University of California

Toxicity studies with sodium chlorate in eighty California soils


A. S. Grafts

Author Affiliations

A. S. Grafts was Assistant Professor of Botany and Assistant Botanist in the Experiment Station.

Publication Information

Hilgardia 12(3):231-247. DOI:10.3733/hilg.v12n03p231. January 1939.

PDF of full article, Cite this article


Abstract does not appear. First page follows.


The successful use of sodium chlorate as a herbicide in a region having such diverse soil and climatic conditions as California requires accurate knowledge of the relation of soil and climatic factors to its toxic action. Several publications have discussed the more important of these factors (1)-(5), (8)-(9)3 and preliminary work on their relative importance has been reported (3)-(5), (8)-(11), (13).

For practical weed control with sodium chlorate, one needs a schedule of dosages to meet various field conditions. The principal difficulty in developing such a schedule is the many factors involved in the end result of chlorate application (2). Besides the initial toxicity4 as determined primarily by nitrate concentration of the soil (5), leaching by rains and difference in susceptibility of weed species to chlorate are involved.

To solve the problems of chlorate toxicity, one must separate these several factors and determine the range through which each may be manipulated independently of the others. Only thus may all possible situations be anticipated and each factor properly adjusted. St. Johnswort (Klamath weed), for instance, on a sandy soil with an annual precipitation of 40 inches will require an entirely different treatment than hoary cress on clay soil in an arid region. In this field, obviously, the commercial concerns distributing sodium chlorate for herbicidal purposes have done little or nothing. Realizing the need for more accurate dosage recommendations, the writer collected 80 type soils of California, including most of the series important in agriculture. The effects of soil type and soil fertility upon chlorate toxicity in these soils were investigated. The relation between fertility and chlorate toxicity (5) revealed in these tests has been used as a basis for a proposed schedule of dosage that should prove useful wherever the chemical may be evenly distributed.

Literature Cited

[1.] Bowser W. E., Newton J. D. Decomposition and movement of herbicides in soils, and effects on soil microbiological activity and subsequent crop growth. Canadian Jour. Research. 1933. 8:73-100. DOI: 10.1139/cjr33-006 [CrossRef]

[2.] Crafts A. S. Physiological problems connected with the use of sodium chlorate in weed control. Plant Physiol. 1935. 10:699-711. DOI: 10.1104/pp.10.4.699 [CrossRef]

[3.] Crafts A. S. Factors influencing the effectiveness of sodium chlorate as a herbicide. Hilgardia. 1935. 9(9):437-58. DOI: 10.3733/hilg.v09n09p437 [CrossRef]

[4.] Crafts A. S. The toxicity of sodium arsenite and sodium chlorate in four California soils. Hilgardia. 1935. 9(9):459-98. DOI: 10.3733/hilg.v09n09p459 [CrossRef]

[5.] Crafts A. S. The relation of nutrients to toxicity of arsenic, borax, and chlorate in soils 1938. Jour. Agr. Research. (In press.)

[6.] Crafts A. S., Raynor R. N. The herbicidal properties of boron compounds. Hilgardia. 1936. 10(10):343-74. DOI: 10.3733/hilg.v10n10p343 [CrossRef]

[7.] Crafts A. S., Rosenfels R. S. Toxicity studies with arsenic in eighty California soils. Hilgardia. 1939. 12(3):177-200. DOI: 10.3733/hilg.v12n03p177 [CrossRef]

[8.] Hulbert H. W., Bristol R. S., Benjamin L. V. Methods affecting the efficiency of chlorate weed killers. Idaho Agr. Exp. Sta. Bul. 1931. 189:1-12.

[9.] Loomis W. E., Smith E. V., Bissey Russell, Arnold L. E. The absorption and movement of sodium chlorate where used as an herbicide. Jour. Amer. Soc. Agron. 1933. 25:724-39.

[10.] Newton J. D., Paul A. D. Decomposition and movement of herbicides in soils, and effects on soil microbiological activity and subsequent crop growth. Part II. Canadian Jour. Research C,. 1935. 13:101-14. DOI: 10.1139/cjr35c-007 [CrossRef]

[11.] Raynor R. N. Chemical control of St. Johnswort. California Agr. Exp. Sta. Bul. 1937. 615:1-38. https://archive.org/details/chemicalcontrolo615rayn DOI: 10.5962/bhl.title.59318 [CrossRef]

[12.] Rosenfels R. S., Crafts A. S. Arsenic fixation in relation to the sterilization of soils with sodium arsenite. Hilgardia. 1939. 12(3):201-29. DOI: 10.3733/hilg.v12n03p201 [CrossRef]

[13.] Wilson H. K., Crim R. F., Larson A. H. Perennial weeds and their control. Minnesota Agr. Ext. Spec. Bul. 1937. 183:1-28.

Grafts A. 1939. Toxicity studies with sodium chlorate in eighty California soils. Hilgardia 12(3):231-247. DOI:10.3733/hilg.v12n03p231

Also in this issue:

Changes in orange marketing: Developing revolution in marketing and distribution of the nation's food products affects fresh and processed oranges

Citrus trees in water cultures: Information derived from studies using nutrient solutions as tools of research is of inestimable value to citrus industry

Effect of nontillage of navels: Relation of some tillage practices to water infiltration, yield, and quality of oranges part of fertilizer experiment

Splitting of Navel oranges: Studies indicate local temperature and humidity more closely related to incidence of injury than is soil moisture content

Albinism in citrus seedlings: Nongenetic absence or deficiency of chlorophyll in seedlings prevented by treating freshly extracted seeds with fungicide

Iron and zinc foliage sprays: Radioactive tracers being used in basic studies on factors influencing absorption and translocation of micronutrients

Chlorine absorption: All portions of citrus trees grown in soil cultures absorbed chlorine in test

Red mite on citrus: Timing control treatments important and influenced by climate of growing areas

Grocery store credit service: Combinations of credit with telephone and delivery services are related to the locations, ownership and sizes of stores

Woolly and green apple aphids: Field trials with new materials in orchard near Watsonville indicate same timing of spray treatment controls both pests

Toxicity studies with arsenic in eighty California soils

Arsenic fixation in relation to the sterilization of soils with sodium arsenite

Webmaster Email: sjosterman@ucanr.edu