Farming communities in the south central coastal region of Vietnam face many challenges relating to infertile sandy soils and water shortages. Since 2007, four projects supported by A$5.4 million from ACIAR have focused on seeking solutions.
The region relies heavily on groundwater for crop irrigation during the dry season, but inefficient irrigation techniques lead to water wastage, nutrient leaching, faster depletion of groundwater and high labour requirements. Given that droughts and floods are common, this region needs resilient agricultural systems that areable to cope with adverse climatic conditions.
A research partnership led by Murdoch University and the Agriculture Science Institute for South Central Vietnam (ASISOV) is introducing technologies that address nutrient and water use efficiency, especially for groundwater-dependent crops grown on sandy soils.
Water-saving and balanced nutrient technologies for peanut and mango have been developed through extensive research and demonstrations on farmers’ fields. The peanut technologies have been assessed by the Department for Agriculture and Rural Development (DARD) in Binh Dinh and approved for further extension and adoption by farmers, while assessment of the mango technologies is under way.
The water-saving technology uses a mini-pan to measure the rate of water evaporation, and irrigation with sprinklers (peanut and vegetables) or drippers (mango). Nutrients are applied in the form of inorganic and organic fertilisers, at balanced rates. Used together, these technologies have given increased yields while using less water. For example, experiments and demonstrations with peanut in Binh Dinh province have shown that, on average, using sprinklers and the mini-pan with balanced nutrients (90 and 30 kg/hectare of potassium and sulphur, respectively), water use decreased by 32% while yield increased by approximately 12%. This was as compared to current farmer practice (using a hose, no mini-pan, 60 kg/hectare of potassium and no sulphur). Water savings of more than 70% were observed using a sprinkler and mini-pan as compared to flooding, again for peanut.
Also in Binh Dinh province, mango farmers irrigating using a hose with the mini-pan saved 49% of their water while increasing mango yield by 1.6 tonnes/ha. Irrigating using drippers with the mini-pan saved 54% water and increased yield by 3.4 tonnes/ha. In addition, the overall quality of the mango fruits improved, leading to higher market prices. Building on these achievements, ASISOV is now testing ‘drip fertigation’.
The project is also investigating the groundwater and surface water resources in Phu Cat district of Binh Dinh, and developing a water balance model that will guide choice of crops for water saving on sandy soils, identify the effects of water-saving technologies for crop production, and determine the likely effects of climate change in this region on water availability.
- Water-saving and balanced nutrient technologies for peanut and mango have been developed through extensive research and demonstrations on farmers’ fields.
- The peanut technologies have been approved for extension and adoption by farmers, while assessment of the mango technologies is under way.