Sustainability assessment of dominant agroforestry practices in Barobbod watershed Nueva Vizcaya, Philippines

The study was conducted in Barobbob watershed to evaluate the sustainability of the dominant agroforestry practices namely multistorey, alley cropping, fallow system, and trees along farm boundary. The evaluation was based on the multi-criteria sustainability rating formulated following the schemes earlier used by Barcellano (2005), Gascon (1998) and Legarda (1998). The parameters used were ecological soundness, economic viability, cultural sensitivity and social equitability. The soil chemical and physical analyses revealed that the multistorey farms had significantly higher pH, OM [organic matter], N, Ca, WHC [water holding capacity] and MC. The soil in the alley cropping system had significantly higher K, Mg and CEC [cation exchange capacity]. The soil in the trees along the farm boundary system had significantly higher P and BD [bulk density]. The multistorey farms had statistically higher infiltration rates and statistically lower recorded runoffs compared to all other agroforestry practices. Sediment yield in the multistorey was significantly lower compared to the amount obtained from other practices. The amounts of litter production and decomposition were statistically higher in the multistorey system compared to the other agroforestry practices. All the agroforestry practices have very rich species diversity. The water in the streams met the Class A criteria or fresh waster classification in terms of pH, turbidity, conductivity, nitrogen,phosphorus, TDS [total dissolved solids] and TSS [total suspended solids]. All the agroforestry practices which provide 86-89% of the farmers' household income produced positive net returns, but these were still below the poverty line. External support and credit were not provided to most of the farmers. The individual beliefs and rituals of the farmers were observed to be diminishing. The practice of agroforestry was observed to have led to increased participation and improved the organization of the farmers. There was inequality in income and land area distribution among the farmers. There were also differences in the quality of living and access to basic services among the farmers. The agroforestry practices that obtained moderately high sustainability rating based on the developed multi criteria evaluation scheme were alley cropping (57.96%), followed by multistorey (56.60%) and trees along farm boundary (55.35%). The lowest sustainability rating was that of the fallow system at 48.73% which was considered moderately low in terms of overall sustainability.