OPCE-STR.vp Acta Bot. Croat. 68 (1), 127–146, 2009 CODEN: ABCRA 25 ISSN 0365–0588 The nutritive value and role of Panicum turgidum Forssk. in the arid ecosystems of the Egyptian desert SELIM Z. HENEIDY1*, MARWA W. HALMY2 1 Botany Department, Faculty of Science, Alexandria University, Egypt 2 Environmental Sciences Department, Faculty of Science, Alexandria University, Egypt Panicum turgidum is one of the most drought resistant plants in the Egyptian desert. Five habitat types were selected for the study: sand dunes (North Sinai and in Wady El-Na- trun), gravel desert, coastal plain, and water runnels of a wadi bed (South Sinai and East- ern Desert). About 47.4% of the studied sites were subjected to high grazing pressure, 26.3% to moderate grazing pressure; the remaining 26.3% were subjected to low grazing pressure. Concentration of the nutrients (K, Na, Ca, P and Ca/P ratio) in the grazeable parts of P. turgidum populations exhibited insignificant variability between habitats and phytogeographical regions. Meanwhile, concentration of potassium showed significant variability between the phytogeographical regions. Ca/P ratio of the grazeable parts of P. turgidum was significantly related to the soil silt and organic matter content. The percent- age of crude protein was higher than the minimum required for the maintenance of the grazing animals, i.e. P. turgidum has a good or excellent forage quality. Due to its high nu- tritive value and ease of cultivation, P. turgidum grains could be considered as a potential crop, which may serve as a supplementary food to the common cereals. It worth noting that the variation in the nutritive values among the cultivated populations was insignifi- cant as all the cultivated populations had a high nutritive value, indicating the effect of edaphic factors on the wild population nutritive value which was proved also from the correlation between the edaphic factors and nutritive variable. Keywords: arid, grazing, protein, nutrients, desert, Egypt. Introduction Grasses play an important role in land stabilization and animal nutrition due to their protein, carbohydrates, fats, fibers and mineral contents. Therefore, planting grasses con- stitutes an important part of any rangeland rehabilitation program. Panicum turgidum Forssk. (Poaceae) is one of the widely distributed and most drought resistant grasses of the Egyptian desert (MIGAHID and EL SHOURBAGY 1961). According to TÄCKHOLM (1974), this species is widely distributed in all phytogeographical regions of Egypt except the western Mediterranean coastal desert. The success and wide distribution of this plant species indi- ACTA BOT. CROAT. 68 (1), 2009 127 * Corresponding author, e-mail: drsheneidy@yahoo.com U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:35 Color profile: Disabled Composite 150 lpi at 45 degrees cates its ability to tolerate certain unfavorable conditions (ISMAIL and SEED 1983). Panicum turgidum has the merit of being very resistant to drought and also a very effective sand-binding xerophyte (MIGAHID and EL SHOURBAGY 1961). It is also considered to be tol- erant to high soil salinity levels as well as to sand accumulation. Therefore, it is a good spe- cies for stabilizing loose soil (EL SHOURBAGY 1958, HENEIDY and WASEEM 2007). Due to the high palatability of this grass it is considered an important fodder and graz- ing plant for many animals, especially in summer when annuals disappear and shortage in natural forage occurs. Also, in dry conditions, P. turgidum provides grazing as standing hay (MANDAVILLE 1990). Since many native grasses of the coastal strip of Egypt are spring growers, the summer growth of P. turgidum may make this species suitable as complemen- tary forage for the deteriorated lands of the western coastal desert of Egypt. The present study aims at assessing the variation in the nutritive value among the studied populations of P. turgidum and its relation to soil characters. Consequently, it has successfully been used in rehabilitation trials in the western coastal deserts of Egypt (HENEIDY and WASEEM 2007). Materials and methods Fresh specimens of P. turgidum were collected from 19 sites, selected to represent a wide variety of habitats within the range of distribution of P. turgidum in the Eastern Desert, Wady El-Natrun and Sinai (Tab. 2). According to TÄCKHOLM (1974) these sampling sites are located in four