Root mass may affect soil water infiltration more strongly than the incorporated residue
This Brief Report includes a single-finding that is reported with descriptions of an unexpected observation. Crop residue incorporation increases stable soil pores and soil water infiltration, consequently, reduces surface water runoff and soil erosion. However, to our knowledge, quantitative study for the relation between incorporated residue and infiltration rate has not been conducted. In this study, we examined the relationship between the quantity of crop residue of the prior crop and the
... prior crop and the water infiltration rate. We grew corn, rose grass, and okra in crop rotation under greenhouses and measured the water infiltration rate at the time of ridge making. A strong correlation was found between the quantity of applied residue and the soil water infiltration rate ( r = 0.953), although there were outliers in the case of no prior crop. By contrast, aboveground biomass of the prior crop showed a stronger correlation with water infiltration rate (r = 0.965), without outliers. Previous studies have revealed the logistical relation between plant root mass and soil erosion. Our data also show a positive relationship between resistance to erosion and root mass when assuming that aboveground biomass is proportional to the underground biomass. The result also showed that the effect of the prior crop root mass disappears within the next crop period. This suggests that maintaining a large root mass is crucial for reducing soil erosion.