Effect of Missing Nutrient Elements on Grain Yield of Wet Season Rice in Bangladesh

摘要

Background and objective: Long-term fertility study is one of the important factors to monitor changes in yield because of different nutrient management options and cropping systems involved in Asian regions. Many short-term and long-term fertilizer trials were conducted for intensive irrigated rice cropping patterns mostly to provide fertilizer rate, but did not considered sustainable soil management for soil health. The objective of the present study was to examine the effect of missing nutrient elements for a long time on rice yield, photosynthetic rate and residual soil fertility. Materials and Methods: The experiment was initiated on a permanent layout at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur during 2000 to 2008 in wet season. Seven treatments in randomized complete block design with four replications were imposed. Grain yield was determined at physiological maturity from three 5 m ~( 2 ) areas within each plot followed by bagging and threshing. Photosynthetic was measure by Li Cor 6400 (USA) machine during study period. Soil sample was analyzed for following standard methods. Results: It was found that grain yield was in decreasing trends for the missing elements that were similar with BR 11 and BRRI dhan 31. On an average, grain yield reductions were 11.6, 7.0, 10.6, 1.1 and 3.4 percent for -N, -P, -K, -S and -Zn, than complete fertilizer treatment (NPKSZn) respectively. Under no fertilization, the ability of soil was to produce 2.9 t·ha ~( -1 ) of BR11 and 3.1 t·ha ~( -1 ) of BRRI dhan 31 respectively. Photosynthetic rate of rice plant was always higher in complete fertilizer treatment (NPKSZn) than missing of any nutrient element. The decrease in photosynthetic rate was more pronounced with N missing than others for both the rice varieties. Conclusion: It is concluded that balance chemical fertilizers (NPKSZn) are to be used for sustained and/or increased rice production and to maintain soil fertility.