George F Antonious
Recycling animal manure could be explored in agricultural production for growing vegetable crops to reduce dependence on inorganic fertilizers. Arugula (Eruca sative) and mustard (Brassica juncea) were grown in a randomized complete block design (RCBD) under four soil management practices: 1) control (no-mulch untreated soil); 2) sewage sludge; 3) horse manure; and 4) chicken manure. Sewage sludge compost elevated soil urease and invertase activities indicating increased soil microbial activities. Total soil enzyme activities were significantly (P < 0.05) greater in sewage sludge amended soil compared to no-mulch native soil. It could be concluded that sewage sludge and chicken manure increased soil fertility and the activities of soil urease and invertase could be used as an indicator of soil biological activity after addition of soil amendments. This investigation revealed that soil incorporated with sewage sludge or horse manure promoted biomass production of arugula and mustard by 26 and 21%, respectively compared to no-mulch bare soil. Future trends in agricultural production should make a good use of natural resources to reduce dependence on synthetic fertilizers.