Soil and Water Engineering Department, College of Agricultural Engineering and Technology, Junagadh Agricultural University, Junagadh-362001, Gujarat, India.
The field experiment was conducted adopting 2-factorial split plot design. Total 16 treatments were different combinations of 3 water application levels (irrigation at 80%, 60% and 40% depletion of ASM) and five growth periods (vegetative, flowering, boll development, boll maturity stages and whole season) and 1 control (stress free conditions throughout season) replicating four times. The moisture stress free conditions (irrigation at 20% depletion of ASM) were maintained during the establishment stage (0–45DAS) and during the days other than the days of considered stage for particular water application/stress level. The relationship between the leaf area index and crop coefficient was developed. The water balance approach was adopted to find the actual evapotranspiration from the treatment plots. The reference evapotranspiration (ETo) was computed using the FAO recommended Penman-Monteith approach. The highest leaf area index was found as 4.430 at 160 days after sowing (DAS). The average Kc value was found as 0.52, 1.03, 1.56, 1.45 and 0.82, respectively, during the establishment, vegetative development, flowering, ball development and boll maturity. The crop coefficient (Kc) uruler water stressed condition was reduced.
Cotton crop, leaf area index, evapotranspiration, crop coefficient, moisture stress
