Impact of sewage sludge as organic manure on some soil properties, growth, yield and nutrient contents of cucumber crop

The present study was conducted in two field experiments with two soil types (sandy and calcareous soils) under greenhouse conditions at the Agricultural and Veterinary Training and Research Station of KFU, Al-Hassa area. The objective of the present study was to investigate the effects of different rates of sludge on some soil properties, growth, yield and nutrients status of leaves and fruits of cucumber plant. The experimental soils have sandy and sandy loam textures. All experimental plots (6 m2 area) cultivated with cucumber. Soil application of sewage sludge, at rates of 0 (control, with no sewage sludge), 25, 50, 75, 100 and 125 t ha-1 was used in the present study. Sewage sludge was mixed with top 30 cm surface layer of each plot, two month before planting of cucumber. The experiments were conducted in a randomized complete block design with 3 replications. The experimental plots received the same agricultural practices as recommended. The obtained results revealed that application of sewage sludge significantly altered the chemical properties of soil. Soil Electrical Conductivity (EC), soluble cations (calcium, magnesium, sodium and potassium), soluble anions (chloride and sulphate), available phosphorous and micronutrients (iron, manganese, copper and zinc) and heavy metals (cadmium, cobalt, lead and nickel) were increased in sandy and calcareous soils with increasing sewage sludge application rate. While, the soil reaction (pH) and HC03- contents were decreased as a result of sludge application. Also, application of sewage sludge improved physical properties of sandy and calcareous soils. It decreased the soil bulk density and increased saturation water content, porosity and organic matter content. Application of sewage sludge improved leaves and fruit contents of macro- and microelements of cucumber plant grown in sandy and calcareous soils. Also, the number of fruits and yield of cucumber were increased with increasing the rates of sewage sludge application. The highest level of application of sludge has a highest effect on the yield of cucumber plants. Generally, application of sewage sludge by mixing it with top 30 cm soil layer was found to be more effective in improving soil physical, chemical and fertility conditions. Moreover, using of sewage sludge as organic manure is considered as a source of nutrients that required for plant which led to increase the growth and the yield of cucumber crop. © 2009 Asian Network for Scientific Information.