Effects of hydraulic lift on growth of neighboring crop

水力提升是指水分通过植物根系从湿润的深层土壤进入干燥的上层土壤。有人建议，在干层土壤水分的增加所造成的水力提升可能会为植物本身和/或TP邻居提供好处。然而，这一可能的优势没有得到充分的记录。在这项研究中，分裂根实验进行检测水力提升，并找到邻居的好处。首先，采用垂直立桩的短根管来展示木豆根系，在深层与湿润土壤桥接，在不浇水的浅根区起维持土壤有效水分的作用。木豆在无灌溉和无水分胁迫的情况下持续蒸腾，保存了上层土壤水分，这导致了木豆在干旱条件下可以从深层土壤中进行足够的水分吸收，以保存表层土壤水分的假设。其次，采用直径为1 m的浅盘作为表层土壤，研究水力抬升对邻近作物的影响。Markhamia种植在位于地面上的锅中，但其主根可以穿透地面。盘的西侧有多条侧根。高地稻种植在西侧和东侧（无侧根）。随着盆内土壤的干燥，水稻与乔木的水分竞争首先发生在根侧，侧根侧植株的气孔导度低于无侧根侧植株。当土壤干燥时，则相反，无侧根侧水稻植株萎蔫，而侧根侧水稻植株保持绿色。本研究发现，当表层土壤干燥时，水力提升可以改善邻近植物的水分状况

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