Application of Alfalfa Residue, Poultry Manure and Potassium Fertilizer on some Soil Properties and Onion Yield

This study focused on the effect of organic manures as well as potassium fertilizer on some soil properties and onion yield at the field condition. The experiments were carried out as factorial in a randomized complete block design with three replications. The treatments were poultry manure (10 t ha-1)، alfalfa residue (10 t ha-1) and control each together with two levels of potassium fertilizer as K2O (0 and 250 kg ha-1). The results showed that application of poultry manure and alfalfa residue resulted in yield increasing about 57. 7 and 40. 9 % in comparison to the control، respectively. On average، the onion yield for the potassium treatment was 7. 8 % higher than for the untreated one. The application of poultry manure and alfalfa residue increased final infiltration rate 73. 2 and 56. 1 %، respectively. Inversely، potassium fertilizer caused a significant reduction in the final infiltration rate. Moreover، application of organic manures particularly poultry manure، significant increases in saturated moisture، porosity، EC، organic carbon and available phosphorous and decrease in bulk density and pH was observed، while potassium only increased soil EC، significantly. Application of poultry manure and alfalfa residue increased soil organic carbon 129. 8 and 80. 2 % and available phosphorous 104. 8 and 51. 9 %، respectively. Among different soil properties، organic carbon showed the highest influence on yield increase.