Chlorophyll Meter-Based Dynamic Nitrogen Management in Wheat (Triticum Astivum L.) Under Subtropical Environment

Md Nazmul Hasan¹, Qazi Abdul Khaliq¹, Md Abdul Baset Mia², Md Nasimul Bari¹, Md Rafiqul Islam¹*

¹Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh.

²Department of Crop Botany, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh.

Corresponding author Email: rafiarib@yahoo.com

DOI : http://dx.doi.org/10.12944/CARJ.4.1.05

Abstract:

Injudicious use of nitrogen fertilizer is very commonly practice in tropical and subtropical regions. SPAD (Soil-Plant Analysis Development) chlorophyll meter-based nitrogen top-dressing may reduce the risk of under or over application. Considering this, the study was conducted to measure the relative advantage of dynamic methods of nitrogen fertilization over conventional method in wheat field. For this, conventional nitrogen (CN) treatments i.e. CN₆₀, CN₉₀, CN₁₂₀, CN₁₅₀ at 60, 90, 120 and 150 kg ha^-1 were compared with four chlorophyll meter-based dynamic nitrogen (DN) treatments i.e. DN₈₀, DN₉₀, DN₁₂₀, DN₁₀₀ at 80, 90, 120 and 100 kg ha^-1 nitrogen. Irrespective of treatments, SPAD meter readings remained above 45 (threshold value) beyond 50 days after seeding, but plant performance varied depending on the methods and doses used in nitrogen top-dressing. Treatment CN₁₅₀ performed better displaying the highest SPAD values, total dry matter production, leaf area index, crop growth rate and net assimilation rate resulting to the highest grain yield (5.10 t/ha) in wheat. The plant performance in DN₁₂₀, DN₁₀₀, DN₉₀ and CN₁₂₀ treatments were statistically similar to that of CN₁₅₀ in respect of all most all plant characters studied. Comparing with CN treatments, DN treatments resulted in better plant growth and grain yield at the same level of nitrogen fertilizer. This is because of maintaining need-based fertilizer at early stage of wheat and application of appropriate amount of nitrogen fertilizer in each time in DN treatments compared to CN treatments. The result suggests that chlorophyll meter can be effectively used for real time nitrogen top-dressing to increase productivity of wheat.

Keywords:

SPAD; Chlorophyll Meter; Nitrogen; Top-dressing; Wheat

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