مرکز منطقه ای اطلاع رساني علوم و فناوري - RESPONSE OF BEAN (Phaselous Vulgaris L. Var. Nanus) TO IRON FERTILIZATION IN RELATION TO DTPA EXTRACTABLE IRON OF SOILS

Abstract :

The aim of this study was to determine to the response of bean (Phaselous vulgaris l. var. nanus) to iron fertilization in relation to DTPA extractable iron of soils and to evaluate the critical levels of iron in soil. For this purpose, the soil samples were taken form 0-20 cm soil depth of agricultural areas in Bafra, Çarsamba and Suluova districs and bean plants were grown in these soils. Extractable available iron was determined with the DTPA method. In the trial with three replications according to the randomize pilot design in greenhouse conditions, 0-2-4-8 ppm in a solution of Fe-EDDHA (6 % Fe) was applied to the soils before sowing. While 11 % of Bafra plain soils and 57 % of Suluova plain soils were deficient in available Fe (lower than 6 ppm), 100 % of Çarsamba plain soils were found to be sufficient in available Fe (higher than 6ppm). However, 86 % of Suluova plain soils, 40 % of Çarsamba plain soils and 33 % of Bafra plain soils in greenhouse condition had significant increase in yield as a result of iron-fertilization. While the extractable iron contents determined with DTPA method of soils increased, the increasment in the dry matter weight of bean plant fertilized with iron decreased. These results showed that DTPA method was reliable to determine iron status of the soils. The critical available Fe content, which is required to be present in the control soil for taking up the 90 % of the highest yield, was found to be 14,80 ppm using the parabolic equation and 15,95 ppm using the linear equation.