Assessing the Plant Phosphorus Status

Abstract

Plant analysis is an approved method to assess the nutrient status of crops. Diverging values for critical nutrient values for one crop species are related among others to growth stage, sampled plant part and interpretation method. This makes it difficult for scientists and farmers alike to decide on correct values. A metadata analysis of existing symptomatological, critical nutrient, no effect and toxicological values for phosphorus with respect to different crop plants has been carried out. Values have been clustered in different groups of crops based on morphogenetic and physiological characteristics and phosphorus concentrations have been agglomerated in three major categories: severely deficient, sufficient and toxic. A total P concentration of 0.175-0.25 % proved to denote severe P deficiency in all crops. Phosphorus contents between 0.30 and 0.34 % P indicate a sufficient P supply of graminoids, legumes and oil crops. Toxic effects may occur if the phosphorus content exceeds 1 % P. Factors which affect the phosphorus uptake of crop plants such as root architecture and features which are closely related to the phosphorus status, for example resistance against diseases are outlined.