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Effect of long-term tillage systems and nitrogen addition on potassium quantity-intensity relationships

Journal Article · · Soil Sci. Soc. Am. J.; (United States)
The effect of 16 yr continuous corn (Zea mays L.) production under conventional tillage and no-tillage management on potassium quantity-intensity (Q/I) relationships was investigated on soil samples taken at 0-50 mm and 50-150 mm depths of a Maury silt loam from central Kentucky. The results show that the Q/I plot components, labile K/sup +/, activity ratio for K/sup +/ at equilibrium (AR/sub K/) and linear potential buffering capacity for K/sup +/ (PBC/sub K/) were affected by tillage and N additions. The no-tillage soil with and without N fertilizer had the highest quantity of labile K/sup +/ at the 0-50 and 50-100-mm-depth. The AR/sub K/ was also the highest for the no-tillage with and without N in comparison to conventional tillage for the two depths. The highest PBC/sub K/ value was that of conventional tillage no N at the 0-50-mm depth. The lowest PBC/sub K/ valus was that of no-tillage no N also at the 0-50-mm depth. The BaCl/sub 2/ CEC determination along with the relative affinity for K/sup +/ (determined from the slope of plots of ExK/CEC vs AR/sub K/; where ExK = BaCl/sub 2/ extractable K/sup +/) were the best predictors of the relationship PBC/sub K/ = CEC K/sub G/. The relative affinity for K at the linear portion of the Q/I plots appears to be influenced by organic matter content and pH. Finally, the increase in organic matter content is shown to have a positive influence on the magnitude of high affinity K/sup +/ sites.
Research Organization:
Univ. of Kentucky, Lexington (USA)
OSTI ID:
6148767
Journal Information:
Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 52:4; ISSN SSSJD
Country of Publication:
United States
Language:
English