LEAF Comment

A new page to stimulate comment and discussion on topical issues, trends and new findings in sustainable agriculture and food.

A series of commentaries, planned for 2012, will consider recent trends in yield of the main cereals, notably the apparent levelling of yield over the last 10 to 15 years. Each article will be available as a downloadable file.

Why has yield stopped rising? 1. Background and questions

Summary

Between 1940 and 1990, the average yield of the main cereal crops in the UK rose about four-fold as a result of continuous scientific and technological innovation. Over the last 10-15 years, the yields appear to have reached a ceiling. Given the many calls that agricultural production (per unit area) has to increase, the cause of this levelling must be understood before any realistic predictions can be given of the scope for further increase and how it might be obtained. This article - the first of series of commentaries - summarises background data on the trends in yield and lists possible reasons for the levelling after the 1990s, including changing weather patterns, reduced inputs, loss of ecological function and lack of innovation. Further commentaries in the series will dissect the underlying causes of recent yield-trends and consider the question of whether yield has now reached its climatic potential.

The article is available as a downloadable pdf file 302kb: Yield commentary 1?