DETERMINATION OF CRITICAL VALUE OF AVAILABLE SOIL PHOSPHORUS FOR WHEAT (TRITICUM AESTIVUM L.) IN CALCAREOUS SOILS FROM GREECE

Abstract

Phosphorus is considered as a basic essential element for plant growth which cannot be substituted or manufactured and is, therefore, a scarce resource to ensure food security; its sound management is considered important. One of the factors that play a significant role in its management is the determination of the critical available phosphorous (P) level in soil, in order to decide whether to apply P fertilizers or not. Since several soil and plant factors affect the value of the critical available soil P, it is considered necessary to carry out special experiments, in order to determine the soil critical P value for an area and a specific crop. The purpose of the present study was to establish critical soil and plant P values for wheat. A greenhouse pot experiment was performed on seven representative calcareous soils from the Thessaly plain in central Greece. The soils were deficient in available P and so they were fertilized with various rates of P. At appropriate stages, the above-ground plant parts were harvested and analysed for basic nutrients, including P. At the same time, soil samples were also taken and analysed for available P. The Cate and Nelson technique was applied, to determine critical values of both soil and wheat tissue P values. It was found that the critical soil P is 11 mg P kg-1 and the critical value for wheat tissue is 0.24% P dry matter.