different phytogeographical regions: the Eastern Desert region; Mediterranean region (north Sinai); Oases of the Western Desert (Wady El-Natrun); and Sinai proper (Fig. 1). The sampling site represents five types of habitats: sandy plains; sand dunes (sampling populations located in North Sinai and in Wady El-Natrun), gravel desert, coastal plain, and water runnels of the wadi bed (sampling populations located in South Si- nai and Eastern Desert). Pasture condition, grazing pressure and the relative abundance of P. turgidum were assessed for the nineteen sampling sites, by direct observations during the field visits. Relative accessibility of the aboveground parts of the studied species for graz- ing was assessed using the ocular estimate method (ETIENNE 1989). The aboveground parts of P. turgidum in each site were assigned to one of the relative accessible parts classes; 40–59, 60–89 and 90–100% (JENSEN and SCOTTER 1977). For the chemical analysis and nutritive value estimation, samples of the fresh grazeable aboveground parts of the studied species populations were collected from at least five bushes from each of the sampling sites. The collected plant materials were cleaned, oven dried at 65 °C to constant weight, powdered before chemical analysis. Mature grains col- lected from all the studied populations were pooled together to form a composite sample. The grains were powdered ready for chemical analysis. The mixed-acid digestion was used for preparing the sample solution for determination of element content. Na, K, Ca and Mg were analyzed using the flame photometer. Phosphorous was determined according to EATON et al. (1995). Ash and ether extract (i.e. crude fats) was determined according to AL- LEN et al. (1974). Total protein was determined according to the modified Lowery method (HARTREÉ 1972). The crude fiber was determined according to AOAC (1960). Nitrogen free extract was calculated according to the following equation (LE HOUÉROU 1980): NFE (in % DM) = 100 – (CP + CF +EE + Ash) where CP = crude protein, CF = crude fibers, EE = ether extract (i.e. total fats). 128 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:35 Color profile: Disabled Composite 150 lpi at 45 degrees Digestible crude protein (DCP) was determined using the equation of DEMARQUILLY and WEISS (1970): DCP (in % DM) = 0.93 CP – 3.52 This equation is only valid in the case of nitrogen concentration from 0.61 to 3% (or CP > 3.81%). Total digestible nutrients (TDN) were estimated according to ABU EL-NAGA and EL-SHAZLY (1970). The gross plant energy was calculated from its chemical analysis com- ponents multiplied by the average of heat of combustion (LOFGREEN 1951). Digestible and metabolized energy (DE and ME) were estimated according to CRAMPTON and HARRIS (1969). Net energy was estimated according to GARRETT (1980). Three soil samples were taken down to the depth of 0–50 cm for each site. Soil samples were air dried, thoroughly mixed, passed through a 2 mm sieve before physical and chemi- cal analysis (BLACK 1965, ALLEN et al. 1974). Soil texture analysis was conducted using the Bouyoucus hydrometer method. Determination of calcium carbonate content was carried out using a calcimeter. Total organic matter was determined by loss-on-ignition. For deter- mination of soil reaction (pH), electric conductivity (E.C.), bicarbonates and some of the available nutrients 1: 2.5 (w/v) soil: water extracts were prepared. Sulfates were carried out using the »gravimetric with ignition of residue method«. Calcium and magnesium were de- termined using direct titration against 0.1N EDTA. A flame photometer was used for deter- ACTA BOT. CROAT. 68 (1), 2009 129 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Fig. 1. Map of northern Egypt showing the locations of the sampling sites from which P. turgidum populations were collected. 