Closing yield gap: The role of investments in land quality improvement
To meet the challenge of ever-increasing food demand while maintaining ecosystem services yield gaps around the world will have to be closed. Previous studies have shown the magnitude of gaps around the world. We now need to focus on methods and policies for closing the gaps. Possible solutions to the gap problem include 1) improve nutrient use efficiency via precision agriculture, 2) farmer education on optimal nutrient application, and 3) soil quality improvement. The goal of this study is to test the hypothesis that investments in land quality improvement could significantly contribute to closing gaps. We measure the impact of investments in land quality on gap size around the world via quantile regression. Yield is regressed on nitrogen and phosphorous uses, investments in land quality improvement, farm equipment values, irrigation status, precipitation, and the number of hot and dry months in the production season. To our knowledge, no previous studies have subjected the hypothesis to a rigorous statistical test.
We find that investments in land quality improvement can substantially enhance nutrient use efficiency but with the differing degree of magnitude depending on the current productivity level. For example, middle-productivity farmers benefit the most from investments in land quality improvement. Benefits to high-productivity farmers are smaller compared to middle-productivity farmers, as there is little room to improve nutrient use efficiency in the first place. Interestingly, investments in land quality improvement have very small impacts on low-productivity farmers. In other words, low-productivity farmers will stay unproductive even after investments in land quality improvement. Therefore, for these farmers it appears other productivity constraints need to be addressed first.