Mini-evaporation pan irrigation scheduling: a tool for improving on-farm water use efficiency for peanut and tree crops in south central coastal Vietnam

ABSTRACT

Groundwater dependent agriculture is an important component of South Central Coastal Vietnam’s (SCC VN) economy and maximising on-farm water use efficiency is a vital factor in sustaining the groundwater resource. During this study mini-evaporation pan (WUE) irrigation scheduling was introduced to cashew, peanut and mango crops in SCC VN. The mini-pan was compared against the common farmers’ irrigation practice for each crop. Irrigation treatments were also combined with several fertiliser treatments in cashew and mango experiments. The mini-pan improved WUE in each crop type with up to 1.4 KL ha^-1 water saved. Mini-pan irrigation scheduling also improved canopy productivity of cashew by 15 to 30 % and peanut yield by 22 %. Yield increases were not observed for mango but the number of irrigation events and, therefore, labour inputs were halved. Labour inputs for peanut were also reduced but increased labour inputs were required for cashew. Outcomes from this study indicate that the mini-evaporation pan has potential for use as a tool to assist SCC VN farmers improve on-farm WUE. The results also indicate that there is further scope to optimise WUE and opportunities to improve fertiliser and micro-nutrient management in tree crops in SCC VN.