effects of crop rotation and nitrogen fertilization on soil chemical and microbial properties in a Guinea Savanna Alfisol of Nigeria

• Published in: Plant and soil 2006-03, Vol.281 (1-2), p.97-107
• Main Authors: Adeboye, M.K.A, Iwuafor, E.N.O, Agbenin, J.O
• Format: Article
• Language: English
• Subjects: Agricultural practices; Agricultural soils; Agronomy. Soil science and plant productions; Alfisols; Biochemistry and biology; Biological and medical sciences; Biomass; Carbon; Centrosema; Centrosema pascuorum; Chemical, physicochemical, biochemical and biological properties; Corn; cowpeas; Crop rotation; Cropping systems. Cultivation. Soil tillage; fertilizer application; Fertilizers; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; Glycine max; Legumes; Microbial biomass; Microbiology; Nitrogen; Nitrogen fertilization; nitrogen fertilizers; Nitrogen, phosphorus, potassium fertilizations; Organic carbon; Organic soils; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Savanna soils; Savannahs; Soil biochemistry; soil chemical properties; Soil microorganisms; Soil organic carbon; soil organic matter; Soil pH; Soil science; Soil sciences; Soil surfaces; soil-plant interactions; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Soybeans; Tillage; Vigna; water-soluble organic carbon; Zea mays
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-005-3828-5

The impacts of crop rotation and inorganic nitrogen fertilization on soil microbial biomass C (SMBC) and N (SMBN) and water-soluble organic C (WSOC) were studied in a Guinea savanna Alfisol of Nigeria. In 2001, fields of grain legumes (soybean and cowpea), herbaceous legume (Centrosema pascuorum) and a natural fallow were established. In 2002, maize was planted with N fertilizer rates of 0, 20, 40 and 60 kg N ha-1 in a split-plot arrangement fitted to a randomized complete block design with legumes and fallow as main plots and N fertilizer levels as subplots. Surface soil samples were taken at 4 weeks after planting and tasselling stage of the maize. Inorganic N fertilization had no significant (P > 0.05) effect on SMBC, SMBN and WSOC, while crop rotation significantly (P < 0.0001) affected both SMBC and WSOC. These results demonstrate that crop rotation do not necessarily influence the gross soil microbial biomass, but may affect physiologically distinct subcomponent of the microbial biomass. The soils under the various rotations had a predominance of fungi community as indicated by their wide biomass C/N ratio ranging from 9.2 to 20.9 suggesting fungi to be mainly responsible for decomposition in these soils. Soil microbial biomass and WSOC showed significant (P < 0.05) correlation with both soil pH and organic carbon but no relationship with total N. Based on these results, it appears that the soil pH and organic carbon determined the flux of the soil microbial biomass and amount of WSOC in these soils.