Fodder beet harvesting

The potential of Jerusalem artichoke as a feedstock for ethanol production has been assessed in many countries in recent years. In New Zealand, for instance, Jerusalem artichoke gave the highest potential ethanol yield (calculated from known crop yields and fermentable content) of a range of crops assessed. From three harvests of the tops a year, estimated ethanol production was 78 It-1 and 11,230 1-ha-1. Although fodder beet (Beta vulgaris L.) remains a favored feedstock for ethanol production in New Zealand, Jerusalem artichoke has been recommended for further study (Judd, 2003). 

Medium-dry-matter fodder beet contains 140-180 g/kg of dry matter, whereas the high-dry-matter varieties may contain up to 220 g/kg. In addition to varietal type, the DM content is also influenced by the stage of growth at harvesting and environmental conditions. Fodder beet is a poor source of protein (see Table 21.1). 

This has been bred from selections from sugar beet and mangels. At one time it was quite popular as a feed for pigs. Fodder beet should not be grown on heavy and/or poorly drained soils, nor on stony soils. There could well be establishment and harvesting problems in these conditions. 

Like sugar beet, fodder beet can produce a substantial yield (about lOt/ha) of tops which can also be fed to livestock. These have a low energy content but much higher crude protein (<15%) than the roots. Some sheep farmers feed them to lambs before harvesting the roots. Alternatively they can be fed in the field after harvesting is complete and, normally, after wilting to reduce the soluble oxalate content which may cause scouring. 

Although the mangel grows with much of its root out of the groimd, harvesting, except by hand, is difficult. The root bleeds very easily and so the tops (not the crowns) are either cut or twisted off. The tops are small and are rarely fed. The roots are not trimmed. Ideally, they should be left for a period in the field to sweat out in small heaps covered with leaves to protect them from frost damage. Following this they can be clamped in the same way as fodder beet. 

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