Soil

Healthy and Productive Soils

Soil is essential to all of life on land. It exists as a slender layer of organically-rich, fine mineral particles, which is a biologically active ecosystem right under our feet. Most of the food upon which we humans depend for our health require healthy and productive soils.

Soils are formed  by combination of processes; the slow breakdown of subsoil rocks,  the decomposition of dead organic matter, but most importantly by healthy plants photosynthesising sugars and exuding this form of ‘liquid carbon’ through their roots to exchange with mycorrhizal fungi for minerals & other nutrients. This symbiotic relationship is crucial for healthy soils, however, it is a fragile co-existence easily damaged by human activities up top.

Like all aerobic ecosystems, soil requires air, water & food for the inhabitants to survive & thrive. Unfortunately, our activities compromise all three of these essential requirements. Compaction is a major issue for Northland with our high soil clay content, coupled with heavy rainfall. This causes compaction layers to form excluding air, preventing free drainage, & causing an acidic zone around the depth of plant roots which compromises that crucial symbiotic relationship. Fungi are also highly sensitive  to other farming activities like ploughing, biocides, and many forms of inorganic fertilizers.

With the physical structure of our soils easily damaged, their biological function also then readily deteriorates, such that the ‘glue’ that holds our soil together starts to vanish. Soil erosion is another major issue for Northland, with tonnes of precious topsoil being carried down our rivers & creeks & out into our estuaries & oceans every year.

As well as all these physical & more obvious problems that we face there is another which is much less visible. Without that crucial plant-fungal interaction our food is mineral deficient, and research shows that the mineral composition of our food has been in steep decline in parallel with the rise of ever more intensive ‘industrial’ forms of farming & food production.

Strangely, despite these challenges, and the centrality of healthy soils to everything we do, there is no National policy on soils in this country, nor a Regional policy in Northland. Soil management is only tackled indirectly at policy level through our freshwater policies, and this has to do more with soil retention than with intrinsic management policies. However, there is much that can be and is being done at a local level to champion the ‘soil first’ approach to land management.