Effects Of Ridge And Furrow Structure And Nitrogen Application On Water And Nitrogen Utilization Of Maize In Semi-arid Region

In the semi-arid area of the Loess Plateau,corn is one of the main food crops.The ridge and furrow semi-mulch planting has been widely used in this area because of its function of collecting rain and protecting moisture and greatly increasing crop yield.Applying nitrogen fertilizer at an appropriate time can not only meet the nitrogen demand of crops,but also obtain higher nitrogen fertilizer utilization efficiency and reduce nitrogen loss.In this study,three corn planting methods?CK:flat cropping without mulching;RF1:ridge ratio furrow60cm:40cm;RF2:ridge ratio furrow 60cm:60cm?and three different nitrogen application periods were set up(A:Nitrogen fertilizer before sowing 230kg·hm^-2;J:Nitrogen fertilizer before sowing 115kg·hm^-2+Nitrogen fertilizer at jointing stage 115kg·hm^-2;B:Nitrogen fertilizer before sowing 115kg·hm^-2+Nitrogen fertilizer in big trumpet stage 115kg·hm^-2).Through comprehensive evaluation of field planting methods and nitrogen application periods for two consecutive years?2018?2019?on farmland soil moisture,water consumption characteristics,corn growth,soil nitrogen,yield,water use efficiency and nitrogen use efficiency.Clarify the suitable planting management methods and nitrogen application periods in the semi-arid areas of the plateau in the Loess Plateau of China.Verification hypothesis"Are farmland production,water and nitrogen utilization efficiency and economic benefits effectively increased with increasing planting costs".It provides a theoretical basis for formulating effective cultivation and nitrogen management measures in the region.The following results were obtained in this study:1. The jointing period to the flowering period is a critical period of water demand for corn. During this period,rainfall will effectively improve the soil moisture status to avoid soil desiccation and meet crop water requirements.The sum of the soil water storage in the corn jointing stage and the precipitation from the jointing stage to the flowering stage has a strong correlation with the yield,which can predict the corn yield.The ridge and furrow semi-mulch planting builds furrows in the field,which can effectively collect rainfall,reduce water evaporation,improve soil moisture status before corn sowing to jointing,and promote crop growth.In the case of less precipitation from the sowing of corn to flowering,the ridge and furrow half-mulch film planting has a greater yield increase benefit;The increase of the furrow cover ratio can further improve the effect of collecting rain and suppressing evaporation.2. Nitrogen application in stages can increase maize yield,especially the effect of increasing the yield by applying it twice before sowing and during the big trumpet period. Among them,nitrogen application in different periods is beneficial to increase the soil inorganic nitrogen content during flowering,promote nitrogen accumulation,and increase the absorption efficiency of nitrogen fertilizer.ridge and furrow semi-mulch planting significantly increased the soil nitrate nitrogen content at 0?200cm before the corn flowering,which reduced the accumulation of soil nitrate nitrogen during maturity.In the years when there was little precipitation in the early stage of corn growth,the effect of nitrogen application on corn nitrogen accumulation was less.The ridge and furrow semi-mulch planting can effectively increase the dry matter quality of corn aerial parts and thus increase the accumulation of nitrogen,and promote the improvement of nitrogen harvesting index and transfer efficiency.3. Drought at the flowering stage reduced the number of spikes per unit area and the number of grains per ear,resulting in a reduction in corn yield. The number of ears,ears per kernel,and 100-grain weight of corn covered by ridge and furrow half-mulch planting,and corn yield and water use efficiency increased significantly,and the increase of furrow covering ratio contributed to the further increase of corn yield.Compared with the one-time application of nitrogen fertilizer,two-time application of nitrogen can effectively improve the nitrogen content and yield of corn grains.Nitrogen application can effectively increase the nitrogen content and yield of corn grains.Nitrogen fertilizer fractional application under ridge and furrow semi-mulch planting can further improve the net profit of corn and increase the ratio of production and investment.Therefore,in the semi-arid area of the Loess Plateau,the ridge and furrow semi-mulch were planted with a 60cm:40cm belt pattern to better improve the soil moisture and inorganic nitrogen status,and increase maize yield.Nitrogen fertilizers should be applied in a stepwise application method.115.5kg·hm^-2 nitrogen-based fertilizer can be applied before sowing.The crop yield and nitrogen accumulation can be predicted through the soil moisture status of the big trumpet stage.Supplementary application at the trumpet stage to reduce nitrogen and increase production,saving costs and increasing efficiency.