Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)


1. Applications of limestone up to three tons per acre increased the total number of soil bacteria which develop on "modified synthetic" agar plates.

2. These increases probably occurred in species more resistant to drought.

3. The three ton application gave a proportionately greater increase in numbers than the two tons.

4. Application of limestone up to three tons per acre increased the ammonlfying, the nitrifying, anil the nitrogen fixing powers of the soil.

5. The ammonification of dried blood and cottonseed meal did not run parallel in tests of field soils subjected to continued drought.

6. The three ton applications of lime gave proportionately greater increases in the ammonifying, nitrifying, and nitrogen fixing powers of the soil than the two tons.

7. Continued drought reduced the nitrifying power of the soil, less reduction occurring in the limed than in the unlimed soils.

8. Continued drought followed by wet weather led to increased nitrogen fixing power.

9. Notwithstanding extreme, irregular moisture and climatic conditions, applications of lime up to three tons per acre increased the crop yield of corn.

10. Increased bacterial activities as indicated by the methods employed were accompanied by increased crop production.



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