Although the differentiation and abortion of vegetative tillers is still proceeding, the process of yield structure formation is practically terminated. Shoot system has no more the adaptation function, which is now provided by ear structures and reproductive organs. Adaptation proceeds by grain filling; the importance of physiological processes taking part in it is increasing. These are usually explained by the theory of source x sink [37,55,56], which has been long applied in scientific papers oriented to yield formation in cereal crops. It is generally accepted that biomass of productive stems at anthesis correlates with the number of grains per m2, and the duration of leaf area correlates with the of 1000-grain weight [36].

Analysis of stand structure was followed by analyses of yield structure. It was logical that in winter wheat (Table 9) higher yield was obtained in variant B compared with variant A by 15.7 % in Zabcice and by 14.8 % in Kromeriz, due to higher number of ears and kernels per m2. Yield differences among variants were just under the limits of statistical significance (Table 11), on the other hand, the effects of year and locations on yield were highly significant. Difference was found between the variants in 1000-grain weight. In spring barley, the highest yield at both locations was reported in variant D and the lowest in variant E (Table 10), which was in accordance with the results of stand structure analyses. Yield differences among the variants were highly significant (Table 12). The effect of year on the yield was also statistically highly significant but the effect of location was only statistically significant. Similarly to winter wheat, the highest number of ears and grains per m2 (Table 10) was formed in the best performing variant D. However, the highest number of grains in ear (21.14) was found in Kromeriz, and high values of 1000-grain weight (44.79 g in Zabcice and 44.34 g in Kromeriz) were found at both locations unlike of winter wheat. Variant C in Zabcice and E in Kromeriz were the least-yielding. They were characterized by the lowest number of grains per m2 and the lowest 1000-grain weight. The results indicate an apparent effect of different pedological-climatic conditions of the locations on grain yield formation. Under drier climatic conditions in Zabcice, higher seeding rate had a positive effect on yield, while at the more productive location of Kromeriz with more balanced ratio of temperatures and precipitation, lower seeding rate in combination with N fertilization was beneficial. High density of plants in variant E in Kromeriz caused obviously a long-term N deficiency, which resulted in higher variability of weight in productive tillers at ripening.

The results also confirmed high yield determination by the number of grains per m2, which corresponds with the data from literature. Further, negative correlation between 1000-grain weight and both ear number per m2 and yield was confirmed in winter wheat. This can be explained by modular structure of cereal plants. High yields are usually obtained by higher

number of ears formed in the plants of a certain stand. Ears in later formed tillers have usually smaller kernels. Then, it is clear that high yields are characterized by high number of grains per m2 and lower 1000-grain weight. Higher 1000-grain weight in variant B in Zabcice (Table 9) can be explained by the fact that the stand was created predominantly by main stems. Number of ears at harvest was lower than the number of germinating seeds sown. In spring barley (Table 10), manifestation of these relationships was not unambiguous either. It is likely due to the fact that compensation processes were not been fully employed as it is evident from low numbers of grains per m2 and grain yields at both locations.

Recently, an interesting discussion on this subject has been reported between Sinclar and Jamieson [57] and Fischer [58]. Both parts consider accumulation of sources till anthesis as important to grain yield determination. However, they differ in their opinion to the hypothesis that in the post-anthesis period yield is predominantly determined by kernel number. Sinclar and Jamieson [57] stated that yield is fundamentally driven by carbon and nitrogen resource accumulation, essentially independent of grain number. Fischer [58] considers the number of grains formed during anthesis, under optimal conditions, as essential for yield formation. Our current and former results concerning grain formation [41] are rather in accordance with the conception of Sinclar and Jamieson [57]. Changes in metapopulations of grains during their formation can be explained based on trophic approach and the rules of plant population biology. The sources for grain formation can be considered analogically to carrying capacity of the environment used to explain processes in plant populations [42].

During the reproductive growth and development, stand structure practically cannot be further influenced. Canopy control should, therefore, be focused on the assessment of the active green area and its heath status. Consequent crop management should predominantly be oriented to maintaining the functionality of the active green area as long as possible with emphasis on the flag leaf and ear supplying assimilates to the forming grains. The following stand parameters can be considered important during the reproductive period:

— number of productive shoots,

— canopy closure,

— total aboveground biomass,

— biomass of productive shoots,

— active green area, its duration and health status,

— resistance to lodging.

The SYNENERGY study makes a reasonably conservative assumption that 10% of land currently used for grazing/pasture and 5% of the fallow land (low scenario) is used to grow perennial grasses. The Technical Potential, if perennial crops are used is estimated to be 15,33 PJ resource. It is assumed that half of this resource would be available for bio-energy industry, or medium-scale CHP installations (individual capacity 5 MWe plus) delivering power to grid and heat to residential / commercial / industrial users. This would support 106 MWe installed capacity that would generate 745 GWh electricity and 1.065 GWh heat annually [5].

6.1.6. Small scale heat with energy crops

In the study it is estimated that the other 50% of the 15,33 PJ for energy crops would support local small scale energy crop fired baled fired boilers or energy crop pellet boilers supplying residential properties with heat. This would equate to 1.703 GWh of useful heat production per year. [5])

The main products produced by the palm oil mills are crude palm oil and palm kernels. However, it also produces huge quantities of residues such as fibre, shell and empty fruit bunches as shown in Figure 2.2. Dry residues from oil palm wastes can be utilised to produce various types of products. EFB had been studied to convert into paper-making pulp by the researches from MPOB because EFB can be categorized as fibrous crop residues know as lignocellulosic residues. The high number of fibres/unit weight indicates the paper from EFB would have good printing properties and a good formation within paper making. EFB could produce thin, high quality printing paper, speciality papers for example for cigarette and photographic papers and security papers. The total chlorine-free methods had been used to bleach the pulp for producing paper [59,81]. Products such as paper and pulp that are obtained by processing the oil palm wastes can be used in many ways such as cigarette paper and bond papers for writing [82]. Normally, the excess shell are used to cover the surface of the roads in the plantation area.

