Abstract
The combination effects of nitrogen (N) fertilizer and planting density on maize yield, N use efficiency and the characteristics of canopy radiation capture and radiation use efficiency are not well documented in the Huanghuaihai Plain region in China. A 2-year field experiment was conducted from 2017 to 2018 in a split plot design with two N levels (240 and 204 kg N ha−1) applied to main plots and three plant densities (67,500, 77,625 and 87,750 plants ha−1) allocated to sub plots. Our results show that a 30% greater plant density combined with a 15% lower N rate (basal N) enhanced N partial factor productivity (NPFP) by 24.7% and maize grain yield by 6.6% compared with those of the conventional high N rate combined with a low density planting management practice. The yield increase was mainly attributed to significantly increased kernel numbers and biomass. The increased intercepted photosynthetically active radiation (IPAR) was the primary factor responsible for the high productivity of maize at increased planting density under reduced N conditions. The results indicate that increase planting density with reduced basal N application might benefit maize cropping for achieving high yields and sustainable development of agriculture.
Highlights
The combination effects of nitrogen (N) fertilizer and planting density on maize yield, N use efficiency and the characteristics of canopy radiation capture and radiation use efficiency are not well documented in the Huanghuaihai Plain region in China
It is well known that biomass production is the product of intercepted photosynthetically active radiation (IPAR), which is a function of both canopy architecture and the leaf area index (LAI), that is converted into biomass (radiation use efficiency, (RUE))[31]
With the exceptions of thousand-kernel weight and the harvest index (HI), ear number, number of seeds per ear, kernel number, yield and biomass were significantly affected by planting density and its interactions with N rate in 2 years (Table 1)
Summary
The combination effects of nitrogen (N) fertilizer and planting density on maize yield, N use efficiency and the characteristics of canopy radiation capture and radiation use efficiency are not well documented in the Huanghuaihai Plain region in China. Previous studies have shown that increasing N application rate is important way to obtain high grain yield[5,6]. Previous studies have shown that increasing density is among the major factors associated with increases in maize grain yield[13,17,18,19,20,21] and N use efficiency[22,23]. To our knowledge, the combined effects of planting density with N application rate on maize canopy development and radiation capture and use efficiency use are not well documented. Our objectives are to develop an optimum combination of an appropriate N rate and planting density aimed at achieving high yields with reduced inputs for environmentally friendly maize cropping.
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