Relationships between root activity and N, P, K, Ca, and Mg contents in roots of field crops

Abstract Based on the previous paper (Osaki et al. 1995, Soil Sci. Plant Nutr., 41, 635-647), crops were classified by root characteristics for nitrogen uptake as follows: Group I (small root dry weight (RW) and high specific absorption rate of nitrogen (SARN)): legumes, potato, and beet; group II (large RW and low SARN): cereals; and group III (large RW and high SARN): sunflower. In the roots of field crops subjected to various treatments in a field of Hokkaido University, the nitrogen, calcium, and magnesium contents in roots were relatively higher in group I than in groups II and III. Potassium content in roots was high in maize and sunflower. Phosphorus content in roots in groups I and II increased linearly with the increase of the nitrogen content, and the contents of both minerals were higher in group II than in group I. However, the phosphorus content in group III remained constant or increased slightly with the increase of the nitrogen content. Potassium content in roots in groups I and II did not...