Biomass Burning in South America: Transport Patterns and Impacts 397 Figure 10c illustrates the PM2.5 meridional flux at 35º S The southward flux started on 24 August, the plume was near the surface between 60º and 50º W, with values from -60 to -120 μgm-2s-1 Fig 10b Vertical cross-sections at 25º S of PM2.5 meridional transport (μgm-2s-1) against the height above the surface Terrain height profile is included Fig 10c Vertical cross-sections at 35º S of PM2.5 meridional transport (μgm-2s-1) against the height above the surface Terrain height profile is included During the next day, two maxima appeared, one located near the surface and the other one centred at 2000m and values ranging from -60 to -120 μgm-2s-1 During 26 August, the upper 398 Biomass – Detection, Production and Usage level maximum, centred at 2500m and east of 60º W strengthened, the values ranged from 60 to -360 μgm-2s-1 On 27 August the southward transport was widespread and ranged from -60 to -420 μgm-2s-1 On the following day, the smoke transport extended up to 5000m, remaining towards the south and east of 60º W and the maximum values ranged from -60 to -360 μgm-2s-1 Close to the mountains a northward transport occurred near the surface, with values between 20 and 100 μgm-2s-1 By 29 August the plume was over the Atlantic Ocean and the northward transport was west of 55º W, ranging from 40 to 60 μgm-2s-1 During the next two days the flux gradually disappeared at this latitude due to the fast movement of the cold front Fig 11a Vertical cross-sections at 15º S of water vapour mixing ratio meridional transport (g m kg-1 s-1) against the height above the surface Terrain height profile is included Figure 11 shows the vertical cross sections at similar latitudes, but illustrates in this case, the water vapour meridional transport At 15º S (Figure 11a) on 23 August there was a prevalence of the southward transport of water vapour, spanning from 72.5º W to 47º W, from the surface up to 3000m, and the maximum flux centred at 1500m with a mean daily value of -60 gmkg-1s-1 The northward transport took place over the oceans near the surface The next day the pattern was similar and the value of the meridional flux increased On the following three days the longitudinal extent of the zone with southward flux was narrower and the values -80 and -60 gmkg-1s-1 respectively West of the Andes, at upper levels the water vapour southward flux also occurred The northward transport over the oceans was still present On 28 and 29 August the longitudinal extent increased as well as the value of the maximum flux, the difference is the location near the surface The northward water vapour transport increased over the Pacific Ocean During 30 August, the incursion of the cold front caused a northward flux near the surface between 65º and 50º W The flux from the north was restricted next to the Andes centred at 1000m The following day the pattern was nearly similar, with a decrease in the southward transport Biomass Burning in South America: Transport Patterns and Impacts 399 At 25º S (Figure 11b) from 23 to 28 August, there was a southward flux at all longitudes east of the Andes from the surface up to middle levels in the troposphere Fig 11b Vertical cross-sections at 25º S of water vapour mixing ratio meridional transport (g m kg-1 s-1) against the height above the surface Terrain height profile is included Fig 11c Vertical cross-sections at 35º S of water vapour mixing ratio meridional transport (g m kg-1 s-1) against the height above the surface Terrain height profile is included 400 Biomass – Detection, Production and Usage The values ranged from -140 to -260 gmkg-1s-1 West of the mountain range, the southward flux also occurred on 26 and 27 August reaching a daily maximum of -80 gmkg-1s-1 From 29 to 31 August the progression of the cold front caused a northward flow that varied between 20 and 120 gmkg-1s-1 with a longitudinal range that moved to the east Figure 11c depicts the water vapour meridional transport at 35º S The southward water vapour transport was present from 23 to 27 August from the surface up to 8000m and 75º W and 35º W, the maximum values varied from -100 to -260 gmkg-1s-1 The opposite transport directions associated with the surface cold front is sharply marked in the cross-sections on 28 and 29 August, and the maximum values are located near the surface The next days showed the contrast in the air masses water vapour as well 3.3 Case study: October 2002 This event extended from 17 to 21 October and was characterised by a variable low level flow pattern, which had a short SALLJ episode and a changing meteorological scenario, with transient perturbations of short duration 3.3.1 Meteorological environment and SALLJ features On 17 October, the 1000 hPa height shows the dominance of a post-frontal high pressure system over central Argentina (Figure 12) The surface front is located over central South America On the south-western region of Argentina, the 500/1000 hPa depths show a baroclinic zone associated with a new frontal system Fig 12 Daily fields of 1000 hPa geopotential height (red solid (positive), blue dot (negative) contours) and 500/1000 hPa thickness (green long dash contours) (both every 40 mgp), from 17 to 21 October Terrain elevations higher than 1500 m are shaded Biomass Burning in South America: Transport Patterns and Impacts 401 During the following day, the anticyclone moved to the Atlantic