Author
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Reicosky, Donald |
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Submitted to: Proceedings of Argentine National No Till Congress
Publication Type: Proceedings Publication Acceptance Date: 8/14/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Intensive tillage reportedly has caused between a 30-50% decrease in soil carbon (C) since many of the soils were brought into cultivation. The objective of this work was to evaluate the long-term effects (3 months) of moldboard plowing on CO2 loss from a Barnes loam (Udic Haploborolls, fine- loamy, mixed) in west central Minnesota, USA (45 deg 41'14" N latitude and 95 deg 47'57" west longitude). Tillage-induced CO2 loss was periodically measured using a large portable chamber for eighty-seven days during summer of 1998. The soil CO2 concentration was measured at 5, 10, 20, 30, 50 and 70-cm depths in the no-till plots and 30, 50 and 70-cm depths in plowed plots. The initial flush of CO2 immediately after moldboard plowing was nearly 100 g CO2 m**-2 h**-1 while that from the not-tilled treatment was less than 0.9 g CO2 m**-2 h**-1. The flux from the plowed plots declined rapidly during the first four hours to 7 g CO2 m-**2 h**-1 and yielded a cumulative CO2 flux from the moldboard plow treatment fourteen times that from not tilled. For the 85-day period following tillage, the cumulative CO2 flux from the plowed treatment was 2.4 times higher that from not tilled. Carbon dioxide concentrations were highest at the 30, 50, 70-cm depths. The decline in soil CO2 concentration on the moldboard plow treatment was more dramatic than on the not-tilled treatment. The results support previous short-term fluxes and confirm the role of intensive tillage in long-term soil C decline. The large differences in CO2 loss between moldboard plow and not-tilled treatments reflect the need for improved soil management and conservation policies that favor conservation tillage to enable carbon sequestration in agricultural production systems. |
