Studies on Fundamental Dynamic Properties of Rough Materials in Livestock Farming in Relation to Bulk Handling. (II)
On the Compressibility of Silage Materials
1967 Volume 29 Issue 1 Pages 33-38
Details
1967 Volume 29 Issue 1 Pages 33-38
Authors investigated the compressiblity of grass (fresh, wilted and semi-dried) and corn, both in the cylindrical bin with the uniaxial compressive load and in the air-tight plastic-film bag, from the inside of which air was extruded by a vacuum pump. Results obtained are as follows:
1. Under vertical loading of 24 hours, the larger the vertical loads are, the higher the rates of compression are and the smaller the final voidratios are. But, except fresh grass, the decreases of void-ratios become slowly under the vertical loads of 0.05kg/cm2or more. The compressibility of grass are raised in proportion to the decrease of moisture content.
2. Even when the initial void-ratios of filled materials are different, the final void-ratios after compression become to almost a certain value, according to kinds of materials. So that, after compression the difference of density may seldom occur due to the difference of initial density, provided that compressive operations are repeated whenever the depth of filled materials reaches to 50cm or less.
3. Under vertical loading of 3 minutes, the permeability of compressive force into grass is raised in proportion to the increase of moisture content and the shorteninig of cutting length. However, the difference of moisture content affects on the permeability stronger than that of cutting length. Therefore, in case of ensiling of haylage materials, it should be noticed to cut materials as short as possible and to give loads as continuously as possible.
4. Corn harvested by a forage harvester has higher permeability of compressive force than grass harvested by a sickle and cut by a cylindrical cutter, perhaps due to the difference of crushing effects on materials between harvesting implements.
5. In case of the air-extruding method, vacuum degree of 250-400mmHg can bring the density of materials to void-ratio 1, which may be suitable to the fermentation as silage. So that, it seems to be practicable to construct a special type of stack silo by the air-extruding method, utilizing an agricultural vacuum pump.
