Efficiency of utilization of nitrogen fertilizers on representative soils from southern New South Wales

Abstract

The effects were examined in a glasshouse study of three forms of nitrogen fertilizer (urea, ammonium sulphate and sodium nitrate) on the yield, and nitrogen and phosphorus uptake of ryegrass (Lolium perenne) in six representative farming soils from the southern slopes and plains of New South Wales. The results indicated an average recovery of 82 per cent of applied nitrogen across the three forms of fertilizer and the six soils. Ammonium sulphate led to decreases in soil reaction of the order of 0.8-1.5 pH units and lower recoveries; sodium nitrate increased pH. Ammonium sulphate as a source of nitrogen is considered undesirable as it gave lower dry matter yields and nitrogen recovery values compared with the other fertilizer forms. In addition, because of its effect on soil reaction, it could lead to the loss of nutrients by leaching or fixation processes.