Various types of wood such as saw-wood and ply-wood or lumber had been produced from oil palm trunk. Oil palm trunks have been chipped and waxed with resin to produce pre formed desk tops and chair seats for schools. The furniture is characterised for resistance against knocks, scratches, ink, termites and fungus The ply-wood or lumber can be utilised as core in producing blackboard. The saw-wood is used for furniture but it is not suitable as building material due to its low specific density. It was found that the strength of the ply­wood made from oil palm trunk was comparable with the commercial ply-wood. The particle board with chemical binders also can be produced from oil palm trunk. Some of the oil palm trunks are mixed with EFB and palm fibres to be combusted to produce energy [81,83,84]. Besides this, the palm shell and palm fibres have been convert of into briquettes in a study [36].

Medium density fibre-boards and blackboards can be produced from EFB and palm fibre [84,85]. Currently, the MDF industry has 14 plants with a total annual installed capacity of 2.9 million. The total export of MDF was RM1.2 billion in 2008. The industry has started utilising acacia mangium and mixed hardwood to produce MDF as alternatives to rubber wood. At present, Malaysia is the world’s third largest exporter of MDF, after Germany and France. MDF from Malaysia has attained international standards such as British (BS), European (EN), Asia-Pacific: Japan Australia and New Zealand (JANS) standards [86]. High-density fiberboard (HDF), also called hardboard, is a type of fiberboard, which is an engineered wood product. It is similar to MDF, but is denser and much harder and stronger because it is made out of exploded wood fibers that have been highly compressed. Agro-Bio Fibre Sdn Bhd in Malaysia holds the patent for the EFB-based MDF over the last 10 years, has invested RM30 million to develop the technology to produce MDF and other products from the oil palm wastes. This company had signed a MoU with the Forest Research Institute of Malaysia (FRIM) to develop HDF used mainly for the production of floorboards that would use 100% EFB as its raw material [87].

Oil palm fibre is non-hazardous biodegradable material extracted from empty fruit bunch that are considered as waste after the extraction oil palm fruits. The fibres are clean, non­carcinogenic, and free from pesticides and soft parenchyma cells. Palm fibres are versatile and stable and can be processed into various dimensional grades to suit specific applications such as erosion control, mattress cushion production, soil stabilization, horticulture and landscaping, ceramic and brick manufacturing, paper production, acoustics control, livestock care, compost, fertilizer and animal feed. Palm fibres can also be used as fillers in thermoplastics and thermoset composites which have wide applications in furniture and automobile components. Production of thermoplastic and thermostat composites has reached commercialization stage when PROTON (Malaysian national car maker) entered into agreement with PORIM (Palm Oil Research Institute of Malaysia) [88,89].

Similar to EFB, according to a study fronds from oil palm trees can be converted into pulp [90]. Oil palm fronds also can be processed as roughage source for ruminants such as cattle and goats [91]. A new product known as oil palm frond based ruminant pellet can be used as balanced diet for fattening beef cattle which is developed by the Malaysian Agricultural Research and Development Institute (MARDI) [91].

11 palm ash (OP A) can be utilised as an absorbent for removing pollutant gases such as nitrogen oxide and sulphur oxide. The combustion of oil palm fibre and shell as boiler fuel to generate steam in palm oil mill will produce OPA. It was found that OPA contains high amount of calcium, silica, potassium and alumina which can be utilised to synthesize active compounds to absorb the pollutant gases into absorbent [92,93]. The presence of some functional groups such as hydroxyl, lactone and carboxylic in oil palm shell have a high affinity towards metal ions. Thus, the charcoal derived from oil palm shell can be coated with chitosan to use as a remover of heavy metal especially chromium from wastewater industry; however, it is still at research stage [94].

Processing the oil palm wastes such as EFB, fibre, shell and palm kernel cake into a uniform and solid fuel through briquetting process will be an attractive option. Palm kernel cake is a by-product of crushing and expelling oil from palm kernel. Briquetting is a process of compacting loose material to form a homogeneous and densified product. The material can be densified into briquettes at high temperature and pressure using screw of extrusion techniques either with or without binder addition. Oil palm briquettes are often favoured for household and industrial heating unit operation such as boiler because of their enhanced physical properties, as well as being easy to handle and feed. According to a study, the equilibrium moisture content for the briquettes made of palm fibre and palm shell is about

12 mf wt.% [36]. It was found that briquettes made from 100% pulverised EFB exhibited good burning properties. It is recommended to blend with sawdust in order to produce better quality briquettes from EFB and palm kernel cake [95]. Oil palm briquettes can be used as fuel in producing steam, district heating and electricity generation for larger commercial scale. The local sawdust briquettes or charcoal briquettes are rarely used in the local market because it could not compete with the availability of cheap fuels such as charcoal and wood which are widely used in the rural areas and restaurants [96]. Therefore, the products are exported for oversea markets [97].

