Effects of watering technique and pot size on response of soybean cultivars to applied zinc

Abstract

Effects of two watering techniques and three pot sizes on the growth of two soybean cultivars in a soil (vertisol) of low zinc status were studied in the glasshouse. Plants responded more to applied zinc when supplied with a constant water table (cwT) than when irrigated by the more common watering-to-weight method. The cwT technique accentuated zinc response through stimulation of growth in plants supplied with zinc, not because of intensified zinc deficiency. Nodule production was also greater in cwT-treated plants than in plants regularly watered to weight. Experimental precision was not significantly different in three experiments, despite differences between them in soil quantity per pot (1500, 750 and 375 g) and plants per pot (three, two or one). The advantages of the c w ~ system, and its use with a single plant growing in 375 g of soil as the test unit, are discussed in relation to screening soybeans for reaction to zinc deficiency.