Acidification of a solonetzic soil by nitrogenous fertilizers |
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| Authors: | K J Perl G R Webster R R Cairns |
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| Institution: | 1. Department of Soil Science , University of Alberta , Edmonton, Alberta, T6G 2E3;2. Department of Environmental Science , Lethbridge Community College , Lethbridge, Alberta, T1K 1L6;3. Solonetzic Soil Substation , Agriculture Canada , Box 531, Vegreville, Alberta, TOB 4L0 |
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| Abstract: | Abstract Annual applications of (NH4)2SO4 NH4NO3 and urea on a Solonetzic soil at 112 kg N/ha for 10 consecutive years reduced pH levels from 5.6 for the check to 4.4, 4.9 and 5.3, respectively for (NH4)2SO4, NH4NO3 and urea. (NH4)2SO4 generated twice as much exchange acidity as NH4NO3 and four times as much as urea. Net extractable cations leached from the Ap horizon closely approximated the amount of exchange acidity generated by (NH4)2SO4 and NH4NO3 fertilizers. The levels of soil extractable Al and Mn were greatly enhanced by (NH4)2SO4 as were plant contents. Similar acidifying effects to that produced by the (NH4)2SO4 occurred when NH4NO3 was applied at 300 kg N/ha annually for 12 consecutive years in another field experiment on the same soil. Liming samples of the field (NH4)2SO4 acidified soils in the greenhouse, significantly increased yields and lowered the Al and Mn contents of the plants to normal levels. |
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| Keywords: | Solonetz acidification nitrogenous fertilizers Al and Mn toxicity liming |
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