畦灌不同施肥模式对夏玉米田间水氮分布的影响

为了探究夏玉米畦灌条件下适宜的灌溉施肥模式,在大田试验条件下对不同施肥方式(液施和撒施)、液施不同施肥时机和不同入畦流量下土壤水氮空间分布状况及其变化趋势进行了研究。结果表明,灌后2d土壤水分空间分布差异明显小于硝态氮,适当增大入畦流量有助于改善沿畦长方向土壤水分空间分布均匀性。灌后2d不同处理间作物有效根系层土壤硝态氮和土壤水分的贮存效率(土壤有效根系层土壤硝态氮占0—100cm土层中硝态氮的比重)变化都不明显。入畦流量相同时,液施情况下硝态氮沿畦长分布均匀性(介于86.1%~96.9%之间)高于撒施(介于89.3%~89.7%之间)。基于入畦单宽流量为4L/(s·m)、灌水至畦长33%处时均匀施肥的畦灌施肥模式,玉米根系层中土壤水氮含量比重较高,而且土壤水分与土壤硝态氮沿畦长分布均匀性最好,从而形成了有助于作物吸收的均匀的土壤水氮空间分布状态。

Effects of Border Strip Fertilization on Soil Water and Nitrogen Distribution in Summer Maize Field

To explore the optimal model of border strip fertilization for summer maize, the distribution and variation of soil water and nitrate nitrogen in the field with different methods (fertigation and broadcast fertigation), timing and rates of fertilization were investigated. Results showed that 2 days after applying water and fertilizer, the spatial distribution variability of soil water was far less than that of soil nitrate nitrogen, and increasing the inflow rate appropriately could improve the distribution uniformity of soil moisture along length direction. The change of the storage efficiency of soil nitrate nitrogen in the effective root zone of summer maize was not obvious and it was same to soil moisture. Under the same condition of inflow rate, the distribution uniformity of soil nitrate nitrogen along length direction of summer maize with fertigation (between 86.1% and 96.9%) were higher than that with broadcast fertilization (between 89.3% and 89.7%). The border strip fertilization with the inflow rate of 4 L/(s·m) and with applying fertilizer as water advanced at 33% of the border length could produce high proportion of soil water and nitrogen accumulation in the effective root zone and provide optimal distribution uniformity along length direction, then formed a spatial homogeneity distribution of soil water and nitrate nitrogen contribution which was beneficial to crop absorption.