Co-Authors:
Bar-Yosef, B., AgriEcology Group, Katif Research Center, Sedot Negev 85200, Israel
Ben Asher, J., AgriEcology Group, Katif Research Center, Sedot Negev 85200, Israel
Silber, A., Agricultural Research Organization, Bet Dagan 50250, Israel
Abstract:
Small perlite volume per plant and strong root activity induce large fluctuations in ionic strength (I) and pH in the growth substrate. We investigated experimentally and by modelling the combined effect of pH and I on Zn partitioning between solution and solid phases of perlite suspensions. Empirically obtained adsorption isotherms had a typical Langmuir shape at each pH with maximum adsorption of 7 mmol kg-1 Zn (pH 8) over a solution concentration range of 0 to 0.3 mM Zn. Zinc adsorption declined as suspension pH decreased from ∼8 to ∼5 or as I increased from 0.001 to 0.01 and 0.1 M. The effect of I stemmed from its effect on perlite surface charge vs. pH relationship. Considering the experimental variability in pH and I, the agreement between empirical and model computed adsorption is satisfactory, both in new and used perlite. The estimated Zn adsorption to organic matter found in used perlite was two orders of magnitude higher than to intact perlite, both per kg adsorbent.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
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