Ionic Balance for Barley as Influenced by P Fertility, Water, and Soil Temperature1

Abstract

AbstractThe relationship between organic anion concentration and yield of spring barley (Hordeum vulgate L., var. ‘Sacramento’) was investigated in a growth room at three levels of P. This relationship was tested at three levels of available soil water (W) and three soil temperatures (T). The concentration of organic anions was determined as the difference between the sum of the meq/kg of inorganic cations (Na+, K+, Ca2+, Mg2+) and the sum of the meq/kg of inorganic anions (CI‐, NO3−, H2PO4−, and SO42−). A normal organic anion (C‐A) concentration was considered to be that giving optimal growth. In this study, P was more important for obtaining a normal (CA) than either W or T. Phosphorus increased yields, decreased (C‐A) to near normal, and decreased the adverse effects of low W and low T. The large differences in (C‐A) between treatments suggests that, under adverse conditions, organic anions may serve as reservoirs of useful metabolites. Nitrate in the total plant tops, expressed as a percent of the total‐N (N/T), was associated with 82% of the yield variance for treatments yielding less than 11 g/can. For treatments yielding more than 11 g/can, the average value for (N/T) was 0.88%. Potassium accounted for over 55% of the inorganic cation charge and appeared to be the major form for both organic and inorganic salts. Changes in soil pH resulted from nutrient uptake, with 61% of the variance of the change in [H+] associated with the difference between inorganic anion uptake and inorganic cation uptake.