University of California

Greenhouse assay of fertility of California soils


H. Jenny
J. Vlamis
W. E. Martin

Authors Affiliations

H. Jenny was Professor of Chemistry and Morphology, and Soil Chemist and Morphologist in the Experiment Station; J. Vlamis was Assistant Soil Chemist in the Experiment Station; W. E. Martin was Associate Agriculturist in Agricultural Extension.

Publication Information

Hilgardia 20(1):1-8. DOI:10.3733/hilg.v20n01p001. May 1950.

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This issue reports a new pot-culture technique …

for studying the supply of available nutrients in California soils. The method gives a fairly reliable indication of whether pasture, field crops, and truck crops on a given soil will respond to nitrogen, phosphorus, or potassium application.

In this technique, various combinations of nutrients (nitrogen, phosphorus, and potassium) are added to pot cultures; Romaine lettuce is grown for definite periods; and relative yields are calculated for partial treatments (N + P, N + K, and P + K) on the basis of yield with full treatment (all three nutrients).

Calibration of pot tests with field tests indicates …

that nitrogen applications can be expected to increase yields of pasture and field and truck crops if the relative yield of the no-nitrogen treatment in pot tests is 30 per cent or less (provided water, other nutrients, and soil conditions are not limiting).

that phosphorus applications can be expected to increase yields of these crops if the relative yield of the no-phosphorus treatment is 20 per cent or less (with the same proviso).

Among over 450 California soils tested …

the percentage found to be low in available nitrogen ranged from 48 to 71 in different soil groups (Storie’s classification).

the percentage low in available phosphorus ranged from about 40 among alluvial soils (groups I and II) to over 70 among claypans and hardpans (groups IV and V). Both highly acidic and strongly basic soils tended to be low in available phosphorus.

nearly all appeared to be well supplied with potassium for the crops and soils included in the study.

Literature Cited

Bingham F. T. Soil test for phosphate. California Agriculture. 1949. 3:11 14

Mitscherlich E. A. Die Bestimmung des Düngebedürfnisses des Bodens. 1930. Berlin: P. Parey. 119p.

Storie R. E., Weir W. W. Manual for identifying and classifying California soil series. 1948. Berkeley, California: Associated Students Store. 58p. (Lithoprint)

Vandecaveye S. C. Biological methods of determining nutrients in soil 1948. pp.199-230. Bear, F. E., et al. Diagnostic techniques for soils and crops. xxii + 308 p. The American Potash Institute, Washington, D.C

Jenny H, Vlamis J, Martin W. 1950. Greenhouse assay of fertility of California soils. Hilgardia 20(1):1-8. DOI:10.3733/hilg.v20n01p001
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