Submitted to: Advances in Agronomy
Publication Type: Book / Chapter
Publication Acceptance Date: 3/5/2002
Publication Date: N/A
Technical Abstract: Acid soils play an important role in the production of world food and fiber and degradation of these soils poses a great challenge to sustainable agriculture. An efficient indexing system is needed to monitor the changes in the quality of these soils. Several microbiological and biochemical parameters have been suggested as indicators of soil quality. They include: :microbial biomass C, N, and P and their turnover rates; the microbial quotient; basal respiration; the microbial metabolic quotient; the ratio of microbial N over total Kjeldahl N; and enzyme activity. Recently, microbial diversity parameters such as community level physiological profile, phospholipid fatty acids, the ratio of gram negative/gram positive bacteria, the ratio of fungal/bacterial microorganisms, and free-living diazotrophic bacteria, etc., have been identified as important indicators of soil quality. All these microbiological and biochemical parameters have been shown to relate to soil productivity and respond to changes of land management practices, vegetative cover, and climatic conditions. Current progress on measurement, interpretation, and potential application of the microbiological and biochemical indices in assessing quality, fertility, and sustainability of highly weathered acid soils are reviewed in this paper.