Eucalyptus grandis and Acacia mangium in monoculture and intercropped plantations: Evolution of soil and litter microbial and chemical attributes during early stages of plant development

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2013-01, Vol.63, p.57-66
• Main Authors: Bini, Daniel, Santos, Cristiane Alcantara dos, Bouillet, Jean-Pierre, Gonçalves, José Leonardo de Morais, Cardoso, Elke Jurandy Bran Nogueira
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Forestry; Fundamental and applied biological sciences. Psychology; Legumes; Life Sciences; Litter; Microbial biomass; Microbiology; Mixed-species; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Soil science
• ISSN: 0929-1393; 1873-0272
• DOI: 10.1016/j.apsoil.2012.09.012

► Litter attributes showed the strongest correlation with soil microbial attributes. ► Soil chemical attributes showed little change over the 20-months study. ► Intercropped plantation showed low C/P and C/N ratios in litter. ► There were similarities between intercropped plantation and N-fertilized Eucalyptus grandis. Soil microorganisms and microbial processes are influenced by the quality and quantity of plant waste entering the soil, by its seasonal and spatial distribution, by the ratio of above- to below-ground inputs, and by changes in nutrient inputs. Soil management strategies sometimes promote mixed-species plantations to mitigate the loss of soil nutrients and improve biogeochemical cycling. The objective of this study was to explore changes in microbiological and chemical attributes of soils and litter in the early stages of the second rotation of mixed and pure plantations of Eucalyptus grandis and Acacia mangium, and to look for correlations between attributes. Soil samples at 0–10cm depth were collected two, seven, 14, and 20 months after planting in the following treatments: monocultures of A. mangium and E. grandis, a monoculture of E. grandis with N-fertilizer, and an intercropped plantation with E. grandis and A. mangium. Microbial soil attributes varied dramatically between treatments 20 months after planting. Total C, N and P contents in litter showed the strongest correlations with microbial biomass C and N (Cmic and Nmic), microbial respiration, and dehydrogenase activity in all sampling periods. Lower C/N and C/P ratios in litter and lower C/N and Cmic/tC ratios in soils after 20 months in the intercropped plantation illustrated the system's capacity for supplying inputs of high-quality organic matter rich in N and P, but this did not result in higher contents of these elements or greater microbial activity in soils. An implication of this finding is that, at least in the initial growth phase of these plantations, chemical attributes of the litter and variation in those attributes govern microbial processes and, consequently, are mostly responsible for plant development. Canonical discriminant analysis revealed changes in the microbiological and chemical attributes of soil in the intercropped plantation due to the plants growth and the leaf litter accumulation. Twenty months after planting, the different plantations could be discriminated by differences in litter chemistry (C, N, and P), total soil C, Nmic, and dehydrogenase activit