Ocean, centred about 40º W and 35º S Behind the baroclinic zone, a low pressure system located near 65º W and 47º S, developed A thickness through oriented from the NW to the SE, is observed over the Pacific Ocean associated to an upper air through The low level flow over north-eastern Argentina was from the north On 19 October, the surface low pressure region had a fast displacement towards the SE On the other hand, an anticyclonic system moved eastward covering the southern region of Argentina North of 30º S, central South America showed relatively lower pressures By 20 October, the thickness through axis was over Los Andes Mountains and then moved eastward The low pressure system on central-northern Argentina displaced to the east and accordingly, the flow near the surface turned and blew from the east over Buenos Aires On 21 October, a low pressure system developed and evolved in agreement with the displacement of the pattern at upper levels It is located around 40º S and 50º W Argentina was under the influence of an extended anticyclone The near surface flow was from the south Fig 13 Daily SALLJ fields from 17 to 21 October Wind (vector); wind speed (shaded) at 850 hPa and wind shear between 850 hPa and 700 hPa (contours) Shaded: wind intensity stronger than 12 m s-1 Contours: wind shear greater than m s-1 Terrain elevations higher than 1500 m are shown Figure 13 illustrates the 850 hPa flow and SALLJ features On 17 October the low level flow associated to the post-frontal anticyclone centred over Buenos Aires is clearly shown A very weak SALLJ is evident in the 850-700 layer, between Los Andes and the west of an anticyclone The smaller wind intensities are observed over the biomass burning source 402 Biomass – Detection, Production and Usage regions By 18 October, the low level flow strengthened and organized in a northerly current due to the approach from the southwest of the new cold front and the presence of the anticyclone now centred at 45º W and 35º S over the Atlantic Ocean The 850 hPa winds did not satisfy the Bonner criteria The north-western edge of the cold front is located near 35º S and 65º W On 19 October the SALLJ spanned from central Bolivia to Paraguay and northern Argentina The wind was from the north Buenos Aires was behind the cold front Another region with low level jet occurrence is over the Atlantic Ocean centred at 15º S South of 30º S, the flow turned counter clockwise and acquired a north-western orientation ahead of the cold front On 20 October, a SALLJ occurred, with its southern edge near 30º S The front remained stationary over central Argentina A low pressure system developed in the central region of Argentina whereas the exit region of the SALLJ was on southern Brazil During the next day, there is a clear evidence of a strengthening and rapid displacement of the cold front that is oriented NW to SE The low-level flow was from the south up to 20º S 3.3.2 Concentration behaviour On 17 October, the vertically integrated AOT clearly depicts the constraint on the southward displacement imposed by the cold front (Figure 14) The higher AOT are observed near the sources in close agreement with the regions in which the smaller wind speeds occurred As the post-frontal anticyclone moves eastward, the southward transport of the smoke plume is favoured on its western region In this particular case, the AOT values are low, indicative of relatively clean air, but the contrary might happen with greater emissions Northern Argentina had AOT greater than During the next day, with the displacement of the anticyclone towards the Atlantic Ocean and the further re-establishment of the northwestern flow, AOT over 0.3 reached Buenos Aires On 19 October, the smoke plume is narrower and the AOT greater than 1.25 reached southern Brazil On the other hand, over Buenos Aires and Córdoba the AOT ranged from 0.2 to 0.5 During the next day, the greater AOT are observed near the source region An interesting feature is that a relative minimum occurs in the same location than the SALLJ core over central Bolivia and northern Paraguay On central Argentina, the development of the cyclonic circulation further helps the transport to the south on its eastern flank AOT values ranging from 0.3 to 0.5 are predicted over Buenos Aires On 21 October the strong south-westerly winds that blew over central Argentina caused the displacement of the smoke plume towards lower latitudes The southern edge of the plume clearly shows the shape of the frontal region 3.3.3 Meridional PM2.5 and water vapour transport Figure 15 shows the PM2.5 meridional transport At 20º S (Figure 15a), during 17 October, there was a northward transport in the layer ranging from near the surface to 1500m, between 65º W and 55º W The values ranged from 20 to 220 μgm-2s-1 This agrees with the higher concentrations in the regional plume Immediately above this maximum there was a southward flow reaching the upper troposphere The maximum meridional transport towards the south was centred at about 2500m and 60º W, with values between -60 and -180 μgm-2s-1 This agrees with the flow pattern that was perturbed by the presence of the NW edge of the cold front As the front moved north-eastward the northern meridional flow reestablished co-located with the SALLJ On the following day, the southward transport strengthened while the northward flow east of 60º W weakened, as well as its vertical Biomass Burning in