PENGARUH PENERAPAN TEKNIK KONSERVASI TANAH TERHADAP PERTUMBUHAN PERTANAMAN MAHONI (Swietenia macrophylla King) DI HUTAN PENELITIAN CARITA, JAWA BARAT

Abstract

Mahogany is a potential species commonly cultivated in West Java. The community usually plants this species in a cropping system with combinations of agricultural crops. Topography, climate, and intensive soil preparation affect on vulnerability of land productivity due to severe runoff and erosion impact on growth and crop production. This condition can be controlled by applying soil conservation techniques such as vertical mulch to reduce runoff and erosion as well as to maintain soil fertility. Eficiency of vertical mulch channel distance is needed to reduce the application cost. This research aims to determine the effect of different distances of vertical mulch channels on mahogany growth and maize production as wel as its effectiveness in controlling runoff , erosion, and nutrient loss. The research was conducted at Carita Forest Research in year 2005-2008 using a randomized block design. Treatment applied was vertical mulch with six and 12 m intervals on the plots of mahogany (Swietenia macrophylla King) and maize (Zea mays L.) cropping system. Observations include height and diameter growth of mahogany, runoff and erosion, and cost required for one hectare area. The result showed that six meter intervals of vertical mulch increased the height and diameter growth of mahogany by 25% and 66% respectively compared to the control. That treatment also reduced runoff and erosion by half, and nutrient loss due to runoff and erosion were reduced up to three and five times respectively. Application of the six meter interval on the mahogany cropping system produced 581 kg/ha/year maize or 47% higher instead of control, and in a hectare the cropping system will require Rp 3,250,000 or more expensive Rp 250,000 compared to control.