Water availability has been a major constraint in crop production technology across the globe. The agricultural sector has been the largest consumer of fresh water for ages and accounts for about two-thirds of the total fresh water used for human consumption. In the scenario of rapid population growth, the share of fresh water allocated to agriculture would get reduced to a great extent. Therefore, there is the ever-increasing need to use the available water efficiently and precisely. It is a high priority to evolve new irrigation methods so that water use efficiency (WUE) can be maximized through optimum management of available irrigation water. Deficit irrigation (DI) is an optimization strategy that requires crops to intentionally endure a certain level of water deficit. This sometimes leads to a decrease in yield, however, with a significant increase in WUE. Partial root zone drying (PRD) is a modified version of DI, which has been practiced to improve WUE by controlling drought stress. In this method of irrigation, the spatial separation of dry and wet roots is maintained during the entire cropping season. The water stress developed in one part of the root zone generates chemical signals in the form of abscisic acid, which leads to partial closure of stomatal opening. Stomatal closure reduces the rate of transpiration, which in turn increases WUE. This paper is an effort to briefly discuss the concept of PRD and to review some important work carried out across the world.

中文翻译：

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灌溉的部分根区干燥方法：综述

水资源可用性一直是全球作物生产技术的主要制约因素。多年来，农业部门一直是淡水的最大消费者，约占人类消费淡水总量的三分之二。在人口快速增长的情况下，分配给农业的淡水份额将在很大程度上减少。因此，对有效和精确地利用可用水的需求日益增加。开发新的灌溉方法是当务之急，以便通过对可用灌溉水的优化管理来最大限度地提高用水效率 (WUE)。赤字灌溉 (DI) 是一种优化策略，要求作物有意识地承受一定程度的缺水。然而，这有时会导致产量下降，WUE 显着增加。部分根区干燥 (PRD) 是 DI 的改进版本，已通过控制干旱胁迫来改善 WUE。在这种灌溉方法中，在整个种植季节保持干湿根的空间分离。在根区的一部分产生的水分胁迫以脱落酸的形式产生化学信号，导致气孔开口部分关闭。气孔关闭会降低蒸腾速率，进而增加 WUE。本文旨在简要讨论 PRD 的概念，并回顾世界各地开展的一些重要工作。在整个种植季节保持干湿根的空间分离。在根区的一部分产生的水分胁迫以脱落酸的形式产生化学信号，导致气孔开口部分关闭。气孔关闭会降低蒸腾速率，进而增加 WUE。本文旨在简要讨论 PRD 的概念，并回顾世界各地开展的一些重要工作。在整个种植季节保持干湿根的空间分离。在根区的一部分产生的水分胁迫以脱落酸的形式产生化学信号，导致气孔开口部分关闭。气孔关闭会降低蒸腾速率，进而增加 WUE。本文旨在简要讨论 PRD 的概念，并回顾世界各地开展的一些重要工作。