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 (SCC) Vietnam’s economy and maximising on-farm water use efficiency (WUE) is a vital factor in sustaining the groundwater resource. During this study, mini–evaporation pan irrigation scheduling was introduced to cashew, peanut and mango crops in SCC Vietnam. Mini-pan scheduling was compared with the farmers’ commonly used irrigation practice for each crop. Irrigation treatments were also combined with several fertiliser treatments in cashew and mango experiments. Mini-pan use improved WUE in each crop type with up to 1.4 kL/ha water saved. Mini-pan irrigation scheduling also improved canopy productivity of cashew by 15–30% 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 farmers in SCC Vietnam improve on-farm WUE. The results also indicate that there is further scope to optimise WUE and opportunities to improve fertiliser and micronutrient management in tree crops in the SCC region.