Vetiver Grass (Vetiveria zizanoides) in Combination with Selected Agricultural Crops in Sloping Areas in the Cordillera (DENR-ERDS-CAR, 2001)

ABSTRACT

The vetiver (Vetiveria zizanoides) grass used as hedgerow had exhibited a promising result as obtained from this study. Soil displacement and deposition which were observed to be prevalent during the early part of the study had decreased on the later years.

Result of the study showed that vetiver can be associated with agricultural crops especially at wider spacing for the agricultural crops to grow. From among the different treatments, the combination of vetiver, ginger, and gabi (T3) had the lowest soil erosion rate of 0.15 tons/ha which is below the acceptable level of <3 tons/ha (R.G. Grimshaw 1998). This is followed by the vetiver and gabi (T2) combination which had a total soil loss of 7.21 tons/ha. While T1 (Ginger and vetiver) had 10.68 tons/ha. Control plots (no treatment) had soil erosion rate of 9.80 tons/ha. The average soil loss during the first year (1998) was 7.25 tons/ha and increased twice on the second year to 14.38 tons/ha, while on the third year, the total soil loss had decreased to a level of 0.24 tons/ha. Apparently, the decrease of soil loss maybe due to the fully grown vetiver grass and denser hedges forming a very effective filter for surface run-off particularly during rainy months or strong rainfall occurrences. On the other hand, the frequent cultivation and tilling of the alleys or in between hedgerows where the agricultural crops were grown had an effect on the rate of soil erosion particularly in areas with rough or steep slopes.

An average number of 1 - 3 vetiver slips initially planted in September 1998 had multiplied to a maximum of 100 - 130 slips in a span of two years. While vetiver grass is observed to be able to grow and to withstand harsh conditions, it has the capacity to multiply numerous slips in shorter period of time and that can be adapted in higher elevations within the Cordillera mountain ranges.