S. K. Biswas
Senior Scientific Officer
IWM Division, BARI, Gazipur-1701.
A. Khatun
Principal Scientific Officer
IWM Division, BARI, Gazipur-1701.
A. J. Mila
Scientific Officer
IWM Division, BARI, Gazipur-1701
P. K. Sarkar
Chief Scientific Officer
IWM Division, BARI, Gazipur-1701
A. R. Akanda
Principal Scientific Officer
IWM Division, BARI, Gazipur-1701
A field study was conducted at BARI, Gazipur during the year of 2011–2012 and 2012–2013 to investigate the effect of different irrigation regimes on onion cultivation. Seven irrigation regimes were considered. Marginal water productivity (MWP) and elasticity of water productivity (EWP) were calculated. A continuous increasing trend in growth parameters and yield was recorded with the increase in seasonal evapotranspiration (SET) up to 140% ETc. Though SET requirement for maximum yield (21.7 and 15.47t ha-1) was 249 and 271 mm but the highest water productivity (WP) of 9.22 and 6.58 kg m-3 was attained with relatively low SET of 202 and 189 mm in the first and second year, respectively. Sprinkler irrigation was found superior over the conventional one. Sprinkler irrigation with 140% ETc found most suitable for bulb yield. WP was found highest in sprinkler irrigation with 100% ETc and declined with the increase in ETc. In water constraint situation, 100% ETc would be the most appropriate irrigation level for onion production with sprinkler irrigation system. This study also confirmed that critical levels of SET needed to obtain maximum bulb yield or WP, could be obtained more precisely from the knowledge of MWP and EWP.
Sprinkler irrigation, Water productivity, Onoin
Crop-Soil-Water Management
This study was formulated for onion crop with the following objectives: (i) to investigate the performance of onion crop under sprinkler irrigation (ii) to develop the relationship between ET and bulb yield, WP; (ii) to determine the water productivity functions (MWP and EWP); (iii) to estimate the critical level of ET for obtaining maximum WUE and maximum yield. (iv) to evaluate the economic feasibility of sprinkler irrigation for onion production.
A field study was carried out with onion (cv. BARI Piaz-1) under sprinkler irrigation system during the rabi season of 2011–2012 and 2012–2013 at the research field of IWM, BARI (Latitude 24.000N, Longitude 90.250E and altitude 8.40 m msl), Gazipur. A total of seven irrigation treatments were tried. Six treatments were based on crop evapotranspiration (ETc) and one treatment was kept as farmers practice. The treatments were as follows:
T1 = Surface irrigation 15 days interval (Farmers’ practice/standard practice)
T2 = Sprinkler irrigation at 60% ETc
T3 = Sprinkler irrigation at 80% ETc
T4 = Sprinkler irrigation at 100% ETc
T5 = Sprinkler irrigation at 120% ETc
T6 = Sprinkler irrigation at 140% ETc
T7 = Sprinkler irrigation at 160% ETc
Each treatment was replicated three times and irrigated using a sprinkler irrigation system while farmers practice treatment was irrigated using pipe irrigation at an interval of 15 days. Irrigation interval for sprinkler irrigation system was 7 days. Each plot was of 4 × 3 m size surrounded by 1.5 m wide buffer strip to restrict lateral seepage of water in-between adjoining plots. Forty days old seedlings of onion (cv BARI Piaz- 1) were planted at 20 cm × 10 cm spacing on 22 December 2012 in the first year and 30 December 2013 in the second year. During land preparation, farm yard manure @ 5 t ha−1 was properly mixed with the soil. Fertilizers were applied @ 115 kg N, 60 kg P and 60 kg K per hectare. Onions were harvested when they turned yellowish on 22 March 2012 and 25 March 2013. Soil water content was measured at 7-day intervals before and after irrigation by gravimetric sampling. The daily irrigation requirement for the crop was calculated by subtracting the effective rainfall from the computed ETa.
Annual Report, IWM Division, BARI
Knowledge on SET is an indicator to fix up the amount of water to be irrigated in terms of maximum yield as well as optimum utilization of irrigation water. Thus precise estimation of SET by using the concepts of marginal water productivity and elastic water productivity will be a useful tool for irrigated agriculture. Under water scarce condition, to achieve maximum WP (7.9 kg m-3), SET requirement would be 196 mm which correspond to the tuber yield of 15.86 t ha−1. If water is not a limiting factor, then maximum yield (18.58 t ha−1) can be achieved with 260 mm of SET. Though sprinklers are more costly to purchase and operate than surface systems, but farmers may achieve higher yield and higher BCR with sprinklers, provided the systems are operated and maintained correctly.
Report/Proceedings