Germination and Yield of Barley When Grown in a Water‐Repellent Sand1

Uneven penetration of rainwater into water‐repellent sands decreases germination of annual plants. To assess the importance of this problem, germination and yield of barley (Hordeum vulgate cv Prior) were observed at two field sites on water‐repellent sands in South Australia. Germination continued throughout the wet winter period and 9 viable ungerminated seeds were recovered from 60 cm of row 3 month after sowing. Germination was controlled by the uneven penetration of rainwater into the soil. At Site I, the number of plants 1 month after sowing averaged 1.6/m in the poor plots and 19.2 plants/m in the good plots. Subsequently 11.0 plants/m grew in the poor rows but produced only 150 kg grain/ha compared with 1,440 kg/ha in the good plots while the average yield for this site was 560 kg/ha. Similar results were obtained at Site II where good plots yielded 1,830 kg grain/ha compared with 16 kg/ha in the poorest rows and an average yield for the site of 1,160 kg/ha. Delayed and incomplete germination of cereals on water‐repellent soil can cause very low grain yields.