TITLE:
Efficacy and Economics of Different Need Based Nitrogen Management Approaches in Winter Rice
AUTHORS:
Nilufar Akhtar Jahan, Sabina Yeasmin, Md. Parvez Anwar, Md. Ariful Islam, Hamidur Rahman, A. K. M. Mominul Islam
KEYWORDS:
Rice Nitrogen Demand, Leaf Color Chart, SPAD Meter, Nitrogen Use Efficiency, Nitrogen Economics
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.13,
December
17,
2018
ABSTRACT: This experiment aimed to study the efficacy of different nitrogen (N) management approaches in winter rice. The experiment consisted of two rice varieties: 1) BRRI (Bangladesh Rice Research Institute) dhan29-an inbred and 2) Dhanigold-a hybrid, and eight N management approaches: 1) BRRI recommended N (control), 2) Soil analysis based N management, 3) N application based on Agro-ecological zone, 4) 20 kg·N·ha-1 at ≤35 SPAD (Silicon photon activate diode) value, 5) 30 kg·N·ha-1 at ≤35 SPAD value, 6) 20 kg·N·ha-1 at ≤3.0 LCC (leaf colour chart) value, 7) 30 kg·N·ha-1 at ≤3.0 LCC value and 8) Urea Super Granule. Between two varieties, hybrid Dhani gold produced higher grain yield (6.67 t·ha-1) than the inbred BRRI dhan29. Application of 20 kg·N·ha-1 at ≤3.0 LCC value gave the highest grain yield (7.10 t·ha-1), whereas the lowest grain yield (5.92 t·ha-1) was found from the SPAD approach with 20 kg·N·ha-1 at ≤35 SPAD value. In case of treatment interaction highest grain yield (7.34 t·ha-1) was found in BRRI dhan29 coupled with 20 kg·N·ha-1 at ≤3.0 LCC value with 18 kg·N·savings·ha-1 over control, maximum gross income (146,800 BDT·ha-1) and net benefit (142,120 BDT·ha-1), which was statistically identical with the grain yield from the interaction of Dhani gold and 30 kg·N·ha-1 at ≤3.0 LCC value but required 42 kg·extra·N·ha-1 (over control). The lowest grain yield (5.19 t·ha-1) was found when Dhanigold was coupled with 30 kg·N·ha-1 at ≤35 SPAD value, while the 20 kg·N·application·ha-1 at ≤35 SPAD value gave moderate yield (6.87 t·ha-1) with considerable higher gross (139,600 BDT·ha-1) and net (136,090 BDT·ha-1) incomes than the control (gross: 121,000 and net: 115,600 BDT·ha-1). The results reveal that 20 kg·N·ha-1 at ≤3.0 LCC value appeared as the promising practice for inbred BRRI dhan29, and 30 kg·N·ha-1 at ≤35 SPAD value for hybrid Dhanigold in terms of yield, N use efficiency and economic benefit of winter rice.