Design and evaluation of a corn silage-making system with shredding.

摘要

A novel harvester using shredding/crushing mechanism was designed, fabricated, and tested during two harvesting seasons. The objective was to create a harvester that could improve the feed value of corn silage for dairy cows by increasing the digestibility of both fibrous components and corn kernels and provide more effective fiber from corn silage. The machine used two pairs of corrugated rolls which turn at different speeds to shred whole-plant corn. Good particle size reduction was achieved with certain machine configurations; corn stalks were shredded and torn apart, kernels were damaged, and there were no large cobs.; Machine power usage and silage particle sizes were recorded for various conditions including combinations of roll speeds, the minimum clearance between the rolls within a pair, and the unit roll forces on the rolls. Effects of machine configurations on power and energy consumptions were studied on dryer crop in 2000 while more moisture levels and various machine throughputs were examined in 2001. A flail cutting mechanism was placed behind the shredding rolls during the 2001 testing.; Average specific energy requirement for shredding ranged from 2.5 to 5.9 kW h/Mg DM. Average specific energy requirements for shredding varied significantly among different roll speed treatments at unit roll force of 15 N/mm (front and rear) but no significant effect of roll speed configuration was found at other unit roll forces. Minimum roll clearances of 10 mm (front rolls) and 1 mm (rear rolls), along with unit roll forces of 15 N/mm (front) and 45 N/mm (rear) produced more processed material with thinner stalks and shorter pieces than other minimum roll clearance and unit roll force configurations.; Samples of treatments and chopped samples were collected to make silage in laboratory scale silos for ensiling evaluation. The shredded particles ensiled well in labscaled silos (approx: 9 kg) with pH values reaching after fermentation 3.8 to 4.1. There was no significant difference in packed density among different roll speed configurations for 51% moisture content silage. Silage harvested at 66% moisture content showed significantly higher packed density than silage harvested at 60 and 71% moisture content for both chopped and flail-cut samples. Particle size distributions of flail-cut samples were similar with moisture of 60 and 66%; however, the 71% moisture crop was coarser. Shredded samples produced fewer small particles (8.98 mm) and more large particles (>8.98 mm) than chopped silage; while shredded and flail-cut samples had more small particles and more large particles than chopped samples.; System simulation on dairy farms showed great potential of the novel harvester in increasing milk production and farm profitability. When shredded corn silage was fed to high producing Holstein cows, milk production was increased up to 2.6% compared to chopping and up to 0.3% compared to kernel processing. Annual profit increased by {dollar}74/cow and {dollar}27/cow compared to chopping and kernel processing respectively on the 250-cow farm; the improvement in annual profits were {dollar}100/cow over standard chopping and {dollar}86/cow over kernel processing for the 100-cow farm. The simulation results were moderately sensitive to the assumption on silage density but insensitive to machine power requirement. The simulation results were very sensitive to changes in stover digestibility, fill and roughage factors for large particles. A great feed would have high stover digestibility, less filling large particles, yet a higher roughage effect. The shredded silage is a move in this direction.