Abstract
In no-tillage farming on clay loam, humid-temperate zone, tendencies of uneven distribution of soil fertility, surface gathered plant root growth and declining of soil percolation and decreasing of yield after continuous cropping can be seen.
In this study, we introduced a fertilizer-injector to no-tillage to the cultivation of dentcorn in order to resolve these problems. This implement can do subsoil breaking and deep-layer fertilizing simultaneously.
The experimental design consists of two main-plots and three sub-plots. Main-plots are no-tillage and rotary tillage (tillage depth: 12cm). Sub-plots are as follows: (1) subsoil breaking and deep-layer fertilizing; (2) subsoil breaking and broadcast fertilizing; (3) broadcast fertilizing.
As a result, subsoil breaking treatment had improved soil hardness, increased air % in the soil three phase, developed root growing especially in the no-tillage plots. But the yield of rotary tillage had declined by the lack of soil moisture. We consider this to be the result of subsoil breaking at dry season. The differences among the no-tillage plots were not significant to the yield.
However, the yields of all no-tillage plots were higher than any rotary tillage plots. It might be possible to get a better result by subsoil breaking when moisture condition is appropriate.
The differences of fertilizer placement did not have any effect on the yield.
For future studies, it is necessary to investigate the optimum season of subsoil breaking and it's remaining effects on the soil.
