Adaptability of Vetiveria zizanioides as contour hedgerows in Baybay, Leyte [Philippines]

Findings showed that with the vetiver hedgerows, the soil organic matter (OM) content increased to an average of 3.72% in a five-year period, while the plots without contour hedgerows gave an average OM content of 2.40%. This was also manifested in the change in soil color from whitist to brownish. The increase in OM could be attributed to the decomposed native weeds and crop residues. The soil's macronutrient levels generally increased with the presence of hedgerows during the five-year period. Nitrogen content (% N) increased to an average of 0.24% N in hedgerow plots, while the plots without contour hedgerows gave an average of 0.14% N. Phosphorous content was also higher in the hedgerow plots, with an average of 3.15 mg/kg, as compared with the non-contour hedgerow plots with an average of 2.77 mg/kg. In a three-year period, potassium (K) increase to an average of 12,696 mg/kg in hedgerow plots while the non-contour hedgerow plots showed an average of 8,642 mg/kg. There was also an increase in the Calcium (Ca) content of hedgerow plots, with a five-year average of 12,696 mg/kg, while the non-contour hedgerow plots had an average of 8,642 mg/kg. After three years, there striking evidences of soil build up within the contour strips, showing the formation of terraces. In the upper contour strips with 18% slope, the average level of soil build-up ranged from 28.0 to 31.5 cm. In the lower strips with 12-14 % slope, the average soil builp-up ranged from 22.5 to 24.5 cm. Corn yields in hedgerow plots were significantly higher than those in non-contour hedgerow plots. Yields increased from an average of 1.15 t/ha for two cropping seasons in 1996 to 2.24 t/ha in 1998. The hedgerow plots gave higher average ear length of 10.74 cm with an average ear weight of 101.88 g, while the non-contour hedgerow plots gave an average ear length of 9.50 cm and an average ear weight of 82.32 g. The cost-benefit analysis of two cropping seasons in 1996 showed a higher net income of P2,983/ha from the hedgerow plots, as compared with to the non-contour hedgerow plots, which gave a negative net income of P90/ha. An even higher net income of P9,222.05/ha was derived from the two cropping seasons in 1998