Simulation of growth and yield of wheat (Triticum aestivum L.) and soil moisture using Ceres Wheat Model in Bhabhar and Tarai agro-climatic zone of Uttarakhand
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Date
2011-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Field experiments were conducted at Norman E. Borlaug Crop Research Center of G.B. Pant University of Agriculture and Technology, Pantnagar (Latitude 290 N, Longitude 79030´ E and Altitude 243.84 m above msl) during rabi seasons of 2009-10 and 2010-11 to simulate the effect of various irrigation treatments on growth and yield of wheat (Triticum aestivum L.) and soil moisture using CERES-wheat model in Bhabar and Tarai agroclimatic zone of Uttarakhand. Experiment was laid out in RBD under five irrigation treatments viz. irrigations at crown root initiation (CRI) stage , I1; CRI + late jointing (LJ) stage, I2; CRI + LJ + milking (M) stage, I3; CRI + late tillering (LT) + flowering (F) stage + M, I4 and CRI + LT + LJ + F + M, I5 of the wheat crop with three replications. The analyzed data of experiments have shown that maximum simulated (3.98) and observed (5.01) LAI was obtained at 90 DAS during 2010-11 compared with 2009-10. Days taken to anthesis were underestimated during the 2009-10 and were overestimated during 2010-11. Model simulated the days to physiological maturity better (R2=0.948) in all the treatments during 2010-11. The days to harvesting maturity under all the irrigation treatments were underestimated by the model during both the years. A slightly higher efficiency of model (R2=0.674) was obtained in 2010-11. The harvest index was also overestimated under all the treatments except I2 during 2009-10 and I4 in 2010-11 crop season. The decrease in observed soil moisture content with increase in the soil depth was simulated well by the model under all the irrigation treatments. The perfect match between simulated and observed soil moisture content was observed at 130 DAS under I2 at 45-60 cm and at 104 DAS under I5 treatment at 15-30 cm soil depth during 2009-10. The extractable soil moisture (ESM) was simulated best at 62 DAS under I3 during 2009-10 and at 20 DAS under same treatment during 2010-11. The model was found to perform most efficiently in predicting the TPSM at 130 DAS under I2 treatment during 2009-10 and at 44 DAS under I4 treatment during 2010-11. Results have shown that maximum root
length density (1.31 cm cm-3) was obtained under I5 treatment at 0-30 cm soil depth at 90 DAS during 2009-10. Higher value of shoot count (365.62 m-2) was obtained under I5. Significantly more number of days to anthesis (80.00 and 88.33) ,physiological maturity (117.67 and 127.33 ), harvesting maturity (137.00 and 151.00), grain yield (49.21 and 48.90 q ha-1), straw yield (104.23 and 104.90 q ha-1), biological yield (153.44 and 153.80 q ha-1) and water use (41.89 and 46.97 cm) were obtained under I5 during 2009-10 and 2010-11 crop seasons. Significantly more spike length (10.05 and 11.03 cm ) and 1000 grain weight (38.02 and 38.70 g) was recorded under I5 and I4 during 2009-10 and 2010-11, respectively. The effect of different irrigation treatments on the grain weight per spike was found to be non-significant during both of the crop seasons. It is concluded from this study that CERES model simulated growth, development and yield of wheat with reliable precision during both years. In simulating most of wheat crop characters the model was observed to be more efficient in 2010-11 than 2009-10, which may be attributed to the increased crop duration, well distributed rainfall and relatively lower atmospheric temperature during 2010-11. The CERES wheat model has tremendous potential in predicting the yield of wheat crop and soil moisture under diverse agro climatic conditions especially in the locations where capital is the main constraint in conducting of the field experiments and providing of the necessary lab facilities.
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Thesis-PhD
Keywords
simulation, growth rate, yield increases, wheats, soil moisture, Ceres Wheat Model, Tarai, agroclimatology, Uttarakhand, irrigation