Non-organismal soil supplements and additives

Soil plays a vital role in the Earth’s ecosystem. It provides anchorage for roots, holds water and nutrients. Soils are home to numerous micro-organisms that fix nitrogen and decompose organic matter. It also filters the rainwater and regulates the discharge of excess rainwater, preventing flooding. However, a third of the world’s soil is moderately to highly degraded, threatening global food supplies and increasing carbon emissions. Desertification is a consequence of severe land degradation and is defined by the UNCCD as a process that creates arid, semi-arid and dry sub-humid areas. Desertification is often the end result of human activities and climatic factors that cause soil erosion, a decline in soil quality and the loss of natural vegetation. This solution focuses on the application of amendments to improve soil quality and mitigate greenhouse gas (GHG) emissions from croplands. Different non-organismal soil supplement and additives exist or are being developed. These have different mechanisms to cope with and/or tackle soil degradation. They will provide a better environment for roots and plant growth: this includes the improvement of the soil structure and water holding capacity, the availability of nutrients, and the living conditions for soil organisms. Several soil amendments optimise water use by increasing the soil moisture holding capacity. These can be used to assist plant growth in infertile (e.g. desert) environments. These include the use of potassium polyacrylate and liquid natural clay treatment. Other amendments include compost and biochar. Biochar is charcoal that is produced by pyrolysis of biomass in the absence of oxygen. It can favour long-term stabilisation of carbon stocks, serving as a net withdrawal of atmospheric carbon dioxide. From an agronomic point of view, high organic carbon input from biochar can enhance the nutrient and water retention capacity of the amended soil, reducing the total fertilizer requirements.