The effects of plant population, spacing and weeding on yields of soya beans

Abstract

In trials in the 1973 short rains and the 1974 long rains at Kabete, Kenya, soyabean cv. Hill was sown at plant populations of 111 111, 250 000 or 1 000 000/ha on the square (10 X 10 cm, 20 X 20 cm or 30 X 30 cm) or in rows 50 cm apart and at within-row spacings or 2, 8 or 18 cm. Plots were either (a) kept weed-free for the 1st 4 wk, (b) after 4 wk, (c) at all times or (d) were not weeded. The short-rains trial failed due to shortage of rain; seed yields were 0-199 kg/ha. In 1974, yields ranged from 1.71 t/ha at 20 X 20 cm to 2.22 at 10 X 10 cm, and from 1.1 t in (d) to 2.50 and 2.52 t in (c) and (a), resp. There was no evidence that high plant populations helped to control weeds or that plant arrangement affected yields.