Characterization and suitability evaluation of major agricultural soils towards rationalizing land area allocation for biofuel feedstocks in Cagayan Valley, Philippines

The Republic Act 9367, otherwise known as Biofuels Act of 2006 mandates the use of biofuel as a measure to ensure availability of alternative and renewable clean energy without any detriment to the natural ecosystem, biodiversity and food reserves of the country, and production shall be done within marginal areas. This study aimed to identify sites considered prime agricultural lands for food and feed production and in the process delineate marginal lands that may be allocated for biofuel feedstock growing in Cagayan Valley. It employed soil characterization and suitability assessment of agricultural soils. Results show that with the total delineated agricultural area of 911,167 hectares in Cagayan Valley, there were about 360,193 hectares considered as prime agricultural lands enough for food and feed crop production to meet the regional requirement up to the project 40 years period. There were also about 431,044 hectares of marginal lands with high to moderate suitability to cassava, coconut, jatropha, oil palm, sweet sorghum, sugarcane, and switch grass. The productivity of the identified marginal areas were limited by shallow rooting depth, steep to very steep slopes, acidity and low inherent fertility, surface run-off and drainage conditions of the soils. To enhance productivity of these areas, investment on soil management and improvement has to be done. A second level suitability assessment showed that 84 percent of the marginal land is suitable for switch grass production and 54 percent was found out to be suited for other bio-energy crops such as cassava, coconut, jatropha, oil palm, sweet sorghum and sugarcane. Furthermore, about 16 percent of the marginal lands were considered permanently not suitable to any of the biofuel crops and were therefore recommended for reforestation/afforestation for watershed purposes. Switch grass, sugarcane, cassava and oil palm proved to be more productive in terms of biomass yield, biofuel potential, and soil suitability than jatropha, coconut and sweet sorghum. Based on the above findings, national together with local planners may find the data generated from this study valuable and therefore be applied as decision criteria in land allocation. Foremost is to esure food security and at the same time allow Cagayan Valley to locally produce alternative energy to conform to the national program of promoting biofuel production.