RESIDUAL EFFECT OF MODIFIED CHITOSAN POWDER ON THE NITROGEN MANAGEMENT OF BORO RICE

Abstract

The experiments were carried out at the research field of Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh during the Boro season (November to May, 2016) to investigate residual effect of modified chitosan (CHT) powder on nitrogen management and yield performance of Boro rice. Two individual field experiments were done using two individual rice variety i.e. BRRI dhan28 and BRRI dhan29. The experiments were laid out in randomized complete block design (RCBD) with four replications. The experiments were comprised of five treatments having four levels of modified CHT powder. The treatments were T = Modified CHT powder @ 0.5 t/ha (applied in the previous experiment) + 2/3 rd 1 N of the recommended dose (RD), T

=Modified CHT powder @ 1.0 t/ha (applied in the previous experiment) + 2/3 N of the RD, T = Modified CHT powder @ 2.0 t/ha (applied in the previous experiment) + 2/3 rd 3 N of the RD, T = Modified CHT powder @ 4.0 t/ha(applied in the previous experiment) + 2/3 rd 4 N of the RD and T =Modified CHT powder @ 0 t/ha + recommended N (control). Yield and yield contributing characters responded positively with increasing the doses of CHT powder except the following characters i.e. plant height, panicle length, total number of grains/panicle, filled grains/panicle, unfilled grains/panicle. The grain yield significantly decreased in T 5 treatment (5.47 t/ha) compared to T 5 1 (6.50 t/ha) control treatment due to the lack of nitrogen. But T treatment shows statistically identical grain yield (6.44 t/ha) to the control treatment (6.50 t/ha) in T which indicates the supplementation of N occurs in higher dose of CHT powder in T 5 treatment. Similarly straw yield (7.50 t/ha), number of effective tillers/hill (17.22) as well as biological yield (13.94 t/ha) of T 4 treatment shows statistically identical compared to the T 5 4 control treatment. The value of pH (7.01), organic carbon content (0.72%), and highest organic matter content (1.23%) in post harvest soil obtained in T 4 treatment were significantly greater than the T control treatment. From these results it can be concluded that yield and yield contributing characters of rice and some chemical properties of soil were improved due to the residual effect of modified CHT powder Taken together, our results suggest that modified CHT powder have some positive residual effect on slow releasing nitrogen supplementation, soil organic carbon and soil pH. 5 rd 2 4