One of the promising technologies which utilise the oil palm wastes or plant matter involves the production of carbon molecular sieve (CMS) from lignocellulosic materials. Production of CMS from oil palm wastes which are cheap and abundant carbon source will enhance the economical feasibility of adsorption process. A CMS is a material containing tiny pores of a precise and uniform size that is used as an adsorbent for gases and liquids, and normally it is used to separate nitrogen from the other gases contained in air. A survey of literature indicated that palm shell have been used the most as the substrate for CMS production by many researcher in Malaysia [97-101]. Basically, there are three steps involve to prepare the CMS from oil palm wastes which are carbonisation of the wastes, activation of the chars produced and pore modification of the activated carbons to obtain CMS. Activated carbon is produced from carbonaceous source materials such as nutshells, oil palm wastes, peat, wood, coir and lignite. Activated carbon also called activated charcoal is a form of carbon that has been processed to make it extremely porous and have a very large surface area, thus available for adsorption or chemical reactions. Activated carbon can be produced by either physical reactivation or chemical activation. In physical reactivation, the precursor is developed into activated carbons using gases by carbonization and/or oxidation process. For chemical activation, prior to carbonization, the raw material is impregnated with certain chemicals such acid, base or salt [102]. According to a study, the optimum conditions for preparing activated carbon from EFB for adsorption of 2,4,6-TCP were found as follows : activation temperature of 814°C, CO2 activation time of 1.9h and IR of 2.8, which resulted in 168.89 mg/g of 2,4,6-TCP uptake and 17.96% of activated carbon yield [103].

Biochar is commonly defined as charred organic matter, produced to abate the enhanced greenhouse effect by sequestering carbon in soils and improve soil properties. Biochar is a stable carbon compound that can be kept in the ground for a long time, until thousands of years. Biochar is created when biomass is heated to temperatures between 300 and 1000"C, under low or zero oxygen concentrations. Universiti Putra Malaysia (UPM) with the collaboration of Nasmech Technology Sdn Bhd have successfully built a plant producing biochar from EFP and also the first large-scale biochar production plant in the region. They have constructed a carbonator — driven plant to produce the biochar from residue materials including the EFB about 20 tonnes daily [104].

Besides converting dried oil palm wastes into various value added products, it also have potential as a source of renewable energy. Utilization of oil palm wastes as a source of energy will bring other environmental benefit like reduction in CO2 .emissions. The greenhouse gases that are present in the atmosphere include water vapor, CO2, methane and ozone, and the increase of greenhouse gases primarily CO2 is the major cause for global warming. Oil palm wastes such as fiber, shell and EFB can be used to produce steam for processing activities and for generating electricity [105]. At present, there are more than 300 palm oil mills operating with self-generated electricity from oil palm wastes. The electricity generated is for their internal consumption and also sufficient for surrounding remote areas [106].

A cement company in Malaysia had used palm shell as fuel in the boiler and they found they the emissions of CO2 can be reduced by 366.26 thousand metric tonnes in the year 2006 alone [107]. Hence, the emission of CO2 in Malaysia can be decreased significantly if all industries in Malaysia can replace or partially replace fossil fuel with oil palm wastes to generate energy without degrading the environment.

Hydrogen is a synthetic fuel, which can be obtained from fossil fuels, nuclear energy and renewable energy sources such as oil palm wastes. In almost any application replacing fossil fuels, hydrogen may be used as fuel especially as feedstock for synthesis of clean transportation fuels or as a gaseous fuel for power generation [108,109]. Gasification is one of the technologies for producing hydrogen. Oil palm wastes such as EFB, fiber, shell, trunks and fronds can be used for gasification [109,110]. The benefits of using hydrogen as transportation fuel are higher engine efficiencies and zero emissions [111]. However, production of hydrogen from oil palm wastes is still at the early stage of research in Malaysia.

3. Conclusions

Malaysia is one of the world’s primary palm oil producers and has been taking steps to promote the use of renewable energy. The utilization of renewable energy resources, in particular oil palm wastes is strategically viable as it can contribute to the country’s sustainability of energy supply while minimizing the negative impacts of energy generation on the environment. It will help the government to achieve its obligation to prolong the fossil fuel reserves. The efficient use of oil palm biomass other than the palm oil itself for food consumption is a promising route to obtain more energy from oil palm plantations. It will also solve the agriculture disposal problem in an environmental friendly manner while recovering energy and higher value chemicals for commercial applications like bio-fuel, coal replacement, building products and many others. The current principle adopted in Malaysia is a cost pass-through mechanism for electricity generation which is the same principle adopted for renewable power generation. This method would result in a small increase in the price of electricity paid by electricity consumers, but at the same time, the consumers may benefit from revenues derived from renewable energy generation. Although this effort pales in comparison to other countries which had become leaders in renewable energy growth, the acceptance of this form of renewable energy contribution calls for a paradigm shift among the people in the realm of sustainable energy. In general, the maturity of the country is marked by an acceptance of the need for the country to wean reliance on a depleting and environmentally damaging fuel source.

Author details

N. Abdullah[1] and F. Sulaiman

School of Physics, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

Acknowledgement

The authors would like to acknowledge the three research grants provided by Universiti Sains Malaysia, Penang (1001/PFTZTK/814087, 304/PFIZIK/6310087, 304/PFIZIK/6310073) that has made this research possible.

Dividing of yield into individual yield components allowed cereal research and practice to get closer to so-called modular concept of plant and plant growth demographical analyses [13]. White [14] and Porter [15,16] report that plants can be studied as developing modular systems and their growth can be described similarly to processes of population type.

The growth and development of cereal plants consist of a number of growth and development stages of modules (leaves, shoots, stems and grains) that ovelap one another. Therefore, the growth and development of individual leaves and shoots are more determined than those of entire plant. The growth of entire plant does not stop unless the growth and development of the last module is finished, whereas the first formed modules finished their growth and development earlier. The size and properties of leaves and stems in the stand depend not only on their position on the plant, however, on the position of plants in the stand, i. e. on micro-conditions influencing the growth of individual plants [5]. Thus, in cereal stands the variability of site conditions is reflected in changes of inter — and intra-plant relationships, which is expressed by changes in variability of plant modular parts [6]. This concept enables to explain compensatory and autoregulatory processes in cereal stands by modification of both the number and size of plant parts. The stand structure can be described by density distribution (histogram, polygon) of their weight. For effective stand management of small-grain cereals it is important to assess the amount of biomass of productive stems per stand unit area or proportion of this "productive" biomass of the total amount of aboveground biomass.

