Biological Indicators for Monitoring Soil Quality under Different Land Use Systems

Abstract

Soil quality not only depends just on the physical and chemical properties, but also on its biological properties. Biological processes provide soil, the resistance, resilience and buffering capacity to ameliorate stress. Soil biota is intrinsically related to the labile fraction of soil organic matter (SOM) involved in energy and nutrient cycling. Several authors over the years have reported that the more dynamic soil parameters such as microbial biomass, soil enzyme activity and soil respiration are more sensitive to changes in crop management practices and land use systems than SOM. Soil respiration is a well-established indicator to monitor decomposition, but is highly variable and can show wide natural fluctuations depending on substrate availability, moisture and temperature. Enzymes are important soil components involved in the soil nutrient dynamics. Enzyme activity in the soil system is considered to be a major contributor of soil microbial activity and quality. Continuous application of manure and fertilizer in tropical soils of India has shown that the soil organic carbon (SOC) and MBC increased with balanced fertilization whereas SOC, MBC, urease and acid phosphatase activities increased with organic amendments. Biological properties such as earthworm population, terrestrial arthropods, soil fauna and flora, lichen, microbial community (biomass or functional groups), metabolic products like ergosteroland glomalin, microbial respiration and enzyme activities have been used as soil quality indicators because of their intrinsic relationship with soil organic matter content which is central to soil health . There are several biological soil parameters that can be used as soil quality indicators, alone or in combination with other chemical or physical indicators. Proper sampling strategies and multivariate analysis of the results are key points to consider when using biological soil indicators. This chapter briefly discusses about the methods of soil quality assessment and importance and characteristics of biological indicators sensitive to land use changes and management practices.