The Optimal Cultivar × Sowing Date × Plant Density for Grain Yield and Resource Use Efficiency of Summer Maize in the Northern Huang–Huai–Hai Plain of China

Abstract

In order to explore the optimal cultivar × sowing date × plant density for summer maize (Zea mays L.) in the Northern Huang–Huai–Hai (HHH) Plain of China, field experiments were conducted over two consecutive years (2018–2019) on a loam soil in the Northern HHH Plain. A split–split plot design was employed in this study, and the main plots included three cultivars (HM1: early-maturing cultivar; ZD958: medium-maturing cultivar; DH605: late-maturing cultivar); subplots consisted of three sowing dates (SD1: June 10; SD2: June 17; SD3: June 24); sub-sub plots include two plant densities (PD1: 6.75 × 104 plants ha−1; PD2: 8.25 × 104 plants ha−1). The results showed that the effects of cultivar and plant density on grain yield of summer maize were not significant, and the sowing date was the major factor affecting the grain yield. Delayed sowing significantly decreased the grain yield of summer maize, this was due mainly to the reduced kernel weight, which is associated with the lower post-anthesis dry matter accumulation. Moreover, radiation use efficiency (RUE), temperature use efficiency (TUE), and water use efficiency (WUE) were significantly affected by cultivar, sowing date, and plant density. Selecting early- and medium-maturing cultivars was beneficial to the improvements in RUE and TUE, and plants grown at earlier sowing with higher plant density increased the RUE and TUE. The interactive analysis of cultivar × sowing date × plant density showed that the optimum grain yields of all tested cultivars were observed at SD1-PD2, and the optimum RUE and TUE for HM1, ZD958, and DH605 were observed at SD1-PD2, SD2-PD2, and SD2-PD2, respectively. The differences in the optimum grain yield, RUE, and TUE among the tested cultivars were not significant. These results suggested that plants grown at earlier sowing with reasonable dense planting had benefits of grain yield and resource use efficiency. In order to adapt to mechanized grain harvesting, early-maturing cultivar with lower grain moisture at harvest would be the better choice. Therefore, adopting early-maturing cultivars grown with earlier sowing with reasonably higher plant density would be the optimal planting pattern for summer maize production in the Northern HHH Plain of China in future.

Future Projection for Climate Suitability of Summer Maize in the North China Plain

“…In order to ensure crop yield, some adaptive agricultural management measures should be taken to counteract the adverse effects of climate change, including variety renovation, adjustment of sowing date, improvement of fertilization and irrigation conditions, and so on [68,69]. For example, the renovation of maize varieties delayed the heading date and maturity date and prolonged the whole growth period at more than 90% of stations in China, while appropriate late sowing can also prolong the whole growth period [5].…”

Canopy development, leaf traits and yield in high-altitude Andean maize under contrasting plant densities in Argentina

“…However, there are some exceptions to this rule. For example, in late sowings, maize yields are usually decreased but optimum plant density can be similar or even higher compared with earlier sowings (Djaman et al, 2022;Zhai et al, 2021). In our work, higher yields were achieved in the first experiment at HOR but no response to plant density was obtained (6356 kg ha −1 , Table 2), whereas in the second experiment, a later sowing date combined with cooler temperatures and lower solar radiation likely resulted in lower yields (4821 kg ha −1 , Table 2) but also in a positive response to increased plant density (26% in both genotypes).…”