4) Under the same condition of nitrogen application, with the irrigation amount increased as N0, N1,N2,spike-let number, grain number per spike and 1000 grain weight all increased. That all were first increased and then decreased in N3. In W2N3, it could maintain a higher yield. Under the condition of the same irrigation quantity, the spike-let number and grain number per spike increased as nitrogen application amount, 1000 grain weight was N2>N1>N0>N3.The results showed that nitrogen was too low or too high were not conducive to grain filling and effect on grain weight. On the basis of ensuring suitable irrigationlevel, proper application of nitrogen fertilizer could promote the formation of yield components and obtain higher yield. Too much water or too much fertilizer, which is not conducive to yield increase. From the interaction nitrogen and water on yield and its component factors, the results showed that it is N3>N1>N2. It was indicated that controlling water was more conducive to water and nitrogen efficient utilization under the condition of high nitrogen(N3).It also could promote the formation of yield organs.Under the low nitrogen(N1), the impact decreased by the water and nitrogen coupling.In N2, water control was seriously affect the production.In conclusion, the wheat yield and yield components were reduced after the first increase trend. In N3W2(the nitrogen application level as 276kg/hm2, the total irrigation as 4050 m3/hm2),the highest yield was 644.473kg/hm2, relatively N3W1, N3W3 treatment decreased by 26% and 23% respectively. With the content of nitrogen increasing, it could improve the wheat yield and other factors at the same irrigation conditions. The interaction between water and nitrogen yield could significantly increase the yield, and the effect of nitrogen fertilizer on yield bigger than water.