Regulatory Effect of Deep Tillage and Straw Returning on Morphological Characteristics of Maize Roots at High Planting Density
In order to explore the effects of deep tillage and straw returning on the root characteristics of different densification-toler-ance maize varieties after densification from the perspective of root morphological characteristics,and to provide theoretical basis for the adoption of this measure to improve the densification-tolerance of maize in production,the present study was conducted on the premise of deep tillage and straw returning to improve soil quality,and to increase the planting density of different densification-toler-ant maize varieties,so as to monitor the dynamic changes of the root growth and development of the densified maize varieties after deep tillage and straw returning deep-turning straw return.The experiment was conducted in 2021 and 2022 to analyze the morpho-logical changes of maize roots before and after densification under the deep tillage and straw returning treatment by using the re-crack-ing zone experimental design of tillage method,planting density,and variety.The results showed that compared with the CK treat-ment,DPR significantly enhanced the soil nutrients,and reduced the soil bulk density,which in turn increased the root length and root dry mass of two different corn varieties in each soil layer at the silk emergence stage under two planting densities.At the same time,it increased the root width,aerial root angle,and crown root angle of corn at the big horn mouth stage,silk emergence stage,and milk maturity stage.After intensive planting,the above indicators of two different corn varieties significantly decreased in each soil layer and period,and the decreases in'XY696'were smaller than those in'JK968'.Under the DPR treatment,the root length of'XY696'in the 0-30 cm soil layer was reduced by 9.53%-12.78%compared with that of'JK968',and the soil layer with no sig-nificant differences of the maize single-plant root lengths after densification of'XY696'under the DPR treatment was 10 cm higher than that of'JK968'.This indicated that density tolerant varieties had a weaker response to the density,while weakly dense-tolerant varieties have a stronger response to the density.In addition,the deep tillage and straw returning method had a more significant ef-fect on the root shaping of dense-tolerant varieties.Therefore,it is recommended to adopt deep tillage and straw returning measures in Inner Mongolia to better achieve the maize densification and increase yield.
Spring cornCultivation methodsPlanting densityRoot characteristics