Hand-held hoses and watering cans are widely used by smallholder farmers to irrigate vegetables in Cambodia and Laos. Overwatering is common. Technology change (e.g., low-pressure drip irrigation) has been used to improve irrigation efficiency but can be unaffordable for many smallholder farmers. The purpose of this study was to identify an appropriate method of predicting crop water demand, develop and field-test improved irrigation schedules for smallholder leafy vegetable farming based on that method, and then develop extension tools to communicate the schedules to smallholder farmers. Improved irrigation schedules for leafy vegetables were developed based on a crop water use prediction technique that is well established (the Penman–Monteith method) but beyond the capacity of smallholder farmers to implement without access to simple aids. Compared to conventional practice, the method approximately halved water and labour use and improved irrigation water productivity 2–3 fold in field research and demonstration trials. Simplified extension tools to assist smallholder farmers with practice change were developed. This work showed that significant efficiencies could be gained through improved irrigation scheduling without changing application technology.

Soils treated with lime-amended biosolids (LAB), poppy seed waste (PSW), anaerobically digested biosolids (ADB) and poppy mulch (PM) and incubated at 12.5°C for 56 days released 45%, 36%, 25%, and −8%, respectively, of total applied N as plant available nitrogen (PAN) by the end of the incubation. The mineralisation rates were contrary to expectations based on the C : N ratios of the four products: LAB (5 : 1), PSW (7 : 1), ADB (3 : 1), and PM (16 : 1). PM showed a significant negative priming effect over the incubation period. These results have implications for production agriculture in temperate regions where application and incorporation of bio-resources traditionally occurs in autumn and spring when soil and air temperatures are relatively low. Current application times may not be suitable for nitrogen release to satisfy crop demand.

Combining soybeans with grass or biomass maize in silage holds promise in addressing the nutritional limitations of individual crops, providing a roughage with a good energy–protein balance. This study evaluated the effects of replacing urea-treated rice straw (UTRS) with silages made from intercropped maize–soybean and Guinea grass (GG) in calf diets on feed intake and growth performance. Sixteen native Yellow calves (130.7 ± 16.1 kg live weight and 12.8 ± 2.6 months old) were used; the experiment had a randomised complete block design with four dietary treatments: Treatment 1 (70% UTRS + 30% GG); Treatment 2 (40% UTRS + 30% GG + 30% Guinea grass silage); Treatment 3 (40% UTRS + 30% GG + 30% Guinea grass–soybean silage); and Treatment 4 (40% UTRS + 30% GG + 30% maize–soybean silage). The animals were fed 0.5 kg concentrate per 100 kg live weight daily, with unlimited access to forage and clean water, for 12 weeks after a two-week adaptation. The results indicate that silages containing soybean increased total weight gain and average daily gain (ADG) and decreased feed conversion ratio (FCR); however, silage replacements had no impact on dry matter intake and body conformation, suggesting that Guinea grass–soybean or maize–soybean silage can effectively enhance the ADG and decrease the FCR of growing calves fed UTRS-based diets.

Growing vegetables after rice harvest allows Cambodian farmers to use land that would otherwise be unproductive between rice crops. Producing vegetables on these soils is limited by low soil pH, low cation exchange capacity and limited nutrient retention capacity. Soil pH in the top 20 cm is generally low (pH 5.5 H₂O) and may limit the availability of nutrients. Farm-based trials in Siem Reap and Kampot provinces assessed the effect of lime and fertiliser on leafy vegetable crop growth and yield. At lime-only sites, lime was applied at rates of 0.5, 1.0 and 2.0 tonnes per hectare (t/ha) in conjunction with farmer practice fertiliser rates. For sites with lime and fertiliser treatments, combinations of farmer practice and optimal fertiliser rates, no lime and 2.0 t/ha of lime were applied. Two consecutive crops were planted at one site to examine the residual effect of lime on soil pH and crop yield. At lime-only sites, all crops responded to lime application with yield increases of up to 100%. For sites that assessed combinations of lime and fertiliser, the treatment of lime and optimum fertiliser rates showed the highest yield increase (92%). Application of 2.0 t/ha lime increased soil pH by approximately 1.0 unit. This effect was still evident after a second crop of Bok Choy. For the 0.5 t/ha lime treatment, an initial soil pH increase of 0.4 units had reduced to 0.2 units after the second crop. The first crop yield was higher than the second crop yield. Long-term field trials are needed to examine residual lime effects.

Production of leafy vegetables, such as lettuce, in Lao People’s Democratic Republic (PDR) is limited by low nutrient soils. Organic fertilisers or composts made from agricultural residues may provide Lao PDR farmers with economical and environmentally sustainable alternatives to chemical fertilisers. Research is needed to increase awareness and knowledge of organic fertilisers suited to vegetable production in Lao PDR. An experiment at the Horticultural Research Centre (HRC) in Vientiane assessed the effect of four organic fertilisers on growth and yield of lettuce. Two commercially available fertilisers (fermented manure compost and an organic fertiliser) were compared with a mixture of cow manure plus rice husks, and a fourth compost made from vegetable leaves, straw and cow manure at the HRC. The experimental design was a randomised block with four replicates for each fertiliser treatment. Lettuce was grown in raised beds with 10 tonnes per hectare (t/ha) fertiliser applied before seedlings were transplanted. The fermented manure compost treatment had the highest yield (1.95 kg/m²) and was significantly higher than the other three treatments (p < 0.001). Growth rates were also highest for the fermented manure compost at all measured growth intervals (14, 28 and 45 days after transplanting). Rapid nutrient release from fertiliser is important for short-term crops. The higher growth rates and yields found for the fermented manure compost indicate that nutrients were released sooner and were more readily available compared to the other treatments. Mature compost releases nutrients more rapidly than compost that contains partially decomposed rice husks, vegetable leaves and straw.

The basket of meat consumption has changed during the last decade in Vietnam, including increased consumption of beef. This paper analyzes the beef consumption behaviors of households in Dien Bien province, located in Northwest Vietnam. Data were collected from a survey of 108 consumers and three focus group discussions. It was evident that the preferences of beef consumers were varied between different ethnic groups. The important criteria used in selecting meat were color, freshness, and tenderness. Consumers mentioned, but had little concern, for meat packaging, nutritional information, or quality certification, while they showed almost no concern for animal welfare in purchasing beef. As the consumers’ choice of purchasing beef was very much influenced by meat appearance, improving the conditions of butcher counters is suggested as an immediate measure. There exists an opportunity to introduce ‘cold’ beef widely as a longer-term measure.