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Topography Influences Management System Effects on Total Soil Carbon and Nitrogen
Author(s) -
Senthilkumar S.,
Kravchenko A. N.,
Robertson G. P.
Publication year - 2009
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2008.0392
Subject(s) - environmental science , agricultural management , plough , soil cover , soil carbon , cover (algebra) , tillage , cover crop , nitrogen , soil management , field experiment , agronomy , soil science , forestry , agriculture , hydrology (agriculture) , soil water , geology , agroforestry , geography , ecology , biology , chemistry , mechanical engineering , geotechnical engineering , organic chemistry , engineering
Topography is one of the major factors affecting soil C and N contents at the field/landscape level. However, topographical effects are likely to differ in magnitude in different agricultural systems. The objective of this study was to examine the interactions between topography and management systems on soil C and N. The study was conducted at the Kellogg Biological Station Long‐Term Ecological Research (LTER) site in southwest Michigan. The studied treatments were chisel‐plow (CT) and no‐till (NT) with conventional chemical inputs and a chisel‐plow organic management system with winter leguminous cover crops (CT‐cover). At the 0‐ to 5‐cm depth in both upperslope and valley positions total C and N contents of NT management were the highest followed by CT‐cover and then CT. At 0‐ to 15‐, 20‐ to 30‐, and 30‐ to 40‐cm depths, treatment effects varied depending on the landscape position. There were no differences among the treatments in upperslopes, while in the valleys total C and N tended to be the highest in NT and CT‐cover followed by CT. The results indicated the importance of accounting for interaction between topography and management practices when assessing C sequestration across landscapes with varying topography. Total C stocks at the 0‐ to 30‐cm depths were around 35, 32, and 27 Mg C ha −1 soil (± 2 Mg C ha −1 standard error) in CT‐cover, NT, and CT, respectively, across upperslopes and valleys. Overall, CT‐cover was found to be as efficient in maintaining C and N content as no‐till with conventional chemical inputs. Power analysis for C and N stocks at the 0‐ to 40‐cm depth revealed that because of high variability in total C and N stocks at greater depths, the 10 to 30 samples per treatment available in this study were inadequate to detect differences in C and N stocks if thh differences were < 26 Mg C ha −1