| The improvement of maize yield is one of the ways to the increase of planting density,but with the increase of density,root-champions league competition between individuals,the root of crown structure variation of production in the further promotion.A large number of studies have shown that it is one of the key measures to find the yield breakthrough in corn production in China by improving the soil structure of tilling soil through deep pine cultivation.For high-yielding spring maize varieties under the condition of more dense appear premature aging lodging,corn increase the potential serious bottleneck problem is hard to play,to explore the influence brought about by the negative factors,increases the density of the starting point of design of experiment,this study adopts the traditional deep loosening and shallow rotary tillage measures,under different planting density gradient,based on the different resistance to dense type varieties of high yield of spring corn root system characteristics-canopy physiological characteristics,yield and yield components of planting density change and response characteristics of the deep loosening measures analysis,illustrate the high yield of spring corn varieties resistant to tightness of deep loosening and increases the physiological mechanism of the response.The main results are as follows:(1)With the increase of planting density,dry weight,length of root system and surface area of root system in underground soil of different high-yielding spring maize varieties with different density-tolerance were reduced.The light transmittance of each layer in the overground population,the dry matter accumulation of a single plant after flowering,the transport volume,the contribution rate to grain,the number of panicles and the weight of thousand grains were all significantly reduced.The planting density of the varieties with strong density-tolerance was higher than that of the varieties with weak density-tolerance,and the decreasing range of the adjacent density-tolerance was smaller than that of the varieties with weak density-tolerance.(2)The deep pine significantly reduced the soil bulk density at 0~50cm soil layers in each fertility period.The soil moisture content of each soil layer from 0~60cm increased,and the soil moisture content of deep pine tillage increased by 55.44%,18.68% and 9.32% respectively in each fertility period.(3)Deep pine reduces the crowding effect of the upper root system and enhances the ability of roots to bind down.After deep pine,root dry weight,root length and root surface area of 0-20 cm soil layer of each species decreased,but the root system distribution proportion of 20-80 cm soil layer increased.Deep loosening raised the corresponding density under the condition of different growth period of each type ear light transmittance and ground floor light transmittance,alleviate the increasing dense after different ears were dense varieties resistant layer and the underlying light transmittance between adjacent density decreased,and the light transmittance in the biggest drop in planting density compared with shallow spin an increase of 15000plants/hm2,at the same time,with the advancement of easing as the birth of different resistance varieties group LAI attenuation amplitude,alleviate the different tightness resistance varieties per plant dry matter accumulation after flowering,transfer capacity,and the grain contribution rate decreased,and the biggest drop in planting density increase.(10)Deep pine can increase the potential of densifying and increasing yield of varieties with different tolerance,and increase yield of varieties with strong resistance to densification is greater than those with weak resistance to densification.The optimum planting densities of JK968,XD20,DH618 and LM33 increased by 16,600 plants /hm2,13,700 plants /hm2,14,400 plants /hm2 and 13,100 plants /hm2 respectively compared with shallow-rotation tillage,increasing by 10.17%,9.83%,15.38% and 13.25% respectively. |
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