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20155
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Subject: Agronomy × End date: 2015 × Start date: 2015 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Assesement of wheat productivity using CERES- wheat modelas influencedby varieties, planting dates and irrigation schedules in vertisols
    (JNKVV, 2015) Thorat, Tushar Narayan; Agrawal, K.K.
    ABSTRACT Wheat (Triticum aestivum L.) is one of the most important widely grown cereal grain crop occupying 17 % of the total cultivated land in the world. It is a major staple food for 35% of the world population and provides more calories and protein in the world’s diet than any other crop. Globally, it occupies an area of 221.1 m ha with an annual production of 697.8 mt and the average productivity of 3.1 t ha-1. In India, wheat is grown over 30 million ha with a production of 94 million tons and contributing about 43% to the country’s granary. In Madhya Pradesh, it is cultivated in 5.3 m ha of land with an annual production of 13.13 mt and productivity of 2.48 t ha-1. The major constraints to wheat yield in Madhya Pradesh are late sowing, poor varietal replacement and heat and moisture stress during grain filling stage of the crop. Sowing of wheat in Madhya Pradesh generally starts from mid November and ends in late December. Late sown wheat face low temperature in the earlier part and high temperature stress in the later part of the growing season. The delay in sowing date not only affects yield, but it also affects the yield components and other aspects of the growth and development. Hence, accurate knowledge of the sowing window of any particular variety at a particular location is critical to achieve an optimum grain yield. During recent years, area under irrigated wheat in Madhya Pradesh is increasing to a considerable extent. Farmers of this region apply irrigation in wheat 4 or 5 times, in addition to a pre-sowing irrigation. Considering upcoming scarcity of water, proper management of irrigation water is the most important parameter to sustain productivity of wheat crop. In current climatic change scenario with more number of extreme weather events like unpredictable rains during winter season, extreme temperatures, frost and hail storms etc. affect growth and productivity of wheat crop in this region. To combat with these situations, a crop simulated model will be useful tool to evaluate projected yield levels of wheat crop of this region that will help to the farmers, policy makers and stakeholders to cope up with the changing climate by making advance planning. Keeping above facts in view, a field experiment was conducted during the rabi seasons of 2013-14 and 2014-15 to assess the wheat productivity using CERES-Wheat model as influenced by varieties, planting dates and irrigation schedules in Vertisols at Research Farm, Department of Physics and Agro-meteorology, College of Agricultural Engineering, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (MP) with the major objectives i) Calibration of genetic coefficients of wheat varieties for projecting yield levels using CERES-Wheat model. ii) Assessment of effect of planting dates and irrigation schedules on growth and yield of wheat varieties. iii) Evaluation of weed infestation in wheat varieties sown at different planting dates and irrigation schedules and iv) Determination of the phenology and heat unit requirements of wheat varieties sown at different planting dates and irrigation schedules. The experiment was conducted in split plot design comprising six main plot treatments and three subplot treatments with three replications. Main plot consist of three sowing dates (27th Nov., 12th Dec. and 27th Dec.) and two varieties (GW 366 and MP 1202) while sub-plot consist of three irrigation schedules (Irrigation at CRI and flowering, Irrigation at CRI, flowering and milking, Irrigation at CRI, late jointing, flowering and milking). The soil of the experimental plot was clay loam in texture with neutral soil pH (7.3), medium in organic carbon (0.59%), and medium in available N (276.11 kg ha-1), P (17.47 kg ha-1) and K (311.14 kg ha-1). The results revealed that the genetic coefficients derived from the calibration of the CERES-Wheat model for both the varieties under different thermal regimes and four irrigations schedule showed reasonably very good agreement between simulated crop phenology, biomass accumulation and grain yield with measured data. The RMSE and d-values showed the accuracy of genetic coefficient better fit to project future wheat yield levels. Simulations of grain yield indicated fairly good predictions under different thermal regimes and three irrigations schedule with a clear tendency to overestimate phenology and biomass accumulation for both the varieties. The growth parameters of wheat like plant height, number of tillers, LAI, dry weight and chlorophyll content (%) decreased with delay in sowing on 12th and 27th Dec while significantly superior under 27th Nov. sown crop at all the intervals during both the years of experimentation. Wheat variety MP 1202 produced significantly taller plants and maximum number of tillers during later stages of the crop growth while variety GW 366 recorded significantly highest dry matter and chlorophyll content. The treatment receiving four irrigations at all the critical stages recorded significantly highest plant height, number of tillers, LAI, dry weight and chlorophyll content (%) than two and three irrigations at different periodical intervals. Yield attributes and yield were found higher under 27th November sown crop than the 12th and 27th December sown crops. The grain (5033 and 4849 kg ha-1) and straw (9506 and 6988 kg ha-1) yield was maximum under 27th Nov. sown crop and it proved significantly superior over 12th Dec. (4197 and 4041 kg ha-1 and 8199 and 6563 kg ha-1, respectively) and 27th Dec. (3503 and 3427 kg ha-1 and 7071 and 6359 kg ha-1 grain and straw, respectively) sown crops during both the years of experimentation. The variety GW 366 produced significantly highest grain (4379 and 4232 kg ha-1) yield than variety MP 1202 (4110 and 3960 kg ha-1) while straw yield was highest during first year of experimentation than variety MP 1202 (8051 and 7323 hg ha-1). The treatment receiving four irrigations recorded significantly highest grain (4396 and 4275 kg ha-1) and straw (9212 and 6931 kg ha-1) yield than rest of the treatments. Water use efficiency was maximum under 27th Nov. sowing and significantly superior over 12th Dec. and 27th Dec. sowing. The variety GW 366 recorded significantly higher WUE than variety MP 1202 during both the years of experimentation. Lower frequency of irrigations recorded significantly higher WUE than higher frequencies of irrigation. The highest weed density and biomass was found in 27th November sown crop than 12th December and 27th December sown crops. Wheat varieties and irrigation schedules showed no variations for density and biomass and wheat crop was mainly infested with major weeds viz., Melilotus indica, Chenopodium album, Anagallis arvensis and Physalis minima. The crop sown on 27th of November took longer duration for attaining different phenophases (50% flowering, milking and dough phases) and maximum GDD, HTU, PTU for maturity which got reduced with subsequent delay in sowing time and recorded the lowest values in the 27th December sown crop. The variety GW 366 took the highest calendar days (111 days), GDD, HTU and PTU for maturity than the variety MP 1202. Irrigation schedules showed practically equal number of calendar days, GDD, HTU and PTU at harvest. The HUE was highest under the crop sown on 27th November being the lowest in 27th December sown crop. Similarly, the variety GW 366 and four irrigations schedule recorded the highest heat use efficiency and grain yield. It can be concluded from the obtained results that the CERES-Wheat model could be acceptable for use as a research tool in the variable climatic conditions of Madhya Pradesh to project future wheat yield levels. The variety GW 366 was most suitable to grow than the variety MP 1202 due to its better performance and superiority of all the growth, yield and yield attributes under early planting date (27th Nov.) and four irrigations at CRI, late jointing, flowering and milking stage.
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    ThesisItemOpen Access