Tuesday, 3 May 2011

Conservation agriculture: Opportunities for the UK?


I have become very interested in the idea of conservation agriculture (CA) recently and, in particular, what opportunities there may be for using it more widely in the UK.  Amir Kassam from the University of Reading is a name well-associated with this concept and one which pops up frequently, and he feels that CA has a considerable role to play in European agriculture.

In a recent paper published in the Journal of Farm Management, Professor Kassam describes conservation agriculture as being characterised by three sets of mutually reinforcing practices:

  1. Continuous no or minimal mechanical soil disturbance (i.e. direct sowing or broadcasting of crop seeds; minimum soil disturbance from cultivation, harvesting or farm traffic);
  2. Permanent organic matter soil cover, especially by crop residues and cover crops; and
  3. Diversified crop rotations in the case of annual crops or plant associations in the case of perennial crops, including legumes.

He argues in relation to the three big challenges identified in Defra’s August 2009 first Food Security Assessment that ‘the approach used and the analysis applied in the Assessment do not address the unsustainable nature of the intensive tillage-based production systems.  Consequently, there is no explicit attempt made to elaborate on what new advice must be formulated for farmers on what changes must be made to current production techniques and practices to make farming more sustainable and environmentally friendly as well as productive and profitable.’

Prof. Kassam is critical of this and other reports published by Defra which do not elaborate on specifically what it is within current intensive agricultural systems which lead to soil degradation and what the remedies are, other than the undefined ‘best practice in soil protection’.  He argues that 'the solutions for much of our agricultural soils are likely to be based on how we can manage the whole soil-crop-landscape system for ecosystem services (including for food and water provisioning) without the use of the plough and the harrow as well as uncontrolled heavy farm traffic.’

Interest in CA has grown during the past two decades, as has the evidence that this ‘win-win agricultural production system’ can help to address the ‘unsustainable characteristics of modern tillage agriculture’.  In the 1940s Edward Faulkner in his revolutionary “Ploughman’s Folly” stated that ‘no one has ever advanced a scientific reason for ploughing’.  CA has achieved economic and environmental benefits wherever it has been introduced and it is increasingly being promoted as making a real contribution to sustainable intensification.  It can do this because it:

  • Provides and maintains an optimum environment in the root-zone to a maximum possible depth.
  • Ensures that water enters the soil so that (a) plants seldom suffer water stress that will limit the expression of their potential growth; and (b) residual water passes down to groundwater rather than over the surface as runoff.
  • Favours beneficial biological activity in the soil to (a) maintain and rebuild soil architecture, (b) compete with potential in situ soil pathogens, (c) contribute to soil organic matter and various grades of humus, and (d) contribute to capture, retention, chelation and slow release of plant nutrients.
  • Avoids physical or chemical damage to roots that disrupts their effective functioning or limits their maximum potential for nutrient uptake.

Prof. Kassam identifies a range of benefits provided by CA, which I have summarised here:

  • Large and demonstrable savings in machinery and energy use, and carbon emissions        
  • A rise in soil organic matter content and biotic activity
  • Reduced erosion
  • Increased crop-water availability and drought resilience
  • Improved recharge of aquifers
  • Reduced impact of climate change-induced weather volatility
  • Reduced production costs, contributing to increased profits
  • More reliable harvests and reduced risk

While CA has been adopted widely across many countries, it has only rarely been ‘mainstreamed’ as an approach to sustainable farming within agricultural development programmes or backed by policy, so the global coverage of CA remains small, at only around 7% of total crop land.  It has been promoted in some EU Member States via the European Conservation Agriculture Federation (ECAF) but it has neither been widely publicised nor seriously researched.  Other barriers include cultural ones, such as a traditional reliance on ploughing, as well as the need for a deeper understanding of ecological processes; CA is therefore knowledge intensive.  In Finland, Germany and Spain the adoption of CA is being encouraged and subsidised in order to address soil erosion, but its adoption in other Member States seems to be driven by economic, rather than environmental influences.

Prof. Kassam appears to subscribe to the ‘growing conviction’ that CA has an important role in transforming agriculture everywhere towards a more sustainable and efficient system.  However, he identifies a number of barriers to the widespread take-up of this type of farming, principally the belief that soil tillage is essential for agricultural production.  In order to foster the widespread take-up of CA, he argues that Europe should rely on (a) the evidence and successful experience outside Europe; and (b) establish a network of publically funded on-farm operational research in which farmers can be provided with an opportunity and financial support to experiment with CA practices and adopt them to suit their socio-economic and agro-ecological conditions.  In addition, the engagement of the machinery sector to develop a new set of mechanical technologies for CA farming will be necessary.

The paper concludes by stating that EU governments must ‘make a firm and sustained commitment to encourage and support CA’.  I agree that this is a desirable objective.  However, in the UK soil loss is generally not a significant issue across much of the country (soil loss to rivers and other water bodies, resulting in contamination and eutrophication clearly is a problem, however).  Without the driver of substantial soil erosion and thinning soils, which are common problems in other parts of the world, in spite of the multiple other benefits of CA we might be waiting some years before we see its widespread adoption in the UK.