Effect of drip irrigation and nitrogen fertigation on water usee efficiency (WUE) and cost economics of guava cv. Khaja

A field experiment was conducted at the Central Research Farm, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal to study the effect of drip irrigation and nitrogen fertigation on performance of guava (Psidium guajava L.) in New Alluvial Zone of West Bengal during February 2007–2008. The experiment was carried out with three levels of irrigation (D₁, D₂ and D₃) along with three levels of nitrogen fertigation (N₁, N₂ and N₃) and these three treatments were compared with conventional irrigation system. The water use efficiency (WUE) and benefit-cost (B: C) ratio were evaluated. Benefit-cost analysis was carried out to determine the economic feasibility of using drip irrigation. The cost of drip irrigation system includes depreciation, prevailing bank interest rate, repair and maintenance of the system. The interest rate and repair and maintenance cost of the system were 12 and 1% per annum of the fixed cost respectively. The useful life of drip system was considered to be 10 years. The cost of cultivation includes expenses incurred in field preparation, cost of seedlings, fertilizer, weeding, crop protection measures, irrigation water and harvesting with labour charges. The income from both the surface and drip irrigation was evaluated and then the benefit-cost ratio was calculated. The B: C ratio was found maximum (2.84) in drip irrigated treatment (along with nitrogen fertigation) than that of surface irrigated treatment. Water use efficiency (WUE) was greatly influenced by drip irrigation and nitrogen fertigation. Maximum WUE (35.1 kg/ha/mm) was noted in the treatment which was irrigated with drip at 80% ETc. The lowest WUE (23.2 kg/ha/mm) was noted in the conventional irrigation system.