Transitions to greater legume inclusion in cropland: Defining opportunities and estimating benefits for the nitrogen economy

Abstract

Grain legumes have declined to a low base in many regions of intensified agriculture yet have the potential both to safeguard food security and satisfy rising ethical demands from food consumers. Here, the scope for legume expansion is examined in a long‐established agricultural region in eastern Scotland where grain legumes declined to <0.3% of cropped area in the 1930s and now vary around 1%. Data from the EU's Integrated Administrative and Control System (IACS) were combined with national agricultural survey to resolve uncertainties over possible restrictions to expansion following 20th‐century intensification. The grain legumes, peas and beans for animal and human consumption, were found to occupy six crop‐grass systems covering a wide range of agronomic input and geographical location. The phase of agricultural intensification between 1950 and 1990 had widened rather than restricted the systems in which they occur and could expand. Moreover, the diversity of the crop‐grass systems provides scope for complementary expansion of several products such as beans for aquaculture, pulses for human consumption, and peas for stockfeed without diminishing the areas of the most profitable crops. Among crop systems, N inputs following 20% legume inclusion would fall from the current 178 to 140 kg/ha (78.6%) at the high‐input end of the range and from 92 to 71 kg/ha (77.0%) at the low‐input end. Further reductions to 50%–60% of the existing N input to intensive crop sequences were estimated assuming a residual fixed nitrogen of 50–75 kg/ha and legume inclusion of 33%. Legume expansion would also bring a range of environmental benefits across all crop‐grass systems. While analysis using IACS brought many insights, major limitations to estimating national N‐balances were identified in lack of data on residual N following legumes, in imported animal feed and in the contribution of forage legumes to grassland.

Yield Performance of Faba Bean Cultivars under Different Environmental Conditions in Greece

“…Grain legumes are an important source of protein for human consumption and animal feed. The integration of legumes into agricultural systems could reduce the current protein deficit, contribute to the sustainable improvement of the environment due to their ability to fix nitrogen and their beneficial effects in soil fertility and carbon storage, thus ensuring the sustainability of agri-food systems and food security (De Ron et al, 2017;Squire et al, 2019). Grain legumes were cultivated on 16.5% of the global arable area in 2018, producing 14.5% of the total production of all grain crops.…”

Regional land use efficiency and nutritional quality of protein production

“…It is likely that development of new varieties is needed to make soya a potentially viable option for protein source in Scotland (Poehlman, 1987). Due to the current limitations in soya production in Scotland and the currently limited availability of other high-quality plant proteins, the plant-based lysine production in this region should be based on leguminous crops other than soya, such as field beans and field peas, although the lysine yield of those legumes per unit land area is globally much lower compared to soya (Squire et al, 2019;Zander et al, 2016).…”

Whole-Systems Analysis of Environmental and Economic Sustainability in Arable Cropping Systems: A Case Study

“…Policy will be particularly effective in achieving more of the latter, since an important environmental benefit that might incur an economic trade-off today can be turned to win-win with appropriate encouragement. For example, supported expansion of grain legumes from their current low base would reduce greenhouse gas emissions, limit pollution to water and benefit biodiversity through creating habitat diversity in-field and in the wider landscape [46].…”