Effects of flooding and system of rice intensification on nitrogen use efficiency in rice production at Mkindo, Morogoro, Tanzania
An experiment was conducted in a glasshouse in 2016 at Sokoine University of Agriculture Morogoro Tanzania to study the effects of system of rice intensification (SRI) and flooding on Nitrogen Use Efficiency (NUE) for the lowland rice ecosystem. The soil used in the experiment was Eutric fluvisol and was analysed in the laboratory to evaluate soil fertility status. The soil was observed to have some plant nutrient below the critical range like N, 0.09%; K, 0.2 cmol kg-1;P, 4.13 mg/kg and OC, 1.23%. The experimental design was split-plot in randomized complete block design with four replicates.The main plot constituted two water management systems viz. SRI and flooding. Subplot treatments were nitrogen levels viz; 0, 125, 250 and 500 mg N kg-1 of soil. Rice variety used was SARO 5 (TXD 306) which is the improved rice variety adapted for lowland irrigated ecosystem. Analysed data for rice grain yield, Nitrogen Use Efficiency (NUE), dry matter yield and plant height did not show a significant difference (P< 0.05) due to the influence of SRI and flooding water management systems, whereby SRI yield ranged from 3.6 – 30.9 g grain yieldpot-1 and flooding was 5.9 – 25.0g grain yield pot-1. NUE ranged from 38.1- 66.1 mg grain mg-1 N for flooding and 54.8-85.7 mg grain mg-1 N. For SRI and flooding, the study confirmed that there was no significant difference (P< 0.05) on rice yield and NUE. The significant P< 0.05) difference on grain yield, NUE, dry matter and N concentration on rice plant was due to the effect of nitrogen application rates. The grain yield under SRI and flooding water management system ranged from 3.6 – 30.9 g pot-1 and 5.9 – 25 g pot-1 respectively.