Food security is a growing concern for our global population of close to 8 billion people. The essential natural resource that controls food production is soil. Without healthy soils, our capability to provide adequate food for billions is seriously in question. And history has shown us that without healthy soils, societies collapse.
Topsoil–the fertile part of the soil essential for plant growth–can take thousands of years to develop, with 500 to 1,000 or more years to produce even an inch of thickness. Vital topsoil is being eroded away and degraded worldwide–and at an unsustainable rate.
High rates of erosion result from land use practices such as deforestation and intensive agriculture. Many agricultural practices can harm soils, including over-tillage that damages the soil structure, insufficient replenishing of the nutrients lost during plant growth, overgrazing, and salinization. Degraded soil has fewer nutrients and produces food that is less nutritious.
Soil salinization is a global problem, with especially large areas affected in Australia, Africa, and South America. Good information about soil development and management is in a post titled Soil salinization: putting food security at risk by Kathelijne Bonne on the website GondwanaTalks. In her post, Kathelijne lists approaches to reclaiming degraded soils, and I describe some of those methods at the end of this post.
The map and explanatory caption below summarize the vast global extent of degraded soil.
There are many agricultural practices that can slow degradation and improve the quality of soil. Increasing the vegetative cover on the land is an important measure, as is planting mixed crops. Practicing crop rotation benefits the soil, as opposed to growing the same crop year after year on the same land (e.g., mono-cropping, frequently used in industrial farming for wheat, maize and soybeans).
Methods for improving degraded soils are available. Municipalities produce a large volume of waste materials that could be soil amendments. Composting vegetative garden and household food debris and adding it to soil increases microbial activity, reduces compaction, and improves the rate of vegetation establishment. Municipal sewage sludge (biosolids) generated by waste treatment can be added to soil to improve organic matter and nutrient content, plus stimulate soil microbial communities. On a larger scale, the industrial waste fly ash, a product that results from combustion of coal at high temperatures, can be combined with organic manure from livestock or other sources to enhance plant production on degraded soils.
A website and blog, Good Climate News —because we can all use positive news (yes!)–-is written by Kathelijne Bonne also, along with her sisters from Belgium, Elisabeth and Helena. A recent post is an interview with the CEO of WastePlant, a food garden facility in New South Wales, Australia. The encouraging findings from the WastePlant project are that simple and sustainable solutions for food waste problems are available through composting and soil regeneration, and these rely on methods that communities can widely implement. Check out the post here: WastePlant: a sustainable hub to turn organic waste into healthy food.
The world is growing more connected all the time. What happens in other parts of the planet will eventually affect our economies and the stability of the world around us. The health of global soils and food security are critically important.
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