Agroforestry; A visit to Martin Wolfe

Having had the pleasure of visiting and researching some of the best agroforestry sites in Europe I thought some folks might enjoy this interview I filmed with Professer Martin Wolf over in Suffolk, UK.  The video is probably far too slow if you suffer a 3-minute-social-media-saturated-attention-span but personally I would happily sit and listen to Martin for hours.

The video begins with Martin recounting his work as a grain disease specialist at Cambrige University- which led to broad scale East German adoption of multi- variety grain production and subsequent huge reductions in fungicides (which quickly fell apart when the wall came down) 350,000 ha under this production system in Germany sadly fell to 20,000ha almost overnight.

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The N-S alley cropping at Martin's site generally utilizes 12m spacings trialling Hazel and Willow coppice, diverse long term hardwood timber species and nut & fruit plantings.  Both pasture and alley cropping with grains are harvested in between.  I've seen systems on 8- 26m spacings, but like Martin we are going to base our system at Ridgedale on 12m spacings for maximum beneficial interactions between our systems.  Our Keyline layout means a lot of our alley rows are conveniently on a N to S orientation.

I constantly see the beneficial opportunities for integrating various tree systems into existing enterprises in my design work.  A lot of farms could benefit from the addition of various tree systems for a whole range of reasons, and this is one element of regenerative design that is usually fairly easily integrated.   Below is a list of some of the benefits of silvopastural/ silvoarbale systems, something we shall explore in detail as we implement our Keyline patterned agroforestry systems in our 2014 Internship program. 

Benefits of silvopastural/ silvoarbale systems

• Integrated tree systems can provide fodder, niche crops, spaced crop harvest, firewood/ fuel, coppice yields, shelter, biomass, lumber, biomeiler material, water cleaning, pollination, organic matter, habitat and riparian protection as well as utilize marginal land
• Controlling runoff and soil erosion, thereby reducing losses of water, soil material, organic matter and nutrients.
• Maintaining soil organic matter and biological activity at levels satisfactory for soil fertility. This depends on an adequate proportion of trees in the system - normally at least 20% crown cover of trees to maintain organic matter over systems as a whole.
• Maintaining more favorable physical soil properties than conventional cropping through organic matter maintenance and the effects of tree roots.
• Help close nutrient cycles. This is true to an impressive degree for forest garden/farming systems.
• Checking the development of soil toxicities, or reduce existing toxicities - both soil acidification and salinization can be checked, and trees can be employed in the reclamation of polluted soils.
• Layered tree/ perennial systems utilize solar energy more efficiently than monocultural systems - different height plants, leaf shapes and alignments all contribute.
• They can lead to reduced insect pests and associated diseases.
• Can be employed to reclaim eroded and degraded land.
• Creation of a healthy environment - interactions from agroforestry practices can enhance the soil, water, air, animal and human resources of the farm. Agroforestry practices may use only 5% of the farming land area yet account for over 50% of the biodiversity, improving wildlife habitat and harboring birds and beneficial insects which feed on crop pests. Tree biodiversity adds variety to the landscape and can improve aesthetics.
• Moderate microclimates. Shelter given by trees improves yields of nearby crops and livestock. Shade in summer can be beneficial for livestock, reducing stress.
• Agroforestry can augment soil water availability to land-use systems. In dry regions, though, competition between trees and crops can be major problem.
• Nitrogen-fixing trees & shrubs can substantially increase nitrogen inputs to agroforestry systems.
• Trees can probably increase nutrient inputs to agroforestry systems by retrieval from lower soil horizons and weathering rock. ('Mining' minerals and trace elements & relationship with fungi)
• The decomposition of tree litter and pruning's can substantially contribute to maintenance of soil fertility. The addition of high-quality tree pruning's (ie high in Nitrogen but which decay rapidly) leads to large increases in crop yields.
• The release of nutrients from the decomposition of tree residues can be synchronized with the requirements for nutrient uptake of associated crops. While different trees and crops will all have different requirements, and there will always be some imbalance, the addition of high-quality pruning's to the soil at the time of crop planting usually leads to a good degree of synchrony between nutrient release and demand.
• In the maintenance of soil fertility under agroforestry systems, the role of roots is at least as important as that of above-ground biomass.
• Agroforestry can provide a more diverse farm economy and stimulate the whole rural economy, leading to more stable farms and communities. Economic risks are reduced when systems produce multiple products.