A dynamical systems model of the interaction of earthworms with plant litter quality and quantity (original) (raw)

An Extension of a Mathematical Model of Soil Organic Matter Evolution

2016

Abstract. This paper exposes an extension of the simplest mathematical model of soil organic matter decomposition. The equation of this model is very common in the literature, for example, Davidescu and Davidescu (1981), or Willigen et al. (2008), considering some changes in a single model-components, such as Schnitzer and Khan (1978). The main idea is that the development of natural processes, is directly influenced only by the natural parameters (temperature, humidity, etc.), and only indirectly by the temporal parameter. The model proposed in this paper express this idea. Time dependence of the concentration of organic matter in soil is due only by the time dependent describing of the natural parameters evolution. This time dependence facilitates on human observer the understanding and communication. The prognosis of the concentration of organic matter in soil and the evaluating of the fertilizer management are application of the model.

Effects of termites growth on litter decomposition: a modeling approach

International Journal of Recycling of Organic Waste in Agriculture

Purpose Litter decomposition is a biological process resulting from enzymatic activities of microorganisms and influenced in a variety of ways by activities of termites in semi-arid regions. We presented a general model of the decomposition process from litter to carbon sequestration and nitrogen. We aimed at building a termite population growth model which could deal with one substrate. Methods Our model divides the decomposition/growth process at the population level. We put these changes into equations using an analogy with chemical reactions at equilibrium. Results Our findings provide evidence that activities of termites can promote the significant activity of microbial decomposers and increase degradation rates of soil organic matter (SOM). Also, termite activity was probably an additional contributor to the difference between fungus-comb chamber and soil environment, in which the fungus-comb compartment was positively related to carbon and nutrients release. According to the ...

Comparison of nonlinear models in the description of carbon mineralization in litter soil

2021

Litter is an important source of nutrients for trees and can improve the quality of degraded soils. The objective of this study was to describe the dynamics of carbon mineralization in litter soils using nonlinear models, estimating half-life times. Soil carbon mineralization under three types of forest cover was evaluated: Atlantic forest fragment (capoeira), Acacia auriculiformis trees (acacia), and Mimosa caesalpiniifolia (sabiá) from a reforested area with a history of degradation. Twelve measurements of the mineralized carbon were made up to 222 days after the beginning of the incubation of litter soils. Stanford and Smith, Juma, and Cabrera models were fitted by the least squares method using the Gauss-Newton algorithm in the R software. The Stanford and Smith model was more appropriate in describing all treatments, based on the Akaike Information Criterion, with estimates of half-life for Acácia, Capoeira, and Sabiá soils at 25, 44, and 51 days, respectively. The Stanford and...