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Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Volume 13

Number 157
April 1933
The Winogradsky spontaneous culture method for determining certain soil deficiencies

Number 158
April 1933
The production of gum by certain species of Rhizobium

Number 159
May 1933
Bacteriology of butter V. Studies on the microorganisms in churns

Number 160
May 1933
The uses of efficiency factors in analysis of farm records

Number 161
June 1933
Variations in swine prices within Iowa including a study in statistical procedure

Number 162
June 1933
Effect of time, depth and method of plowing upon yield and eradication of biennial sweet clovers

Number 163
June 1933
Factors affecting experimental error in field plot tests with corn

Number 164
June 1933
Annual fluctuations in the price of corn

Number 165
June 1933
The relation of moisture to respiration and heating in stored oats

Number 166
November 1933
The pathogenicity and seasonal development of Gymnosporangium in Iowa