Agri Kultuur November 2018 | Page 8

Minimum soil disturbance Physical soil disturbance, such as tillage with a plough, disk, or chisel plough, that results in bare or compacted soil is destructive and disruptive to soil microbes and creates a hostile, instead of hospitable, place for them to live and work (See Photo 1). The soil may also be disturbed chemically or biologically through the misuse of inputs, such as fertilizers and pesticides. This disrupts the symbiotic relationship between microorganisms and crop roots. By strategically reducing chemical inputs, we can take advantage of these soil ecosystem services to allow plants to freely access essential nutrients. Diversify with crops and animals Sugars made by plants, through the miracle of photosynthesis, are released from their roots into the soil as liquid carbon and traded to soil microbes for nutrients to support plant growth. This soil ecosystem service is a vital element of healthy soils and can be enhanced through the inclusion of as many different plants and animals as practical. Livestock utilizing cover crop mixtures, for example, contribute to this diversity. With ultra-high density grazing utilizing 30-50% of available material, livestock can stimulate root development and recycle 80% nutrients in the form of dung (See Photo 2). Biodiversity directly leads towards a diverse array of soil microbes from a range of functional groups, which again improves the soil’s ability to support nutrient dense, high vitality crops, pastures, fruit and vegetables. residues, such as straw, chaff, husks, stalks, flowers, and leaves. Lastly, they feed on other organisms lower in the soil food web. Healthy soil is dependent upon how well the soil food web is fed. The provision of plenty of easily accessible food (liquid carbon) helps soil microbial communities to colonise and recycle nutrients for plants to grow. The functioning of the soil ecosystem is therefore determined by the presence, diversity and photosynthetic rate of actively growing green plants and roots. Cover crop mixtures produce root exudates with varying composition and effects, and have different zones of nutrient uptake, because they differ in amount, depth, and patterns of root branching. Permanent organic soil cover Soil should always be covered by growing plants and/or their residues, and soil should rarely be visible from above. A mulch keeps the soil cool and moist which provides favourable habitat for many organisms that begin residue decomposition by shredding residues into smaller pieces (See Photo 4). Biodiversity is ultimately the key to success of any agricultural system. Lack of biodiversity severely limits the potential of any cropping system and disease and pest problems are increased. A diverse and fully functioning soil food web provides for nutrient, energy, and water cycling that allows a soil to express its full potential. Grow living roots throughout the year There are many sources of food in the soil that feed the soil food web, but there is no better food than the liquid carbon exuded by living roots (See Photo 3). Soil organisms feed on liquid carbon from living plant roots first. Next, they feed on dead plant roots, followed by above-ground crop AgriKultuur |AgriCulture Photo 3: There is no better food for the soil food web than the liquid carbon exuded by living roots 8