| Autor: |
Conti, M. E., de la Horra, A. M., Effron, D., Zourarakis, D. |
| Předmět: |
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| Zdroj: |
Communications in Soil Science & Plant Analysis; 2001, Vol. 32 Issue 17/18, p2679, 12p |
| Abstrakt: |
Potassium (K) fixation in Argentine soils and its effects on fertilizer K dose effectiveness remains an under-researched topic. The effects of K addition doses and clay type and content on the K fixation/release dynamics of added K in four soils, two Argiudols, an Ultisol and an Andisol were studied. Fixation responded to soil type, but not to K doses. From 5 to 24% of the applied K was fixed by the soils ranking from highest to lowest: Aquic Argiudol, Typic Palehumult, Typic Udivitrand and Typic Argiudol. The trend for K fixation relative to clay content was reversed. The soils fixed between 0.23 and 2.38 (cmol[SUBc]kg[SUP-1]) (g clay)[SUP-1] in increasing order: Typic Argiudol, Typic Palehumult, Aquic Argiudol and Typic Udivitrand. Potassium fixation by occlusion in clay pores could account for the high activity of the Andisol. The Q/I isotherms results were consistent with those from the fixation experiment. The residuality index, B, ranged from 0.65 (Aquic Argiudol) to 0.95 (Typic Argiudol), a trend consistent with K fixation by these soils. Exchangeable K measured in the fertilized soils and calculated through the residuality index was highly correlated (r = 0.95; p < 0.01). This study shows that the B index is a useful tool in quantifying the potential of contrasting soils for net K fixation and in adjusting K rates to accommodate for this process. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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