Regulation Of Cultivation Measures On Canopy Structure And Yield Of High-yield Maize(Zea Mays L.) In Cold Region

The sown area of maize in Heilongjiang Province accounts for 44.2%of the total grain area of the province in 2016,and it is the most important cereal grain crop in Heilongjiang Province,however,due to the national corn structure adjustment plan,the sown area of corn in Heilongjiang Province will be reduced by more than 10 million mu,in the background of the downregulation of the planting area,the future maize production can only depend on the increase of yield and benefit.A large number of studies have proved,rational close planting is an effective way to improve the yield of maize.In response to the problem of canopy deterioration caused by the increase in the density of corn,people regulate the population indicators and yield components through measures such as wide/narrow row planting and chemical treatment,and achieve the purpose of increasing density and increasing production.However,there are still no systematic studies on the optimization of the canopy structure of the dense plant community in the cold region and the mechanisms of increasing the yield of these two key cultivation measures of integration.So this study aims to(1)To discuss the effects of key measures such as wide/narrow row planting,chemical control treatments and their interactions on maize grain yield;(2)Analyze the canopy structure,dry matter accumulation and light energy interception rate of maize population under different cultivation patterns to elucidate the mechanism of yield increase;(3)Constructing cultivation technology system that is suitable for the development of corn production in cold regions of Heilongjiang Province,so as to provide theoretical basis and technological reference for maize close planting and yield increase in the future.The results of the present study are as follows:(1)Wide/narrow row planting and chemical control interaction between technology and density by adjusting the grain number and 100-kernal weight,significantly increased the Density Tolerance Maize Population,has a significant effect on the final grain yield.There is a significant regularity in this interaction,that is,the regulative effects of cultivation techniques on yield and yield components increase with increasing density.In addition,there are also significant differences in the response of different cultivation measures to density,the optimal density of the dual-item interaction model is higher than that of the individual technology,that is,in the cultivation mode of wide/narrow line and chemical-control technology,the spring maize showed higher potential for dense planting and yield increase(the maximum increase is 26%).(2)Wide/narrow row and chemical control technology had significant regulation effect on maize population index,and the interaction mode had stronger resistance to drought.The mechanism of optimizing canopy structure by wide/narrow row cultivation techniques is mainly to change the distribution of LAI canopy,increase the proportion of functional leaves at the top of the canopy,and increase the light energy interception and photosynthetic rate of corn populations,the chemical control agent can effectively delay the leaf senescence during and after grain filling.Double item collocation,its interaction is significantly better than single measures and controls,It can increase grains per spike and 100-kernal weight by regulating LAI(closer to the optimal LAI value),increasing light energy interception rate(transmission decreased by 2.47%),promoting the accumulation of dry matter at the late growth stage of maize,and promoting the transport of photosynthetic products to grains.In order to achieve the purpose of increase planting density and increase yield.(3)After research and screening,it is believed that the simultaneous adoption of double measures in Heilongjiang Province is the best model for achieving high yields in cold-sea corn,and it is further clear that the recommended density is 80 000 plants/hm~2.Main effect analysis results show,the regulation effect of row spacing in the comprehensive cultivation mode mainly contributes to yield.At the same time,under the conditions of severe stage drought stress(24 days rainfall is 0 mm;July 2017),interactions of wide/narrow row and chemical control technology has the highest yield(up to 10 599.142 kg/hm~2),compared with other treatment groups,the structure is more stable,shows higher population resistance.Therefore,we can achieve a breakthrough in output.