INFLUENCE OF TEMPERATURE ON THE AVAILABILITY OF IRON TO AN OAT CROP

Abstract

The availability of Fe-59 added as FeCl3∙6H2O to sandy-textured soils decreased in relation to the total amount of Fe taken up by oats when the temperature of the soil-root system was raised from 10 to 27 °C. When the soil temperature was raised to 27 °C, the ratio of Fe-59/total-Fe in the forage material of the oats decreased over the entire temperature range, even though maximum yield and total-Fe uptake occurred near 20 °C. Changing the aerial environment by lowering the dark-period air temperature from 25 to 10 °C markedly reduced the yield of dry matter and raised the concentration of total-Fe in the plant but did not consistently affect the ratio Fe-59/total-Fe. Incubating the soil for 30 days prior to adding the Fe-59 and seeding also reduced the proportion of Fe-59 in the plant material.