Study On Increasing Density And Yield Of Maize Varieties Suitable For Mechanical Harvesting In Eastern Hebei Province

Reasonable dense planting is an important guarantee for high yield of corn.In this experiment,the maize varieties Jingnongke 728 and MC812 with good pole characteristics selected by the research group in the early stage were selected for density tolerance research,and five densities(60000 plants/hm2,67500 plants/hm2,75000 plants/hm2)were set,82500 plants/hm2 and 90000 plants/hm2),the effects of density on yield,agronomic traits,grain filling and dehydration,and plant moisture content were studied to provide a scientific basis for the high-density planting of spring maize in eastern Hebei.The main findings are as follows:1.With the increase of planting density,the competition for nutrients in the group is fierce,the plant height and ear height rise,the leaf layers are shielded from each other,the canopy light transmittance decreases,the dry matter accumulation decreases,and the stem thickness decreases accordingly.The difference in the puncture strength of the stalks is not obvious,but the transverse fold strength and the breaking strength of the stalks decrease significantly.2.The 100-grain weight of seeds during the filling period showed a“slow-fast-slow” S-shaped upward trend.Both the filling rate and the dehydration rate showed a “first rise and then fall” parabola,and the peak appeared at the same time,at low density All appeared at 26 days after spinning,and all appeared at 33 days after spinning at high density.Under different density conditions,the grouting rate of Jingnongke 728 and MC812 reached the maximum at 67500 plants/hm2 density and the dehydration rate reached the maximum under 67500 plants/hm2 and60000 plants/hm2 density,respectively.3.With the increase of spinning days,the moisture content of the two varieties of grains,stalks and bracts as a whole showed a "slow-fast-slow" downward trend,and the moisture content of each part at low density was higher than that of high density The performance is even lower.The dehydration rates of stems and bracts as a whole showed a fluctuating trend of "first rise and then fall",and the change range under low density conditions was greater than that under high density conditions.Combinedwith the analysis of meteorological factors,the moisture content of stems and bracts increased in a short period of time and the dehydration rate appeared negative values may be affected by rainfall.4.The grain number,ear length and ear grain weight of Jingnongke 728 and MC812 decreased significantly with the increase of planting density as a whole,and reached the maximum under the density of 67500 plants/hm2 and 60000 plants/hm2respectively;Two varieties The number of spikes per hectare increased significantly with the increase of planting density,and the maximum was obtained at a density of90,000 plants/hm2.With the increase of planting density,the output of Jingnongke728 and MC812 showed an overall upward trend.Comparing different planting densities,the difference of Jingnongke 728 reached a significant level,and the difference of MC812 did not reach a significant level.Compared with different varieties,MC812 output is higher than Jingnongke 728.