Optimizing row spacing increased radiation use efficiency and yield of maize

The objective of this study was to determine the effect of row spacing and plant density on maize (Zea mays L.) yield and radiation use efficiency (RUE). This experiment that was conducted in 2018 and 2019 contained two plant densities (90,000 and 120,000 plant ha(-1)) and four row spacings (60-50, 70-40, 80-30, and 90-20 cm). In this experiment the distance between four rows in the 60-50 treatment was 50, 60, and 50 cm, whereas the distance between four maize rows in the 90-20 treatment was 20, 90, and 20 cm. For a given planting rate, the leaf area index (LAI) for the 70-40 treatment was higher than the 60-50, 80-30, or 90-20 treatments. The averaged post-silking RUE was 11.1% higher in the high (HD) than low density (LD) seeding. Planting maize in a 70-40 arrangement had higher post-silking RUE than planting in the 80-30 and 90-20 cm arrangements. These grain numbers per ear decreased and grain numbers per square increased with increased planting densities under the same planting patterns. Compared to LD, the average annual grain yield of DH618, KWS9384 and KWS2030 in HD increased by 5.21, 4.84, and 3.68%, respectively. Compared to 90-20 treatment, the average annual grain yield under 60-50, 70-40, and 80-30 treatments increased by 7.20, 6.39, and 5.20% in LD, and 5.15, 6.39, and 1.72% in HD, respectively. Therefore, we concluded that 60-50, 70-40, and 80-30 treatments in LD, 60-50 and 70-40 treatments in HD will increase grain yields in the tested environment.