A rising world population requires increased food production. The achievements of Green Revolution have dramatically reduced hunger in certain parts of the World. However, these methods have most reached the limit of further intensification. Moreover, the methods of the Green Revolution such as synthetic fertilizers, herbicides, pesticides, river change flow for irrigation and plant breeding constitute a substantial fraction of the agricultural footprint and contribute to environmental degradation. That is why scientific community is on the run for new ways to feed 9.8 billion people expected by 2050 and saving the environment to produce this food.
Closing the yield gap is considered as part of the solution for sustainable intensification and attracts a lot of attention, however, studies on the subject do not provide with a simple answer. While the yield gap normally refer to the difference between realized yields and either potential yield (for irrigated conditions) or water-limited yield (for rain-fed conditions), depending on what is taken into the account, there are, for instance, at least three methods to measure yield.
The main difficulties in measuring yields or, in other words agricultural productivity, appear to be in about the inclusion of the additional environmental as well as social and economic value that farmers gain from growing or not growing particular crops. It is lack of this additional value that usually determines the existence of the yield gaps. Yields can be below potential because of insufficient or imbalanced nutrients; insufficient or excess water; pests, diseases, and weeds; soil problems; physical damage; poor seed; and suboptimal planting. They can also be low because it is not profitable for farmers to raise them further, because of resource constraints, or because of lack of knowledge. Attributing yield gaps to specific causes is challenging – it is easy to mis-attribute causes, and causes are often interconnected.
This discussion brief looks into the measurement of the yield gap and offers possible sustainable solutions to close it, particularly in Sub-Saharan Africa and Southeast Asia, where the ‘yield gap’ is the greatest. It finds that assessing the yield gap is a challenge in itself, because common measures of productivity fail to account for economic, environmental and other factors that affect yields, especially among smallholders who may be growing multiple crops. It is concluded that closing yield gaps is fundamentally about farmers practicing the best-known management solutions for their crops and locations.