Effects Of New Barrier Materials On Soil Nitrogen And Phosphorus Loss And Utilization Efficiency

In recent years,with the continuous development of agriculture in China,the input amount of nitrogen and phosphorus fertilizer increases year by year with the gradual decline of fertilizer utilization rate,which causes a series of environmental pollution problems.This research adopts the indoor soil column leaching experiment and pot experiment,set different type and rate of fertilizer,explored the way two kinds of different specifications of the new block materials and their application on soil nitrogen and phosphorus losses and the impact of Pakchoi nitrogen utilization,to reduce agricultural non-point source pollution,improve agricultural nitrogen and phosphorus use efficiency to provide the reference.The main findings are as follows.1.The water holding capacity of the soil was significantly improved after entering the soil with two specifications of round and small column barrier materials.In the process of constant temperature evaporation in 60° incubator for 8 hours continuously,the water loss rate of different barrier materials was 8%-15%,which was 2%-9% lower than that of the control treatment without barrier materials.Among them,the addition of columniform barrier layer at5 cm of columniform barrier material has the lowest water loss rate and the best effect of increasing soil water holding capacity.2.With the increase of nitrogen application rate,the total leaching loss of soil nitrogen increased significantly.The total amount of nitrogen leaching under 1.5 times of N application was 129.83% higher than that under the corresponding control treatment without resistance control material.The total amount of nitrogen leaching in the treatment with barrier material was reduced by 68.47% on average compared with that without barrier material.The two kinds of barrier materials,circular type and small column type,show good effect of controlling leaching of ammonium nitrogen,nitrate nitrogen and total nitrogen.In low N treatment,routine of N fertilizer treatment and 1.5 times the amount of N(urea)form processing,after 8 times in 48 days of leaching test,different block material were significantly reduced the soil total nitrogen,ammonium nitrogen,nitrate nitrogen leaching,than without blocking materials processing on the control of the lower 15.19% 、45.27%,the small pillar type block total nitrogen leaching resistance of the material handling control effect is best.3.After the conventional nitrogen application of urea and ammonium nitrate into the soil,the leaching of nitrate was the main form of soil nitrogen leaching,which accounted for83.68%-86.44% in the leaching solution.The tested barrier material significantly reduced the leaching effect of nitrate nitrogen and total nitrogen by 29.66% and 28.37%,respectively.The best leaching effect of nitrate nitrogen and total nitrogen was achieved when the columniform barrier material was applied to the barrier layer 5cm in the topsoil.4.The barrier material can significantly reduce the leaching loss of nitrogen and phosphorus in the soil of Pakchoi and improve the utilization efficiency of nitrogen and phosphorus fertilizer.The results showed that the leaching of nitrate nitrogen and total nitrogen was decreased by 56.19% and 69.25% compared with the control treatment,respectively.At the same time,the utilization rates of nitrogen and phosphorus fertilizers and the yield of pakchoi were significantly improved.The utilization rates of nitrogen and phosphorus were 51.32% and16.63%,respectively,which were increased by 20.42% and 5.74% compared with the treatment without barrier material,respectively,and the yield of pakchoi was increased by 23.36%.