Rainwater-use efficiency of tea (Camellia sinensis (L.)) under different conservation measures in the high hills of south India

Enhancing productivity of rainfed crops is vital to meet the growing population needs through effective rainwater conservation measures. A field study was conducted during 1995–2003 with rainwater conservation measures, viz., contour staggered trenches (CST), cover crop of French bean (Phaseolus vulgaris) and CST + cover crop in tea plantation on 25% land slope. Rainwater-use efficiency (RWUE) of tea was maximum in cover crop (4.34–18.09 kg ha mm−1) followed by CST + cover crop (4.69–16.79 kg ha mm−1), and CST (3.71 - 16.50 kg ha mm−1) in comparison to the control treatment (no conservation measure). Six years average rainwater productivity of tea leaves was 1.01, 0.98, 0.94 and 0.85 kg m−3 for cover crop, CST + cover crop, CST and control, respectively. Rainwater productivity was increased by 19% with cover crop and 16% with CST + cover crop over control. Mean increase in yield of tea leaves by 25–37%, was associated with reduction in runoff (29–51%) and soil loss (25–68%) due to rainwater conservation treatments. Canopy development of tea had direct relationship with yield of tea and reduction in runoff and soil loss. It was recommended to adopt cover crop along with CST for increasing rainwater productivity and socio-economic status of the small tea growers in the region.

Research highlights
► The sustainable productivity of tea plantation depends on availability of green water.
► Rainwater conservation measures are effective in erosion control and increasing productivity.
► We conclude that French bean with contour staggered trenches for rainwater conservation in new tea plantation.
► Rainwater conservation measures are more beneficial to small tea growers.