1- Bir Lahfen; 2- El-Koseima road; 3- Abu Aekela; 4- Geble Libni; 5- Spika; 6- Ras El-Deeb (El Zaranik protected area); 7- El Zaranik protected area; 8- El-Qaa plain (15 Km from El-Tur city); 9- El-Qaa plain (35 Km from El-Tur city); 10- Wadi Kid, Rahila road (Nabq protected area); 11- Wadi Kid (Nabq protected area); 12- Wadi Kid, Khashm El-Fakh (Nabq protected area); 13- Wadi El Sokhen (Abu Galum protected area); 14- Wadi Mamlah (Abu Galum protected area); 15- Wadi El Rasassa (Abu Galum protected area); 16- Km 101, Cairo-Suez Road; 17- Km 75, Cairo-Suez Road; 18- West of Al-Gaar Lake (Wady El Natrun); 19- East of Um-Risha Lake (Wady El Natrun). U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:35 Color profile: Disabled Composite 150 lpi at 45 degrees mination of K and Na. Phosphorous was determined using the ascorbic acid method ac- cording to EATON et al. (1995). The significance of variation in the soil parameters, chemical constituents and nutritive variables of the plant materials in relation to habitat and to the phytogeographical regions was assessed using one-way ANOVA test. Simple linear correlation analysis was applied to detect the relationship between the chemical composition and nutritive variables of the studied populations and the soil parameters of the sampling sites to investigate the influ- ence of soil characteristics on the plant chemical composition and hence on its nutritive values. Two multivariate analysis techniques (classification and ordination) were conducted on the data of the chemical composition and the nutritive variables of the plant materials of the studied populations. One way-ANOVA test was applied for the soil parameters of the re- sulting groups from cluster analysis. The significance of variation in chemical composition and nutritive variables among the cultivated populations were assessed using one-way ANOVA test. All the statistical analyses were conducted with the Minitab 13.1 release-PC computer program (MINITAB 2000). Results Habitat characteristics The soil characteristics of the studied habitats and the phytogeographical regions from which P. turgidum populations were collected showed variation among the different habi- tats and the phytogeographical regions (Fig. 2, 3). The soil of sampling sites was generally alkaline with pH ranging from 7.71 to 8.22. The pH- value exhibited significant variation between habitats while it showed insignificant variation between phytogeographical re- gions (Tab. 1). The soil texture varied from loamy sand to sandy. Calcium carbonate con- tent, sand, silt and clay percentages showed significant variation between different habitats and also between phytogeographical regions. Potassium content showed significant varia- tion between habitats and insignificant variation between phytogeographical regions. Bi- carbonate and phosphorus content of the soil showed significant variation between habitats and also between phytogeographical regions. Generally, all the studied soil parameters showed significant difference between the studied habitats and also between the phyto- geographical regions from which P. turgidum was collected, with the exception of the pH and the potassium content, which did not show any significant variation between the phytogeographical regions. 130 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Tab. 1. One way-ANOVA testing the significance of variation in soil characteristics among the phytogeographical regions and among the investigated habitats from which P. turgidum was sampled. · significant P < 0.05; ·· very significant P < 0.01; and ··· highly significant P < 0.001 pH (%) mg/ 100g CaCO3 Sand Silt Clay K HCO3 P Phytogeographical regions 3.21 4.69 · 8.49 ··· 6.75 ·· 6.45 ·· 3.01 5.16 · 4.99 · Habitats 3.92 · 29.02 ··· 6.01 ·· 4.90 · 9.96 ··· 3.86 · 11.71 ··· 16.24 ··· U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:35 Color profile: Disabled Composite 150 lpi at 45 degrees ACTA BOT. CROAT. 68 (1), 2009 131 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Fig. 2. The variation in soil parameters between the studied habitats (CP: coastal plain; GD: gravel desert; SD: sandy dunes; SP: sandy plain; and WB: wadi bed) of the studied P. turgidum po- pulations. U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:35 Color profile: Disabled Composite 150 lpi at 45 degrees 132 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Fig. 3. The variation in soil parameters between the studied phytogeographical regions (NS: North Sinai; SS: South Sinai; ED: Eastern Desert and WN: Wady El-Natrun) from which P. turgidum populations was sampled. U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees ACTA BOT. CROAT. 