The adsorption data obtained for lanthanides using Buccinum tenuissimum shell biomass were analyzed using Langmuir and Freundlich equations. The correlation coefficient (R2) of Langmuir and Freundlich isotherms for lanthanides using ground original shell biomass is shown in Table 7 along with other relevant parameters.

From this table, it is found that R2 value for lanthanides is comparatively high. It indicates the applicability of these adsorption isotherms satisfactorily for lanthanides in this sample. The dimensionless parameter Hall separation factor (RL) for lanthanides is in the range of 0<Rl<1, which means that the sorption for lanthanides by this shell biomass is favorable. Furthermore, the negative value of ^G indicates that the sorption is spontaneous. The higher R2 value for Freundlich model rather than for Langmuir isotherm (0.638-0.886 for Langmuir isotherm and 0.844-0.932 for Freundlich one) suggests that the adsorption on this sample is due to multilayer coverage of the adsorbate rather than monolayer coverage on the surface. It is noted that the value of 1/n less than unity indicates better adsorption mechanism and formation of relatively stronger bonds between adsorbent and adsorbate [10]. That is to say, favorable adsorption for lanthanides by this shell biomass is presented.

On the other hand, R2 and other parameters of Langmuir and Freundlich isotherms for lanthanides using "heat-treatment (480°C) sample" is shown in Table 8. It is noteworthy that R2 value for REEs in this sample is still more large (0.947-0.982 for Langmuir isotherm and 0.948-0.975 for Freundlich one), compared with the original ground sample (Table 7).

Futhermore, this result indicates the stronger the monolayer adsorption (the surface adsorption) on the heat-treatment sample relative to on the original sample (before heat- treatment). Judging from the value of Rl or 1/n in Table 4, the heat-treatment (480°C) sample also exhibits the favorable property for lanthanides adsorption.

The correlation coefficient (R2) and other parameters of Langmuir and Freundlich isotherms for lanthanides using "heat-treatment (950°C) sample" is shown in Table 9. It is found that R2 value for lanthanides in this sample is fairly small compared with the values of "ground original sample" or "heat-treatment (480°C) sample" (In case of La, Ce, Yb and Lu, R2 can not be estimated due to the lack of sorption data at low initial concentration). The low correlation coefficient (R2) in this "heat-treatment (950°C) sample" may indicate that the removal of lanthanides occurred not by adsorption mechanism,

Particularly R2 value is remarkably small for Langmuir isotherm, and then other relevant parameters can not be estimated. As for Freundlich one, not only R2 value is relatively small (0.157-0.625), but the value of 1/n for most lanthanide is more than unity. That is to say, the almost perfect removal of lanthanides for this sample may be due to other mechanism rather than the adsorption on the biomass. However, the cause or mechanism of lanthanides removal on this sample has yet to be sufficiently clarified in our work, and further investigation to survey the mechanism is needed.

Finally, R2 and other parameters of Langmuir and Freundlich isotherms for lanthanides using "heat-treatment (950°C) and water added sample" is shown in Table 10. It is found that R2 value for lanthanides in this sample is fairly large particularly for Langmuir isotherm (0.992-0.999 for Langmuir isotherm and 0.885-0.951 for Freundlich one). This result is similar to that for "heat-treatment (480°C) sample", and indicates the stronger the monolayer adsorption on this sample. Judging from the value of Rl or 1/n in Table10, this sample also exhibits the favorable conditions for lanthanides adsorption.

As mentioned above, biosorption studies have been mainly focused on toxic metals elements such as Cd, Pb, As and Cr so far, and a few reports are focused on lanthanides. The sorption experiments using shell biomass in this work were carried out under low concentration of lanthanide (i. e., 100 cm3 of multi-element standard solution including known initial lanthanide concentration (10 to 500 qg-dm-3)). Then, sorption experiment for three lanthanides (La, Eu and Yb) in single component system by this shell biomass is being planned using the solution individually prepared by each nitrate salt: La(NO3)3-6№O, Eu(NO3)3-6H2O, or Yb(NO3)3-3H2O as the case of seaweed biomass in our work.

4. Conclusion

From this work, it was first quantitatively clarified that seaweed biomass could be efficient sorbents for lanthanides, and exhibit high ability of chemical adsorption. Particularly, Ulva pertusa is found to be a promising biosorbent for removing La. It is also suggested that the adsorption on seaweed biomass is mainly due to monolayer sorption because of well-fitting for Langmuir model.

Biosorption characteristic of Buccinum tenuissimum shell biomass was also studied for lanthanides. Sorption isotherms were analyzed using Langmuir and Freundlich equations to confirm the efficiency of shell biomass as sorbent. The shell biomass samples showed excellent sorption capacity for lanthanides under our experimental condition, even the presence of diverse ions (Ca2+, Mg2+, Na+ and K+) up to the concentration of 200 mg-dm-3.

From these results, it was quantitatively clarified to some extent that shell biomass can be an efficient sorbent for lanthanides. It is very significant information from the viewpoint of environmental protection that the shell (usually treated as waste material) can be converted into a biosorbent for lanthanides.

The data obtained and the method used in this work can be useful tool from the viewpoint of resource recovery in future work.

The technical potential of straw production is limited by competing uses (e. g. animal feed and bedding), the need to leave material on the ground for nutrient replenishment etc, and is estimated to be 6,63 PJ. Moreover, this resource is highly dispersed. Modern, straw-fire power stations require a considerable scale to be financially viable. Hence, it is assumed that one third of this resource could be exploited via local small scale straw fired baled fired boilers or straw pellet boilers supplying residential properties with heat. This would account for 491 GWh of heat annually [5].

