*5.3.4. Biomass yields and characteristics*

There are considerable differences in yield between different soils. Kukk et al. [77] reported that soils with low N content produce yields of almost 1 t DM ha−1 in years with unsuitable weather conditions for plant growth. On the other hand, it is possible to achieve an average dry matter production of up to 6–7 t DM ha−1 within limited years on soils with N contents of more than 0.6%. They found that fertilization increases the yield as well as decreases yield variability in soils with low organic matter content, but soils with high N content show an increase in production risks when fertilizer applications increase. Pociene et al. [78] have reported that under favorable climatic conditions reed canarygrass yields are 7–11 t DM ha−1. Moreover, reed canary grass can produce over 15 t DM ha−1 in Canada [79], from 6 to 11 t DM ha−1 in Sweden [80].

*5.4.2. General species description*

*5.4.3. Ecological demands*

that reach deep water sources [11].

*5.4.4. Biomass yields and characteristics*

ash ranged from 4.8 to 7.8%.

*5.4.5. Giant reed as a bioenergy crop*

origin, reflecting restricted migration of germplasm [11].

Giant reed is a tall, perennial C3 grass, and it is one of the largest of the herbaceous grasses that is widespread in the riparian areas of the Mediterranean and found over a wide range of subtropical and warm-temperate areas of the world [11]. The root system consists of tough, fibrous, lateral rhizomes and deep roots. The rhizomes form compact masses from which arise tough fibrous roots that penetrate deeply into the soil. The rhizomes usually lie close to the soil surface, while the roots are more than 100 cm long [86]. The stems arise during the whole period of growth from the large knotty rhizomes. It is reported that primary reproduction is asexual (sprouts from disturbed stems or rhizomes), due to seed sterility, caused by the failure of the megaspore mother cell to divide [87]. Due to the vegetative reproduction of giant reed, its genetic variability and the chances for finding new genotypes or varieties are low. However, according to the results from electrophoresis tests on some giant reed populations, there was a clustering of the selected populations in relation to their geographical

Bioenergy from Perennial Grasses

13

http://dx.doi.org/10.5772/intechopen.74014

Giant reed forms dense, monocultural stands and often crowds out native vegetation for soil moisture, nutrients, and space. It tolerates a wide variety of ecological conditions and, however, prefers well-drained soils with abundant soil moisture. It tolerates a pH in the range of 5.5–8.3 and soils of low quality such as saline ones. It can grow in all types of soils from heavy clays to loose sands and gravelly soils, but prefer wet drained soils [88]. Giant reed is a warmtemperate or subtropical species; however, it has little tolerance to survive frost, but when

Giant reed is commonly known as a drought-resistant species due to its ability to tolerate long periods of severe drought accompanied by low atmospheric humidity. This ability is attributed to the development of thick drought-resistant rhizomes and deeply penetrating roots

Biomass yields in a study conducted in Spain showed 45.9 t DM ha−1 on average, ranging from 29.6 to 63.1 t DM ha−1 [90]. Angelini et al. [91] reported an average biomass yield of 37.7 t DM ha−1 in a study conducted in coastal Tuscany (Central Italy), and Di Candilo et al. [92] reported an average biomass of 39.6 t DM ha−1 in a study carried out in the Low Po Valley (Northern Italy). In Greece, the recorded average dry matter yields on irrigated plots for the first, second, third, and fourth growing periods were 15, 20, 30, and 39 t ha−1, respectively. The high heating value of different aerial parts of a number of giant reed populations grown in Greece ranged from 14.8 to 18.8 MJ kg−1. Depending upon the population and the growing period, the contents of

Due to seed sterility, giant reed has to be vegetatively propagated from fragments of stems and rhizomes. This may limit large-scale cultivation, since it involves considerable cost and effort

frosts occur after the initiation of spring growth, it is subject to serious damage [89].

The main biomass characteristics of reed canarygrass are listed in **Table 1**. During the combustion of the reed canarygrass biomass, problems of ash fusion or corrosion have been detected. However, in the delayed harvest system, these problems are almost eradicated. During the winter, there is a decrease in the content of elements such as K, Ca, Mg, P, and Cl. This change in chemical composition is mainly caused by leaching and loss of leaves during the winter, which significantly modifies the chemical and physical characteristics of the ash. It has been reported that the ash content and ash composition show considerable differences between different locations. The type of soil has a great influence on the quality of the biomass. For example, high ash contents have been found in reed canarygrass biomass grown on heavy clay soils and low contents of ash in biomass grown on humus-rich and organic soils [74].

#### *5.3.5. Reed canarygrass as a bioenergy crop*

Reed canarygrass is established mainly by seeding. The recommended seeding rate is 15–20 kg ha−1. Seeds of reed canarygrass generally have a slow germination and show varying degrees of dormancy. Therefore, weed competition can reduce crop yields during the first year. Broadleaf weeds can be controlled with common herbicides. From the second year on, an established reed canarygrass stand becomes quite competitive, and as a result, weeds are no longer a problem. The number and timing of harvests during a growing season directly affect biomass yield of reed canarygrass and biofuel quality. Several studies have shown that reed canarygrass has higher than acceptable levels of silica [81], chlorine, and nitrogen [74]. However, delaying harvest of biomass from autumn to late winter or early spring, before regrowth begins can reduce the levels of undesirable components [76].
