Studies on development of reduced tillage cultivation in sugar beet. I. Response of the growth and yields to reduced tillage.

Abstract

Five experiments on the method of tillage were conducted to determine the growth and yields of sugar beets to changes of soil physics from 1979 to 1983 in Sapporo. The treatments (reduced tillage and normal tillage : both planted in late 10 days of April and conventional cultivation : planted in early 10 days of May) were set in black andosol. Sugar beets were grown with the method of transplanting. The following results were obtained. 1. Soil hardness between rows was harder in reduced tillage than in normal one, and solid ratio larger and air ratio smaller in reduced tillage. Soil hardness and three phase of soil between plants showed no differences between reduced tillage and normal tillage. 2. Soil water in response to making the tillage varied in soil layers of plowed soil and the growth stages. In the upper layer (0-5 cm) of reduced tillage, water ratio of soil was larger in early growth stage, and smaller in the lower layer (20-25 cm). 3. The growth was more vigorus in normal tillage than in reduced one. In the early stage, the growth of conventional cultivation was inferior, being planted 10 days after. But later, its growth was almost the same as that of the reduced tillage. 4. Root weight of normal tillage was the largest among three treatments and it was slightly larger in conventional cultivation than in reduced tillage. It seems to be clear that the tillage is useful to promote the growth of sugar beet. 5. Sugar content of reduced tillage was the largest among three treatments. Its available sugar yield was slightly larger than that of the conventional cultivation, because the ratio of harmful N and Na in the reduced tillage were smaller.