Based upon livestock data (pigs, chickens, cattle), the amount of slurries and manures produced has been estimated. This could be exploited via anaerobic digestion (AD). The Theoretical Potential is 6,50 PJ biogas production. However, it is assumed that much of this resource could not be aggregated between farming units to provide sufficient feedstock that a typical AD unit may require. It is assumed that 20% of theoretical potential could be realized, or 1,30PJ. The installed capacity would be 18 MWe and annual output would be 126 GWh of electricity. Given both the remote, rural location of AD units, it is assumed that the amount of heat used would be negligible [5].

3.2.1. Agricultural sector overview

Out of the total Bosnia and Herzegovina territory, amounting to 5,112,879 ha, FBiH takes up 2,607,579 ha, while RS takes up 2,505,300 ha. Farmland covers approximately 2,600,000 ha (around 52%) of that territory, and the remaining 2,400,000 ha are woodlands (around 48%).

Fragmentation of farmland in BiH constitutes an additional problem, 54% of property is under 2 ha in size, 13.5% is between 2 and 3 ha, 16% of property is between 3 and 5 ha, 10% of property is between 5 and 8 ha, about 3% of property is between 8 and 10 ha in size, and only 2.9% or property is over 10 ha in size [7].

The crops structure of cultivated plants and their share in the total sowing structure constitute an important segment of the BiH plant production. According to statistics, in the RS, harvest areas amounted to 443,300 ha in 1990, to 285,731 ha in 1996, and to 356,548 ha in 1997. In the period between 2000 and 2006, about 67.17% of total area in crops was sowed with cereals, and 26.66% with fodder crops. The situation in Federation of BiH is not much different as the total sowing area is considerably smaller and it amounted to about 206,000 ha in 2001, and 197,000 ha in 2006. [1,2].

It is clear that the sowing structure is not favourable as it is not satisfactory in terms of the size of areas in crops and in terms of the yield per unit area, which are very small and low, respectively [1,2].

The crop structure is very unfavorable. The production of cereals in areas of 1-3 ha cannot be economically justified and a commercial livestock production cannot be built on it.

Another issue that brings us to the analysis of the technological level of agricultural production in BiH are average yields of the most common crops (over 80% of arable land in BiH). The comparison of yields with the same yields in the neighboring countries gives a clear picture of average yields of main agricultural crops, and it clearly shows that the agricultural production in BiH is completely behind—between 1.1 and 4.4 times less productive.

Thus, in addition to the unfavorable structure of agricultural crops, average yields in BiH are very low, which fully qualifies this production as extensive, unproductive and therefore barely sustainable. However, the natural conditions for agricultural production are favourable, and for some crops they are even optimal in comparison with some of the neighboring countries.

The analysis of production of main types of livestock in BiH clearly reflects the habits of autarchic village farms orientated towards satisfying their own needs and keeping their own livestock numbers at the biological minimum on one hand and the tardiness of the state and its institutions, i. e. agricultural experts, to launch development process on the other.

Based on the data from the RS Statistical Institute, in 1999, over 17% of total land in the RS — BiH were pastures. If we add 10% of natural meadows to this, we arrive at the fact that almost one third of the total land can be used for livestock production.

There are great possibilities for a quality livestock production on the territory of BiH, but the number of heads of cattle must be increased, the structure must be changed and the stock composition must be improved.

NDVI, as the most frequently used spectral characteristic of the vegetation cover, is used above all for the assessment of the total amount of aboveground biomass per unit area. It is also known that NDVI is well correlated with the total biomass within the period of intensive growth but during canopy senescence the correlation gradually decreases [59]. This was also confirmed in our cereal canopy investigations. Correlations between NDVI and different canopy characteristic are presented in tables 13,14,15 for winter wheat and 16, 17, 18 for spring barley (see Appendix part).

Higher values of NDVI indicated:

— a greater amount of biomass and its dry matter per m2, this corresponded with higher values of LAI, above all in the period of tillering (in spring barley) and in the period of stem elongation (winter wheat)

— a greater average weight of plants, a higher number of tillers per plant, and a higher number of plants per m2 in the period of tillering,

— a greater average weight of tillers and a higher number of tillers per m2 at the beginning of stem elongation,

— a more intensive green colour of the stand, which indicated a better nutritional status of the stand as far as nitrogen supply was concerned,

— a higher content of chlorophyll, above all in biomass of productive tillers.

This means that NDVI is positively correlated with the amount of aboveground biomass and its colour. Similar values of NDVI may obviously indicate either a greater amount of aboveground biomass with a nitrogen deficiency or a smaller amount of biomass in a good nutritional condition. It is also difficult to estimate on the basis of NDVI whether a given amount of aboveground biomass was produced by a higher number of less tillering plants or, on the contrary, by a lower number of plants with a higher number of tillers. This means that correlations between morphological (structural) and the physiological parameters of the stand condition and values of NDVI require further investigations. This is obviously one of the reasons of different results presented in papers dealing with possibilities of application of NDVI for the assessment of nutritional condition of crops and for the prediction of yields and quality of cereal grains.

Freeman et al. [60] found out weak correlations between NDVI and grain yield and grain protein content. These authors also mentioned that in the course of growing season there were no consistent relationships between NDVI and content of nitrogen in grain or in straw in different locations and years. Aparicio et al. [61] mentioned that, within the period from the stem elongation to ripening of grains, it was possible to explain 52 % and 39 % of variability in yields of durum wheat grown under and without irrigation, respectively, by means of NDVI values. Fetch et al. [62] reported a low efficiency of NDVI when applied for the determination of agronomic factors in barley (5-77 %). In spite of this, however, they concluded that the estimation of canopy reflectance might be a potential tool for the assessment of agronomic factors. At the same time they also pointed out that the effect of cultivars and developmental stage of on obtained results may be also important.

