Irrigation planning: dealing with the current water crisis

According to the International Water Management Institute (IWMI), about 70 per cent of Earth’s fresh water diverted for human needs is currently being used to sustain the agricultural sector. Low irrigation water productivity is perceived as one of the primary contributors to the current global water shortages. If immediate global action is not taken, we could be contributing to an already-brewing geopolitical controversy that would jeopardise the entire global economic system. For most crops, farmers want to avoid drought stress throughout the growing season because it can quickly reduce yield and lead to undersized and prematurely ripened crops. To avoid these issues, farmers tend to give too much water, so when the Soil Water Content (SWC) in the active root zone reaches its limit, it exceeds the field capacity. Field capacity is the limit beyond which applied water is lost for crop use as it starts draining by gravity out of the root zone. This also induces the leaching of valuable nitrates which result in groundwater contamination. Excess SWC also promotes root diseases and can severely shorten the productive life of trees. Therefore, over-irrigation is not solely...