Research On Effect Of Water And Fertilizer For Summer Corn And Control Of Preferential Flow

The main grain-producing areas in China are generally faced with the predicament of high output and corresponding high input.Fully utilization of water and fertilizer,and significantly increase crop yield,are a long-term pursuit of farmland managers.Excessive application of water or fertilizers and preferential flow can increase the leaching potential of soil.There is valuable on how to achieve higher yield and utilization efficiency of water and fertilizer in grain production.Plot experiments of summer corn were conducted at Shandong Irrigation Experiment Center Station in Jinan to investigate the coupling effects of two irrigation?I1,I2?and five N-P2O5-K2O fertilization levels?N1P2,N2P2,N3P2,N2P1,N2P3?on the distribution characteristics of soil moisture content,nitrogen?N?and phosphorus?P?content,crop growth indexes and yield.Preferential flow dyeing experiments were conducted at bare field near the Station to explore a scheme that can prevent the development of preferential flow.Combining the above two experimental results,a management scheme of synergy of water and fertilizer and preferential flow control was discussed.The main conclusions were as follows:?1?Water and fertilizer had significant effects on soil moisture content distribution of various treatment of summer cron at 0⁶0 cm soil layer.The effect of irrigation on soil moisture content was significantly higher than that of fertilizer application,as demonstrated by that moisture content increased with increased irrigation.The NO₃^--N was the main form of residual N in soil,and N migrated to the lower layer with the advance of growth period.P mainly distributed differently in the upper layer.N and P migrated downward more quickly under high irrigation,and the migration speed of N was faster than that of P.Results from analysis on the soil and soil leachate showed that the N and P concentration increased with the increased the fertilization rates.?2?It was found that the high irrigation and medium fertilization was more conducive to the growth of summer maize and the accumulation of aboveground dry matter in late stage.According to analyse effect of water and fertilizer on yield components,showed that the number of grains per ear was the main factor affecting yield.The single effect of N and P on yield coincided with the law of diminishing return in the analysis of the correlation between yield and fertilizer.The yield reached its maximum 8473.58 kg/hm²when the N application rate was 191 kg/hm²and P application rate was 89 kg/hm²under the condition of irrigation of94.5 mm,indicating that rational fertilization rate of N and P was beneficial to the growth of summer maize.?3?From the results of partial productivity of N and P fertilizer?NPFP and PPFP?,it can be seen that the irrigation was inversely proportional to the NPFP/PPFP.Under the same irrigation,the NPFP decreased with an increase with in N fertilization rate and increased first and then decreased with increased P fertilization rate,by contrast,PPFP increased first and then decreased with increased N and P fertilization rate.?4?Results from analysis on the effects of different amounts of irrigation,surfactant and biochar on the morphological characteristics of the preferential flow showed that preferential flow would be transformed into matrix flow with the increase of irrigation.In the design concentration,biochar was added in the soil can better control the degree of preferential flow,reducing the preferential flow fraction up to 6%¹7.5%.When surfactant was added in the soil,preferential flow fraction decreased about 6.5%⁷.5%as the surfactant application rate above 0.9 t/hm²,preferential flow fraction increased as the surfactant application rate above1.8 t/hm².?5?Principal component analysis and gray correlation analysis were used to evaluate the water and fertilizer schemes comprehensively with the four evaluation indexes of dry matter content,yield,NPFP and PPFP.These results suggested that the management with 121.5 mm irrigation,191 kg/hm²nitrogen,89 kg/hm²phosphorus and 40 t/hm²biochar was the best cultivation practice for higher water and fertilizer utilization efficiency and higher yield.