On the other hand, Zhao et al. [63] reported that vegetation indexes characterizing the canopy reflectance in green and red bands of electromagnetic spectrum were correlated highly significantly with the content of nitrogen in leaves at the stage of anthesis and with the protein content in wheat grains. They also mentioned a possibility of the use of correlations between spectral indexes and water content in leaves for the estimation of the protein content in grains. Jorgensen et al. [64] confirmed the possibility of the assessment of the stand nutritional condition by imaging in three 2-nm wide bands (450, 700, and 810 nm) which indicate well the lack of nutrients. Zhang et al. [65] mention 82-94 % and 55-70 % of determination using an NDVI-based regression model and validating experimental data from different locations, respectively. They concluded that NDVI can be used for remote sensing of nitrogen supply and nutritional status of stands. Similarly, Reyniers et al. [23] report close correlations between NDVI values and yield and N-content in grain at heading. Alvaro et al. [66] found out strong correlations between NDVI and growth characteristics and mentioned that the reliability of spectral reflectance measurement and non-destructive nature convert this method into a promising tool for the assessment of growth traits in spaced individual plants.

Negative correlations between NDVI and CV of plant weights and tillers identified in our investigations also indicate the importance of a spatial distribution of plants. This effect of stand heterogeneity should be taken into account when interpreting values of NDVI especially within the period before a canopy closure, i. e. usually till the beginning of the stem elongation (BBCH 31). The assessment of NDVI values in this period could be used for the evaluation of quality of stand establishment (i. e. uniformity of spatial distribution of individual plants). Nevertheless, Flowers et al. [20] mention the existence of close correlations between NIR digital counts and tiller density at BBCH 25 (r = 0.67-0.87) and also Philips et al. [22] recommended to use a high determination of the correlation between NDVI and density of tillers at BBCH 25 (r2 = 0.67-0.99) for a variable application of nitrogen.

The contemporary level of knowledge enables a practical application of NDVI, especially for the evaluation of cereal crops heterogeneity in precision agriculture [23]. A great advantage is a possibility of quick and areal evaluation of canopy enabling variable cropping measures. In spring barley, this can be used within the period from stem elongation till the beginning of grain formation. Later on, when the canopy is already senescent, the correlation between NDVI and production traits is not so strong, which is mentioned by many authors [59,67,68]. This was confirmed partly by low and insignificant values of correlation coefficients between NDVI and productive traits and partly by results of variance analysis, which revealed lower values of NDVI during grain filling (BBCH 87).

Regarding the fact that NDVI correlates the most with the amount of aboveground biomass, it can be expected that it is potentially usable also for an indirect assessment of local differences in the stand microclimate from the viewpoint of the spread of fungal diseases. Relationships between NDVI and productive traits of the stand are the most significant within the period of stem elongation it can be concluded that for winter wheat the NDVI could be used for a variable application of nitrogen production doses or for growth regulators to protect stands against lodging. As usual, these measures are taken at the beginning of stem elongation. At later stages of growth and development (i. e. after anthesis) the relationships between NDVI and productive characteristics of the stand are not so significant. This is confirmed partly by low and insignificant correlations between NDVI and productive traits and partly by results of ANOVA which revealed lower values of NDVI at anthesis (BBCH 65).

Maybe most obvious example of unsustainable energy systems in Bosnia and Herzegovina are district heating systems, there are several reasons for that: most of them are old, built in seventies, and requires reconstructions and technical improvements, a lot of them running on expensive liquid of gaseous fossil fuels, and tariff system is more socially oriented than market oriented. There is also one important issue which makes whole concept unsustainable and requires urgent solutions, mayor shareholders of those systems are local communities, and functioning of DHS is directly affecting on their annual budgets. Due to that bioenergy can became solution for some of them, particularly with approach which consider use of clean development mechanisms of Kyoto as the one of the approaches which can make those projects sustainable.

The Clean Development Mechanism (CDM) is the one of the three flexible mechanisms (the other two are l Emission Trading — ET, and Joint Implementation — JI) which allows entities from Annex I (developed) parties to develop emission-reducing projects in non-Annex I (developing) countries, and generate trade able credits — CER credits (CER — Certified

Emission Reduction, one CER is equivalent to one tonne of CO2 emission reduction) corresponding to the volume of emission reductions achieved by that project.

Depending on the scale of the projects CDM projects can be classified into large-scale or small — scale projects.

There are three types of small-scale project activities; Type I: renewable energy project activities with a maximum output capacity of 15 megawatts (or an appropriate equivalent); Type II: project activities relating to improvements in energy efficiency which reduce energy consumption, on the supply and/or demand side, by up to 60 GWh hours per year (or an appropriate equivalent); Type III: other project activities that result in emission reductions of less than or equal to 60 kilotonnes of carbon dioxide equivalent annually.

Any CDM project activity not possessing the above mentioned characteristics is considered a large-scale CDM project activity.

Several options proposed under the CDM rules allow the development of CDM programmes, among them being bundles, PoAs, and several stand-alone CDM activities.

By definition, a CDM PoA is considered »a voluntary coordinated action by a private or public entity which coordinates and implements any policy/measure or stated goal (i. e. incentive schemes and voluntary programmes), which leads to GHG emission reductions or increases net GHG removals by sinks that are additional to any that would occur in the absence of the PoA, via an unlimited number of CDM programme activities (CPAs)« Bundling is a modality allowing the validation and registration of several project activities (small or large scale ones) within one CDM entry. Just like PoAs, bundles allow significant economy of scale while developing several CDM activities together.

In Bosnia and Herzegovina District Heating Systems are generally concentrated in larger cities. According to available data, currently in Bosnia and Herzegovina exists 25 District Heating Companies (12 in Republic of Srpska and 13 in Federation BiH).

District Heating Companies in Republic of Srpska mainly relies on its own boiler facilities, which mainly use fossil fuels (fuel oil, coal, gas). The exception is the District Heating Plant in Pale which as addition to coal use also biomass (waste wood) and Sokolac (only biomass). Estimated consumption of biomass in district heating sector in Republika Srpska in 2012 amounts about 1218,00 tonnes (0,1219 PJ) [16].

