How local ecosystem service management may reduce climate change impact of weed control : case studies in organic vegetable production

Abstract: This study was performed in cooperation with a participatory research group called ‘Climate-Smart Agriculture – Sustainable Solutions for the Future’. It investigated how the use of local ecosystem services in organic weed management could decrease the impact on climate change of fossil fuel-intensive mechanical and thermal weeding methods. The study was designed to examine global challenges that have been internationally emphasised during recent years, such as climate change, peak oil and ecosystem degradation. A premise of the study was that it is necessary not only to increase efficiency or replace the energy source but also to perform large reductions in the total amount of energy used. Participatory research methodology and a systemic approach were used. Weed management strategies that reduce the use of fossil fuels with the help of ecosystem services were developed for three farms in consultation with their owners. An on-farm experiment with mechanically spread green mulch from fresh ley was performed on one of the farms. Other weed control methods discussed within the study included green mulch from leftover silage, intercropping vegetables with a permanent red clover ley, consumer participation in weeding, weed-competitive ley species mixes, annual ley species mixes grazed by horses in late autumn, increasing the amount of autumn-sown crops and/or ley, increasing the amount of annual crops, which are less labour-intensive than vegetables, and inter-row cultivation, i.e. vegetables transplanted into a dead cover crop. Some of the methods could be adopted immediately, while others need to be developed and tested for different local specific conditions. A sustainability evaluation tool was developed based on the system conditions of the Natural Step and spider diagrams. The tool needs further development but proved suitable for the purpose of evaluating agricultural practices from a wide perspective of sustainability and for identifying knowledge gaps concerning the sustainability of the agricultural practices. Suggestions are given on how to use participatory methods to increase the development and adoption of climate smart weed management strategies.