is organic the way forward?

In recent years organic farming has become increasingly popular.  Not only is it perceived as being healthier, it is also believed that it can mitigate climate change.  Organic farming, as its name suggests is natural farming, where food is produced using techniques such as crop rotation, green manure, compost and biological pest control.  This is different to conventional farming which uses manufactured or synthetic fertilisers and pesticides, plant growth regulators livestock antibiotics, food additives and genetically modified organisms.  It is common belief that organic farming could mitigate climate change as it seems more natural.  This post is going to discuss ways organic farming can reduce greenhouse gas emissions and whether it is a feasible mitigation strategy.  

This article by the ITC (2007) suggests reasons why organic farming is a possible mitigation strategy, here is a summary of some of the main arguments put forward:  

The article stipulates how important synthetic nitrogen fertilisers are in conventional agriculture as high nitrogen concentrations are required to meet the required yield.  It states that in 2005 global nitrogen fertiliser consumption was 90.86 million tones, and it takes approximately 90 million tonnes of fossil fuel to produce this nitrogen fertiliser, this is about 1% of global fossil energy consumption.  By changing to organic farming it would not be necessary to produce this fertiliser, reducing carbon dioxide emissions.  

Organic agriculture is self sufficient in nitrogen, mixed organic farms recycle manures form livestock and crop residues into compost, these are then used as fertiliser.  Leguminous crops also provide additional nitrogen in sufficient quantities.  Emissions of nitrous oxide are directly related to the concentration of available nitrogen in the soil, therefore as I mentioned in a previous post if adequate nitrogen is in the soil for the crop then less is lost.  As mineral fertilisers are not used and there are reduced livestock units per hectare there is less nitrogen in the soil resulting in a smaller amount of loss as nitrous oxide.  

A reduction in nitrous oxide emissions can also be achieved though using diverse crop rotations, this improves soil structure and quality, reducing erosion which leads to loss of nutrients.  Soils managed organically are much more aerated and have significantly lower mobile nitrogen concentrations. 

Similarly, as soil quality is better where it is organically farmed, less carbon is lost.  Conventional farming encourages carbon loss due to soil erosion.  Carbon is stored in organic soils due to the use of green and animal manures, crop rotations with inter cropping, cover cropping and composting techniques.  Organic farms generally use conservation tillage or no-till, I explained how this benefits the soil in a previous post.  

this picture shows organic soil (on the left) to have better drainage and water holding capacity, it is less waterlogged than conventional (on the right) this reduces soil erosion

When looking at an opposing angle, put forward by Cassman et al (2003) surrounding nitrogen levels it is possible to see a different perspective on organic farming.  This article states that although it is believed that organic farming offers environmental benefits, it is just as difficult to prevent nitrogen loss from the soil from organic fertilisers as it is synthetic.  There have been many studies on leaching from organic soils, with varied results, some show it to be higher than synthetic and others lower.  Yield reductions are also associated with organic farming, and organic farming produces more expensive products whilst requiring more government subsidies to remain economically viable.  

Consequently this has created the idea of including some practices from organic farming in conventional systems.  This is suggested by Pimentel et al (2005).  There are many benefits of organic farming such as improved soil quality which could make conventional agriculture more sustainable.  Lal (2004) suggests that using practices from organic farming, such as no-till farming, cover crops, nutrient management, argo forestry, can improve carbon content of soils.  This in the long run can improve food security, which is becoming a more pressing issue as more soils are degraded. 

It would be effective to include some areas of organic farming in conventional farming, to make it more sustainable.  It does not seem logical to use organic farming as a mitigation strategy as it is not possible to determine whether producing food this way would yield enough for the global population.  Producing food organically also requires higher economic investment and produces more expensive products.  As Cassman et al state, organic farming could be feasible in industrialised countries but it would not be able to secure the food supply in the developing world where it is necessary to maintain low food prices.