Drip Fertigation with Relatively Low Water and N Input Achieved Higher Grain Yield of Maize by Improving Pre- and Post-Silking Dry Matter Accumulation

Abstract

Appropriate irrigation and nitrogen (N) management strategies are necessary to achieve a sustainable yield of maize with relatively low water and N inputs. Here, a 2-year field experiment with two irrigation methods (drip irrigation and flood irrigation) and five N application rates (0, 225, 300, 375, and 450 kg N ha−1) was conducted to evaluate maize yield and water and N use efficiency in the North China Plain (NCP). Compared with flood fertigation (FF), drip fertigation (DF) improved the soil water content (SWC) in the 0 to 40 cm soil layer and maintained a greater soil mineral N content (Nmin) of that soil layer. This resulted in increased soil Nmin in the 0 to 40 cm soil layer for the 375 kg ha−1 (N3) under DF compared with the 450 kg N ha−1 (N4) treatment under FF during both pre- and post-silking of maize. The maize crop accumulated greater N at both pre- and post-silking compared using N3 under DF compared to N4 under FF. Greater pre-silking N accumulation increased both leaf area and plant growth rate, leading to more dry matter (DM) accumulation and develop more kernels, while sufficient post-silking N accumulation maintained high leaf area to produce more DM post-silking and promote maize ability to support grain filling. As a result, maximum maize yield (10.4 Mg ha−1) was achieved due to increased kernel number and kernel weight for N3 (375 kg N ha−1) under DF with a 20% reduction in N fertilizer input compared with the N4 (450 kg N ha−1) treatment under FF. Due to greater grain yield and N uptake and less water consumption, the agronomic N efficiency (AEN), N partial factor productivity (PFPN), water use efficiency (WUE) and net income for the N3 treatment under DF increased by 30.4%, 28.6%, 58.3% and 11.0% averaged over two years, respectively, compared to the N4 treatment under FF. Therefore, drip fertilization could improve maize grain yield with a relatively lower water consumption and N application rate compared with flood irrigation with higher N fertilization, as well as increase the economic benefits.