Emergence of Crops in Clay Soils of the Central Sudan Rainlands in Relation to Soil Water and Air-Filled Pore Space

Abstract

SUMMARYPoor emergence of crops is common during the rainy season on the clay soils of the central Sudan. Arachis hypogaea, Sesamum indicum, Hibiscus cannabinus and Gossypium hirsutum were studied under a range of soil water and air-filled pore space conditions by sowing on earth ramps; these were covered with water which was subsequently drained either completely or so as to leave water standing. Air-filled pore space was estimated by air-picnometer and water content by oven drying. The conditions in the sloping beds were related to those normally found in experimental plots (using Triticum aestivum). When the effective air-filled pore space was as low as 10 per cent all crops emerged poorly. Sesame emerged well at 40 per cent and all others at 20 per cent. The best emergence was found when water was drained completely at the shortest interval included in the experiments, i.e. on the day after covering the beds.