Calcium Deficiency in Serpentine Soils as Revealed by Adsorbent Technique

Publisher Website
Google Scholar
Abstract
The Conejo soil series near Morgan Hill, Calif., comes from outwash material of a serpentine rock area. The soil is deep and rich in clay, the pH of the surface is 7.2, and the clay contains about 5.5 m.-e. of exchangeable Ca/100 g. of soil. Additions of N, P, and K increased growth of romaine lettuce significantly. After 2-4 wks. the plants on the fertilized soil developed a rosette disease. No consistent differences in Cr, Ni, and Co content between these and normal plants could be observed. Adding these elements to good Yolo soil or spraying normal leaves with their soluble salts did not produce rosette disease. The disease was overcome by gypsum. The question whether the disease was caused by Mg excess or Ca deficiency was studied with cation amberlites. Ca-amberlite added to Yolo soil did not retard growth, but added to Conejo soil it overcame the disease. Mg-amberlite on Yolo soil produced rosette disease and when added to Conejo soil it enhanced the disease. These expts. eliminate Cr, Ni, and Co as causative agents. K-amberlite in Yolo soil produced the disease, and it emphasized the disease in Conejo soil. This eliminates Mg as the primary factor, and in Yolo soil it eliminates the absolute level of exchangeable Ca. These expts. suggest that the degree of satn. with Ca is the prime factor in the origin of lettuce rosette. Sr-amberlite on Yolo soil produced no disease. In Conejo soil it improved growth slightly but did not appreciably reduce the disease. This suggests a partial substitution of Sr for Ca in the growth of romaine. The crucial aspects could also be demonstrated with water culture expts. Similar results were obtained with barley plants, which exhibit other specific symptoms.

This publication has 2 references indexed in Scilit: