In-vitro Digestibility Organic Materials – Relation with Field Mass Loss Litter Bag Method

Abstract

Decomposition and litterfall are the primary mechanisms by which plants release their organic matter and nutrients into the soil, which helps prepare the stage for beneficial pathways in the restoration of damaged ecosystems. Species selection and allocation for the successful use of litter in ecological agricultural fields relies on knowing the mechanisms of plant litter decomposition and its influence on soil nutrients, which are crucial aspects of the ecosystem material cycle. In current study, In-vitro dry matter digestibility (IVDMD) used for evaluating quality animal feed reveals some potential in the decomposition of organic matter estimated. Nevertheless, some consensual advantages as laboratory incubation, this methodology demands a validation procedure. Therefore, the present work aimed to validate the IVDMD methodology by comparison with field buried litter bag mass loss, for 27 organic materials with different origins and chemical quality. The results reveal significant differences among the organic materials studied, reflecting their chemical quality variation, with digestibility values varying between 10.1 g kg-1 in composted sewage sludge and 982.0 g kg-1 in pig meat meal. IVDMD presented high accuracy results for all studied periods, with best results observed for 28 days incubation period (r2adj=0.959 ***). Taking the chemical fractions that participated in initial decomposition process the IVDMD is a potential indicator of a labile decomposable pool of organic materials. Considering the high accuracy, repeatability (CV=4.6%) and practicability, the IVDMD is a reliable alternative to the litter bag method in field mass loss availability.

Keywords

• in-vitro digestibility
• mass loss
• litter-bag
• decomposition