Grain Guide 2018

Grow living roots throughout the year  There is no better food for the soil food web 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 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 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 keep 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 ). Dr Hendrik Smith, conservation agriculture facilitator, Grain SA 72 Conservation Agriculture and soil fertility management PHoto 2 PHoto 3 PHoto 1 PHoto 4  This soil ecosystem service can be enhanced through the inclusion of as many different plants and animals as practical (see PHOTO 2 ).  Biodiversity directly leads towards a diverse array of soil microbes from a range of functional groups.  A diverse and fully functioning soil food web provides for nutrient, energy, and water cycling that allows a soil to express its full potential. 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 ac­ tively growing green plants and roots.  Cover crop mixtures produce root exudates with varying composition and effects, and have different zones of nutri­ ent uptake, because they differ in amount, depth, and patterns of root branching. 75 Fertiliser