Changes in soil organic matter under different land management in misiones province (Argentina)
Open Access
- 1 January 2008
- journal article
- Published by FapUNIFESP (SciELO) in Scientia Agricola
- Vol. 65 (3), 290-297
- https://doi.org/10.1590/s0103-90162008000300009
Abstract
Highly weathered tropical soils rapidly loose soil organic matter (SOM) and may be affected by water erosion and soil compaction after deforestation and intensive cultivation. With the main objective to estimate the SOM balances in a subtropical soil we determined the dynamics of SOM in a degraded yerba mate (flex paraguaiensis Saint Hil.) plantation introduced after deforestation and with elephant grass (Pennisetum purpureum L.) as a cover crop. The study site was in Misiones, Argentina, and we use the natural C-13 abundance methodology and a descriptive model. The study was conducted on three contiguous 50 x 100 m plots of a typic Kandihumult soil with: (i) native forest, (ii) 50 years of continuous yerba mate monoculture with intensive tillage, and (iii) yerba mate associated with elephant grass as a cover crop and no tillage. We determined bulk density, carbon (C), nitrogen (N) and C-13 content of the soil (0 - 0.05, 0.05 - 0.15 m layers) and the grass biomass. Yerba mate monoculture reduced soil C and N content as well as porosity at 0 - 0.15 m depth by 43 and 23%, respectively, as compared to the native forest. After ten years of yerba mate - elephant grass association soil C and N contents at the same depth increased by 19 and 12%, respectively, compared to the yerba mate monoculture, while soil porosity remained similar. Total C input, C-13, and soil organic C were incorporated into a three compartment model to evaluate elephant grass C dynamics. Through the natural C-13 abundance methodology we tracked the elephant grass C incorporation and the "old" soil C loss, and determined the model parameters - humification (k(l)) and mineralization (k) coefficients and stable C (C-s)- unambiguously. The high k(l) and k predicted by the model are probably explained by elephant grass root system incorporation under no tillage and humid subtropical climate, respectively. In soil under yerba mate monoculture, C, was counted as 91% of the total soil organic CKeywords
This publication has 34 references indexed in Scilit:
- Tropical agriculture and global warming: impacts and mitigation optionsScientia Agricola, 2007
- A method for estimating coefficients of soil organic matter dynamics based on long-term experimentsSoil and Tillage Research, 2006
- Effects of forest conversion to pasture on soil carbon content and dynamics in Brazilian AmazoniaAgriculture, Ecosystems & Environment, 2004
- Modelling soil carbon dynamics with various cropping sequences on the rolling pampasAgronomy for Sustainable Development, 1999
- Estimating C inputs retained as soil organic matter from corn (Zea Mays L.)Plant and Soil, 1999
- The use of stable carbon isotopes for estimating soil organic matter turnover ratesGeoderma, 1998
- Organic carbon and 13C contents in soils and soil size-fractions, and their changes due to deforestation and pasture installation in eastern AmazoniaGeoderma, 1994
- Dynamics of soil organic matter as reflected by natural 13C abundance in particle size fractions of forested and cultivated oxisolsSoil Biology and Biochemistry, 1992
- Soil Organic Matter Turnover in Long‐term Field Experiments as Revealed by Carbon‐13 Natural AbundanceSoil Science Society of America Journal, 1988
- Natural 13C abundance as a tracer for studies of soil organic matter dynamicsSoil Biology and Biochemistry, 1987