Runoff Management Technique for Soil Conservation and Water Harvesting in Rubber Plantations

Runoff and erosion are substantial and seriously limit crop production in the traditional rubber growing tracts in India. The conservation practices commonly adopted in rubber plantations are contour terracing, construction of stone-pitched retaining walls (edakayyalas) , cover cropping and digging of conservation pits. The effect of conservation pits on soil and moisture conservation and growth and yield of rubber was evaluated in a field experiment in a mature rubber plantation in the central region of the traditional rubber rowing tract in India. The treatments comprised of combinations of conservation pits taken at the rate of 150, and 250 per hectare and two methods of fertilizer application viz., placement in pits and broadcasting. Plots without pits and fertilizer served as control. The experimental field was well drained with an average gradient of 14 per cent. Yield of rubber was significantly influenced by the presence of pits. Yield enhanced by 18% in the plots with 250 pits ha⁻¹. The girth increment also showed a positive trend and the highest girth increment was recorded in the plots with 250 pits. The soil moisture content differed distinctly with respect to different treatments. Soil moisture storage estimated up to a depth of one meter was distinctly higher in the plots with 2~0 pits per haindicating the contribution of pits towards ground water recharge. A higher leaf water potential was maintained in the plots with pits. Growth and yield were not significantly influenced by different methods of fertilizer application.