|
|
||||||||
ABSTRACT
Identical portions of productive Gila clay loam, an important irrigated soil in the southwest, were treated with Na2CO3 to obtain increasing levels of exchangeable sodium. After being incubated to equilibrium at field (moisture) capacity the soils were dried, ground and sieved for laboratory tests and greenhouse experiments.
The treated soils showed increases in exchangeable sodium percentage, soluble Na, soluble carbonate and pH, and a decrease in soluble Ca. Approximately 75% of the added Na2CO3 was adsorbed as exchangeable sodium. The dispersion ratio and moisture retention of the soil increased with the increase in exchangeable sodium percentage.
Alfalfa and cotton were grown under greenhouse conditions, and the plant tissues were analyzed. Reduction in yield of alfalfa and cotton was first noticeable at about the 35% level of sodium saturation. Treating the soil with a synthetic soil conditioner increased growth of the alfalfa at sodium levels that were detrimental on the unconditioned soils. The synthetic soil conditioner had no appreciable effect on cotton growth. This finding indicates that exchangeable sodium probably has a direct as well as an indirect, adverse influence on crop growth.
Associated with decreased yields of the plants tested was an increase in the sodium content and a corresponding decrease in the calcium content of the plant tissues. This reciprocal relation between Ca and Na in soil and in the plant tissue suggests the feasibility of determining the sodium status of a soil by plant analysis. The term "sodium-induced Ca deficiency" in plant nutrition is proposed. A reddish coloration on the lower leaves of alfalfa, followed by collapse of the petioles, appears to be indicative of this "sodium-induced Ca deficiency."
1 Journal series paper No. 90 of the New Mexico Agr. Exp. Sta., State College, N. Mex. Presented before Division II, Soil Science Society of America, Dallas, Tex., Nov. 16–20, 1953.
2 Associate Professor and Professor of Soils, respectively. The authors are indebted to Isaac Barshad, University of California, for identifying the clay minerals; to J. L. Gardner, U. S. Department of Agriculture, for making the photographs; and to M. L. Seal, U. S. Department of Agriculture, for checking a part of the chemical analyses. Harry I. Nightingale, student assistant, helped in several phases of the experiment.
Received for publication September 10, 1954.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Vadose Zone Journal | Journal of Plant Registrations | ||||
| Journal of Natural Resources and Life Sciences Education |
Journal of Environmental Quality |
||||