Impact of Forage Harvester Settings on Whole-Plant Corn Physical Properties and Corn Silage Processing Score

Highlights Processing roll clearance significantly influenced grain fragmentation and the Corn Silage Processing Score (CSPS). Reducing roll clearance to improve CSPS negatively affected the quantity of effective fiber. Length of cut had minimal impact on CSPS. The fractional mass of fragmented grain larger than 4.75 mm exhibited a strong correlation with CSPS. ABSTRACT. Two physical properties of whole-plant corn (WPC) silage are important to its utilization in ruminant nutrition. The first, the physically effective fiber, affects rumination, whereas the level of grain fragmentation affects starch utilization. The latter is quantified by a surrogate measurement known as the corn silage processing score (CSPS). Forage harvester settings can affect these metrics by manipulating the theoretical length-of-cut (TLOC) and crop processor roll clearance (PRC). These variables were manipulated across three corn hybrids and two harvest dates to reveal their control over multiple harvest conditions. Changing the TLOC from 7 to 19 or 25 mm significantly (p < 0.001) increased the particle size of the whole-plant and stover fractions but had limited impact on grain particle size and CSPS. On the other hand, adjusting PRC from 3 to 1 mm significantly reduced grain particle size (p < 0.001) and showed a tendency to reduce stover particle size (p = 0.091). Grain particle size showed a moderate relationship with CSPS (R 2 = 0.61, RMSEP = 4.92). However, the relationship between CSPS and the fraction of grain mass greater than 4.75 mm was strong (R 2 = 0.77, RMSEP = 3.91). A multiple linear regression model incorporating TLOC and PRC modestly improved this relationship. A key conclusion is that future on-harvester computer-vision systems for predicting acceptable levels of grain fragmentation should focus on detecting large kernel fragments and incorporate machine settings. Keywords: Chopping, Corn, Forage harvester, Particle size, Processing, Silage.