EFFECTS OF ZINC AND PHOSPHORUS ON ABSORPTION OF IRON AND NITROGEN BY SUBMERGED PADDY

Abstract

ABSTRACT

We studied the effects of zinc and phosphorus on the concentration and uptake of nitrogen and iron in paddy plants at different growth stages at Haryana Agricultural University, Hissar, India. Zinc was added at 0, 5, 10, and 20 parts per million and P at 0, 25, 50, and 100 ppm. Nitrogen concentration, in parts per million, and uptake, in milligrams per pot, in dry matter at tillering and heading and in straw, grain, and husks at maturity increased with increasing P. Nearly always, the N concentration was less when 100 ppm P was added, compared with 50 ppm P. Nitrogen uptake, however, increased with the increase in added P up to 100 ppm. Zinc application from 0 to 20 ppm increased N concentration and uptake in paddy at tillering, heading, and maturity in all plant parts.

Iron concentration, in parts per million, and uptake, in micrograms per pot, in paddy plants at heading and in grain and husk at maturity decreased with increasing P application up to 100 ppm when Zn was not added or when 5 ppm Zn was added. At tillering and in straw at maturity, however, the situation was different. When 10 ppm Zn was added, the Fe concentration and the uptake in rice grain increased with 25 ppm P and then decreased with the added P up to 100 ppm. When 20 ppm Zn was added, the Fe concentration and the uptake increased with the increasing P application up to 100 ppm.

Zinc application from 0 to 20 ppm in the absence of added P decreased the Fe concentration and the uptake in all cases, but when P was also added, effects were more influenced by P. Zinc application increased the concentration and the uptake of N in both the absence and presence of added P.