EFFECTS OF ORGANIC AND INORGANIC SOURCES OF NITROGEN ON THE YIELD, NUTRIENT UPTAKE AND NITROGEN USE EFFICIENCY OF BRRI DHAN 29

Abstract

A field experiment was conducted during the boro season of 2014 at the Soil Science Field Laboratory, Hajee Mohammad Danesh Science and Technology University, Dinajpur to evaluate the effects of organic and inorganic sources of nitrogen on the yield, nutrient uptake and nitrogen use efficiency of BRRI Dhan 29. The experiment was laid out in the randomized complete block design (RCBD) with four replications. There were seven treatment combinations comprising of incorporation of recommended dose of nitrogen (RDN) from organic and inorganic sources along with a control. Cowdung and urea was used as organic and inorganic sources of nitrogen, respectively. All the treatments also received the recommended doses of P, K, S and Zn through TSP, MP, gypsum and ZnSO4, respectively. The grain and straw yields as well as the yield contributing characteristics like plant height, number of tillers hill-1 , number of effective tillers hill-1 , panicle length, number of grains panicle-1 , number of filled grains panicle-1 and 1000 grain weight were significantly influenced by the different treatments. The highest grain (5.89 t ha-1 ) and straw (6.14 t ha-1 ) yields were recorded in the treatment T1 (100% RDN from urea) closely followed by T6 (80% RDN from urea + 20% RDN from cowdung). In general, organic source of nitrogen alone did not produce higher yields but incorporation of both sources produced higher yields. A significant increase in the NPKS contents as well as their total uptake and nitrogen use efficiency were observed due to combined application of nitrogen from cowdung and urea. Analyses of post-harvest soil fertility status revealed that the application of cowdung as organic source of nitrogen positively influenced the bulk IX density, porosity, organic carbon, total N, available P, exchangeable K and available S contents while all the treatments slightly decreased the bulk density and soil pH. Considering the above results, the treatment T6 may be suggested for sustained rice cultivation.