Two field experiments were conducted in newly reclaimed sandy soils deficient in P and Zn located at an extension field in El–Salhia region, Sharkia Governorate during 2004/2005 and 2005/2006 seasons. This study aimed to evaluate the interactive effects of three levels of P (15, 30 and 45 kg P2O5/fad as ordinary superphosphate, 15.5% P2O5) and four zinc rates (4, 8, 12 and 16 kg ZnSO4.7H2O/fad) on growth, yield and the contents of P and Zn in leaf and grain of wheat (Gemmeiza 9 cv). The most important findings could be summarized as follows:
Application of 30 kg P2O5/fad or 12 kg ZnSO4/fad significantly increased leaf area index, net assimilation rate, total chlorophyll, 1000-grain weight, grain and straw yields in both seasons. The increase of P level up to 45 kg P2O5/fad did not add any significant increase in these traits or grain P content, but decreased leaf P and Zn contents in leaf and grain were significantly reduced to the critical levels in both seasons. Leaf and grain Zn contents did not respond to more than 12 kg Zn SO4/fad, but leaf area index, net assimilation rate, total chlorophyll, 1000-grain weight, grain and straw yields were significantly reduced and as well the contents of P in leaf and grain in both seasons. These results confirmed that the over P and Zn application induced an antagonistic effects and significantly depressed growth, yield and their concentrations in leaf and grain. The balanced supply of P and Zn helped to alleviate the negative effects of P-Zn antagonism. Application of 12 kg zinc sulphate with 30 kg P2O5/fad as ordinary superphosphate could be used and afforded the best beneficial interaction effects on wheat grown in these soils. Further researches are needed to identify the suitable crops and the main areas of phosphorus and zinc deficient soils in order to treat them with the proper nutrient balance. Also, it is important to screen crop varieties so that the more efficient varieties could be grown in these soils.