Abstract
Phosphorus and zinc interact both in plants and soil; hence may affect the availability and utilization of each other. A pot experiment was conducted to study these interactions in brassica, maize and sunflower. Two levels each of P (0 & 100 mg kq") and Zn (0 & 15 mg kg-1 ) were applied along with recommended doses of Nand K. Species differed significantly for their response to applied P and Zn for shoot dry matter (SDM), P and Zn concentration in shoots, their uptake and use efficiencies. In maize, combined application of both P and Zn increased SDM, shoot P and Zn concentration, and their uptake compared to control. Increase in shoot P uptake due to P application ranged between 31 to 77% over control. Application of Zn increased shoot P concentration in maize (19%) but reduced in sunflower (66%) over control. Combined application of both P & Zn caused 56 % increase in Shoot P concentration in maize over control. Phosphorus induced reduction in shoot Zn concentration ranged between 22 % (in maize) and 50 % ( in sunflower). Maximum reduction in shoot Zn concentration and uptake due to applied P was observed in brassica. Zinc use efficiency was decreased in maize and sunflower with combined application of P and Zn over plants grown with only P application. Differential P and Zn use efficiencies of maize, sunflower and brassica caused significant differences in P-Zn interactions in these species Key words: P-Zn interaction, P induced Zn deficiency, brassica, maize, sunflower
