Nitrogen uptake from organic manures and chemical fertilizer and yield of lowland rice

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 (Nov-April) in Chhiata clay loam soil. The experiment aimed to evaluate the effect of N from organic and inorganic sources on dry matter and N uptake pattern of rice. We compared (i) N-control, ii) Optimum dose of nitrogen (164 kg N/ha) from urea, iii) 50% N from urea and 50% N from CD, iv) 50% N from urea and 50% N from PM, v) 100% N from CD and vi) 100% N from PM. Two mega varieties BRRI dhan28 and BRRI dhan29, were used as test crops. Application of N from urea, urea + PM and absolute PM increased dry matter significantly both in BRRI dhan28 and BRRI dhan29. The combination of urea and PM, absolute urea and absolute PM gave greater N uptake compared to other treatments in different growth stages of rice. The urea + PM treatment gave similar yield to that of urea in both the varieties, however, BRRI dhan29 gave about 1.17 t /ha higher yield than BRRI dhan28. The PM treatment gave similar yield to that with urea + PM in BRRI dhan28, but BRRI dhan29 gave significantly lower yield in PM than the urea + PM. Sole cowdung or poultry manure application produced significantly lower grain yield than urea + PM treatment and sole urea application. Because of insufficient mineralization of N from CD and PM, sole organic sources of N were not as good as combined use of organic and inorganic fertilizer amendments.