South America: Transport Patterns and Impacts 403 extent In this case the transport reached a value of 80 μgm-2s-1 The greater northern flow is observed in the longitudes between 65º W and 55º W centred at 2000m and reached a maximum of -240 μgm-2s-1 On 19 and 20 October the southward transport is dominant and the maximum values (-240 and -300 μgm-2s-1, respectively) appear closer to the surface with an eastward displacement The pattern remained almost similar on 21 October, with a slight decrease in the southward transport Fig 14 Daily means of AOT500nm from 17 to 21 August (shaded) and wind field (streamlines) at 1400 m above the surface At the southernmost latitude considered in the vertical cross sections -30º S- (Figure 15b) during 17 October, the transport was from the south in the longitudes ranging from 60º W to 45º W from the surface up to 2000m, reaching a maximum value of -240 μgm-2s-1 On the next day, the flux was from the north in a layer from the surface up to middle troposphere, from 65º W and 50º W The greatest value was -180 μgm-2s-1 centred at 57º W and 1500m The northward transport was smaller and over the Atlantic Ocean During 19 October, the dominance of the southward transport was evident in the layer from the surface up to 3000m where had its greatest strength The following day showed almost similar shape, with a slight decrease in the intensities 404 Biomass – Detection, Production and Usage Fig 15a Vertical cross-sections at 20º S of PM2.5 meridional transport (μgm-2s-1) against the height above the surface Terrain height profile is included Fig 15b Vertical cross-sections at 30º S of PM2.5 meridional transport (μgm-2s-1) against the height above the surface Terrain height profile is included On 21 October, the vertical cross section shows northward transport associated with the progression of the cold front, from 65º W to 55º W in the layer near the surface up to 1000m, and the opposite flux over the Atlantic Ocean, east of 45º W The values reached 120 and 120 μgm-2s-1 respectively Biomass Burning in South America: Transport Patterns and Impacts 405 Fig 16a Vertical cross-sections at 20º S of water vapor mixing ratio meridional transport (g m kg-1 s-1) against the height above the surface Terrain height profile is included The water vapour meridional flow at 20º S (Figure 16a) on 17 October, showed opposite flows immediately east of the Andes, with northward water vapour flux near the surface up to 1000m and the contrary above this height Contrarily to what happened with the PM2.5 transport, the southward transport east of 50º W was greater than that observed near the mountains, and this is related to the location of the water vapour and particulate sources The southward transport reached values equal -80 gmkg-1s-1 at 62.5º W and -140 gmkg-1s-1 at -42.5º W during this day On 18 October, the transport to the south was dominant with a strengthening of the maximum close to the Andes, with a mean daily value equal to -120 gmkg-1s-1 The next two days, in accordance with the occurrence of the SALLJ, the transport to the south was dominant at this latitude, with the highest value coincident with the jet core, reaching -220 gmkg-1s-1 On 21 October the region with southward flux moved slightly to the east, and the highest value was -160 gmkg-1s-1 At 30º S (Figure 16b), on 17 October, there was northward transport near the surface from 60º W to 42º W, with a maximum value of 140 gmkg-1s-1 The flux to the south took place in a narrow region close to the Andes and reached -60 gmkg-1s-1 Another zone with southward transport was over the Atlantic During the next day, the region with southward transport extended to 47º W, with the highest value below 1000m, centred at 55º W An interesting feature is that the transport of water vapour and PM2.5 maximize in different altitudes and longitudes This difference is also evident on 19 October, when the maximum water vapour transport reached -180 gmkg-1s-1 The following day, the southward flux had two maxima below 1000m, one centred at 57º W and the other one at 42º W The values reached -180 gmkg-1s-1 On 21 October, 55º W marked the divide between the flux towards the north and the south in coincidence with the PM2.5 transport, but, once more, the layers of transport were different 406 Biomass – Detection, Production and Usage Fig 16b Vertical cross-sections at 30º S of water vapor mixing ratio meridional transport (g m kg-1 s-1) against the height above the surface Terrain height profile is included Discussion The fire spots experience an important increase during the dry season in Tropical South America and the regional smoke plume is driven by the low level flow The South American Low Level Jet is a frequent pattern that contributes and patronizes the dispersion and its importance was documented The smoke plume can travel a long distance from the source region and cause several impacts on remote locations Among these effects are the increase in the aerosol load and characteristics The pattern that emerges in the prolonged episode in August is that during the warm stage of the cold front incursion, the southward penetration of the smoke is favoured The level of the transport is in close relationship with the maximum meridional wind that develops in the SALLJ event Owing to the cold front displacement, there is a northward transport of the regional plume Behind the cold front the air is clean The horizontal