不同秸秆还田模式对大豆根系分布的影响

对免耕、灭茬还田和传统耕作条件下大豆根系在土壤剖面中的垂直分布的变化规律进行了研究,为改善在保护性耕作条件下大豆根系发育条件提供参考。结果表明,免耕、灭茬还田和传统耕作模式的根长、根表面积、根体积及根干重均主要分布于土壤剖面0～10 cm深度。在0～10 cm深度内,不同耕作模式之间的根体积密度、根干重密度差异显著,其中免耕模式最低。在10～20 cm深度内,免耕模式根长密度、根表面积密度、根体积密度和根干重密度最低,其根长、根表面积、根体积和根干重占土壤剖面比例最低。土壤剖面根长、根表面积、根体积和根干重累加值亦表现为免耕最低,灭茬还田与传统耕作差异不显著。灭茬还田模式的根长密度、根表面积密度、根体积密度及根干重密度与传统耕作差异不显著,同时其根长、根表面积、根体积及根干重的垂直分布与传统耕作间差异亦不显著。土壤机械阻力和根长密度、根表面积密度、根体积密度及根干重密度呈显著负相关,土壤机械阻力是限制免耕模式大豆根系发育的重要因素。

Impact of Different Residue Retention System on Soybean Root Distribution in Soil Profile

Soybean root vertical distribution in soil profile under different residue retention system was studied in order to provide theoretical guidance for improving soybean root development environment.The experiment consisted of three treatments:NT(no-tillage),SCRR(Stubble cut off with residue retention),and CT(Conventional tillage).Root length,root surface area,root volume,and root dry weight distributed mostly in 0-10 cm soil depth.There were significant differences in root volume density and root dry weight density between different tillage treatments and the minimum values under NT in 0-10 cm depth.Not only root length density,root surface area density,root volume density,and root dry weight density but also root length percentage distribution,root surface area percentage distribution,root volume percentage distribution,and root dry weight percentage distribution were the lowest under NT in 10-20 cm depth.There were no significant differences between tillage treatments not only on root length density,root surface area,root volume density,and root dry weight density but also on root length percentage distribution,root surface area percentage distribution,root volume percentage distribution,and root dry weight percentage distribution.Soil penetration resistance was one of important factors restricting soybean root development for the significant negative relationship between soil penetration resistance and root length density,root surface area density,root volume density,and root dry weight density,respectively.