Is Litter just Trash?
What is the Role of Litter in Pastoral Production?
What is the Role of Litter in Pastoral Production?
If we look at seasonal environments like coastal Marlborough where distinct wet and dry seasons occur we find a huge mass of green leaf dies off as the dry season takes hold. Through grazing and animal impact, this dead material is either eaten or crushed to the soil surface as litter or trash to allow new growth to emerge when rain returns. In temperate environments like Golden Bay or the West Coast where green leaf and biological decay occur all year round the accumulation of dead material is often less obvious. Therefore some confusion exists about what is litter in such environments because grass remains green all year.
As Andre′ Voisin reminds readers of his book Grass Productivity, for every bite an animal chews, it stands on four more. Most litter settles between the grazing horizon and the soil surface, therefore, the role of litter is to feed the soil, not animals. There are two layers of litter, both having different roles; the top layer refers to all dead vegetation that is covering the soil whereas the lower layer is the humus or soil-forming layer that results from the decay of the top layer.
The importance of the top layer is to cover and protect a bare soil surface. By protecting the soil surface, litter simultaneously improves water and nutrient cycling, the harvesting of sunlight, and encourages a greater diversity of soil life forms by creating a sheltered microclimate for decay to occur. This microclimate prolongs biological activity to create the layer of humus that then helps to improve pasture performance. Nothing enhances soil organic matter than a covering of litter.
The carbon in plant litter provides energy for microorganisms to recycle organic matter and minerals. There is panic when a large amounts of litter build up in a pasture yet when moisture and temperature levels coincide, litter converts to soil organic matter and disappears very quickly allowing green shoots to emerge and plants to grow.
The trick is understanding how animals and their grazing behaviour can be used to hasten the biological decay process to strengthen pasture longevity thereby reducing erosion, lengthening growing seasons, and preventing scrub invasion. This is what farming families are taught using Holistic Management® planned grazing and having their animals in the right place at the right time for the right reasons.