transport mechanism is related to the tangential component of the wind, parallel to the frontal region Therefore, ahead of the front, there is a preferred exit region from South America towards the Atlantic Ocean Another interesting feature is that the material is forced to ascend at the frontal slope, and the level of maximum transport occurs at higher levels in the cold stage, so they are generally uncoupled from the surface and above the atmospheric boundary layer The regional transport of smoke is clearly shown The smoke plume originated in the vegetation fires over tropical South America and was transported first westward, then deflected by the Andes barrier and finally southward, reaching mid-latitude regions farther south of 40º S The cold front approach moved afterwards the polluted air mass towards southeastern Brazil and the Atlantic Ocean In the October episode, the short duration transient systems contributed to the dispersion and re-circulation of the smoke plume The southward incursion of the smoke plume was Recycling of Phosphorus Resources in Agricultural Areas Using Woody Biomass and Biogenic Iron Oxides 433 Collected Fe (g/kg) period and 0.187 g/kg during the non-irrigation period The respective values for the Japanese cypress were 0.332 and 0.172 g/kg The differences between the values during the irrigation and non-irrigation periods were significant (p < 0.05) The average PO4–P concentration of the water during the irrigation period (0.058 mg/L) was much higher than that during the non-irrigation period (0.022 mg/L) This is probably because the anaerobic conditions caused by flooded water on the paddy fields during the irrigation period lead to the reduction of ferric phosphate (FePO4) compounds and the release of Fe2+ and phosphate (PO43-) ions There were no significant differences in the adsorbed P during the irrigation and the non-irrigation period between the Japanese cedar and the Japanese cypress (Fig 12) When these values are expressed in ppm, the P adsorbed during the irrigation period was 350 ppm for the Japanese cedar and 332 ppm for the Japanese cypress, while the PO4–P concentration was 0.058 ppm Therefore, the concentration of the P on the woody carrier was 5,700- to 6,000-fold greater than the P dissolved in the water, and for the non-irrigation period, it was 7,800- to 8,500-fold greater 10 (a) Japanese cedar Collected Fe (g/kg) Irrigation period 10 (b) Japanese cypress Irrigation period Concentration (mg/L) Non-irrigation period Non-irrigation period 1.5 (c) D-Fe Concentration * p < 0.05 1.0 0.5 0.0 Irrigation period Non-irrigation period Fig Fe content after the immersion test (a), (b): collected Fe after weeks immersion; (c): D-Fe concentration of the water (means and standard errors, n=8) 434 Biomass – Detection, Production and Usage (a) Irrigation 10 period 12 Collected Fe (g/kg) Collected Fe (g/kg) 12 (b) Non-Irrigation 10 period Japanese cedar Japanese Japanese cedar cypress Japanese cypress Adsorbed P (g/kg) Fig 10 Comparison of collected Fe between Japanese cedar and Japanese cypress (n=8) 0.5 (a) Japanese cedar 0.4 * p < 0.05 0.3 0.2 0.1 0.0 Adsorbed P (g/kg) Irrigation period (b) Japanese cypress 0.4 * p < 0.05 0.3 0.2 0.1 0.0 Irrigation period Concentration (mg/L) Non-irrigation period 0.5 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00 Non-irrigation period (c) PO4 -P Concentration * p < 0.05 Irrigation period Non-irrigation period Fig 11 P contents from the immersion test (a), (b): adsorbed P after weeks immersion; (c): PO4–P concentration of the water (means and standard errors, n=8) Recycling of Phosphorus Resources in Agricultural Areas Using Woody Biomass and Biogenic Iron Oxides 0.5 (a) Irrigation 0.4 Adsorbed P (g/kg) Adsorbed P (g/kg) 0.5 435 period 0.3 0.2 0.1 0.0 (b) Non-Irrigation 0.4 period 0.3 0.2 0.1 0.0 Japanese cedar Japanese cedar Japanese Japanese cypress cypress Fig 12 Comparison of adsorbed P between Japanese cedar and Japanese cypress (n=8) 100 Rice Yield Index 120 100 Rice yield index 120 80 60 40 20 80 Adsorbed P 60 (averages in Fig 11) 40 20 (a) Low fertile (b) High fertile 0 0.01 0.02 0.03 Bray-2 P (g/kg) 0.04 0.1 0.2 0.3 0.4 Bray-2 P (g/kg) Fig 13 P fertility of the immersed carrier in the relationship between the Bray-2 P in arable soils and the rice yield index (adapted from Komoto, 1984) Figure 13 shows the P fertile position of the immersed carrier on the relationship between the Bray-2 P in arable soils and the rice yield index (adapted from Komoto, 1984) In lowfertility soil (Fig 13(a)), the yield index increases with Bray-2 P, but does not increase over the fertile level of 0.025 g/kg of Bray-2 P As shown in Fig 13(b), soils containing greater than 0.1 g/kg are categorized as high-fertility soil The P values from this study were between 8- and 17-fold higher than the required level (0.025 g/kg) and categorized in the range of high-fertility soil Therefore, the immersed carrier had obtained sufficient P fertility 436 Biomass – Detection, Production and Usage 3.3 Heavy metals on the carrier Figure 14 shows an example of an X-ray fluorescence spectrum of the immersed carrier Fe was the main species detected, although silicon (Si), calcium (Ca), aluminum (Al), P, sulfur (SO4), potassium (K), chlorine (Cl) were also present Heavy metals were not detected on most of the carriers, but traces of Pb and Zn were detected in some samples (Table 2) However, they were well below regulation