Can new organic cropping systems produce vegetables with lower use of resources and losses of nitrate?

Summary

To secure a sustainable production of plant foods for the future, there is a need to develop new cropping systems. These systems should have reduced needs of external resources and reduced environmental impact, while product yields are maintained at high level. Therefore, field trials were performed in Italy, Slovenia, Germany and Denmark with the aim to study new organic cropping systems for production of vegetable crops; and the systems’ effect on labor and energy consumption and the risk of losing nitrate to the water environment. The cropping systems included an in-season living mulch to exploit ecosystem services by attracting beneficial insects, suppressing weeds, and taking up excess nitrogen during production of two high-value crops of leek and cauliflower. The first year results show that high yields and quality were maintained if the living mulches were properly managed e.g. by sowing date or root pruning to control plant competition. The systems including living mulches changed the costs from +22 to -2% and total energy consumption from +14 to -4% compared to sole cropping depending on the change of management techniques in each country. The proportion between human power and fossil fuel consumption was changed. The risk of nitrate leaching was affected to a minor degree depending on the spatial layout of living mulch and crop rows. The study indicates that new cropping systems can be developed based on in-season living mulches for organic production with high yields, weed suppression and reduction of the risk of nitrate leaching. However, the management of the living mulches in terms of machinery, agronomic techniques and timing needs to be developed to optimize outcomes for food security, energy use and environmental impact. The study is part of the INTERVEG project.