Yield Performance Characteristics and Regulation Effects of Plant Density and Sub-Soiling Tillage System for High Yield Population of Summer Maize

A 2-year field trial using high yield varieties Zhengdan 958 and Zhongdan 909 with densities and tillage systems was conducted in Xinxiang, Henan Province during 2010–2011 growing season to study the characteristics of yield performance parameters and the effect of main cultivation practices for high yield population. Results indicated that compared with Zhengdan 958, Zhongdan 909 increased grain yield by 11.36% significantly, as well as kernel number per ear (KN) and 1000-kernel weight (KW) (P0.01). There was no difference (P0.05) in duration (D), harvest index (HI), and ear number (EN) between two hybrids. Mean leaf area index (MLAI) and leaf area duration were improved significantly (P0.01), mean net assimilation rate (MNAR) was increased significantly (P0.05). Moreover, Zhongdan 909 retained higher maximum growth rate, biomass at the maximum growth rate, average growth rate and active growth duration compared with Zhengdan 958. There were significantly positive correlations between EN and MLAI (P0.01), and between KN, KW, and MNAR (P0.01). There were significantly negative correlations between MNAR, KN, KW, and MLAI (P0.01). Zhongdan 909 had a higher yield because of the mechanism of asynchronous improvement of yield performance parameters. The optimize population of Zhongdan 909 was 27.3% higher than that of Zhengdan 958, with the higher MLAI, MNAR, and KN. Grain yield increased by 8.71% and 13.02% in subsoiling tillage system for Zhengdan 958 and Zhongdan 909, respectively, resulting from increasing MNAR and KN significantly. There was no difference in MLAI and D between both varieties. HI, EN and KW were increased differently in different varieties. Thus, yield performance parameters for high yield of 11 250–12 000 kg ha 1 were MALI 3.05–3.55, MNAR 4.80–6.27gm2d1 , growth days 109–111, harvest index 0.50–0.52, harvest ears 9.60–10.38×104ha1 , kernel number per ear 352.0–370.1, 1000-kernel weight 314.7–315.9 g. Increasing population density (about 9.50×10 4 plants ha1) with sub-soiling tillage system is one of main management practices for high yield in Yellow Huai Valley areas.