What are the available tools to achieve the sustainable intensification of agriculture in areas of already intensive agriculture? Cristina Cruz, of the BioClub Project, reflects
EU agriculture requires solutions with low inputs and which are capable of leading to economic, social, and environmental sustainability for the whole of Europe. The intensification of food production with minimum negative environmental impacts and zero increase in land degradation is the new frontier for the EU, as well as the objective of the sustainable intensification of agriculture (SIA).
EU agriculture is one of the world’s leading producers of food and guarantees food security for over 500 million human beings. But Europe is currently consuming twice what its land and seas can produce. The EU’s farmers are guardians of environmental sustainability as they care for the natural resources (soil, water, air, and biodiversity) of 48% of the EU’s land, on which all of us depend. But the Global Footprint Network estimates that over the last 40 years, Europe’s ecological footprint increased by 33%.
What is the sustainable intensification of agriculture?
SIA is a complex concept with many dimensions, but in Europe, where agriculture is already very intensive, it can only be achieved through the development of new techniques targeted at increasing the use efficiency of the available resources in order to produce healthy food outputs with minimal disturbance to all components of the agro-ecosystems. For this, we need to bring research and innovation out of the labs and onto the fields and markets to create a better link between what we know and what we grow.
In fact, soil, the pillar of our society, is a biological system, ruled by biological laws. The support/sustenance of soil’s functionality and provision of ecosystem services, related to natural, societal, and productive capital, is its biological community. In highly managed systems, the biological community is the first to be destroyed due to the use of high levels of fertiliser, pesticides, herbicides, and soil mobilisation. Therefore, the recovery of a functional soil biota may represent an opportunity to increase sustainable productivity (even in certain places in Europe this would imply a de-intensification of agriculture).
Although our knowledge of soil ecology is still in its infancy, we know that the way to improve nutrient use efficiency (NUE) is a partial substitution of the recommended mineral fertiliser dose (RMFD) by plant growthpromoting micro-organisms. PGPMs are able to promote rootsystem development, increase acquisition of nutrients, and improve plant defence in exchange for root exudates.
Translating theory into practice
In our project ‘Rhizospheric microbial consortia to increase nutrient use efficiency’ (PTDC/AGRPRO/115888), we demonstrated the advantages of using biofertilisers on plant development and NUE. We produced a microbial consortium (CONS) that would allow a reduction in the use of fertilisers by 30% by 2020 without decreasing productivity. An additional benefit of using CONS is a 21% increment of the zinc concentration in the grain, which shows the potential of the biofertiliser to increase the nutritive value of food.
The results obtained with CONS stimulated the team to check its effect on other crops, soils, and environmental conditions. Although results were generally good and reproducible for the same culture and edaphoclimatic conditions, high variability (80140% in relation to plants receiving 100% of the recommended fertiliser dose) was found when applied to other crops, soils, or stress conditions.
Although even in this scenario the use of biofertilisers such as CONS is still viable, we know that, based on the scientific advances made in the area of microbial communication, improvements to high-throughput technologies, and microbial ecology, CONS can be developed into a next generation of biofertilisers based on the reinforcement of the positive symbiotic strength between the micro-organisms composing the biofertiliser and the plant – while reducing the production costs of the inoculant.
Options for the future
One way of strengthening the symbiotic relationship between the species taking part in the consortium is to design biofertilisers that include micro-organisms with an endophytic lifestyle. Endophytes (fungi and bacteria) have been found in virtually every plant studied, where they colonise the internal tissues of their host plant and can form a range of different relationships leading to plant growth and yield promotion, and act as biocontrol agents.
With our new project, BioClub, we can say that the endophytic bacteria consistently activated the plant defence pathways (Fig. 2). So we are anxious about our upcoming results and field trials.