Biological Indicators for Soil Health: Potential for Development and Use of On-Farm Tests

Abstract

Agricultural sustainability can be supported by monitoring soil quality. Laboratory soil tests are available to assess a range of soil chemical, physical, and biological characteristics. Farmers can also monitor the state of their soil according to its general appearance and response to disturbance. Soil organisms have significant roles that contribute to the sustainability of agricultural systems. While on-farm tests for assessing the abundance and diversity of larger soil fauna (e.g., earthworms and other macrofauna) are available, on-farm tests for soil mesofauna, microfauna, and microorganisms are not commonly used. Adaptation of laboratory methods for quantifying soil mesofauna and arbuscular mycorrhizal (AM) fungi have potential for on-farm assessment by farmers. This chapter focuses on these two groups of soil organisms because of their multifunctional contributions to physical, chemical, and biological components of soil fertility. Soil processes in which soil mesofauna and AM fungi are involved include stabilization of aggregates. Several laboratory-based methods are available for quantifying soil mesofauna and AM fungi which can be adapted for use on-farm by farmers. Farmer motivation for investigation of soil health could lead to more sustainable land use if contributions of soil organisms are optimized. Existing farmer knowledge of soil chemical and physical characteristics based on off-farm soil tests and their use could be complemented by local knowledge of soil biological characteristics, especially those that involve soil mesofauna and AM fungi.