Do soil enzymes respond to long-term grazing in an arid ecosystem?

NELDA L. OLIVERA; LUCIANO PRIETO; ANALÍA L. CARRERA; HEBE SARAVÍ CISNEROS; MÓNICA B. BERTILLER

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 2014 p. 1 - 14

0032-079X

Background and aims Our objective was to assess theeffects of long-term continuous grazing on soil enzymeactivities in relation to shifts in plant litter attributes andsoil resources in an arid ecosystem, considering bothspatial and temporal variations.Methods We randomly extracted soil samples with therespective litter cover at 5 modal size plant-coveredpatches (PCP) and the nearest inter-canopy areas (IC)at Patagonian Monte sites with low, medium and highgrazing intensity in winter and summer from 2007 to2009. We analyzed enzyme activities (dehydrogenase,ß-glucosidase, protease, alkaline and acid phosphatase),microbial biomass-C, organic-C, total soil-N, and moisturein soil and mass and quality in plant litter. Weassessed faeces density and plant cover in the field.Results and conclusions Grazing led to reduced grasscover, decreasing plant litter mass with increasing solublephenolics, and reduced phosphatases, ß-glucosidaseand microbial biomass-C at PCP. A localized nutrientinput from animal excreta seems to promote microbialbiomass-C, alkaline phosphatase and dehydrogenaseactivities but only at IC from the site with high grazingintensity. Plant heterogeneous distribution, plant litterquantity and quality, nutrient inputs from grazers andseasonal variation in soil moisture, also affecting soilresources and microbial biomass, modulate soil enzymeresponses to long-term grazing in the arid PatagonianMonte.