Celebrating the International Year of Soils: Exploring some soil biological indicators


Nov 2015

Soils are of central importance for delivering ecosystem services, such as food production and climate mitigation. These services depend heavily on carbon (C) sequestration and nutrient cycling, processes that are governed by soil biota or biology. Soil biology is the study of microbial and faunal activity and ecology in soil. However, soil biology is one of the most unexplored frontiers associated with understanding the dynamics of soil resources and their subsequent health or quality. There is growing recognition for the need to develop sensitive indicators of soil health and biology that reflect the effects of land management on soil and assist land managers in promoting regenerative conservation agriculture (CA).

Producers intuitively recognised the importance of healthy soils and have used qualitative terms (i.e. colour, taste, touch and smell) to describe soil condition and performance for crop production since the dawn of agriculture about 10 000 years ago. At the beginning of the 20th century, qualitative “life measuring” descriptions, however primitive they were, gradually became replaced by analytical procedures to assess and evaluate soil almost exclusively from the perspective of inorganic nutrients (chemistry) and crop yield.

In this article, a few soil biological indicators are discussed, which are part of a growing pool of analytical options gaining ground in measuring short term changes in soil biology or health inflicted by changes in land management. They are discussed in relation to actual field measurements done for different cropping practices evaluated in the Ottosdal CA project, which is funded by the Maize Trust (MT), implemented by the Ottosdal No-till Club and co-ordinated by Grain SA’s CA Programme. These cropping treatments (bare soil, monocrop, rotations, mixtures and natural grassland or veld) include cash crops (maize, soybean and sunflower), as well as cover crops (e.g. Dolichos lablab, grain sorghum, babala, black oats and mixtures).


Posted on

November 5, 2015

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