Abstract
With planting by a no-tillage seeder of triple disc method (no-tillage system), we examined the effect of soil physical properties on the seeding accuracy and early growth of silage corn (Zea mays L.) on the compacted soil field by previous several runnings of tractor. Soil physical properties, such as soil hardness, soil density, soil clod-size and shearing resistance in the no-tillage system increased compared with the field plowed by rotary tiller. At the same time, the percentage of seedling establishment and early growth in the no-tillage system were much smaller than those in the plot plowed by rotary, though seed had been installed into a no-tillage seed slot made by a triple disc opener. These results indicate that tractor running causes deterioration of soil physical property for the germination and early growth of silage corn. Since the rise in shearing resistance decreased harrowing effect by triple disc, bigger clod-size of soil resulted in the decrease in the percentage of seedling establishment and additionally the rise in soil hardness which suppressed early growth of the crop. From these results, it should be effective to prepare the finer soil clod that contact with seeds more tight to obtain higher percentage of seedling establishment in silage corn.
