深翻秸秆还田对高种植密度下玉米根系形态特征的调控效应

Regulatory Effect of Deep Tillage and Straw Returning on Morphological Characteristics of Maize Roots at High Planting Density

为从根系形态特征的角度探求深翻秸秆还田对不同耐密性玉米品种增密后的根系特征的影响,本研究在深翻秸秆还田改良土壤质量的前提下,采取不同耐密性玉米品种增加种植密度,监测深翻秸秆还田对玉米增密后的根系生长发育的影响,分析、明确深翻秸秆还田方式促进玉米品种玉米根系生长发育的调控效应。试验于2021年和2022年采取耕作方式、种植密度和品种的再裂区试验设计,分析深翻秸秆还田处理下玉米增密前后根系的形态变化。结果表明:较CK处理,DPR显著提升了土壤养分,降低了土壤容重,进而增加两种玉米品种在两种种植密度下吐丝期各土层的根系长度和根干质量,同时增加了大喇叭口期、吐丝期和乳熟期的玉米根幅、气生根根角和冠根根角。增密种植后,两种玉米品种的上述指标在各土层、各时期均显著下降,且‘XY696’的降幅均小于‘JK968’。DPR处理下,‘XY696’的0~30 cm土层根系长度较‘JK968’降低9.53%~12.78%,且‘XY696’在DPR处理下增密后玉米单株根长无明显差异的土层较‘JK968’上移10 cm。这说明耐密性品种对增密的反应较弱,而弱耐密品种对增密的反应较强,加之深翻秸秆还田对耐密性品种根系塑形效果更加明显,因此推荐在内蒙古地区采取深翻秸秆还田措施能够更好地实现玉米增密增产。

In order to explore the effects of deep tillage and straw returning on the root characteristics of different densification-tolerance 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-tolerant 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 morphological changes of maize roots before and after densification under the deep tillage and straw returning treatment by using the re-cracking zone experimental design of tillage method,planting density,and variety.The results showed that compared with the CK treatment,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 significant 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 effect 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.