The experiment was conducted at BARI, Gazipur during the rabi season of 2016-2017 with Pumpkin crop of variety, BARI Hybrid Mistikumra -1. It was a warm dry climate with maximum temperature which was recorded in April. The average relative humidity was recorded highest at the month of November and gradually decreased after words. A total rainfall of 113.4 mm was recorded during the crop season. The soil characteristics of the experimental field were sandy clay loam in texture with field capacity and bulk density was 29% and 1.50 g/cc respectively. Seven irrigation treatments were replicated four times with randomized complete block (RCB) design. The treatments were as follows:
T1 = FI using ring basin method at 10 days interval with mulch
T2 = FI using ring basin method at 15 days interval with mulch
T3 = DI25% using ring basin method at 10 days interval with mulch
T4 = DI25%using ring basin method at 15 days interval with mulch
T5 = DI50% using ring basin method at 10 days interval with mulch
T6 = DI50%using ring basin method at 15 days interval with mulch
T7 = Drip irrigation at 3 days interval with mulch
* 2t/ha of straw mulch was used for all treatments.
Land preparation was done by using tractor, power tiller etc. Fertilizers were applied at the rate of N75, P36, K60, S21, Zn2, B1.4 kg ha-1 and cowdung 5.0 t ha-1. All fertilizers except nitrogen will be applied in pit 5-7 days before planting and mixed thoroughly with the soil. N should be applied around the plant as side dressing at 15, 35, 55 and 75 days after planting under moist soil condition and mixed thoroughly with the soil as soon as possible for better utilization. Seeds were sown on 21 November, 2016 on seed bed to produce seedling and these seedlings were transplanted in experimental plots on 6 December, 2016 at the rate of 1 seedling/pit. Each treatment contains 4 plants and unit plot size was 4 m × 4 m. Pit dimension was 60 cm × 60 cm × 60 cm with a spacing of 2.5 m between two plants. A common irrigation of 15 Liter was applied from seedling to proper plant establishment. After one month of transplanting, every treatment was mulched by using paddy straw @ 2.0 t/ha. Sex feromen
trap was given to control fruit fly infestation. Pruning was done continuously up to 8 to 10 nodes on the main branch. To control disease infection and insect infestation otistin @20g/20 liter of water, Admire @ 4ml/15 liter of water and secure @ 30g/30 liter of water was sprayed. Weeding was done according to necessary.
The soil moisture was monitored in each plot by using the gravimetric method at 30 cm intervals down to 60 cm. Then, irrigation water amount of each plot was converted to time (min) and applied (treatment T1-T6). The amount of applied water was measured by time-volume technique. Soil moisture was collected before sowing, before irrigation and after harvest. Irrigation water was applied by ring basin method to bring the soil moisture up to field capacity considering the effective root zone depth of 60 cm. Soil moisture according to irrigation intervals was measured during the crop period. However, scheduled irrigation was applied at 31 December 2016. In case of drip irrigation, (treatment T7) two drippers were installed per plant and dripper emission was assumed to be uniform. A 400 liter tank was installed between two treatments and irrigated according to the design of irrigation treatment. Pumpkin fruit was harvested on 15 March 2017 (green fruit) and 17 April 2017 (matured fruit).
Seasonal evapotranspiration was calculated by adding applied water, effective rainfall (ER), and soil water contribution (SWC). Water productivity (WP) was calculated as the ratio of fruit yield and water use (WU). Vine length was monitored during the crop period. Data on number of fresh and damaged fruit, green unit fruit weight, matured unit fruit weight, green yield, matured yield, yield per plant and yield was recorded. All the data were analyzed statistically by using R software and mean separation was done duncan multiple range test at 5% level of significant.
Financial analysis was done with considering water-limiting situation (Ali et al., 2007, and English, 1990). In this situation water applied less than the crops actual need and saved water will be utilized to cover additional land. Total cost was calculated by adding total operating cost, interest on operating cost, and land use cost.