Abstract
The installation of commercial stands with exotic forest species on low fertility soils originally covered by native pastures is an unusual situation worldwide. In recent years, the area occupied by forest systems designed for pulp or wood production with immediate replanting has increased strongly in the Pampean region of South America. In this context, the study of nutrient recycling from forest litter decomposition acquires particular relevance. This work seeks to evaluate and compare the nutrient release from the decomposition of forest litter produced by 14-year-old Eucalyptus grandis Hill ex Maiden and Pinus taeda L. stands and test the applicability of a new sampling methodology in the nutrient recycling assessment. For two years, the evaluation of N, P, K, Ca, Mg, Fe, Mn, Cu and Zn dynamics during litter decomposition was carried out. In general, K concentration decreased through decomposition, meanwhile, all other nutrients showed some degree of immobilization, but this was counteracted by biomass loss for most of them. This mainly resulted in net nutrient release from litter. A higher release rate of all nutrients from P. taeda forest litter compared to E. grandis, with the exception of Mn, was verified. Fe immobilization was observed in both species showing a higher immobilization rate in E. grandis compared to P. taeda. Finally, Zn exhibited immobilization processes in E. grandis and releases in P. taeda. This might suggest higher temporal and quantitative availability of nutrients in P. taeda, due their faster return to the soil. These findings could be relevant in the development of models for sustainable management, adapting the demand for nutrients to the supply during forest rotations.
Highlights
During the last years, the installation of commercial stands with different species of Eucalyptus and Pinus in sites originally covered by native pastures in the Pampean region of South America has experienced a relevant growth [1,2,3]
The concentrations of P and Zn of all considered litter layers were higher in P. taeda than in E. grandis, following the response demonstrated by the average results
The variation in the concentration of the evaluated nutrients during the decomposition process is dependent on the considered nutrient and can significantly alter the evidenced behavior for the biomass loss
Summary
The installation of commercial stands with different species of Eucalyptus and Pinus in sites originally covered by native pastures in the Pampean region of South America has experienced a relevant growth [1,2,3] These systems are designed for pulp or wood production, in relatively short rotations, with immediate replanting, usually on soils with low natural fertility [3,4]. This change in coverage implies the incorporation of a new component to the soil–plant system, the forest litter [5]. Differences in the availability of nutrients will be influenced by their mobility, as well as by the material quality and the environmental conditions [1,6,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