levels set out in the Fertilizers Regulation Act (Ministry of Agriculture, Forestry and Fisheries, 2007) and the Guidelines against Heavy Metal Accumulation in Arable Soil (Environment Agency, 1984) This was probably because the study site was in a rural area that had not been contaminated by heavy metals and also because the immersion period was too short for these metals to accumulate 0.04 FeKa FeKb 4.07 0.61 Intensity (cps/uA) 0.03 MnKa SiKa CaKa 0.02 RnKa RnLa 0.01 TiKa SrK RnKa RuKb 0 10 15 Energy (keV) Fig 14 X-ray fluorescence spectrum of immersed carrier 20 25 Recycling of Phosphorus Resources in Agricultural Areas Using Woody Biomass and Biogenic Iron Oxides Element Concentration (mg/kg) 437 Regulation value (mg/kg) As ND 50* Cd ND 5* Cr ND 500* Hg ND 2* Ni ND 300* Pb 5.3 100* Zn 4.0 120** Cu ND 125** * Ministry of Agriculture, Forestry and Fisheries, 2007 ** Environment Agency, 1984 Table Heavy metal concentrations in immersed carrier (maximum for n=45) 3.4 Possible further applications The findings reported in this chapter have been obtained from a specific region in Japan However, Fe is the third most abundant metal found in the soil (Spark, 1995), and Feoxidizing bacteria are not rare (Emerson et al., 1999; Emerson & Weiss, 2004; James & Ferris, 2004) Thus, this method can be applicable in many places, provided suitable aquatic conditions supporting the growth of Fe-oxidizing bacteria (low concentration of oxygen and circumneutral pH) are available In addition, the immersed woody carrier can be applied directly to agricultural land in the form of a fertilizer, without P extraction procedures, which are commonly required for P recovery methods Therefore, this method is a low-cost technique that should contribute to P resource recycling and the improvement of the aquatic environment, if adopted on a large scale Conclusions A new method of P recovery from natural water bodies using Fe-oxidizing bacteria and woody biomass (Japanese cedar and Japanese cypress) was applied in an agricultural canal during irrigation and non-irrigation periods The amounts of P adsorbed on the carrier during these periods were 0.332–0.350 and 0.172–0.187 g/kg, respectively, while the PO4–P concentrations of the water were 0.058 and 0.022 mg/L Expressed these values in parts per million, the P adsorbed on the carrier was 5,700- to 8,500-fold more concentrated than the P dissolved in water The P on the carrier was 8- to 17-fold higher than the required level for sufficient fertility to support rice production, and it was categorized in the range of highfertility soil Some traces of heavy metals adsorbed on the carrier were detected, but they were much lower than the regulation levels In addition, the woody carrier can be applied directly to agricultural land without P extraction Therefore, this method is a low-cost technique that should contribute to P resource recycling and the improvement of aquatic environment Acknowledgement This study was partially supported by a grant from the Shimane University Priority Research Project and a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (#20380179) 438 Biomass – Detection, Production and Usage References Batjes, N H (1997) A world data set of derived soil properties by FAO-UNESCO soil unit for global modeling Soil Use Manage, 13, pp.9-16 Bjerrum, C & Canfield, D (2002) Ocean productivity before about 1.9 Gyr ago limited by phosphorus adsorption onto iron oxides nature, 417, pp.159-162 Byrnside, D S & Sturgis M B (1958) Soil phosphorus and its fractions as related to response of sugarcane to fertilizer phosphorus Louisiana Agricultural Expansion Station Bulletin, 513, pp.56-66 Boujelben, N., Bouzid, J., Elouear, Z., Feki, M., Jamoussi, F., Montiel, A (2008) Phosphorus removal from aqueous solution using iron coated natural and engineered sorbents Journal of Hazardous Materials, 151, pp.103-110 Cordell, D., Drangert, J & White, S (2009) The story of phosphorus: Global food security and food for thought Global Environmental Change, 19, pp.292-305 Condron, L M., Turner, 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Akhavan Kharazian1 2Department 1Department of Biology, University of Isfahan, of Biology, Sciences and Research Branch of Fars, Islamic Azad University, Iran Introduction Soil salinity is one of the main problems for plant growth in agriculture, especially in countries where crops should be irrigated (Ahloowalia et al., 2004) Soil salinity has been considered a limiting factor to crop production in arid and semi arid regions of the world (Munns, 2002) Saline soils are estimated about – 10% of the world’s arable land (Szabolcs, 1994), and the area affected by salinity is increasing steadily (Ghassemi et al., 1995) Saltaffected soils are distributed throughout the world and no continent is free from the problem (Brandy and Weil, 2002) Globally, a total land area of 831 million hectares is saltaffected (Kinfemichael & Melkamu, 2008; FAO, 2000) However, soil salt accumulation can change with time and place, as a function of soil management, water quality (Almodares & Sharif, 2005), irrigation method, and the weather conditions Salt accumulation is mainly related to a dry climate, salt-rich parent materials of soil formation, insufficient drainage and saline groundwater or irrigation water (Almodares et al., 2008a) Salts in soils are chlorides and sulfates of sodium, calcium, magnesium, and potassium that among them sodium