68 (1), 2009 133 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Tab. 2. Description of the sampling sites from which P. turgidum populations were collected, the relative accessibility of the above-ground parts and the relative abundance of P. turgidum in each site (*cc= very common, c; common). S it e R e g io n H a b it a t S o il te x tu r e P a st u r e c o n d it io n G r a z in g p r e ss u r e R e la ti v e a c c e ss i- b il it y (% ) * R e la ti v e A b u n d a n c e 1 N o r th S in a i Sandy plain, with deep very fine sand deposits Sandy Good High 60–89 c 2 Sandy plain, with deep very fine sand deposits Sandy Good High 90–100 c 3 Sandy plain, with very deep sand deposits Sandy Good High 60–89 c 4 Sandy plain, with very deep sand deposits Sandy Poor High 60–89 cc 5 Sand dune Sandy Fair Mode- rate 60–89 cc 6 Sand dune Sandy Fair Low 40–59 cc 7 Sand dune Sandy Fair Low 40–59 cc 8 S o u th S in a i Coastal plain, drainage lines of the plain covered with alluvial deposits Loamy sand Good Mode- rate 90–100 c 9 Coastal plain, drainage lines of the plain covered with alluvial deposits Sandy Good High 60–89 cc 10 Wadi bed, drainage lines of the wadi covered with alluvial deposits Loamy sand Fair Mode- rate 90–100 cc 11 Wadi bed, mouth of the wadi covered with alluvial deposits Sandy Good High 90–100 cc 12 Wadi bed, drainage lines of the wadi covered with alluvial deposits Sandy Good High 60–89 cc 13 Wadi bed, mouth of the wadi covered with alluvial coarse deposits mainly boulders and gravels Loamy sand Fair High 60–89 cc 14 Wadi bed, mouth of the wadi covered with alluvial coarse deposits mainly boulders and fine gravels Sandy Fair High 60–89 cc 15 Wadi bed, mouth of the wadi covered with alluvial coarse deposits mainly boulders and gravels Loamy sand Fair Mode- rate 90–100 cc 16 E a st e r n D e se r t Gravel and sand formations, drainage lines of the gravel desert covered with fine deposits Sandy Fair Mode- rate 60–89 cc 17 Gravel and sand formations, drainage lines of the gravel desert covered with fine deposits Loamy sand Fair Low 60–89 c 18 W a d y E l N a tr u n Sandy plain, with fine deep sand deposits Sandy Fair Low 40–59 cc 19 Sandy plain, with fine deep sand deposits Sandy Good Low 60–89 cc U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees Grazing status and pasture condition Generally, pasture conditions can be classified as poor, fair and good. About 42.1% of the studied sites (1, 2, 3, 8, 9, 11, 12, and 19) are considered good pastures. At the same time 52.6% of the studied sites (5, 6, 7, 10, 13, 14, 15, 16, 17 and 18) were fair in pasture condi- tion, while site 4 had a poor pasture condition. Grazing pressure in the studied populations ranged from low to high (Tab. 2). About 47.4% of the studied sites (1, 2, 3, 4, 9, 11, 12, 13 and 14) were subjected to high grazing pressure (Tab. 2), while 26.3% of the studied sites (5, 8, 10, 15 and 16) were subjected to moderate grazing pressure. The remaining 26.3% of the studied sites (6, 7, 17, 18 and 19) were subjected to low grazing pressure. The relative accessibility of the aboveground parts of P. turgidum for grazing (by which we mean the ra- tio of the green to the dry old shoots in each plant bush) ranged from 60 to 89% in most of the sampling sites (1, 3, 4, 5, 9, 12, 13, 14, 16, 17 and 19). The highest relative accessibility (>90%) was recorded in sites number 2, 8, 10, 11 and 15, while sites number 6, 7 and 18 ac- quired the lowest values (40–59%). The coastal plain, the water runnels of the wadi bed and the gravel desert showed a higher percentage of accessible parts than the sandy plain and sand dunes habitats. The relative abundance of the studied species in all the examined sam- pling sites was very common in 73.7% of the studied sites and common in the rest of the populations. The relative accessibility of the aboveground parts of the plant was high in moderately and highly grazed sites, while it was low in areas with low grazing pressure. Chemical composition of the studied populations The variation of the different nutrients in the grazeable parts of P. turgidum populations between the investigated habitats and phytogeographical regions in nutrients content of the studied populations were insignificant except for potassium content, which exhibited sig- nificant variation in the different phytogeographical regions (Tab. 3). It is obvious that pop- ulations of P. turgidum collected from Eastern desert region attained a maximum mean so- dium and potassium contents (1.04, 1.32% respectively), while those collected from north Sinai region attained maximum mean calcium, magnesium and phosphorus