According to data listed in [17] the installed capacity of boilers in District Heating Companies in Republic of Srpska is 483.5 MW, the district heating sector is heated about 40 000 flats with a total area of about 2.3 million m2 and about 460 000 m2 of office space. According to available data, during the 2010 District heating companies in Republic of Srpska delivered to consumers about 1483 TJ of heat energy [1].

In Federation of BiH, the largest number of district heating systems also use fossil fuels (coal, fuel oil, gas). A certain number of district heating companies do not have their own thermal aggregates such as boiler units, but are connected to local heat production facilities — thermal power plant on coal (Tuzla, Lukavac, Kakanj) or Ironworks in which is also the primary fuel coal (eg, Zenica). The largest district heating system is in Sarajevo (installed capacity of boilers is 488.694 MW and the connected heat load is about 333.162 MW) that uses mainly gas as a fuel [18].

In Federation of BiH, also two district heating systems (in Gradacac and in Livno) use biomass as primary fuel. According to available data, consumption of biomass in these two companies during the heating season 2010/11 amounted to 14 980 m3 (Gracanica 12880 m3, Livno 2100 m3) and to consumers has delivered around 25.6 TJ (Gracanica 20,218 TJ, Livno 5,381 TJ) of heat energy.

According to available data, during the 2010 District heating companies in Federation of BiH delivered to consumers about 3913 TJ of heat energy [2].

One way to improve the current situation in the district heating systems which using fossil fuels is the partial or complete replacement with biomass fuels where it is possible. Those projects can be attractive as CDM project.

The analysis conducted in the District Heating Companies in Gradiskaand Prijedor] which use heavy fuel oil as fuel has shown that realisation of proposed CDM Programme of Activities (PoA) would led to lower heat prices, openning of the new jobs, reduction of fossil fuels dependency of Bosnia and Herzegovina and reduction of CO2 emission. In addition, by selling CERs District Heating Companies would provide additional revenues that could invest partially in the modernization of existing systems.

The District Heating Company in Gradiska provides heating for about 1740 buildings (residential buildings, public buildings such as kindergarten, schools etc. and other facilities). The vast majority of these, about 50%, are residential apartment buildings. Heated floor area in residential buildings is about 75 000 m2. It produces heat in a central boiler house, consisting of two 11.8 MW boilers with a combined capacity of 23.6 MW. The boilers are fired by heavy fuel oil, and the total connected heat load in the town is about 16.8 MW.

Average annual fuel consumption during the heating seasons (2008-2010) is about 1516 tonnes of heavy fuel oil, and heat supplied to the district heating network is about 13,35 GWh/yr. Consumption of heavy fuel oil has been increasing each year because of connection of new customers to the existing district heating network.

The District Heating Company in Gradiska intends to install a new 6 MW wood biomass boiler for production of thermal energy for heating residential and commercial facilities in Gradiska. The new biomass boiler will be installed within the existing boiler house of the company. During the heating season, the biomass boiler will provide the base heat load. In that way, the Public Communal Company "Toplana" A. D. Gradiska has estimated less consumption of heavy fuel oil (which is currently the only fuel for production of thermal energy) by approximately 1080 tonnes annually.

As part of the project, the wood biomass boiler will be connected with the existing boilers in a parallel function enabling the use of both heavy fuel oil boilers for covering peak heat load during the coldest winter days. As a result of implementation of this project, the new installed heat capacity in production will be 29,6 MW.

Biomass fuel should be transported by a truck from the local Forestry Company or local biomass factory, about 30 km to a storage area, which will be built close to the existing boiler house. The amount of transported biomass will be supported by invoices. Calculation shows that payback period with estimated investment of 2.87 million EURO and CDM is about 6 years and 5 months.

Toplana A. D. Prijedor, the district heating company (DHC) is a main producer of heat for the town of Prijedor and it covers nearly 320 000 m2 of building surface for heating. Installed heat power is 2×30 MW via two boilers. Total connected heat load in the town is about 30 MW (the second boiler is technical reserve). Annual heat energy production is approximately 50 GWh.

Today DHC uses heavy fuel oil for combustion. One of the existing boilers of 30 MW will be reconstructed in order to use wood pellets. This boiler will be the base load boiler, while the other existing boiler will be reserve and peak load boiler. The needed wood pellets will be produced by the DHC and it is a part of the project.

Production of wooden pellets includes a complete introduction of the new technological line for production of wood pellets (Figure 1). The wood pellets will have the following parameters: 6 mm diameter, 10% of moisture, 1 % of ash, and 5 kWh/kg calorific value.

The capacity of the technological line for production of wood pellets will enable production of 4 t of pellets per hour. This capacity will be sufficient for the continuous production of heat during the heating season. In addition, pellets will be produced outside the heating season and all production surpluses will be sold on the market. Raw materials used for the production are wooden sawdust, waste wood and wooden logs that are categorized as firewood. Warehouses for the reception of raw materials are located near of the boiler house and have the capacity of 20 000 m3. Energy from wood pellets will replace energy from 4901 t of heavy fuel oil. The total amount of pellets needed per heating season is about 11272 t. To produce this amount of pellets, DHC in Prijedor should provide at least 25362 m3 spatial raw wood with 50 % humidity.

Calculation shows that payback period with estimated investment of 4.4 million EURO and CDM is about 5 years and 8 months, which is one year shorter than project without CDM. Reduction of CO2 emission from the project will be 14 381 t/yr.

