This is a section of an article written by Marten Stapper describing Biological Farming and the benefits of Carbon in the soil. I will post his whole article as well which goes into Real Food arguments and can say it all so much better than me. The second article is quite a long one! Degrading soils, rising input costs and difficulties in making the shift to organics led to the development of biological agriculture, which allows minimum use of synthetic fertilisers and chemicals. Emerging in the United States as a practice distinct from organics, biological agriculture is an easily adopted agroecological practice. It takes the best practices and materials from industrial and organic agriculture to enable farmers to make a profitable, gradual transition towards organics. Healthy soils are created step by step using biological inputs, thus minimising synthetic inputs that work against biology and balance. Fungicides and insecticides, which also kill beneficial microbes, are avoided and are not needed in any case as plants become resistant to pests. Pests become indicators of unbalanced plants; weeds become indicators of unbalanced soils. Further agroecosystem improvements to develop fields within a sustainable landscape may be achieved by managing natural energies and water through permaculture, Yeomans’ Keyline Design or Natural Sequence Farming principles. Healthy Soils with Carbon for Healthy Food A healthy soil in an agroecosystem is a soil in harmony—with the physics, chemistry and biology in balance. These factors are interactive and have strong links with soil organic carbon, the foundation for a living soil and life on earth. Soil biology seems to be the driver, using the diversity and abundance of microbes (algae, bacteria, fungi) and larger organisms (mites, beetles, earthworms) in the soil foodweb. Genes switch on and off in order to adapt to local conditions, and plants in healthy soils become more productive by activation of gene expression for self-protection. Microbial activity forms soil aggregates—crumbs—for stable soil structure. This feature greatly benefits soil aeration, which is important for water infiltration, and allowing deep and dense root systems. Soil structure and soil carbon are also aided by earthworms (present only when there is an abundance of microbes), which make humus. The organisms in a soil foodweb work together by creating a home to sustain life. Beneficial organisms make soil nutrients plant-available and protect plants against insects and diseases. Abundant and diverse soil biology ensures that under all circumstances there are beneficial species active to undertake any task. Symbiosis is this balanced, mutual interdependence of different species. It is a protective mechanism in nature that develops in response to compatible needs. Such systems run on carbon, water and nitrogen free from the sky. A healthy soil is a self-organising system that endeavours to optimise the environment for optimum plant growth. Soil microbes feed nutrients to plants on demand and in return they are fed carbon exudates from the roots, which ultimately become soil organic carbon. Soil health requires biodiversity not only in soils but also in the surrounding landscape, for example, in predator–prey species and pollinators. Windbreaks and shelterbelts improve the soil surface microclimate and provide a ‘home’ for the aerial component of the soil foodweb. Ecology is about balance. Too little is deficient and too much is toxic; it has to be just right for each factor, the balance being achieved through self-regulation. In agroecological farming, except organics, synthetic fertilisers and chemicals can be applied in small amounts, below toxic levels that would breach critical thresholds. A functional agroecosystem is resilient as it can recover from such a small application. It is the larger, combined and repeated applications that cause system collapse. Soil organic carbon with a large humus proportion acts as a sponge for water, air and nutrient retention, and a home for soil biology. Soil carbon is of critical importance for soil fertility but has generally been more than halved (up to 80 per cent) with industrial agriculture and thus has significantly contributed to the increase of carbon dioxide in the atmosphere. In Australia, soil carbon content is now less than 1 per cent for most fields. Soil carbon above 2 per cent makes plant growth markedly less susceptible to environmental conditions, because minerals and water are more available to plants, and there is less variation in diurnal soil temperature. Soil organic carbon is maximised through capture by green plants, ground cover being important in this respect. In Australia, with agroecological management, topsoil organic carbon can increase more than ten times faster than the 1 per cent over forty years science says is possible under industrial agriculture best management practice. Sequestration of carbon at depth is also higher because of greater root activity with microbes that make humus: three to eight tonnes of carbon per hectare per year is achievable. Thus soil carbon not only improves soil fertility, it also helps to slow global warming through lowering carbon dioxide in the atmosphere. It further restores the water cycle by maintaining moist topsoils, with dew formation and evapotranspiration keeping the soil surface cooler, thereby attracting rainfall. Once confirmed by science, and with the relevant policy changes, soil management via agroecological practices could become an option for carbon credit payments to farmers.
Posted on: Wed, 19 Jun 2013 22:47:19 +0000
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