Използване на комплексообразувателните агенти EDTA и DTPA за оценка съдържанието на подвижин микроелементи в почва от продължителен торов опит

摘要

The available content of Fe, Mn, Zn and Cu in soil samples taken from a long-term fertilization experiment has been studied. The purpose of this work was to provide information on microelement content of soil in a long-term fertilization trial and evaluation of the use of three chelation agents (0.005 M DTPA+0.1 M TEA pH 7.3; 0.01 M EDTA+1 M (NH_4)CO_3 pH 8.6 and 0.05 M Na_2EDTA pH 6.0) as extractants for determination of the avaiable Fe, Mn, Zn and Cu. The long-term mineral fertilization had no recordable influence on available Fe, Mn, Zn and Cu content. It has been found that combined organic and mineral fertilizer application increased the available Fe, Mn and Zn content. 0.05 M EDTA extracted the highest quantity of Fe, Mn and Zn. The extractability of Cu was in the following order: EDTA pH 8.6>0.05 M EDTA>DTPA pH 7.3. Extractable Fe, Mn and Zn by different procedures were significantly correlated with each other. Therefore, All tested extractants are effective for determination of the available iron, manganese and zinc content in the experimental soil (Rendzic Leptosols).