The Combined Impact of Planting Density and Amount of Water and Nitrogen Application on Yield of Spring Maize

Abstract

【Background】 The imbalance between water supply and crop demand for water is the bottleneck limiting agricultural production in Xiliaohe plain of China. Long-term flooding irrigation in this region has deteriorated its environments including decline in water and nitrogen use efficiency and dropping of groundwater table. Improving water and nitrogen use efficiency has become essential to sustaining its agricultural production. 【Objective】 The objective of this paper is to investigate how planting density can be combined with irrigation and fertigation to increase water and nitrogen use efficiency of spring maize. 【Method】 The field experiment was conducted from 2017—2019 in a field with all treatments randomly arranged in the field. All treatments were watered and fertilized with subsurface drip irrigation. During the three years of experiment, we measured and analyzed the change in maize yield (Y) in response to irrigation amount (W), nitrogen application rate (N) and planting density (D). 【Result】 An increase in W, N or D boosted Y, with the significance of their impact ranked in the order of N>W>D. The combined impact of any two factors on Y was ranked in the order of ND>WN>WD. With the increase in each pair of factors, Y increased first followed by a decline. It was found that sufficient nitrogen application coupled with moderate irrigation and intermediate planting density gave the highest yield, followed by sufficient irrigation and fertigation coupled with intermediate planting density. The yield of the maize was 1 958.40~2 228.00 m3/hm2 under rain-feeding. Irrigating at 1 958.40~2 228.00 m3/hm2 and fertigating at 209.34~275.70 kg/hm2, along with planting density of 67 350~78 150 plants/hm2, increased the yield to 12 000~12 716.82 kg/hm2. 【Conclusion】 Spring maize yield was modulated jointly by irrigation, fertigation and planting density. Our three-year experiments revealed that their optimal combination for Xiliaohe plain was: irrigating at 1 958.40~2 228.00 m3/hm2, fertigating at 209.34~275.70 kg/hm2, and planting at 67 350~78 150 plants/hm2.

Keywords

• subsurface drip irrigation
• spring maize
• irrigation amount
• nitrogen application rate
• planting density
• yield