STUDIES ON SOME FACTORS AFFECTING THE IMPLICATIONS OF APPLYING ZINC AND COPPER TO THE SOIL-PLANT SYSTEM

Abstract

Fertility problems in the soils of Egypt, greatly contribute to factors affecting agricultural production. In most of the newly reclaimed soils which are mainly sandy and calcareous, nutritional disorder and deficiency of rnicronutrients are considered limiting factors contributing to tl1e low productivity. Zinc and copper are two of those micronutrients which are required in traces for nonnal plant growth. Zinc plays essential metabolic roles in plant, and it also works as a regulatory cofactor for several enzymes. Zinc is very closely involved in the N metabolism of the plant. In Zn deficient plants protein synthesis and protein levels are markedly reduced, and amino acids and arnides are accumulated. However, copper is an important nutrient as a co-enzyme having vital functions in plant metabolism. It also plays a significant role in several physiological processes such as photosynthesis, respiration and N-reduction and fixation. Nitrogen application can accentuate Cu deficiency. Copper entering leaves is bound by N compounds such as proteins and is only released for retransport in the phloem when these compounds are hydrolyzed. Nitrogen application can thus retard the movement of Cu from old to young leaves. It is of great interest to study tl1e availability of such nutrients to plants and their relationships with the other macro and rnicronutrients. Therefore, tl1e present work aims at studying the effect of applying different sources and levels of zinc and copper on the growth and micronutrient contents in wheat plants. Zinc and copper relationships with nitrogen source and rate were also considered in this investigation.