chloride has the highest negative effect on the plant growth and development Salinity causes slow seed germination, sudden wilting, and reduce growth, marginal burn on leaves, leaf yellowing, leaf fall, restricted root development, and finally death of plants The inhibitory effects of salinity on plant growth include: (1) ion toxicity (2) osmotic influence (3) nutritional imbalance leading to reduction in photosynthetic efficiency and other physiological disorders Among agricultural crops, sorghum (Sorghum bicolor L Moench) is naturally drought and salt-tolerant crop that can produce high biomass yields with low input Also, it can thrive in places that not support corn, sugarcane and other food crops In addition, sweet sorghum has potential uses (six F) such as: food (grain), feed (grain and biomass), fuel (ethanol production), fiber (paper), fermentation (methane production) and fertilizer (utilization of organic byproducts), thus it is an important crop in semi-aired and aired regions of the world Sorghum is grown on approximately 44 million hectares in 99 countries (ICRISAT, 2009) An estimation of the world-wide tonnage produced in 2007-2008 is shown in Table The increasing cost of energy and deplete oil and gas reserves has created a need for alternative fuels from renewable sources The consumption of biofule may reduce greenhouse gases Also it can be replaced with lead tetraethyl or MTBE (Methyl tert-butyl ether) that are air and underground water pollutants, 442 Biomass – Detection, Production and Usage respectively (Almodares & Hadi, 2009) Plants are the best choice for biofule global demands Currently, ethanol production is based on sugar or starch of crops such as sorghum, corn, sugarcane, wheat and etc In comparison with other crops, carbohydrate content of sweet sorghum stalk and its grain starch is similar to sugarcane and corn, respectively but its water and fertilizer requirements are much lower than both sugarcane and corn Thus, in many tropical and temperate countries where sugarcane and corn cannot be grown, a growing interest is being focused on the potential of sweet sorghum to produce bioethanol feed stock (Almodares et al., 2006, 2008d) Sweet sorghum biomass has rich fermentable sugars such as sucrose, glucose, and fructose so it is an excellent raw material for fermentative production (Almodares et al., 2008d) The total soluble sugars can be increase in sweet sorghum with increasing salinity level and sucrose content could be an indicator for its salt tolerance (2008b) Salt-stressed sorghum plants additionally accumulate organic solutes, like proline, glycinabetaine, sugars, etc (Lacerda et al., 2001) These organic solutes may contribute to osmotic adjustment, protecting cell structure and function, and/or may serve as metabolic or energetic reserve (Hasegawa et al., 2000) Inorganic and organic solutes concentrations maintained during salt stress, therefore, they may be important during the salt stress recovery period (Pardossi et al., 1998) Since sweet sorghum is more salt tolerant than sugarcane and corn which currently are the main sources of bioethanol production Therefore, it is suggested to plant sweet sorghum for biofule production in hot and dry countries to solve problems such as increasing the octane of gasoline and to reduce greenhouse gases Table World Sorghum Production 2007-2008 (Quotation from U.S Grain Council, 2008) Salinity problem and ways to resolve it About 7% of the world’s total land area is affected by salt, as is a similar percentage of its arable land (Ghassemi et al., 1995) Salinity is often accompanied by other soil properties, such as sodicity and alkalinity, which exert their own specific effects on plant growth There Sweet Sorghum: Salt Tolerance and High Biomass Sugar Crop 443 are three ways in which salinity stress of crops could be reduced; 1- Farm management practices; 2- Screening; 3- Breeding which will be discussed in the followings: 2.1 Farm management practices All irrigation waters contain some dissolved salts Thus, soil salinization may be expected by crop irrigation Removal of salts from the root zone may be the most effective way to eliminate the effects of salinity However, it is expensive and requires good drainage system It is not always possible to carry out this operation; thereby a number of other different ways could be considered such as: a Soil Reclamation; in a case Na ions are the major cause of soil salinity, it may be replaced with Ca ions by adding of gypsum (calcium sulfate) to the soil b Reduction of the salt from seed germination zone; Seed germination and seedling establishment are the most sensitive stages to salinity A number of approaches have been used 1) Removal of surface soil (Qureshi et al., 2003) 2) Pre-sowing irrigation with good quality water (Goyal et al., 1999) 3) Planting seed on the ridge shoulders rather than on the ridge top of the furrow 4) Planting in a pre-flooded field with good quality water (Goyal et al., 1999) c Reducing soil salinity by adding mulch, organic matter or deep tillage to the soil 2.2 Screening Salinity and waterlogging co-exist in the lower reaches of several river basins throughout the world, affecting agricultural production and the livelihoods of the affected communities (Wichelns and Oster, 2006) Efforts being made to overcome salinity and waterlogging problems by consist of engineering solutions such as installation of a drainage system to