Effects Of Shallow Drip Irrigation Fertilization Without Seed Fertilizer On Yield And Nutrient Utilization Efficiency Of Spring Maize

In maize production,the conventional sowing mode with seed fertilizer has problems such as low nutrient utilization efficiency due to the easy fixation of seed fertilizer mainly phosphorus and potassium fertilizer by the soil,high labour consumption for solid fertilizer hauling,and the quality and efficiency of sowing affected by the application of seed fertilizer,while the shallow buried drip irrigation water and fertilizer integration technology provides the possibility of applying all nutrients of nitrogen,phosphorus and potassium in stages with drip irrigation.Based on this,this study used the autotrophic growth of maize before the three-leaf stage with nutrients mainly in the seeds,and used shallow buried drip irrigation technology as a vehicle to select a new NPK water soluble fertilizer.By dynamically monitoring soil nutrient dynamics,maize nutrient status and yield formation and other characteristics,we analyzed the effects of water-fertilizer integration without seed fertilizer under shallow buried drip irrigation on maize yield and nutrient utilization,and provided a basis for improving traditional fertilizer application methods and exploring new water-fertilizer integration models for efficient utilization of nutrients in maize.The main research results are as follows:（1）Compared with the conventional fertilization mode and water-soluble fertilizer twice drip application（LF-2）,four-leaf stage（V3）+jointing stage（V8）+big bell stage（V12）three times drip application（LF-3）can increase the SPAD value and leaf area index of spring maize,prolong the leaf green degree after flowering,increase the dry matter accumulation,optimize the yield components,and increase the yield of spring maize.The SPAD value of LF-3 three leaves increased by 3.71%,7.88%and 6.18%respectively from top to bottom.The leaf area index,green degree and dry matter accumulation increased by 5.24%,7.98%and 7.85%,respectively.The grain number per spike and 1000-grain weight increased by 4.07%and 3.75%,respectively,and the yield increased by 8.43%.（2）Compared with CK,the reduction of 13%,50%and 50%of nitrogen,phosphorus and potassium in LF-3 could promote the accumulation of nutrients after anthesis,improve the transport of nitrogen,phosphorus and potassium from vegetative organs to grains,and then improve the transport rate and contribution rate to grains.The absorption of nitrogen,phosphorus and potassium at silking stage and maturity stage increased by 15.85%,4.40%,30.80%and 11.36%,5.24%,10.63%,respectively,and the transport amount after anthesis increased by 24.08%,23.05%and 37.61%,respectively.The utilization efficiency and partial factor productivity of nitrogen,phosphorus and potassium fertilizers increased by 66.46%,164.82%,147.47%and29.02%,104.53%,89.14%,respectively.The application mode of water-soluble fertilizer without seed fertilizer was mainly due to the improvement of fertilizer absorption efficiency and utilization efficiency.Compared with CK,the absorption efficiency increased by 55.78%,131.74%and 136.09%.（3）Compared with CK,the content of alkali-hydrolyzable nitrogen in 0～15cm,15～30cm and 30～45cm increased by 6.56%,6.96%and 4.02%after fertilization in LF-3 large bell stage,which increased the soil nitrogen supply level at high booting stage.In the mature period,the content of available phosphorus and available potassium in each soil layer was lower than that of CK,the content of available phosphorus decreased by14.07%,9.94%and 20.94%,and the content of available potassium decreased by15.23%and 13.75%.Reduce soil nutrient residues and reduce environmental pollution;compared with LF-O,LF-T increased the level of soil phosphorus and potassium in the later stage of large bell mouth,and had a positive effect on promoting grain filling at flowering stage.（4）Compared with CK,the cost of drip irrigation facilities and water soluble fertilizer increased by RMB 183.8 hm^-2for LF-2 and LF-3,and the mechanical cost input decreased by RMB 225 hm^-2for a total input reduction of RMB 76.8 hm^-2and an increase in net return of RMB 2993.5 hm^-2,resulting in a 10.19%increase in the yield-to-input ratio.