1. Allison LE (1965) Organic carbon. In: Black CA (ed) Methods of soil analysis. Part II. American Society of Agronomy, Madison, pp 1367–1378
2. Amato M, Ladd JN (1988) Assay for microbial biomass based on ninhydrin reactive nitrogen in extracts of fumigated soil. Soil Biol Biochem 20:107–114
3. Analytical Software (2003) Statistix 8: user’s manual. Analytical software, Tallahasse
4. Anderson JPE (1982) Soil respiration. In: Page AL, Miller RH, Keeney DR (eds) Agronomy monograph number 9, part II. Chemical and biological properties, 2nd edn. American Society of Agronomy and Soil Science Society of America, Madison, pp 831–871
5. Anderson T-H (2003) Microbial eco-physiological indicators to assess soil quality. Agric Ecosyst Environ 98:285–293