Corn root length density as affected by soil physical properties due to different manure and short-term tillage systems

摘要

Soil physical properties and root attributes are affected by agricultural practices. This study was conducted to investigate short-term changes of soil bulk density (BD) and cone index (CI) and corn (Zea mays L.) root length density (RLD) under different management regimes. The interaction effects of tillage (no-till, NT; chisel plow, CP; and moldboard plow, MP) and composted cattle manure applications [0, 30, and 60 Mg (dry weight) ha{sup}(-1)] on BD, CI, and RLD were assessed in a split-plot design under corn plants. The RLD was determined from 10 cm diameter soil core samples. The BD and CI were determined by core method and cone peneterometry, respectively. Tillage methods and manure applications had significant effects on RLD, CI and BD. The MP system had higher values of RLD with lower values of both CI and BD. The NT system resulted in lower RLD, and higher CI and BD. The increased BD and CI of the topsoil in the NT treatment probably restricted root growth. Increasing manure to the soil significantly increased RLD in the order of 60>30>0 Mg. manure ha{sup}(-1). There were also significant differences in CI and BD among manure treatments. The positive effects on CI and BD of manure applications are attributable to manure incorporation in soil structural improvement. The significant overall relation between RLD and CI illustrated the dominant effect of soil mechanical impedance on root growth. Our results indicate short-term beneficial effects of manure application on corn root length density as well as soil physical properties while combined with the tillage systems.