Nitrogen Use Efficiency of Low Land Rice as Affected by Organic and Chemical Sources

Abstract

Given the increasing dairy and poultry industries, cowdung (CD) and poultry manure (PM) might become alternative sources of nitrogen (N) for rice production in South Asia. A field experiment was conducted during dry season (November-April) in Gazipur, Bangladesh. The experiment aimed to evaluate N use efficiency (NUE) in rice under varying sources of N application. Six treatments—1) N-control; 2) optimum dose of nitrogen (164 kg N ha﹣1) from urea; 3) 50% N from urea and 50% N from CD; 4) 50% N from urea and 50% N from PM; 5) 100% N from CD; and 6) 100% N from PM— were compared. Two mega varieties—BRRI dhan28 and BRRI dhan29—were used as test crops. In BRRI dhan28, the urea treatment had the highest agronomic use efficiency (AUE), utilization efficiency (UE) and partial factor productivity (PFP) followed by urea PM treatment and absolute PM treatment. In BRRI dhan29, the urea PM treatment had the highest AUE followed by absolute urea treatment while the urea PM treatment gave the highest UE and PFP followed by urea treatment and urea CD treatment. The absolute PM treatment gave the highest physiological efficiency (PE) followed by absolute urea treatment in BRRI dhan28. In BRRI dhan29, the absolute PM treatment had the highest PE followed by urea treatment and urea PM treatment. The absolute PM treatment had the highest agro physiological efficiency (APE) both in BRRI dhan28 and BRRI dhan29. Based on this finding, it is concluded that the practice of integrated use of organic and chemical fertilizer has the scope to reduce chemical fertilizer and also contribute to increasing nitrogen use efficiency.