contents (1.37, 0.91 and 0.29% respectively). Populations collected from south Sinai region attained the maximum mean Ca/Mg and Ca/P ratios (1.70 and 5.71 respectively; Fig. 4). Generally, the studied populations collected from the Eastern desert region attained the highest mean values of ether extract and crude protein content (2.7 and 7.6% respectively; Fig. 4). North Sinai populations attained the highest mean values of ash and crude fiber content (9.6 and 37.5% respectively). On the other hand, the studied P. turgidum popula- tions collected from Wady El-Natrun region attained the highest mean values of nitrogen free extract (46.4%). A highly significant variation in the total carbohydrates content (NFE) was established among the phytogeographical regions, while the variation in crude fiber and in crude protein content in the different habitats was significant (Tab. 3). The vari- ation in the ash and fat content of the grazeable parts of the studied P. turgidum populations is not significant among either the habitats or the phytogeographical regions. Nutritive value assessment of the studied population In general, Eastern desert populations showed the maximum mean of digestible crude protein content (3.53%; Fig. 4). The studied P. turgidum populations of Wady El-Natrun re- 134 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees ACTA BOT. CROAT. 68 (1), 2009 135 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Fig. 4. The variation in the nutrients in mg/g, ash (%), Ca/Mg, Ca/P ratio, metabolic constituents (EE: ether extract (%), CF: crude fiber (%), CP: crude protein (%), NFE: nitrogen free extract (%) and OM: total organic matter (%) and nutritive variables (DCP: digestible crude protein (%), TDN: total digestible nutrients (%), GE: gross energy (Mcal kg–1 DM), DE: digestible en- ergy (Mcal kg–1 DM), ME: metabolized energy (Mcal kg–1 DM), and NE: net energy (Mcal kg–1 DM) among (a) the studied habitats (SP: sandy plain; SD: sandy dunes; CP: coastal plain; WB: wadi bed; and GD: gravel desert) and (b) the studied phytogeographical regions (NS: North Sinai; SS: South Sinai; ED: Eastern Desert and WN: Wady El-Natrun). U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees gion had the maximum of mean total digestible nutrients (64.91%), gross energy (4.27 Mcal kg –1 DM), digestible energy (2.85 Mcal kg –1 DM), metabolized energy (2.44 Mcal kg –1 DM), and net energy (1.22 Mcal kg –1 DM). The digestible crude protein showed sig- nificant variation among the studied habitats (Tab. 3). The correlation analysis between the chemical compositions, nutritive variables of the studied wild populations of P. turgidum and the soil parameters of the sampling sites from which these populations were collected (Tab. 8) reveals significant negative relationship between the bicarbonate content of the soil, the digestible crude protein content and the crude protein content of the plant. A highly significant negative relationship existed be- tween the crude fiber content of the studied population and the calcium carbonate content of the soil. The Ca/Mg ratio of the studied population showed a significant negative rela- tionship with the pH of the soil, while exhibiting a significant positive relationship with magnesium and potassium content of the soil. The Ca/P ratio of the studied populations ex- hibited a significant positive relationship with the organic matter and the silt content of soil. The digestible energy and the metabolized energy of the studied populations exhibited a significant positive relationship with the phosphorous content of the soil. 136 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Tab. 3. One way-ANOVA testing the significance of variation in the content of nutrients, Ca/Mg, Ca/P ratios, ash, ether extract (EE), crude fiber (CF), crude protein (CP), nitrogen free ex- tract (NFE), total organic matter (OM), digestible crude protein (DCP), Total digestible nu- trients (TDN), gross energy (GE), digestible energy (DE), metabolized energy (ME) and net energy (NE) in the aboveground parts of P. turgidum among the phytogeographical regions and among the investigated habitats from which P. turgidum was sampled. · significant, P < 0.05; ·· very significant, P < 0.01; and ··· highly significant, P < 0.001. Parameter Phytogeographical Regions Habitats m g g – 1 Na 0.65 0,09 K 3.81 · 0.42 Ca 0.89 0.21 Mg 0.57 0.47 