Submitted to: Transactions of the ASAE
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/12/1999
Publication Date: N/A
Citation: Interpretive Summary: At the end of the growing season, potato growers would like to remove the potato vines. The vines may harbor diseases and insects that could attack the next year's crop. Furthermore, the vines are normally killed prior to harvest so that the potatoes will keep better in storage. This is normally done with herbicides. An alternative is to harvest the vines for cattle feed. This would reduce both herbicide and pesticide use. However, a good method for storing the vines is needed. Because the vines are very wet (85 to 90% water), making silage appeared to be the best way of storing the vines. Vine silages were made with or without the addition of other crops (chopped alfalfa hay, barley grain, chopped whole-plant corn). The potato vines by themselves fermented poorly in the silo and spoiled relatively easily when exposed to air. In addition, substantial seepage from these silages would be expected that could cause environmental damage if not collected. The crop additions reduced the moisture content of the mixtures so that seepage would not be a problem. All three mixtures fermented well, producing high quality, spoilage-resistant silages. These results suggest potato growers with cattle farms nearby may be able to harvest and store the vines by ensiling provided that a suitable crop is available to mix with vines at ensiling.
Technical Abstract: Potato vines are a potential feed for cattle if the vines can be preserved. The objectives of this study were primarily to study alternative methods to preserve potato vines by ensiling and determine the effects of soil contamination on ensiling. In experiment 1, four potato varieties were harvested individually with a flail chopper set at three heights to vary soil contamination. The chopped vines were ensiled in minisilos alone or amended (3:1, vines to amendment, w/w) with either chopped alfalfa hay or barley grain. Silos were opened after 90 d. In experiment 2, vines of one variety were hand harvested and ensiled fresh or after wilting one day, alone or in combination with corn at one of four levels. Silos were opened for analysis after 1, 2, 6, 14 and 90 d ensiling. The vines in both experiments had high crude protein (194-261 g/kg) and low neutral detergent fiber contents (286-359 g/kg). However, ash contents were relatively high even in the low soil contamination (220-307 g/kg) and hand harvested vines (169 g/kg). In both experiments, unamended vines were poorly preserved, underwent a secondary fermentation, and were unstable aerobically. Little or no lactic acid was present in these silages, acetic acid was the predominant fermentation product, and butyric acid was detected in some of these silages. In contrast, all three amendments produced well preserved silages. The lowest pHs were with the barley-amended silages (4.06 average) and the highest with hay-amended (4.97 average). In a 5-d aerobic stability test, some barley-amended replicates heated while none of the hay- or corn- amended silages heated. Level of soil contamination had no consistent negative effect on fermentation, but substantially diluted vine dry matter in the high soil level treatments.