Row placement affects yield and water use efficiency of continuous corn

Abstract

AbstractThe planting of crops in rows results in a large amount of variation in soil nutrient levels and soil water. The hypothesis of this paper is that row spacing can be adjusted to optimize water use efficiency (WUE). The objective was to investigate the effects of row placement on corn (Zea mays L.) growth, leaf photosynthetic characteristics, yield, soil water, inorganic nitrogen (N), evapotranspiration (ET), and WUE in the Corn Belt of Northeast China (CBNC). Corn was planted in either the intra‐row or inter‐row space of the previously planted corn in a 2‐yr (2017–2018) field experiment in Jilin Province, China. All corns were planted at a row spacing of 60 cm, a plant spacing of 28 cm, and a density of 60,000 plants ha−1 per year. The inter‐row corn treatment maintained higher leaf area index, net photosynthetic rate, and transpiration rate at the R3 growth stage in 2017 and 2018. The corn yields of inter‐row treatment were 6.0% and 8.5% higher (P ≤ .05) in 2017 and 2018, respectively, compared with intra‐row treatment. The ET in inter‐row treatment was 4.4% (P < 0.01) lower in 2017 and its 2‐yr WUE was 11.5% higher (P = 0.016) than that of intra‐row treatment. These findings suggest that corn rows should be arranged at the inter‐row of the previous corn in a continuous corn cropping field, and an intra‐row position of the previous crop should be considered in the definition of continuous monocropping for row‐planted crops.