| Huanghuaihai Region is one of major corn producing areas in our country. And diversified of row spaces are not conducive to the development and extension of mechanical. Therefore, it has important significance to identify the feasibility of unified row spaces in Huanghuaihai summer maize area. In this paper, we studied the effects of nitrogen uptake and utilization, and yield of summer maize with different row spaces, and analyzed the feasibility of unified row spaces in Huanghuaihai summer maize area. In 2012-2014, field experiments were set at Fangcheng and Huixian. To study the effect of row spaces on plant growth, nutrient uptake and accumulation, yield under different hybrids and densities, we used different height types maize hybrids(Xianyu 335 is a height of maize hybrid, Zhengdan 958 is a middle height of maize hybrid, and 512-4 is a dwarfing of maize hybrid) as test materials, two plant population densities(60000 plant·ha-1 and 75000 plant·ha-1), and five row spaces(50 cm, 60 cm, 70 cm, 80 cm uniform, 80+40 cm wide and narrow form). The results were as follows: 1. Effects of row spacing on yield of mechanism of summer maize.With different hybrids and densities, it had got higher yield in different row spaces. Under the lower density of 60000 plant·ha-1, 60-70 cm uniform got increased higher yield than the other treatments, and there was no significant difference among 60 cm and 70 cm uniform. Under the higher density, 60 cm uniform got the highest yield than the other treatments. In general, 60 cm uniform increased the yield compare to 50 cm, 70 cm, 80 cm uniform, 80+40 cm wide and narrow form by 2.45%, 1.82%, 5.12% and 3.56% and there was no significant difference among 50 cm, 70 cm uniform and wide and narrow form, were increased significantly in 80 cm uniform under different hybrids and densities. 2. Effects of row spacing on morphology and structure of canopy.With different hybrids and densities, plant height,ear height were increasing, and stem diameter, height of ear to plant were decreasing with the increasing of row spacing, Lamina length was increased, lamina width was reduced, and increased plant rectangularity promoted a reduction in the proportion of leaves and roots parallel to the rows, which was accompanied by an increase in the proportion of those perpendicular to the row, the angle between leaf and stem of ear-leaf were larger, and LOV were diminish, plant tends to stay more compact. Once maximum leaf area index(LAI) was decreasing with the increasing of row spacing, and there were not significant difference among hybrids and row spacing for different densities. Root weight showed an increased tendency. 60 cm uniform had higher LAI, stem diameter and root weight, and relatively low height of ear to plant and LOV, to strengthen lodging resistance, also reduces the shade among leaves, as well had more advantageous to enhance the resistance of group. 3. Effects of row spacing on micrometeorological factors of population.With different hybrids and densities, better transmittance and CO2 concentration, air temperature and humidity, light interception rate in lower part were decreased with the increasing of row spacing. 60-70 cm uniform had better light interception rate in lower part, and had the suitable light distribution, at the same time, 60-70 cm uniform were significant increase resistance, contemporarily, benefit the usage of resources. 4. Effects of row spacing on uptake and accumulation of water and nutrients.With different hybrids and densities, the evaporation of soil water was accelerating, soil NO3--N, NH4+-N, uptake and utilization of N, P, K of plant were decreased with the increasing of row spacing. Whereby, 60 cm uniform had higher uptake and utilization of nutrient than the other treatments, and and taken into account different hybrids of height types and densities to obtaining a high yield. 5. Effects of row spacing on the effect and mechanism of population hardiness.With different hybrids and densities, rate of damage and diseased plant were decreased, but lodging resistance of the culm was enhancing with the increasing of row spacing. Thus it can be seen that, proper increased row spacing could improves resistance, and lower the incidence rate of pest and disease damage. However, 60 cm uniform had better resistance than the other treatments.As a whole, in the conditions of this study, we hold that 60 cm uniform can full coordinate the relation of resource of underground and aboveground portion, benefit the uptake and utilization of nutrient and light. Moreover, the appropriate row spacing can construct a good environmental and soil ingenious fertility for yield, the environment of soil nutrient, give full play to perform the yield increasing potential of individuals and groups, and obtaining a high yield. Therefore, is the optimal row spacing of summer corn for present and future, in Huanghuaihai Region. |
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