Enhancing Broccoli (Brassica oleracea L. var. italica Plenk) Yield with Efficient Water Use: A Marginal Analysis of Irrigation and Water Saving Techniques

Abstract

Climate change impacts are more evident in agriculture sector at micro level in general, and technological interventions (e.g. cropping patterns, crop diversification, soil health management, rainwater harvesting, use of modern irrigation system with precise irrigation quantity etc.) are some of the interventions which can play a significant role in enhancing the current capacity of farmers to cope with climate change. The experiment was conducted at the “C” Block  Research Farm at Kalyani of the BCKV, Mohanpur, India during winter season (November–January) of the year 2016–2017and 2017–2018; to study the relationship between ET and fruit yield, water use efficiency (WUE), net evapotranspiration efficiency (ETWUE) and irrigation use efficiency  (IWUE), to develop the MWUE and EWP functions, to estimate the critical level of ET for obtaining maximum WUE and maximum yield, to screen out most suitable and efficient water saving techniques on the basis of the above production function.  The experimental design was a split plot with four irrigation regimes  (I1.0, I0.75, I0.50 and I0.25) as main treatment and five water saving techniques {no water saving techniques (MC – controlled); MH - hydrogel; MK - potassium nitrate (KNO3) ;  MBP - black polyethylene mulch and MPS - paddy straw mulch  as sub treatment. Net head fresh yield under I1.0 was 15.17 Mg ha-1; which reduced by 6, 19 and 35 % respectively under I0.75; I0.50 and I0.25. Different water saving techniques increased yield by 5-34 % over non-water saving techniques condition. Irrespective of water saving techniques, WUE, ETWUE and IWUE were found to be the highest (11 kg m−3, 15 kg m−3 and 17 kg m−3 respectively) under moderately wet (I0.75) soil environment. Among different water saving techniques, MBP recorded the highest WUE (13 kg m−3), ETWUE (19 kg m−3) and IWUE (18 kg m−3) values. The marginal analysis showed difference in critical values of SET against maximum WUE and maximum yield was narrowed down under bio or polyethylene mulches and hydrogel compared to the bare situation.