manage the drainage effluent generated by irrigated agriculture This is a long term strategy; however drainage installation is expensive The areas under salt-affected and waterlogged soils are expanding because of inappropriate on-farm water and soil management Selection and cultivation of high-yielding salt-tolerant varieties of different crops is a potential interim strategy to fulfill the needs of the communities relying on these soils for their livelihoods (Ayers and Westcot, 1989) Many crops show intraspecific variation in response to salinity Sorghum is moderately salt-tolerant Generally, substantial genotypic differences exist among sorghum cultivars in response to salinity stress (Sunseri et al., 2002; Netondo et al., 2004) 2.2.1 Screening methods based on growth or yield Screening large numbers of genotypes for salinity tolerance in the field is difficult, due to spatial heterogeneity of soil chemical and physical properties, and to seasonal rainfall distribution Frequently, short-term growth experiments have revealed little difference between genotypes that differ in long-term biomass production or yield Many short-term growth experiments measuring whole shoot biomass revealed little difference between plant genotypes in their response to salinity, even between those known to differ in long-term biomass production or yield (Rivelli et al., 2002) Longer-term experiments are necessary to detect genotypic differences in the effects of salinity on growth: it is necessary to expose plants to salinity for at least two weeks, and sometimes several months (Munns et al., 1995) Even with rice, a fast growing and salt sensitive species, it is necessary to grow plants for 444 Biomass – Detection, Production and Usage several weeks to be confident of obtaining reproducible differences in salinity tolerance between genotypes (Zhu et al., 2001) 2.2.2 Screening methods based on damage or tolerance to very high salinity levels Techniques that can handle large numbers of genotypes include: germination or plant survival in high salinity, leaf injury as measured by membrane damage (leakage of ions from leaf discs), premature loss of chlorophyll (using a hand-held meter), or damage to the photosynthetic apparatus (using chlorophyll fluorescence) These methods can identify genotypes able to germinate, or survive, in very high salinities (over 200 mM NaCl), but not discriminate between genotypes in their ability to tolerate the low or moderate salinities typical of many saline fields (50–100 mM NaCl) A major limitation to the use of injury or survival to identify salt-tolerant germplasm arises when the cause of injury is not known 2.2.2.1 Screening methods based on physiological mechanisms Because of the complex nature of salinity tolerance, as well as the difficulties in maintaining long-term growth experiments, trait-based selection criteria are recommended for screening techniques (Noble and Rogers, 1992) Traits used for screening germplasm for salinity tolerance have included Na+ exclusion, K+/Na+ discrimination (Asch et al., 2000) and Cl− exclusion (Rogers and Noble, 1992) The relationship between salinity tolerance and K+/Na+ discrimination was also considered, because K+/Na+ rather than Na+ alone has been used as an index of salinity tolerance for cultivar comparisons in wheat (Chhipa and Lal, 1995) and rice (Zhu et al., 2001) One of the mechanism of salinity tolerance that could be considered was tissue tolerance of high internal Na+ concentrations Tissue tolerance cannot be measured directly, and is difficult to quantify Yet it is clearly important; overexpression of vacuolar Na+/H+ antiporter that sequesters Na+ in vacuoles improved the salinity tolerance of Arabidopsis, tomato and brassica (Aharon et al., 2003) 2.3 Breeding Breeding programs for new varieties of sweet sorghum suited to semi arid tropics, temperate areas with rainy summer, Mediterranean areas with dry summer and soil salinity, are under development (Cosentino, 1996) Why sweet sorghum? 3.1 Agricultural advantages 3.1.1 Salt tolerance Sorghum is characterized as moderately tolerant to salinity (Almodares and Sharif, 2005; Almodares and Sharif, 2007) Salinity reduces sorghum growth and biomass production Salinity greatly reduced sorghum growth and this effect was more pronounced at 250 mM than at 125 mM NaCI (Ibrahim, 2004) However it was reported that sorghum growth was significantly reduced at all salinity levels from 50 to 150 mM (El-Sayed et al., 1994) Imposition of salt stress resulted in decreases in the percentage of seeds germinated (Almodares et al., 2007), although the strongest decline in germination occurred at the highest salt concentration (Table 2) Nevertheless, the development of high-yielding salinity tolerant sorghums is the best option to increase the productivity in soils (Igartua et al 1994) Similarly, Gill et al (2003) observed a great reduction in germination rate due to salt stress, in sorghum seeds at 37 ◦C in NaCl (−1.86MPa) 445 Sweet Sorghum: Salt Tolerance and High Biomass Sugar Crop Relative percent germination(%)in osmotic potential (Mpa)created by NaCl Cultivars -0.4 -0.8 -1.2 -1.6 -2.0 -2 IS 9639 48d 4e 0f 0e 0b 0b Sova 87.5abc 70abc 30de 12.5de 7.5b 7.5b Vespa 80abc 51.5bcd 17ef 3de 0b 0b S 35 83abc 74.5ab 54.5bcd 8.5de 3b 3b M 81E 73bc 85.5a 36de 0e 0b 0b IS 19273 81abc 46.5cd 29.5de 0e 0b 0b IS 6936 87abc 77a 33.5de 5de 0b 0b MN 1500 72.5bc 47.5cd 20ef 2.5de 0b 0b