An analysis of commercial vegetable farms in relation to sustainability in the uplands of Southeast Asia

Commercial vegetable production systems in the uplands of Southeast Asia are important to supplement the demand for fresh vegetables in lowland Asian cities. A farm survey and soil sampling was done to characterise and identify major factors limiting vegetable productivity in the uplands of the Manupali watershed, Mindanao, the Philippines. Large yield differences were found among the four most common crops: tomato (Lycopersicon esculentum), cabbage (Brassica oleracea var. capitata), potato (Solanum tuberosum), and Chinese cabbage (Brassica pekinensis). The most closely correlated factors with crop yields were: nitrogen application rates for tomato and cabbage; topsoil per cent sand and fungicide usage for potato; and reliance on family labor for Chinese cabbage. Following multivariate data analysis, two vegetable farming systems were identified: the higher external nutrient (HEN) and the lower external nutrient (LEN) systems. To enhance their sustainability, both systems should adopt more appropriate soil conservation practices, cropping sequences, and plant protection techniques. Additionally, the LEN farmers should increase nutrient application, while the HEN farmers would benefit from labor saving technologies, crop diversification, and more judicious fertiliser application.