P 2.34 1.61 Ca/Mg 0.22 0.48 Ca/P 0.61 0.67 % Ash 1.94 0.64 EE 0.81 0.26 CF 2.58 6.82 ·· CP 2.11 3.60 · NFE 7.38 ·· 1.92 OM 1.95 0.58 DCP 2.11 3.60 · TDN 1.93 1.41 M c a l k g – 1 GE 1.35 0.38 DE 1.99 1.63 ME 1.99 1.63 NE 1.8 1.26 U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees Discussion The variation in the accessible aboveground parts of P. turgidum among the different sites with different grazing levels may be attributed to the variation in the physical configu- ration of the plant (the ratio between the green to dry old shoots) in the highly grazed sites compared to low-grazed sites. The plant bushes in the low-grazed sites were characterized by being very tangled, with large accumulations of dry old branches. This is in agreement with VALENTINE (1990). He indicated that some of the positive effects of grazing are the in- crease in nutritive value of grasses by increasing the ratio of new growth: old growth, re- moval or prevention of thatch buildup and reduction of the accumulation of dry old shoots that may stunt new growth. In the present study, the forage value of P. turgidum was evaluated according to its chemical composition. According to LE HOUÉROU (1980) the forage value of the consumed plant is the result of its nutritive value, i.e. chemical composition and digestibility. It is highly affected by the stage of maturity, edaphic influence; climate and range condition. In addition, the nutritive value of any forage is dependent upon its content of energy-produc- ing nutrients as well as its contents of physiologically essential nutrients (SHALTOUT and EL-BEHEIRY 1997). The concentration of nutrients varied from population to another, which may be attrib- uted to the variation in the edaphic and climatic factors. The results of the present study showed that the Ca/P ratio of the grazeable parts of P. turgidum was significantly related to the soil silt and organic matter content (Tab. 8). On other hand, Ca/Mg ratio was signifi- cantly related to soil magnesium, potassium content and soil reaction (pH). This agrees with the reported accumulation of nutrients in the grazeable phytomass of a species that may differ considerably from one habitat to other (ABDEL-RAZIK et al. 1988b). It is worth noting that the Ca/Mg ratio in the grazeable parts of P. turgidum in the pres- ent study was comparable to the mean of the natural forage in the western Mediterranean coastal rangelands (Tab. 4). However, according to BOUDET (1975) the Na, K, Ca, Mg and P contents of P. turgidum meet the level required for the maintenance of animals. In addition, ACTA BOT. CROAT. 68 (1), 2009 137 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Tab. 4. Nutrients contents (%), Ca/Mg and Ca/P ratios of the studied wild P. turgidum populations compared to other related studies, to the maximum tolerable level and to the maintenance level of these nutrients required for animal feed. Panicum turgidum Determined by (%) Ca/P Ca/Mg Na K Ca Mg P Mean of the studied wild populations Present Study 0.92 1.14 1.15 0.76 0.24 5.07 1.57 Wadi Eithely (Eastern Desert) KABIEL (2001) 0.31 0.69 0.78 0.26 0.25 – – Western Mediterranean coastal rangelands (El Omayed) ABDEL-RAZIK et al. (1988b) 0.87 1.68 2.95 2.23 0.09 32.6 1.34 Maintenance levels BOUDET (1975) 0.08 0.4 0.2 0.2 0.12 – – Maximum tolerable level NRC (1984) 10 3 2 4 1 – – U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees according to NRC (1984) the P. turgidum Na, K, Ca and P content does not exceed the max- imum tolerable level (Tab. 4). Comparing the mean of the composition of nutrients of P. turgidum in all the studied wild populations with the mean of natural forage in the western Mediterranean coastal rangeland – the most important rangelands in Egypt according to EL-KADY (1987) – showed that the concentration of K, Ca, and Mg is lower than that of the mean of natural forage in the western Mediterranean coastal rangeland (Tab. 4). However, the phosphorus content is much higher than that of the mean of natural forage in the west- ern Mediterranean coastal rangeland. P. turgidum is characterized by the association of mycorrhizae (vesicular-arbuscular type) with its roots as stated by KHALIEL (1989) and SRIVASTAVA et al. (1997), which may explain the high content of phosphorous in P. turgidum. It was asserted by PENNING DE VRIES et al. (1980) that if too little P is available, the N