Vegetables are important sources of vital nutrients such as vitamins, minerals and even antioxidants essential in combating the most common and even life-threatening illnesses and diseases. This might be the reason, why vegetable consumption is continuously increasing over the years. The trend of changing in lifestyle among Filipinos has opened many opportunities such as more market for the vegetable harvests of the poor upland farmers.
However, productivity sometimes compromised the sustainability and poses threat to the environment and even in the life of the people in the community.
According to the AVRDC-World vegetable Center, the increased in production of vegetables in the Philippines reflects both yield increases and expansion of areas planted with vegetables (G. Johnson et.al, 2008). The Department of Environment and Natural Resources (DENR) also reported that, in 2007 forest areas are rapidly converted into vegetable plantations. For instance, in Cordillera Administrative Region (CAR) alone – one of the major production areas for vegetables in the country converted an average of 220 hectares per year of forest lands into vegetable gardens (Cariño, 2007). This poses a serious threat in the country’s forest areas and increased the risks of soil erosion incidents.
In the study on agroforestry and sustainable vegetable production in Southeast Asian watersheds, presented by Dr. Agustin R. Mercado Jr. in a seminar series of the Bureau of Agricultural Research (BAR) says that, intensive vegetable production in the Philippine uplands particularly monoculture systems are not sustainable, however, integrating trees in vegetable production systems as contour hedges to control soil erosion will provide multiple of benefits such as increase in the income of upland farmers and enhance on-farm biodiversity and environmental sustainability. This technology is called “vegetable agroforestry” or VAF.
VAF is a technology that understands the relationship and or interaction of trees and vegetable in the uplands as key factor in successful vegetable farming endeavor. According to Dr. Mercado, VAF is the most appropriate technology for the uplands farmers to enhance the productivity and profitability while reducing production risks and environmental hazards inherent to vegetable production systems.
In order to improve economic viability of vegetable agroforestry systems, the following factors should be considered said Dr. Mercado. First, reduce competition between trees and vegetables. In planting vegetable in the upland areas, always consider crop with high adaptability indices and can thrive in low light environment, use trees which are less competitive, implement tree root pruning and root barrier, and employ irrigation to supplement water needs of the crop.
Second, increase trees-vegetable complimentarity. Appropriate pruning procedure is very important in vegetable agroforestry systems. It will provide a good growing environment both for trees and vegetables in the area, and thirdly, choose valuable trees as integrated component of vegetable production system. It also provides additional income to upland farmers, said Dr. Mercado.
Aside from increasing farmer’s income due to agri-diversity (tree and vegetable products), vegetable agroforestry system will also provide a favorable environment for vegetable production due to tree micro-climate amelioration such as reduction of wind speed, high relative humidity, and higher surface moisture of the soil. VAF will also maintain soil organic matters due to litterfalls and root decays and purposively will reduce soil erosion as trees served as contour hedges or barrier to soil erosion particularly on sloping farms.
This study was funded and supported by the Sustainable Agriculture and Natural Resources Management – Collaborative Research Support Program (SANREM-CRSP) and the World Agroforestry Centre (ICRAF).(Edmon B. Agron)