ABSTRACT
Water will be the principal limiting factor to growth in global food production in the twenty-first century. Without significant improvements in agricultural water management, neither will the demand for water of two or three billion additional human beings be met, nor will the impact of climate change be dealt with. However, a recent modelling study by German and Swedish researchers revealed that improved on-farm water management could increase global crop production by about one-fifth (Rost et al., 2009). Improved management would entail a 25% collection of surface run-off (i.e. water harvesting, WH) and a 25% reduction in evaporation (e.g. by mulching). An increase of about 20% in global crop production compares favourably with current irrigation practices, which will increase global production by only 17% if they continued to be applied.