Naoki Kano

Additional information is available at the end of the chapter http://dx. doi. org/10.5772/51 164

1. Introduction

Contamination of toxic metals in the aquatic environment is one of the most debated problems in the world with industrial development. Thus, the minimization and recovery of harmful pollutants such as heavy metals in natural environment is very significant [1]. Various treatment technologies such as ion exchange, precipitation, ultrafiltration, reverse osmosis and electrodialysis have been used for the removal of heavy metal ions from aqueous solution [2]. However, these processes have some disadvantages, such as high consumption of reagent and energy, low selectivity, high operational cost, and difficult further treatment due to generation of toxic sludge [3].

Among environmentally friendly technologies for the removal of heavy metals from aquatic effluent, biosorption has attracted increasing research interest recently [4-5]. The major advantages of biosorption are its high effectiveness in reducing the heavy metals and the use of inexpensive biosorbents [6]. Biosorption studies using various low cost biomass as adsorbents have been currently performed widely for the removal of heavy metals from aquatic effluent [7-18].

Among many biosorbents, marine seaweed can be an excellent biosorbent for metals because it is well known to concentrate metals [19-20]. Seaweeds are reported to accumulate hydrocarbons (as well as metals); and they are exposed to the ubiquitous presence of organic micropollutants and can work as suitable biomonitors [21]. Furthermore, it is considered that the shell (usually treated as waste material) can be also an promising adsorbent. The shell has an internal structure comprised of three distinct layers. The innermost layer (i. e., hypostracum) consists of aragonite; the middle layer (i. e., ostracum), which is the thickest of the three, consists of various orientations interbedded with protein molecules (conchiolin); and the outermost layer (i. e., periostracum) consists of chitin, which is represented as (C8H13NO5)n [22]. Particularly, it is considered that protein (called

© 2013 Kano, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons. org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

"conchiolin") including amino acid group play an important role for collecting trace metal in shell [23].

Biosorption studies have been mainly focused on toxic elements such as Cd, Pb, Cu, As and Cr for subject elements [24]. In our research, the objective elements are mainly rare earth elements (REEs) from the viewpoint of resources recovery, although REEs do not represent a common toxic threat.

Rare earth elements (REEs) find wide range of applications as functional materials in agriculture and as other industrial products, then the demand of REEs in modern technology has increased remarkably over the past years [25-26]. These elements and their compounds have found a variety of applications especially in metallurgy, ceramic industry and nuclear fuel control [27]. For example, current applications of lanthanum as a pure element or in association with other compounds are in super alloys, catalysts, special ceramics, and in organic synthesis [28]. However, the shortage of trace metals including REEs (and the problem of stable supply for these metals) has been a concern in recent years. Therefore, the establishment of the removal or recovery method for trace metals is important from the viewpoint of resources recovery.

It is known that alginate is an exopolymer extracted mainly from brown algae (and various bacteria) that has been used both as immobilization material and as biosorbent of several heavy metals [29]. Then, biosorption studies using seaweed have been generally concentrated on brown algae so far [30-31]. Green and red algae as well as brown algae were also used for biosorbent of REEs in the present work.

Considering the above-mentioned, laboratory model experiments for confirming the efficiency of marine biomass (seaweed and shell) as sorbent for REEs was designed in present work. Furthermore, the surface morphology of the marine biomass used in this work was determined by SEM (Scanning Electron Microscope) before and after metal adsorption.

The crystal structure, and the specific surface area of the shell biomass were also determined by by XRD (X-ray powder diffraction), and BET (Brunaeur, Emmet and Teller) and Langmuir method, respectively.

The cereal stand is usually interpreted as plants growing per unit area rather than individuals assembled in the population, and their interrelationships are most frequently measured as an average or average reaction [17]. However, some authors have earlier referred to relationships between the average and other statistical parameters — variance and skewness [18,19]. Kren [5,6] documented that these parameters enabled to evaluate intra­plant relations.

The canopy closure can be established both through an increased number of stems and their increased size (weight). Stand productivity, as a result of compensatory and autoregulatory processes, depends on total productive stem weight per unit area and is limited by site productivity (carrying capacity that represents a summary of all sources which are available to plants in given space and time).

The identical yield of aboveground biomass can be obtained by lower plant density and a longer period of their growth or vice versa. This logically results in mutual compensation of plant density and size. In practice it means that at the formation of biomass amount corresponding to site carrying capacity self-thinning takes place during the further growth.

Changes in the number and size of shoots in cereal stand during the growing season are analogical to changes in natural plant populations and can be illustrated using frequency curves. A large potential number of shoots capable to reproduce are formed by tillering. This amount, however, reduces to a final spike number, which usually corresponds to 1/2 to 1/4 of the tiller number at the beginning of stem elongation (BBCH 31), by the period of anthesis (BBCH 61), when the organization of stand structure is finished.

The presented rules reveal that the stand structure is always a result of a response of the plant population to site conditions. Their good knowledge should be a basis for assessment of stand structure, which will enable more effective utilization of vegetation factors of the location, cropping treatments and properties of varieties.

From this point of view, the development of root system is of a great significance. Strong root system is important for nutrients and water uptake, and leads directly to increasing the site carrying capacity. By the lower density of plants, they form more tillers and more roots. The rooted tillers exhibit better tolerance to unfavorable conditions. It leads to a general conclusion that to ensure high yield it is necessary to obtain as high number of productive stems and their biomass amount as possible by as the lowest plant number per unit area as possible. These are requirements for optimum development of plants in the stand and canopy closure. However, this general standpoint can be hardly implemented in practice since a large number of factors influencing the plant growth and development are impossible to control completely. Growers should take into consideration that the site productivity and duration of the growing season do not exhibit stable values that would enable to determine exactly sowing time, appropriate seeding rate and stand development during the vegetation. In particular cases, ability of knowing how to respond to the weather course in individual years using a way of stand establishment and consecutive cropping treatments is important. Thus, effective methods for the assessment of the stand during the growing season can be a valuable tool for farmers.