THE EFFECTS OF COMPOST AND CROP ROTATIONS ON CARBON TURNOVER AND THE PARTICULATE ORGANIC MATTER FRACTION
作者:
A. Fortuna,
R. Harwood,
E. Paul,
期刊:
Soil Science
(OVID Available online 2003)
卷期:
Volume 168,
issue 6
页码: 434-444
ISSN:0038-075X
年代: 2003
出版商: OVID
关键词: Compost;rotation;POM;13C natural abundance;C4-C;turnover time;SOC
数据来源: OVID
摘要:
Management practices that influence the quantity of C inputs returned to the soil from cropping systems and compost applications alter subsequent biotic activity broadly, contribute to seasonal fluctuations in nutrient dynamics, and may increase C sequestration. The effects of crop rotations and compost applications on soil-C sequestration and decompostion, and the turnover time of C4-derived corn C were assessed via changes in the C content and13C values of particulate organic matter (POM) and total soil organic C (SOC). The majority of organic inputs entered the POM fraction, defined as the sand-sized soil separates remaining on a 53-μm sieve after removal of residues (>2 mm), dispersion in 5% sodium polyphosphate, and 12 h of shaking. Before the application of compost to soil, 85% of the C in the compost material was classified as POM. Measurements of POM-C in the soil were 45% higher and SOC was 16% greater where compost was applied in place of N fertilizer. Addition of compost to POM-C diminished the value of POM as an indicator of short-term changes in nutrient dynamics. However, POM-C remaining from compost applications made during the period 1993 to 1997 may be an indicator of enhanced macroaggregate stability: improved soil tilth and the retention of soil C and N. The turnover time of C4-derived C in the POM fraction was 11 years compared with 22 years in SOC. The presence of compost C did not affect the turnover time of corn-derived C. High cropping intensity and chisel plow management increased C sequestration relative to the preceding alfalfa management.
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