Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2000
Publication Date: November 1, 2000
Citation: VARVEL, G.E., DORAN, J.W. COMPARISON OF SOIL C ANALYSES BY DRY COMBUSTION AND LOSS ON IGNITION IN A LONG TERM CROP ROTATION STUDY. AGRONOMY ABSTRACTS p. 363. 2000. Technical Abstract: Understanding soil and crop management and N fertility effects on changes in soil organic matter is required before producers or regulators can make informed decisions regarding management or policy. A long-term study with 7 cropping systems, (i) continuous corn, (ii) continuous soybean, (iii) continuous grain sorghum, (iv) corn-soybean, (v) grain sorghum-soybean, (vi) soybean-corn-oat+clover-grain sorghum, and (vii) corn-soybean-grain sorghum-oat+clover; with three N fertilizer rates conducted at Mead, NE was used to collect data to help make these types of decisions. Soil samples taken to a depth of 180 cm in 30 cm increments after 16 years of cropping were analyzed for total C (dry combustion) and organic matter by loss on ignition (4 hours at 450 ?C). Results from these 2 methods were highly correlated (0.88), indicating both methods could be used for soil organic matter assessments. Comparison of results from both methods indicated cropping system and N fertility had significantly affected results in the surface 30 cm, but results from lower depths were not affected. These results will be compared to analyses of samples taken at the beginning of the study to determine changes in soil organic matter caused by these management systems. These results could then be used to make better management or policy recommendations with regard to long-term soil organic matter changes.