The role of complex agroecosystems in sequestering carbon and mitigating climate change

OELBERMANN, M.; ECHARTE, L.; VACHON, K.; DUBOIS, C.

Copenhagen, Denmark

Congreso; Congress on Climate Change: Global Risks, Challenges and Decisions; 2009

  Land-use change, including the conversion of forests to agricultural land, has depleted the global soil organic carbon (SOC) pool and has contributed to the accumulation of greenhouse gases (GHG) in the atmosphere.  One of the challenges under global climate change is to maintain agricultural productivity to meet current and projected trends in food production, and to minimize GHG emissions from such practices.  Implementing sustainable cropping practices helps to maintain levels of soil organic matter (SOM) leading to the long-term sequestration of carbon (C) in the soil.  There is currently a lack of information on the potential of complex agroecosystems, such as intercrops where more than one crop is grown on the same land area at the same time, to sequester C.  Although the idea of intercropping is not new, most research has focused on yield, quality, competition, pest management, weed control, erosion control, and nutrient-use efficiency but no research has focused on C and nitrogen (N) dynamics and intercropping system design relating to the number of rows of each crop.  The objectives of this study were to quantify C and N inputs from crop residues and its rate of decomposition; to evaluate soil biophysical characteristics and microbial community dynamics; and to quantify and compare GHG production rates in conventional (soybean and maize sole crop) and complex agroecosystems [1:2 intercrop (1 row maize:2 rows soybeans); and 2:3 intercrop (2 rows maize:3 rows soybean)].  The design was a RCBD (n=3) and the study was located in Balcarce, Argentina (37º45’S,58º18’W).  This study represents the first results of soil biophysical characteristics of the intercropping system and its respective sole crops in its primary year of implementation.  As such, information reported here represents base-line data upon which further research will be added as the site is monitored over the long-term.