Improvement of crop yield, soil moisture distribution and water use efficiency in sandy soils by clay application

摘要

Cultivating sandy soil is a promising solution to overcome the fight against hunger especially in the developing countries. The main problems of sandy soil are water and nutrients deficiency. A containers experiment was carried out to study the enhancement of water productivity and crop yield of sandy soils treated with clay. The container size was 31 x 15 x 60 cm with one transparent side for visual viewing of the root development beside growth characteristics. The soil with bulk density of 1.5 g/cm~3 mixed with CaCO_3 and P_2O_5 fertilizers was packed in the containers to 50 cm height. Three treatments: control, overlay and incorporation with four replicates were studied. The control treatment was only sandy soil, 4% by weight of clay was overlaid on the surface of sandy soil to constitute the overlay treatment (5.6 kg soil with 21.4% clay overlay on 28.4 kg sandy soil with 93% sand) while the same percentage of clay was incorporated with the upper 20 cm of sandy soil to represent the incorporation treatment. All the treatments received the same amount of irrigation water and fertilizers during the growing stage. The results indicate that the leaf area in cucumber and stem length, stem diameter and number of leaves in maize were increased in the treatments treated with clay. About 2.5 times of yield was obtained from those treatments compared to control. Roots grew intensively in the layers treated with clay. The incorporation treatment retained higher amount of water compared to control but with small differences compared to overlay treatment. The water use efficiency and water saving is highly increased by clay application and about 45%-64% of irrigation water can be saved compared with control.