Quality and Quantity of Organic Fractions as Affected by Soil Depth in an Argiudoll under Till and No-till Systems

DUVAL, MATIAS; BAIGORRI, ROBERTO; DUVAL, MATIAS; BAIGORRI, ROBERTO; GALANTINI, JUAN; MORA, VERÓNICA; GALANTINI, JUAN; MORA, VERÓNICA; MARTINEZ, JUAN; GARCÍA-MINA, JOSÉ; MARTINEZ, JUAN; GARCÍA-MINA, JOSÉ

International Journal of Plant & Soil Science

SCIENCEDOMAIN international

Año: 2016 vol. 10 p. 1 - 12

The turnover rate of labile organic fractions varies continuously due to different soil uses and managements, weather conditions and time of sampling. The aim of this study was to quantify the effect of different agricultural management, season and soil type on soil organic carbon (SOC) and its different fractions. The study was conducted on four sites located in the Argentinean Pampas. In each site, three treatments were defined: Good Agricultural Practices (GAP), Poor Agricultural Practices (PAP) and Natural Environment (NE). During two consecutive years (2010 and 2011) and at two different times (February and September) undisturbed soil samples were taken at0-20 cm depth. Variables assessed included: SOC and its organic fractions: coarse and fine particulate organic carbon (POCc and POCf, respectively), SOC associated with a mineral fraction (MOC), total and soluble carbohydrates (CHt and CHs, respectively), bulk density, and large pores (P>30). Also, indices associated with soil and management variables were determined. SOC reductions caused by agricultural practices were mainly from POCc. This fraction represented 34-52% and 50-74% for PAP and GAP, respectively, of the observed in NE. The carbon pool index (CPI) shows that agricultural treatments induced greater variations in all the labile organic fractions compared with SOC and MOC. In turn, the magnitude of variability was different among fractions, where temporal fluctuations increased according to the following order MOC< SOC