EVALUATION OF ZINC LEVELS IN CHERNOZEMS FROM THE ELEMENTAL COMPOSITION OF PLANTS

摘要

The effect of zinc deficiency or excess in a cis-Caucasian Calcareous Chernozem on the interaction of 14 macroelements and trace elements in corn was studied in model experiments an in a production field. In the presence of zinc deficiency and abundant phosphorus, with an alkaline soil reaction, a large increase in the concentration of mobile zinc in the soil (up to 240 ppm) presents no serious danger of excessive zinc levels in corn. A self-produced excess of iron may develop and a highly undesirable separation of nutrient elements into antagonistic groups can occur on zinc-deficient Calcareous Chernozems if the content of mobile phosphorus is high. The principal ecological consequences of both a zinc deficiency and a zinc excess in the soil involve a disruption of the balance of nutrient elements that interact strongly with zinc and phosphorus in the leaves. Optimum rations of phosphorus and zinc levels (P/Zn) in corn plants are suggested. The zinc supply in soils can be evaluated from the P/Zn ration in the leaves of young corn plants.