We find that there are pretty dramatic increases in crop production – on the order of 45 to 70% for most major crops – possible from closing the so-called 'yield gaps' between the least and most productive areas with the same growing characteristics," Nathan Mueller of the University of Minnesota, US, told environmentalresearchweb. "We also analyse what we expect the changes in fertilizer and irrigation management might need to be to close these yield gaps. This is our first consistent, global picture of management changes on global croplands necessary to close yield gaps."
Mueller and colleagues from the University of Minnesota and McGill University, Canada, found that global yields are strongly controlled by fertilizer use, irrigation and climate. These factors could account for 60–80% of yield variability for most major crops. Under the right conditions, maize production could see an increase of 64%, wheat a 71% rise and rice a boost of 47%.
Even if yields were increased to only 50% of those attainable, areas such as Eastern Europe and Sub-Saharan Africa could show large production gains. The team says East and South Asia also have "substantial intensification opportunities" because of their vast agricultural lands and the variability in their yields.
"We need to dramatically increase global food production to meet growing demands from population growth and diet," Nathan Mueller of the University of Minnesota, US, told environmentalresearchweb. "At the same time, we need to improve the environmental performance of agriculture, particularly in terms of water use and water quality, often tied to fertilizers. We wanted to understand how these two great challenges could be tackled together."
During the study, the researchers developed a global crop-specific data set of nitrogen, phosphate and potash fertilizer-application rates. The nations using high fertilizer-application rates tended to be high income and some rapidly developing countries, they discovered. Irrigation, meanwhile, was strongly concentrated in South Asia, East Asia and parts of the US.