Strip intercropping strategy for biomass to energy production while on the same time maintaining soil fertility

Summary

In contrast to energy technologies like solar and wind, energy in the form of biomass can be stored and bioenergy produced when needed using a wide range of technologies. However, a substantial rise in the use of biomass for energy is expected, which means additional pressure on farmland sustainability. Organic agriculture (OA) is facing a big challenge producing bioenergy from local resources and on the same time maintaining soil fertility. There is a clear goal to reduce reliance on fossil fuels and thereby decrease greenhouse gas emissions, but the question is how to reach it? In a four year ICROFS (www.icrofs.org) project titled “BioConcens” (www.bioconcens.elr.dk/uk/) one objective is to design and test a strip intercropping concept.
Strip intercropping (IC) is based upon general IC principles focusing on the management of plant interactions to maximize productivity and resource utilizations (Willey, 1979). The crops are not necessarily sown and harvested at the same time, but the crops co-occur for a significant period of their growth. IC is a practice with crops grown in strips wide enough that each can be managed independently, yet narrow enough that the strip components can interact. This kind of cropping strategies was common in developed countries before the ‘fossilisation’ of agriculture (Matson et al., 1997) contributing to yield stability and soil fertility, lowering nutrient losses and reducing weeds, diseases and pests (Hauggaard-Nielsen et al. 2007).
The first total crop biomass production during the two years will be presented together with initial conclusion on the interspecific competitive interactions between strips. Is it possible at this stage to identify advantages and possible drawbacks? And is the inclusion of a perennial grass-clover strip sufficient to enhance soil fertility, extract nutrients form deeper soil layers, fix N2 and compensate for the effect of annual crops on soil fertility?