Modelling of Regulated Water Management on Water Use Efficiency and Economics of Wheat (Triticum aestivum L.)

Abstract

Wheat is the most extensively grown cereal crop in the world, playing a crucial role in ensuring food security. Climate change impacts, soil degradation, pest and disease outbreaks, and market volatility all pose challenges to modern wheat cultivation affecting yields and profitability. Heat stress and erratic rainfall, exacerbated by climate change, are major concerns nowadays. Therefore, the present field experiment was laid out in wheat crop during rabi 2021-22 at Irrigation and Water Management Farm of Department of Soil Science, CSK HPKV, Palampur to study the effect of regulated water levels on the water use efficiency and economics of wheat (Triticum aestivum L.). The treatments include a selected combination of four deficit levels: high (50% ETC), medium (70% ETC), low (90% ETC), and no deficit (100% ETC), as well as three application phases: phase I (CRI and jointing), phase II (flowering), and phase III (dough stage). A total of eight combinations viz. FFF: Deficit free at all three phases; LLL: Low deficit at all three phases; MMM: Medium deficit at all three phases; FMM: Deficit free at phase I, Medium at phase II, Medium at phase III; HFM: High at phase I, Deficit free at phase II, Medium at phase III; MFH: Medium at phase I, Free from deficit at phase II, High at phase III; MFM: Medium at phase I, Free from deficit at phase II, Medium at phase III; HFH: High at phase I, Deficit free at phase II and High at phase III, were tested using a randomized block design and were replicated three times. The soil of the experimental site was silty clay loam in texture, acidic in reaction, medium in organic carbon, available potassium, high in available phosphorus and low in available nitrogen. Results showed that highest irrigation water use efficiency was recorded under MMM (41.1 kg ha-1 mm-1), followed by FMM (40.5 kg ha-1 mm-1) both being statistically at par and lowest irrigation water use efficiency was recorded under HFM (27.5 kg ha-1 mm-1) followed by HFH (27.7 kg ha-1 mm-1). Results showed that among all regulated water deficit regimes the adoption of regulated water deficit regimes of LLL (90% ETC at CRI & jointing, flowering and dough stage) resulted in water productivity comparable to water deficit free cultivation (FFF) with a water saving of 11 per cent under limited water availability conditions, in wheat crop. The net returns (₹ 72303 ha-1), benefit-cost ratio (2.35) and returns per unit of water use (₹ 229.89 mm-1) were higher under no deficit condition (FFF), but it was closely related to net returns (₹ 67603 ha-1), benefit-cost ratio (2.26) and returns per unit water use (₹ 222.81 mm-1) of low deficit at all three phases (LLL). The lowest net returns (₹ 33465 ha-1), benefit cost ratio (1.30) and returns per unit water use (₹ 116.61 mm-1) was observed under HFH followed by HFM.