Agricultural productivity depends on the organisms that inhabit the soil.
Different forms of agriculture have very different effects on the soil's complex ecology by impacting on soil fertility, the cycling of inorganic compounds and the development of soil structure. A microtitre plate with 96 wells and each containing a different carbon substrate provide information on the capacity of the microbes present to use the range of carbon sources. However, with microbiologists now interested in the diversity of substrates used by microbes in the soil, a single measure allowing comparison among microbial communities was seen as an important quantitative tool for better understanding how microbial diversity contributes to soil health. Use of the Gini coefficient in conjunction with hypothesis testing techniques provides scientists with different, but complementary information to that given from descriptive data analysis. This has led to the proliferation of papers on substrate utilisation using dimension reduction techniques, such as principal component analysis and correspondence analysis.