Giant reed, or Arundo donax, is mainly known as an herbaceous, perennial and rapidly growing energy crop, with an innumerable list of uses. Among its uses there is a potential to forage livestock. To know more about giant reed as a feedstock for domesticated animals, read the article below.
Forage Livestock: The dual-use of bioenergy perennials
Compared with the first-generation biofuel equivalents, second-generation biomass crops require lower inputs and still produce greater energy on a landmass basis. They also reduce greenhouse gas emissions, and do not compete for arable land for food production, since they can be adapted to marginal lands as well.
In 2002 already, as much as 21.3 million hectares of existing farming land in the United States were planned to be used to plant perennial grass feedstocks, therefore, second-generation feedstock crops may indirectly compete for hay and grazing landmass. For this reason, in order to alter the forage-livestock industry towards second-generation biofuels without affecting grassland resources for animal operations, recognising dual-use perennial forage feedstocks is highly important.
A new market for energy crops and biomass is emerging because the Energy Independence and Security Act will require 36 billion gallons of renewable fuels by 2022 in the US. To meet this goal, an estimated 1 billion Mg (ton) / year dry lignocellulosic biomass would be converted into renewable, liquid biofuels.
The candidates to forage livestock
Studies were carried out to examine the potentials of several perennials as feedstock, such as giant reed, sugarcane, Miscanthus and Miscane.
Giant reed (Arundo donax) was proven to serve well as animal feedstuff and also a great bioenergy resource. Fresh, whole-chopped sugarcane is comparable to other fibre sources, like cottonseed (Gossypium hirsutum), when fed to cattle. Sugarcane and giant reed leaves has adequate in vitro dry matter digestibility (IVDMD) for livestock, while these values in the stems of Miscanthus were reported low.
Giant reed as forage feedstock was also found to be rich in fibre (NDF > 65% DM, lignin 7-8% DM), and analytical forage reports by Weston Technologies to Fibrecell Australia found 16.6, 14, and 11.6% total protein on a dry mass basis in Arundo donax stems 1, 1.5 and 2 m high, respectively.
Given the history of cultivation and use of perennial grasses, an existing knowledge base on cultural practices, availability of harvesting technology, and familiarity with livestock production, farmers might have an easy transition opportunity to a dual use system if given a bioenergy market option. In the case of Arundo donax, the plant requires low input and has low cost production, which could contribute to an even easier shift from food crop cultivation for livestock to bioenergy perennial cultivation.
The values of bioenergy perennials as forage livestock
When investigated, giant reed was found to have greater leaf IVDMD (>642 g/k) than giant Miscanthus and Miscane. Giant reed leaf and stem IVDMD concentrations were stable across the years of a 3 year long study, whereas giant miscanthus stem IVDMD concentration decreased with every season. Giant miscanthus also had lower ratoon leaf (<495 g/kg) and ratoon stem IVDMD concentrations (<303g/kg) than giant reed and all the other species studied.
As for acid detergent lignin (ADL=cellulose) concentrations giant miscanthus and giant reed have similarly great concentrations in leaf (>91.5 g/kg) than Miscane (<80.2 g/kg) and any other feedstock source. This fact is relevant, since lignin is high in combustible energy, similar to that of cellulose, and the values found in the study should not cause excessive tar production during gasification after digestion.
Giant reed leaf tissue had relatively high concentrations of IVDMD, nitrogen (N), and stems had high total non-structural carbohydrates (TNC) suggesting good value as a livestock feed.
The leaves and the stems of energy crops may be an underappreciated crop residue, but their use could reduce the competition of cropland for bioenergy production. Of course, like many traditional livestock feeds, green-harvested tissues of these perennials can be fed fresh-chopped or ensiled.
It must be pointed out, despite of the studies carried out so far, that further research is needed temporally and spatially on dietary composition, acceptability, voluntary intake, and live weight gain before any of these feedstocks could be recommended for livestock feeding.
If you are interested in getting to know more about Arundo donax and its other possible uses, visit our website and read our other articles. For general information on Arundo as forage feedstock, visit our site here. Whilst you’re here, why don’t you order your own Arundo plantlets – inquire at info@arundobioenergy.com!
