Improvement of Irrigation Water Efficiency and Productivity Using Supplementary Irrigation: A review

Abstract

Supplementary irrigation (SI) is an effective response to mitigate the negative effects caused by soil moisture stress on the yield of rainfed crops during dry periods. Soil moisture deficit often occurs in dry rainfed areas during the most sensitive growth stages of the plant (flowering and grain filling) as a result, the growth of the rain-fed crop becomes weak, which leads to lower yields. As for (SI), which provides limited amounts of water, especially during critical periods of crop growth, it leads to a significant improvement in yield and water productivity. This article presents review methodologies used for significant increases in the yield of rainfed crops in response to the use of relatively small amounts of water and the state of the art of (SI) in the dry lands, which (SI) should be appropriately integrated with other production inputs including crop and soil management options, climate change, and other options necessary to achieve the required results. The main contribution of this work lies in farms using water  supply system on demand and small farms that use wells or nearby surface water sources. This study will help the farmers to understand the technology transferred to them and how to properly employ and manage it. Here, agricultural extension and human capacity building must play a key role in this field. Long-term training and  advisory programs must be designed and implemented at various levels.