Improving the growth, lodging and yield of different density-resistance maize by optimising planting density and nitrogen fertilisation

Abstract

Matching the planting density, fertilisation, and genotype is crucial to improve the maize yield. Here, two-year field trials, including 4 densities and 3 nitrogen (N) rates for 2 maize cultivars, were conducted to study the effects of planting density and N rate on maize growth, lodging, spike characters, and yield. Compared with 360 kg/ha, N application of 180 kg/ha decreased the plant, ear height, and stem circumference of WeiKe 702 (WK702), while increased the plant height and stem circumference, but decreased ear height of ZhongDan 909 (ZD909). Meanwhile, the N application of 180 kg/ha greatly reduced the lodging rates of maize under the high density. The maize yield increased and reached the maximum yield at 7.5 × 10<sup>4</sup> plant/ha, and then decreased with increasing density. The N application of 180 kg/ha increased yield by 0.49, 0.73, 5.38, 7.81% from low to high planting densities, and reduced the bald tip length by 18.86%. WK702 was more sensitive to the planting density and N application, with greater variation of yield and spike traits than ZD909 under the densification. Therefore, the N application of 180 kg/ha and a density of 7.5 × 10<sup>4</sup> plant/ha could improve maize growth and lodging, and therefore increase maize yield.

Maize grain yield enhancement in modern hybrids associated with greater stalk lodging resistance in high planting density: A case study in Northeast China

“…Increasing planting density brings about ercer competition for solar radiation and other resources available of the individual plant, which results in the higher canopy morphology of PH, EH and GH. Our results are consistent with the previous results of Zhao et al, 31 who found that the PH and EH were enhanced with the planting density raised from 4.5 to 8.0 × 10 4 plant/ha under three N levels. As known, cultivars with high stalk and ear position are more susceptible to lodging due to higher plant gravity and enhanced upper fresh weight 21 .…”

“…Stalk lodging induced bending and/or breakage of stems during maize growing season generally cause damages to vascular bundles 31 , and thereby prevent water transport from root to leaves and impair assimilates phloem transportation from the mesophyll into the stalk phloem, thus may allocating more photoassimilates to leaves or stalk than the ear 2,32 , hence affecting grain lling and decreased the kernel weight and effective ear number, that's why the decreased yield components of 100-grain weight and ear number were found in the less lodging-resistant hybrid of Xy335 in the present study.…”

Maize grain yield enhancement in modern hybrids associated with greater stalk lodging resistance at a high planting density: a case study in northeast China

“…Stalk lodging induces bending and/or breakage of stems during maize growth, generally caused by the damages to vascular bundles 28 , and thereby preventing water transport from root to leaves and impairing phloem transportation of assimilates from the mesophyll into the stalk phloem. Thus, more photoassimilates may be allocated to leaves or stalks than to the ear 2 , 29 , affecting grain filling and decreasing the kernel weight and effective ear number.…”

Methodology of Analyzing Maize Density Loss in Smallholder’s Fields and Potential Optimize Approach

“…Therefore, the density under the highest yield demonstrated by agronomists in the plant density experiments was taken as the optimal density. The experimental results of Zhao et al [28] in Kangcheng Village were adopted. The results of the two cultivars in 2015 and 2016 showed that the yield was the lowest when the density was 45,000 plants ha −1 .…”

“…There is a need to enhance smallholder awareness and competencies and increase farmer confidence and willingness [10]. For example, it is important to improve farmer adoption of the optimal water and fertilizer management, pest control, chemical control and lodging prevention through field demonstration, education and training [51] in order to optimize the growth and development of maize and reduce the risk of lodging [28,52]. At the same time, this can reduce the plant density loss caused by other agronomic factors.…”