Бурение грунтовых зондов, установка энергетических колодцев

Miscanthus giganteus is capable of producing up to 20 tons of bio­mass per acre in a year, which has the potential to be converted to 3,250 gallons of ethanol fuel; whereas a typical acre of corn yields around 7.6 tons of biomass per acre and 756 gallons of ethanol. But the major benefit of Miscanthus grass is that it is not a food crop. A number of studies suggest that Miscanthus even outperforms other grasses, such as switchgrass, which typically yields around 6-10 tons of biomass/acre in a year and 400-900 gallons of ethanol fuel. Chemical analysis of Miscanthus shows high cellulose content, and the average analysis results are shown in Table 3.14 [139, 140].

The potential of Miscanthus as a cellulosic ethanol raw mate­rial is discussed in a number of recent review articles [141-143]. A detailed account of the botany of Miscanthus varieties is described in a 2010 review in Advances in Botanical Research [141]. This review describes what is known to date on Miscanthus giganteus from

extensive research in Europe, and more recently in the US. Research trials have shown that Miscanthus giganteus productivity is among the highest recorded within temperate climates. The crop’s high productivity results from greater levels of seasonal carbon fixation than other C-4 crops during the growing season. Genetic sequenc­ing of Miscanthus giganteus has identified a close homology with related crop species such as sorghum and sugarcane, and breeding of new varieties is underway. Miscanthus giganteus has high water use efficiency; however, its exceptional productivity causes higher water use than other arable crops, potentially causing changes in hydrology in agricultural areas. Nitrogen use patterns are inconsis­tent and may indicate association with nitrogen fixing microorgan­isms. Miscanthus giganteus has great promise as an economically and ecologically viable biomass crop; though, there are still chal­lenges to widespread commercial development [141].

Productivity of Miscanthus grass has been studied in field trials across Europe since 1983 under a large number of national and EU programs [144]. However, only a portion of the numerous academic and industrial field trials that have been conducted is reported in English and published in easily accessed, peer-reviewed publica­tions. Most studies cover a 2 to 5 year growth period, even though the lifetime of a Miscanthus giganteus can range from 15 to 30 years [145], and only a few studies have followed Miscanthus giganteus growth over a longer term such as 10 or more years [146, 147]. In general, Miscanthus giganteus is not harvested in the first year, or year it is planted, because of low yields and possible negative impacts on survival during the crop’s critical first winter. Normally, winter kill is only a problem in the first season; if a plant survives through the first winter, it will nearly always survive subsequent winters, even if they are much harsher [148, 149].

In the United States Miscanthus giganteus field trials and yield stud­ies started much later, where the focus was on switchgrass instead of Miscanthus giganteus as a model herbaceous energy crop [145]. The first replicated trials were conducted in the Midwestern United States where trials at three locations in Illinois demonstrated some of the highest productivity on record, with average harvestable yields of 30 Mg ha-1 without irrigation and only 25 kg ha-1 of nitrogen fertil­izer applied in one season [148]. These yields are 2-4 times higher than regionally adapted switchgrass varieties. Furthermore, the ster­ile nature of this clone is considered particularly advantageous in the light of invasion potential from new biomass crops [150, 151].

Additionally, US field trials demonstrated that M. giganteus is 60% more productive than maize, even in the heart of the US "Corn Belt." This may be due to the fact that Miscanthus giganteus has more leaf area and a longer canopy duration, allowing it to assimilate more carbon into biomass over the entire growing season, although maize has higher light-saturated photosynthetic rates as well as higher rates of primary carboxylation and substrate regeneration [151]. A similar result has been observed in a separate field trial in Kansas as well, where Miscanthus giganteus has yielded more than maize (12.8 Mg ha-1 vs. 10.1Mg ha-1), though yields of both crops were half of those realized by the photoperiod sensitivity in sorghum (S. bicolor) [152].

The ability to internally cycle or remobilize nutrients between above — and belowground tissues is one of the imperative advan­tages of perennial grasses in general, and particularly of Miscanthus giganteus. These types of seasonal patterns in nutrient accumu­lation in shoots and rhizomes of Miscanthus giganteus have been documented by several botanists [153, 154]. In Miscanthus giganteus rhizome, biomass peaks after 80% of aboveground dry matter accu­mulates in the late summer/early autumn, then stays constant or decreases slightly over the winter. Furthermore, rhizome biomass then declines dramatically during shoot emergence in the spring, presumably as mobile carbohydrates and nutrients are translocat­ing to the actively growing shoot tissue.

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