Adequacy assessment of mathematical models in the dynamics of litter decomposition in a tropical forest Mosaic Atlantic, in southeastern Brazil

Abstract

The study of litter decomposition and nutrient cycling is essential to know native forests structure and functioning. Mathematical models can help to understand the local and temporal litter fall variations and their environmental variables relationships. The objective of this study was test the adequacy of mathematical models for leaf litter decomposition in the Atlantic Forest in southeastern Brazil. We study four native forest sites in Parque Estadual do Rio Doce, a Biosphere Reserve of the Atlantic, which were installed 200 bags of litter decomposing with 20×20 cm nylon screen of 2 mm, with 10 grams of litter. (2005), which considers the variable K through QMR, SQR, SQTC, DMA and Test F. The Fountain and Schowalter (2004) model was inappropriate for this study by overestimating decomposition rate. The decay curve analysis showed that the model with the variable K was more appropriate, although the values of QMR and DMA revealed no significant difference (p> 0.05) between the models. The analysis showed a better adjustment of DMA using K variable, reinforced by the values of the adjustment coefficient (R 2 ). However, convergence problems were observed in this model for estimate study areas outliers, which did not occur with K constant model. This problem can be related to the non-linear fit of mass/time values to K variable generated. The model with K constant shown to be adequate to describe curve decomposition for separately areas and best adjustability without convergence problems. The results demonstrated the adequacy of Olson model to estimate tropical forest litter decomposition. Although use of reduced number of parameters equaling the steps of the decomposition process, no difficulties of convergence were observed in Olson model. So, this model can be used to describe decomposition curves in different types of environments, estimating K appropriately.Keywords: litterfall, nutrient cycling, organic matter and nutrient loss, mathematical models, biosphere reserve. Adequação da utilização de modelos matemáticos em estudos da dinâmica de decomposição da serapilheira em um Mosaico de Floresta Tropical Atlântica, no sudeste do BrasilResumo O estudo da ciclagem de nutrientes através da decomposição de serapilheira é essencial para conhecer a estrutura e funcionamento das florestas tropicais nativas. Em decorrência da sua dependência de variáveis ambientais, o uso de modelos matemáticos pode ajudar a compreender as variações locais e temporais da decomposição do folhedo. O objetivo deste estudo foi testar a adequação dos modelos matemáticos para avaliar a dinâmica da decomposição da serapilheira em um mosaico

Metabolizable Protein: 1. Predicting Equations to Estimate Microbial Crude Protein Synthesis in Small Ruminants

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Litterfall deposition and nutrient return in pine-oak forests and scrublands in northeastern Mexico

“…Litterfall is a fundamental process in ecosystem dynamics, it is indicative of ecological yield, and is of vital importance in soil formation and maintenance of soil fertility (Andivia et al, 2010;Nunes & Garcia, 2015). The decomposition of the organic matter contributed by litterfall regulates nutrient and energy patterns in forest ecosystems (Facelli & Pickett, 1991;Chapin, Matson, & Mooney, 2002;Weltzin et al, 2005).…”