Nitrogen Uptake Dynamics and Dry Matter Production of Rice in Response to Nitrogen Fertilizer Application

Abstract

Nitrogen is one of the most important nutrients in rice production but its uptake dynamics remained relatively unexplored. The present investigation evaluated uptake dynamics over the growing season at different levels of nitrogen fertilizer application. The experiment was conducted during Boro season (November-April) at Bangladesh Rice Research Institute experimental farm, Gazipur, Bangladesh. The experiment involved two modern rice varieties—BRRI dhan28 and BRRI dhan29 and six N rates: 0, 50, 100, 150, 200 and 250 kg⋅ha. The N uptake pattern was determined at every 15 days from transplanting to maturity. At 150 kg⋅N⋅ha, initially N uptake was 0.1 kg⋅ha⋅day which increased to 0.2 in BRRI dhan28 and 0.4 in BRRI dhan29, respectively. During 30 to 45 DAT, per day N uptake was 2.0 kg⋅ha in BRRI dhan28 and 2.2 in BRRI dhan29 which increased to the peak at 2.4 and 2.8 kg⋅ha⋅day in BRRI dhan28 and BRRI dhan29, respectively, during 45 to 60 DAT. The grain yield showed a stronger correlation with N uptake during 45 to 60 DAT in both the varieties. The highest N uptake contributed to the highest dry matter production in both the varieties.