Chemical seedbed preparation and the efficiency of nitrogen utilization by sod-sown oats. 1. Comparison of seedbeds

Abstract

Conventional sod-seeding in a paspalum (Paspalum dilatatum) sward was compared with both chemically prepared and cultivated seedbeds for growing oats. Experiments were conducted on red and chocolate basaltic soils on the North Coast of New South Wales. Three times of sowing, and three rates of herbicide for chemical seedbed preparation were also used in the red soil experiment, and two times of sowing were used in the other. Sod-sown oats yielded poorly on the red soil and either cultivation or chemical seedbed preparation gave much higher yields at all times of sowing. Sod-sown oats grew better on the chocolate soil and yield increases from cultivation or chemical seedbed preparation were proportionately less than on the red soil. There was a trend, but not significant, for higher yields to be obtained from cultivated than from chemical seedbeds in the earliest sowings on the red soil. This effect was significant on the chocolate soil. The results indicate that under low fertility conditions, it is essential to use some form of seedbed preparation when growing oats.