Cultivation of beans ( Phaseolus vulgaris L.) in limed or unlimed wastewater sludge, vermicompost or inorganic amended soil

Abstract

Wastewater sludge can be vermicomposted to increase its nutrient content and reduce pathogens. The effect of vermicompost wastewater sludge on soil characteristics and growth of bean plants ( Phaseolus vulgaris L.) was compared with that of inorganic fertilizer, untreated sludge or sludge treated with lime to pH 12. Plants cultivated in vermicompost amended soil developed best while those amended with inorganic fertilizer least. Bean plants grown in the unlimed amended soil had the highest total N content of 3.97 g kg −1, but only 6 active and 8 total nodules. Plants cultivated in unamended soil and added with inorganic fertilizer had >20 active and total nodules, but ≤2.12 g N kg −1 dry plant. It was found that limed and unlimed sludge stimulated development of bean plants to a larger extent than those cultivated in inorganic fertilized soil or unamended soil in the greenhouse, but less than those cultivated in vermicompost amended soil.