The Effects of Cropping and Manure Applications on Some Physical Properties of a Heavy Soil in Eastern Nebraska1
- B. R. Bertramson and
- H. F. Rhoades2
A study was made of the effects of cropping and manure applications on some of the physical properties of a heavy soil in eastern Nebraska. The results may be summarized as follows:
The addition of manure had no appreciable effects on the consistency constants, the moisture constants, the volume weight, or the aggregation.
For the first six-inch depth, the values for the uncultivated soil exceeded the average values for the cropped soil as follows: (
a) the upper plastic limit, 9.8 per cent; ( b) the lower plastic limit, 6.9 per cent; ( c) the plasticity number, 2.9 per cent; ( d) the scouring point, 7.4 per cent; ( e) the moisture equivalent, 6.9 per cent, ( f) the hygroscopic coefficient, 1.2 per cent; and ( g) the maximum water capacity, 16.2 per cent.
The average “state of aggregation” for the cultivated soils was seventy-three per cent of that for the uncultivated soil. The great difference was in the aggregates larger than 0.5 mm. The cultivated soil had only 12.8 per cent as many aggregates larger than 0.5 mm., as were found for the uncultivated soil.
Air-drying the soil greatly decreased the size of the aggregates.
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