Effects of hydraulic lift on growth of neighboring crop

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Hydraulic lift refers to the movement of water from deep wet soil layers into the drier upper horizons through plant root systems. It has been suggested that increases in soil moisture in the dry layer resulting from hydraulic lift may provide benefits to the plant itself and/or tp neighbours. However, this possible advantage is poorly documented. In this study, split root experiments were conducted to detect hydraulic lift and to find benefits to neighbours. Firstly, vertically staked sprit-root tubes were applied to show a pigeon pea root system, bridged to a moist soil in depth, function to maintain available soil water in non-watered shallow root zone. The pigeon pea saved the soil moisture of the upper layer under no irrigation and continued transpiration without water stress, this leaded to the assumption that pigeon pea can perform a sufficient water uptake from deep soil to save water in surface soil layer under drought conditions. Secondly, a pan of 1 m in diameter was used as a surface soil layer to study effect of hydraulic lift on neighboring crop. Markhamia was planted in the pan located on the ground, but its main root could penetrate into the ground. Several lateral roots grew in west side of the pan. Upland rice was planted in the west side and east side (no lateral roots). As the soil in the pan dried, water competition first occurred between the tree and rice plants in the root side, and stomatal conductance of the plants in the lateral root side was lower than that in no lateral root side. When the soil was drier, reverse occurred, and the rice plants in no lateral root side wilted, while the rice plants in the lateral root side kept green. In this study, it was found that hydraulic lift enable to improve water status of neighboring plants when surface soil layer dries