BALING OF MISCANTHUS: THE EFFECT OF HARVEST TIME ON PRODUCTIVITY, CONSUMPTION AND BIOMASS LOSSES

摘要

Within the last few years Miscanthus has been shown as the most productive perennial grass under different climate conditions, resulting suited for biomass production both in northern and in southern countries of Europe. Factors which may affect the final yield are soil texture, fertilization rate, water availability and harvest time. In particular many authors stressed the fact that a late harvest, in the winter season, allows to obtain a better biomass quality (i.e. low moisture level and reduced ash content), even if considerable biomass losses could occur, in form of leaves and tops, respect to the yields that could be obtained with an early harvest in autumn. On the other hand, early harvest poses the problem of high moisture levels, which makes the biomass unsuited for baling shortly after cut. Thus the biomass requires to be left on the field for drying for a time span, between mowing and baling, that can vary from few to several days, depending on air temperature and rain. Within the LogistEC EU project, a set of field trials were conducted in order to assess the feasibly of early harvesting under different climate conditions, in Italy, France and UK. In Italy, a three-passage harvesting system, consisting in mowing, windrowing and baling, was adopted for early harvest and compared with a conventional winter harvest, carried out with a single-passage system (mowing and baling in one operation) at the end of the winter. In both harvest systems tractor power, as well as machinery types for mowing and baling were the same. Productivity, fuel consumption and biomass losses were measured. Preliminary results showed that fuel and operation times needed for the three passage system were significantly higher than for the single-passage system, while biomass losses were slightly lower in the early harvesting than in the late winter harvest. Our results allowed to conclude that early harvest, with the three-passages system, can help to extend the harvesting season also to the autumn period, especially in those regions where seasonal air temperature allow to bale the biomass at proper moisture content, where the risk of wet winters is high, wherever cultivated areas are small and widespread within the single farm and in the case expected yields should be low.