Open AccessIntensification enhances litter carbon and nitrogen decomposition dynamics in subtropical grazinglands
Author(s) -
Kohmann Marta M.,
Sanchez Joao M. D.,
Silveira Maria L.,
Brandani Carolina B.,
Baldo Amanda,
Borges Bernardo M. M. N.,
Ribeirinho Victor S.,
Vendramini Joao M. B.
Publication year - 2020
Publication title -
agrosystems, geosciences and environment
Language(s) - English
Resource type - Journals
ISSN - 2639-6696
DOI - 10.1002/agg2.20075
Subject(s) - agronomy , litter , chemistry , plant litter , nitrogen , soil water , perennial plant , soil carbon , paspalum notatum , zoology , nutrient , biology , ecology , organic chemistry
Increased grazing land management intensification through the selection of productive species and the use of N affects the amount and quality of C and N inputs to the soil. This study evaluated the short‐term impacts of litter quality on litter decomposition and C and N distribution among soil size–density fractions. A 168‐d litter bag mesocosm experiment and a 120‐d incubation study evaluated the decomposition of three perennial species [rhizoma peanut ( Arachis glabrata Benth., RP), bahiagrass ( Paspalum notatum Flügge; BG), and saw‐palmetto ( Serenoa repens Bartr., SP)] on grazing land soils with contrasting C concentrations (3.4 and 18 g C kg −1 ; Buck Island Ranch and Ona, respectively). Soil did not affect litter decomposition. There was less remaining biomass at the end of incubation for RP and BG (58%) than SP (79%). Nitrogen immobilization occurred on SP litter, probably because of its high initial lignin/N and fiber‐bound N/N ratios (43 and 384 g kg −1 organic matter, respectively). Litter had no effect on soil C and N concentrations in size–density fractions; however, greater proportions of C and N (∼47 and 59%, respectively) were found in the light‐free fraction. Nitrogen addition promoted C and N accumulation in the mineral fraction. These results suggest plant litter chemical characteristics played a more important role on litter decomposition than soil C and N concentrations. Management intensification through changes in plant species and N fertilization had positive effects on C and N dynamics in coarse‐textured soils, with enhanced decomposability of cultivated forage species relative to native vegetation.