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Publication Date

1981

Description

In this syst􀀇m, termed wet fractionation, fresh forage is macerated and pressed to remove approximately 50 % of the moisture. The result is a forage product containing 32 %-38 % dry matter (DM) that can be ensiled directly. In addition, the protein con­tained in the plant juice can be coagulated and removed. The remaining deproteinized juice contains large quantities of mineral nutrients that can be returned to the soil. This process has several potential advantages: (1) less weather-dependent harvesting, which minimizes harvest losses; (2) reduced harvesting time; (3) reduced fertilizer requirements; and (4) ability to harvest protein from land unsuited to row crops because of slope. Maceration of the crop is accomplished by extrusion through small openings, resulting in rupture of plant cells. Juice expres­sion is required to increase the DM percentage of the crop from an initial level of 18%-20% to 32%-38%, which is necessary for proper ensiling. A cone-type press is 􀀑der development to accomplish juice expression. Steam has generally been utilized to raise the temperature of the juice to 8h0c to coagulate the protein. New protein-coagulation methods being studied include fermentation and acidification by mineral acids. Pressing reduces the crude-protein concentration of alfalfa forage and increases th􀀛 neutral and acid detergent fiber concen­tration compared with field-wilted, ensiled alfalfa. The apparent digestibility of pressed-forage dry matter averaged 61. 8 % , compared with 62.8% for wilted silage. When formic acid (0.6% w/w) was idded to the pressed forage at ensiling, the dry­matter intake was increased to a level similar to that of wilted alfalfa silage. Deproteinized juice from alfalfa has been found to contain considerable quantities of nutrients that can be reapplied to alfalfa or other crops as a fertilizer. Deproteinized juice from the heat-coagulation process from first-crop alfalfa grown on high-fertility soil contained 0.021 % phosphorus (P), 0.232% potassium (K), and 0.012% sulfur (S). Juice deproteinized by fermentation contained 0.083% P, 0.515% K, and 0.055% S but also contained 0.40% N compared with 0.09% Nin heat-deproteinized juice. Research is underway to evaluate juice from other deproteinization methods.

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Wet Fractionation of Alfalfa: A Direct Forage-Harvesting System

In this syst􀀇m, termed wet fractionation, fresh forage is macerated and pressed to remove approximately 50 % of the moisture. The result is a forage product containing 32 %-38 % dry matter (DM) that can be ensiled directly. In addition, the protein con­tained in the plant juice can be coagulated and removed. The remaining deproteinized juice contains large quantities of mineral nutrients that can be returned to the soil. This process has several potential advantages: (1) less weather-dependent harvesting, which minimizes harvest losses; (2) reduced harvesting time; (3) reduced fertilizer requirements; and (4) ability to harvest protein from land unsuited to row crops because of slope. Maceration of the crop is accomplished by extrusion through small openings, resulting in rupture of plant cells. Juice expres­sion is required to increase the DM percentage of the crop from an initial level of 18%-20% to 32%-38%, which is necessary for proper ensiling. A cone-type press is 􀀑der development to accomplish juice expression. Steam has generally been utilized to raise the temperature of the juice to 8h0c to coagulate the protein. New protein-coagulation methods being studied include fermentation and acidification by mineral acids. Pressing reduces the crude-protein concentration of alfalfa forage and increases th􀀛 neutral and acid detergent fiber concen­tration compared with field-wilted, ensiled alfalfa. The apparent digestibility of pressed-forage dry matter averaged 61. 8 % , compared with 62.8% for wilted silage. When formic acid (0.6% w/w) was idded to the pressed forage at ensiling, the dry­matter intake was increased to a level similar to that of wilted alfalfa silage. Deproteinized juice from alfalfa has been found to contain considerable quantities of nutrients that can be reapplied to alfalfa or other crops as a fertilizer. Deproteinized juice from the heat-coagulation process from first-crop alfalfa grown on high-fertility soil contained 0.021 % phosphorus (P), 0.232% potassium (K), and 0.012% sulfur (S). Juice deproteinized by fermentation contained 0.083% P, 0.515% K, and 0.055% S but also contained 0.40% N compared with 0.09% Nin heat-deproteinized juice. Research is underway to evaluate juice from other deproteinization methods.