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 studies for the relation between incorporated residue and infiltration rate has not been conducted. To know the relation is important for avoiding soil erosion under crop rotation in practically. We continuously grew corn (cleaning crop), rhodes grass, and okra under greenhouses. The water infiltration rate was measured on the ridge at similar soil moisture conditions, on the day incorporating the prior crop residue. The simple linear regression analysis was conducted. The coefficient of determination R2 was 0.91; however, that for aboveground dry matter of prior crop was 0.93, unexpectedly. Though, our experiment not designed for distinguish those effect; previous studies have revealed the positive relation between plant root mass and soil erosion resistance. Our data also show a positive relationship between resistance to erosion and root mass when assuming that the aboveground biomass is proportional to the root mass. 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.