Evaluation the Distribution of Different Zinc Forms and their Relations with Soil Properties in some Calcareous Soils of Lorestan Province

Zinc (Zn) is an essential plant nutrient. Knowledge about distribution of Zn between its different chemical forms is useful in understanding the chemistry of this element in soil and also in development of soil testing procedures. The present study was conducted to obtain such information about distribution of zinc forms in 20 soil samples of Lorestan province by the use of a sequential extraction procedure to extract different zinc forms in these soils and determination of relations between those and some of soil properties. The percentages of distribution of Zn forms with respect to sum of obtained forms were 0.35 for carbonated bound, 0.41 for exchangeable + water soluble, 0.79 for amorphous Fe-oxide bound, 3.03 for organic bound, 3.97 for crystalline Fe-oxide bound and 91.43 for residual (Mnox bound form was not detected and ignored). Correlation coefficient of equivalent carbonate calcium percent was negative with all the Zn forms (with the exception of organic bound) but with exchangeable + water soluble and Fe-oxides bound was significant.The relation between the available P with Fe-oxides bound and residual form obtained significant. The correlation of organic matter percent of soils with organic bound form was negative and significant. The extractable Zn with DTPA also showed significant correlations with Fe-oxides bound and residual Zn forms. There were significant correlations between some of Zn forms and this result probably showed the existence of a dynamic relationship between them in the soils.