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Effects of cover crop growth and decomposition on the distribution of aggregate size fractions and soil microbial carbon dynamics
Author(s) -
Linsler D.,
Kaiser M.,
Andruschkewitsch R.,
Piegholdt C.,
Ludwig B.
Publication year - 2016
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12267
Subject(s) - incubation , nitrogen , agronomy , chemistry , soil carbon , crop residue , residue (chemistry) , carbon fibers , total organic carbon , field experiment , nutrient , soil water , environmental science , environmental chemistry , soil science , biology , ecology , mathematics , biochemistry , organic chemistry , algorithm , composite number , agriculture
Although the effects of cover crops ( CC ) on various soil parameters have been fully investigated, less is known about the impacts at different stages in CC cultivation. The objective of this study was to quantify the influence of CC cultivation stages and residue placement on aggregates and microbial carbon (C mic ). Additionally, the influence of residue location and crop species on CO 2 emissions and leached mineralized nitrogen (N min ) during the plant degradation period was also investigated. Within an incubation experiment, four CC species were sown in soil columns, with additional columns being kept plant‐free. After plant growth, the columns were frozen (as occurs in winter under field conditions) and then incubated with the plant material either incorporated or surface‐applied. With CC , concentrations of large and medium macroaggregates were twice that of the fallow, confirming positive effects of root growth. Freezing led to a decrease in these aggregate size classes. In the subsequent incubation, the large macroaggregates decreased far more in the samples with CC than in the fallow, leading to similar aggregate size distributions. No difference in C mic concentration was found among the CC cultivation stages. CO 2 emissions were roughly equivalent to the carbon amounts added as plant residues. Comparison of columns with incorporated or surface‐applied residues indicated no consistent pattern of aggregate distribution, CO 2 emission or C mic and N min concentrations. Our results suggest that positive effects of CC cultivation are only short term and that a large amount of organic material in the soil could have a greater influence than CC cultivation.