Abstract :
ABSTRACT: In this research, the effects of applying different rates of phosphorus and the micronutrients zinc and manganese on the absorption of phosphorus in the seeds and leaves of the cultivar Tear of soybean were studied in the summer of the year 2011. An experiment was conducted in the form of factorial – split using the randomized complete block design in Dasht – e – Naz situated in the city of Sari in the province of Mazandaran, Iran. Results of the experiment suggested that with an increase in the rates of phosphorus and manganese application, the net phosphorus absorption in the leaves at full flowering and at complete seed maturity showed an increasing trend. However, when the rate of zinc application was raised, the phosphorus content of the seeds remained unchanged and that of the leaves exhibited a decreasing trend. The same trends were observed regarding the dual and the triple effects of applying these elements: although the maximum phosphorus contents of the seeds and of the leaves of soybean were obtained as a result of the mutual effects of applying high rates of phosphorus and manganese, the mutual effects of the levels of phosphorus and zinc application indicated that the phosphorus contents of the seeds and of the leaves (with 0.533 and 0.292 mg/kg, respectively) in the treatment of zero phosphorus and zero zinc application, decreased to 0.527 and 0.262 mg/kg when phosphorus was not applied but zinc was. Furthermore, it was observed that the phosphorus content of the seeds and the leaves declined from 0.571 and 0.369 mg/kg, respectively, at the third level of phosphorous application and no zinc application to 0.566 and 0.360 mg/kg when zinc was added to the soil and the third level of phosphorous application was used.
