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In many parts of the world, conditions for small scale agriculture are worsening, creating challenges in achieving consistent yields. The use of automated decision support tools, such as Bayesian Belief Networks (BBNs), can assist producers to respond to these factors. This paper describes a decision support system developed to assist farmers on the Mekong Delta, Vietnam, who grow both rice and shrimp crops in the same pond, based on an existing BBN. The BBN was previously developed in collaboration with local farmers and extension officers to represent their collective perceptions and understanding of their farming system and the risks to production that they face. This BBN can be used to provide insight into the probable consequences of farming decisions, given prevailing environmental conditions, however, it does not provide direct guidance on the optimal decision given those decisions. In this paper, the BBN is analysed using a novel, temporally-inspired data mining approach to systematically determine the agricultural decisions that farmers perceive as optimal at distinct periods in the growing and harvesting cycle, given the prevailing agricultural conditions. Using a novel form of data mining that combines with visual analytics, the results of this analysis allow the farmer to input the environmental conditions in a given growing period. They then receive recommendations that represent the collective view of the expert knowledge encoded in the BBN allowing them to maximise the probability of successful crops. Encoding the results of the data mining/inspection approach into the mobile Decision Support System helps farmers access explicit recommendations from the collective local farming community as to the optimal farming decisions, given the prevailing environmental conditions. [ABSTRACT FROM AUTHOR]

The Mekong Delta is the most important rice- and shrimp-producing region for food and economic security in Vietnam. Rice-shrimp farming is practised where salinity fluctuates substantially between wet and dry seasons. Research points to several potential risk factors for rotational systems, but how these link directly to both rice and shrimp production remains poorly quantified for systems that stock and harvest animals year-round. We examined water and soil quality of 18 rice-shrimp-crab ponds, in which shrimp and crab are grown in both wet and dry seasons, in the Cà Mau Province of Vietnam. Multiple lines of evidence indicated that environmental conditions experienced by both rice and shrimp were suboptimal and contributed to low yields and survival. Year-round cropping of shrimp and crab was associated with sustained suboptimal salinity, intensified by drought, for the wet-season cultivation of rice. Although rice seedlings were sown in all 18 ponds, only three had a harvestable crop. Low shrimp production and survival was associated with sustained suboptimal water temperatures (too high), salinity (too high in the dry season and too low in the wet season) and dissolved oxygen concentrations (too low). Food availability and quality may also have affected shrimp production. Improving productivity of rice-shrimp-crab ponds in the study region may require (1) separation of rice and shrimp crops and improving efficiency of soil washing practices such that salinity conditions are more suitable for each when grown, and (2) management intervention to increase oxygenation of water, and the availability and quality of food for shrimp. [ABSTRACT FROM AUTHOR]

Inland saline intrusion is occurring during the dry season in the Mekong River Delta (MRD), Vietnam. Rising sea levels, tidal fluctuations, drought, and changes to upstream flow contribute to extensive salinisation of rice producing areas of the MRD, leading to substantial rice crop losses. The identification, evaluation and implementation of alternative crop and soil management solutions are required to complement on-going rice production in the region. A review of scientific and grey literature was conducted regarding the nature and extent of salinisation in the MRD and the adoption and management of alternative crops to rice. Familiar crops in Vietnam (e.g., maize, soybean), as well as novel crops to the MRD (e.g., quinoa, cowpea) were explored as potential options to replace dry season rice. Management options including surface soil mulches and plastic coverings help maintain soil moisture and reduce salinity damage to plants, and the use of drainage and seed preparation techniques can improve plant establishment and yield. Factors contributing to the success of alternative crops include salt tolerance, timing and efficiency of water use, ability to grow in the dry growing season, tolerance to pests and diseases, labour intensiveness and the crops' marketability. The identification of suitable alternative crops to replace dry season rice in saline affected areas of the MRD, combined with management practices like mulching and soil moisture monitoring, could provide farmers with income opportunities to offset rice losses. Documenting the factors contributing to successful crop diversification can assist with decision-making and support initiatives among farmers, agribusiness, and government agencies. [Display omitted] • Inland saline intrusion is causing substantial rice losses during the dry season of the Mekong River Delta, Vietnam. • Alternative crops and management practices need to be identified to supplement the loss of rice income. • Numerous biophysical, environmental, and socioeconomic factors are identified that determine alternative crops suitability. • Mulching, raised beds and soil water monitoring can decrease salinity stress and improve water use efficiency. • Combining alternative crops and management practices provide farmers with options for saline affected areas. [ABSTRACT FROM AUTHOR]