Forest recovery, especially of riparian forests, has become a key factor in the environmental planning of agriculture, to protect water resources and the biota. However, traditional agricultural crops have not only affected nutrient cycling by the loss of organic matter and of microbial biomass and activity, but also increased soil compaction, which can later affect reforestation. The aim of this study was to identify the soil (physical, chemical and microbiological) properties that most influence the litter moisture contents of C, N, and P in areas of recovering riparian forests (20, 10 and 5 years old), in comparison with a native site (NT). The analyses ANOVA, Duncan's test and Pearson's correlation were used to identify the properties influenced by time of recovery and to identify the relationship between them. Multivariate analysis and partition of inertia (pRDA) were used to identify the most important soil properties to explain variations in litter C, N, P, and moisture content. The highest litter C:N ratios (26.8 and 29.9, respectively) were found at the recovery sites after 20 and 5 years. Among the microbiological properties, basal respiration (CO2-C), microbial biomass carbon (MBC) and dehydrogenase and urease activities increased with the age of the recovery sites. Soil total C and N, NO3-N, microbial biomass nitrogen (MBN) and dehydrogenase and urease activities showed a positive correlation with litter C and N content, while microporosity shower a negative correlation. According to the pRDA analysis, NBM and soil C were the most important variables to explain litter C and N content. Besides, these variables together explained more than half of the total variation or 28.2 %. The improvement of the soil physical conditions and the addition of organic matter with higher N content could be a possibility of improving the soil microbiological and chemical conditions and accelerate the recovery process.
dehydrogenase and urease activity; microbial biomass; nutrient cycling; soil compaction; land restoration
