Raj Kumar PalDhir, Abhishek2020-01-162020-01-162019http://krishikosh.egranth.ac.in/handle/1/5810140534The Present study entitled “Effects of microclimatic modifications on phenological development and seed cotton yield using CROPGRO-cotton model” was carried out at two Locations viz., Punjab Agricultural University (PAU) Regional Research Station, Bathinda, (latitude 30°58‟N, 74°18‟E longitude and altitude 211m above mean sea level) and Faridkot (latitude 30°40‟ N, longitude 74°44‟ E and altitude 200m above mean sea level) during the kharif 2018. The soil of the both the experimental sites is sandy loam. The experiments were laid out with Bt cotton hybrid RCH 773 BGII and sown at three dates i.e. April 30, May 15 and May 30 with two row orientations (North-South: N-S and East-West: E-W) and three plant spacings (67.5cm×45.0cm, 67.5cm×60.0 cm and 67.5cm×75.0cm) in factorial split-plot design with three replications. The study indicated that the days taken to achieve various phenophases like emergence, first square, anthesis, boll opening and maturity (DAS) were found to be decreased with delayed sowing and recorded more days to attain various phenophases with 30th April sown crop. Delay in sowing from April 30 to May 15 reduced the cotton yield by 6.0% at Bathinda and by 13.1% at Faridkot and further delayed sowing from May 15 to May 30 reduced the seed cotton yield by 17.4% and 8.7% at Bathinda and Faridkot, respectively. Moreover, delay in sowing time of one month from April 30 to May 30, caused reduction in seed cotton yield by 22.36% and 20.37% at Bathinda and Faridkot, respectively. Besides, crop sown in East–West row orientation reported highest seed cotton yield than North–South direction at both the study regions. Similarly, among plant spacings, wider plant spacing of 67.5cm×75.0cm produced more seed cotton yield due to proper aeration and light distribution within the canopy. Among weather parameters, higher variation was observed between sowing dates, while lesser variation was recorded among row orientations and plant spacings. Furthermore, the model output in terms of seed cotton yield was found in good agreement over observed having higher value of R2 (0.75 for Bathinda and 0.83 for Faridkot) and lesser RMSE (253.8 kg ha-1 for Bathinda and 198.3 kg ha-1 for Faridkot). Similarly, simulated phenology of the crop was also shown close proximity over observed value having R2 value of 0.49, 0.51 and 0.61 at Bathinda and 0.59, 0.43 and 0.87 at Faridkot for emergence, anthesis and maturity. Hence, the CROPGRO-cotton model can be used as research tool for the prediction of cotton phenology and yield of the crop.ennullThesis