Sumac 100a 62.5abcd 67.5abc 47.5ab 45a 45a IS 686 63cd 40d 66abc 14de 0b 0b SSV 108 87.5abc 85a 72.5ab 25bcde 5b 5b Roce 87abc 74ab 89.5a 42abc 34.5a 34.5a Sofrah 89.5ab 84a 53bcd 23.5bcde 5.5b 5.5b Satiro 95ab 42d 32de 0e 5b 5b IS 2325 89.5ab 77a 46cd 28bcd 0b 0b E 36-1 62.5cd 42.5d 30de 2.5de 0b 0b IS 6973 85.5 abc 74.5ab 71.5ab 20cde 23ab 23ab SSV84 94.5ab 84.5a 64bc 64a 0b 0b Values of letters (a, b,…) within each column followed by the same letter are not significantly different at 5% level, using Duncan multiple rang test Table Effects of salinity on relative percent germination in 18 sweet sorghum cultivars (Quotation from Samadani et al., 1994) According to Prado et al (2000), the decrease in germination may be ascribed to an apparent osmotic ‘dormancy’ developed under saline stress conditions, which may represent an adaptive strategy to prevent germination under stressful environment Germination time delayed with the increase in saline stress and root growth was more sensitive to salt stress than was germination (Gill et al., 2003) It seems that grain weight is related to salt tolerance in sweet sorghum It showed that higher total seedling dry weight was obtained with larger 446 Biomass – Detection, Production and Usage seed size in 18 sweet sorghum cultivars under salt stress (Table and Fig 1) The presence of large genotypic variation for tolerance to salinity is reported in sorghum (Maiti et al, 1994) Sorghum seems to offer a good potential for selection, as intraspecific variation for germination under saline conditions (Table 2) or in the presence of other osmotic agents that has already been reported Selection of salt tolerant cultivars is one of the most effective methods to increase the productivity of salinity in soils (Ali et al., 2004) By using these salt tolerant plants in breeding they produced progranuned an improved plant having higher chlorophyll concentration, more leaf area, early and better yield potential etc The advancement of salinity tolerance during the early stages of sorghum growth been successfully accomplished through selection Thousand Grain Weight (g) Total Seedling Fresh Weight (mg/20grain) IS 9639 18.75 79 Sova 19.77 197 Vespa 15.35 180 S 35 30.63 349 M 81E 14.59 127 IS 19273 27.69 267 IS 6936 34.33 418 MN 1500 24.59 192 Sumac 12.63 81 IS 686 17.15 194 SSV 108 39.61 381 Roce 17.16 159 Sofrah 16.68 170 Satiro 15.21 246 IS 2325 31.35 335 E 36-1 33.33 434 IS 6973 38.52 344 SSV84 40.05 524 Cultivar Table Thousand Grain Weight (g) of 18 sweet sorghum cultivars and Total Seedlings Fresh weight (mg/20 grain) grown in osmotic potential (-0.4 Mpa) of NaCl after 12 day treatment (Quotation from Samadani et al., 1994) Sweet Sorghum: Salt Tolerance and High Biomass Sugar Crop 447 Genotypes possessing salt tolerance characteristics will help in boosting up plants production in salt-affected soils (Ali et al., 2004) Azhar and McNeilly (1988) found that, for salinity tolerance of young sorghum seedlings, both additive and dominant effects were involved, the latter being of greater importance Attempts have been made to evaluate salt tolerance at the germination and emergence stages in sorghum (Igartua et al., 1994) In fact, the variation in whole-plant biomass responses to salinity was considered to provide the best means of initial selection of salinity tolerant genotypes (Krishnamurthy et al, 2007) The presence of large genotypic variation for tolerance to salinity reported in sorghum (Krislmamurthy et al., 2007) There are large genotypic variations for tolerance to salinity in sorghum (Table 4) The other possible solution could be either using physical or biological practice (Gupta and Minhas, 1993) Sudhir and Murthy (2004) reviewed both multiple inhibitory effects of salt stress on photosynthesis and possible salt stress tolerance mechanisms in plants Salinity reduced relative growth rates and increased soluble carbohydrates, especially in the leaves of salt sensitive genotype (Lacerda et al., 2005) In addition salt-stressed sorghum plants additionally accumulate organic solutes, like proline, glycinabetaine, sugars, etc (Lacerda et al., 2001) The total soluble sugar increased in sorghum sap with increasing salinity level (Ibrahim, 2004; Almodares et al., 2008a) Sucrose content of plant parts is an indicator of salt tolerance (Juan et al., 2005) The imposition of strong water or salt stresses in sorghum has been demonstrated to be accompanied to an increase in the sugar levels of embryos, which may help in osmoregulation under stress conditions (Gill et al., 2003) The fructose level is always higher than glucose and sucrose levels in response to various salinity treatments (Gill et al., 2001; Almodares et al., 2008a) Fig Correlation between total seedling fresh weight and thousand grain weight in sweet sorghum (Quotation from Samadani et al., 1994) ... was Biomass Burning in South America: Transport Patterns and Impacts 407 prevented by the fast displacement of a cold front, and in this case the exit to the Atlantic was observed over southern... with the SALLJ On the following day, the southward transport strengthened while the northward flow east of 60º W weakened, as well as its vertical Biomass Burning in South America: Transport Patterns. .. southward transport Biomass Burning in South America: Transport Patterns and Impacts 399 At 25º S (Figure 11b) from 23 to 28 August, there was a southward flux at all longitudes east of the Andes