Karunakar, Dr. A.P.GANVIR, MAHIPAL MAROTI.2020-09-222020-09-222018-12-17GANVIR, MAHIPAL MAROTI. (2018). Exploring resilience of rainfed cotton to weather variability through high plant density and fertilizer regime: Field andSimulation study. Department of Agronomy, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Ph. D. 2018. Print. xx,304p.(Unpublished).https://krishikosh.egranth.ac.in/handle/1/5810151795A field experiment was conducted during kharif season of 2013-14 and 2014-15 at the All India Coordinated Research Project for Dryland Agriculture (AICRPDA), Dr. PDKV, Akola. The experiment was laid out in split plot design with three replications keeping six combinations of two weather variability viz., monsoon sowing and late sowing with three plant densities i.e. 60 x 15 cm (1,11,111 plants ha-1), 60 x 10 cm (1,66,666 plants ha-1) and 45 x 10 cm (2,22,222 plants ha-1) under main plot and three fertilizer regimes viz., 100% RDF (60:30:30), 150% (90:45:45) and 200% (120:60:60) NPK kg ha-1 under sub plot. The simulation of cotton phenology and seed cotton yield was carried out through DSSAT v. 4.5 CROPGRO-cotton model.A field experiment entitled “Exploring resilience of rainfed cotton to weather variability through high plant density and fertilizer regime: Field and simulation study” was conducted during kharif season of 2013-14 and 2014-15 at the All India Coordinated Research Project for Dryland Agriculture (AICRPDA), Dr. PDKV, Akola. The experiment was laid out in split plot design with three replications keeping six combinations of two weather variability viz., monsoon sowing and late sowing , with three plant densities i.e. 60 x 15 cm (1,11,111 plants ha-1), 60 x 10 cm (1,66,666 plants ha-1) and 45 x 10 cm (2,22,222 plants ha-1) under main plot and three fertilizer regimes viz., 100% RDF (60:30:30), 150% (90:45:45) and 200% (120:60:60) NPK kg ha-1 under sub plot. Cotton crop under monsoon sowing exhibited better growth and development with better canopy radiation interception and yielded higher seed cotton encountering comparatively better rainfall and thermal regime across the growing period with prevalently high canopy temperature depression and accrual of higher thermal units with high photo-thermal use efficiency. Population density of 60 x 15 cm (1,11,111 plants ha-1) produced higher growth and yield attributes of individual plant compared to population density of 60 x 10 cm (1,66,666 pl/ha) and 45 x10 cm (2,22,222 plants ha-1). However, higher planting density of 45 x 10 cm (2,22,222 plants ha-1) produced maximum seed cotton yield per hectare as increased number of plants compensated for fewer yield attributes plant-1 and cumulatively yield output was higher.Application of higher fertilizer regime 120:60:60 NPK kg ha-1 exhibited increased growth and yield attributes and; produced higher seed cotton yield availing higher thermal units with high photo-thermal use efficiency. Late sowing, higher plant density and lower fertilizer regime prompted earliness in phenological events and total crop duration. Crop under monsoon sowing, higher plant density and higher fertilizer regime recorded higher uptake of N, P and K in cotton seed, stalk of cotton and total uptake. Fibre length and micronaire value was more with monsoon sowing and higher fertilizer regime. Monsoon sowing and normal plant density showed higher seed index.By and large, rainfall, minimum temperature and humidity positively influenced the seed cotton yield whereas higher day time (maximum) temperature and diurnal temperature showed negative impact on seed cotton yield.CROPGRO-Cotton model simulation performance in respect of phenological phases was found to be reliable. The model predicted the seed yield reliably under weather variability and fertilizer regimes; however, performance of simulation of seed cotton yield was closely predicted in normal population density (100%) and with a greater degree of variability (underestimation) across higher population density (150% and 200%) . Both monsoon and late sowing recorded maximum seed cotton yield under high planting density of 45 X 10 cm (2,22,222 plants ha-1) with fertilizer regime of 120:60:60 NPK kg ha-1 followed by plant density of 45 X 10 cm (2,22,222 plants ha-1) with fertilizer regimes of 90:45:45 NPK kg ha-1. Pooled net monetary returns was statistically equal with the application of fertilizer 120:60:60 NPK kg ha-1 and 90:45:45 NPK kg ha-1 with similar benefit:cost ratio.EnglishCrop, Field crop, Biological yield, Canopy temperature, Canopy temperature depression, Cotton, Correlation, DSSAT CROPGRO- Cotton, Diurnal temperature, Fertilizer regime, Growth, Light interception, Light transmission, Nutrient uptake, Plant density, Properties, Rainfall, Relative humidity, Regression, Seed cotton yield, Temperature, Weather variability,Thesis