I. Wheat seedling emergence under controlled climates

Abstract

Abstract Experiments to determine the effects of the machinery and techniques used in creating direct-drilled seed grooves, and of covering the seeds, on wheat seed fate and soil physical characteristics are described. Comparisons were initially made in soils at either end of the available moisture range, and under contrasting controlled climatic conditions. Three coulter types were compared—an experimental chisel coulter, and commercially available triple-disc and hoe coulters. The technique used steel tillage bins containing dry, undisturbed fine sandy loam. In dry soil the seedling emergence count was significantly superior when the chisel coulter was used (58.4%) compared with the hoe coulter (31.3%), which was itself significantly superior to the triple-disc coulter (10.5%). In a moister soil the chisel and hoe coulters gave similar emergence counts (mean 68.8%), but both were superior to the triple-disc coulter (42.0%). A significant increase in seedling emergence was observed when the seeds were pr...