absorption, and hence production are reduced. This demonstrates the importance of introducing P. turgidum in the western Mediterranean coastal rangelands to compensate for the deficiency in phosphorous, the only element in which the forage of this region is defi- cient according to ABDEL-RAZIK et al. (1988a). The importance of the adequate Ca/P ratio of 2–3 is considered by AYYAD and LE FLOC’H (1983) to be a major factor affecting the utili- zation of the whole animal diet. In addition, the high Ca/P ratio leads to lower utilization of both Ca and P. According to ABDEL-RAZIK et al. (1988b) the mean Ca/P ratio of the natural forage in the western Mediterranean coastal rangelands is notably high (32.6). In the pres- ent study, Ca/P ratio ranged from 3.36 in P. turgidum populations collected from Wady El-Natrun to 5.71 in those of South Sinai; this low Ca/P ratio gives a further reason for the introduction of P. turgidum as a natural forage plant in the western Mediterranean region. Crude protein (CP) and crude fibers (CF) are viewed classically as an indicator of the nutritional value of food for grazing animals (BRYANT and KUROPAT 1983, HENEIDY 2002). The percentage of crude protein in the grazeable parts of the studied wild P. turgidum popu- lations is higher than the minimum (6% of forage dry matter) required for the maintenance of animals, if compared with many tropical grasses (Tab. 5). The crude fiber (CF) content of the grazeable parts of the studied P. turgidum populations was quite high. It ranged from 34.8% in Eastern desert to 37.5% in north Sinai (Fig. 4). The mean value of the studied wild populations (36.7%) was higher than that obtained by KABIEL (2001), but lower than that obtained by FAROOQ et al. (1989) and HENEIDY (1996). The importance of lipids (ether ex- tract or EE) to plants in terms of structure and use in metabolism is well known. 138 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Tab. 5. Ash, ether extract (EE), crude protein (CP), crude fiber (CF) and nitrogen free extract (NFE) contents (%) of the studied wild P. turgidum populations compared to other related studies and to cultivated P. turgidum. Panicum turgidum Determined by (%) Ash EE CP CF NFE Mean of the studied wild populations Present Study 8.8 2.5 6.7 36.7 45.2 Mean of cultivated populations 7.7 3.7 9.2 31.4 48.1 Peshawar (Pakistan) FAROOQ et al. (1989) 12.2 2.2 6.5 37.4 37.4 Gulf of Aqaba (Sinai) HENEIDY (1996) 9.1 5.3 6.6 39.9 39.4 Wadi Eithely KABIEL (2001) 12.1 2.3 4.8 35.1 45.7 U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees The development of mankind has reached the point at which a variety of new resources need to be tapped in order to fill the basic needs for food and feed, especially in the devel- oping countries (LIETH 2002). Information on the seeds of wild species and wild relatives of cultivated crops is scarce but with the increasing interest in new food sources and the use of genetic diversity in breeding programs, the seeds of wild plants are now receiving more at- tention (IRIONDO and PÉREZ 1997). Wild plants have provided a safety net for human beings from time immemorial, whenever crop harvests were poor. They are consumed daily and traded at markets through special rural-urban marketing channels. In addition, some of the wild plants play an important food security role in the time of famine (e.g. Cenchrus biflorus and P. turgidum). The results of this study indicated that P. turgidum grains are characterized by high nutritive value comparable to that of the common cereals (corn, wheat and barley, Tab. 6) and other cultivated grain-producing grasses. Many scientists (IRVINE 1952, WILLIAMS and FARIAS 1972, HARLAN et al. 1989) reported that the local in- habitants of the Western Sahara use and eat the grains of P. turgidum, grinding the grains into flour, using it in making porridges and baking it into bread. Grain shattering is one of the main problems, resulting in low yield. Generally, in many grasses the cleaning of the grains is necessary to obtain adequate grain quality. Unfortunately grains of most species of tropical pasture grasses are characterized by being very difficult to thresh and to clean be- cause of the strong attachment of palea and lemma to the caryopsis (e.g. Stipagrostis plumose, Lasuirus sindicus and Cenchrus ciliaris). This makes these species difficult to domesticate (LE HOUÉROU 1985). However, it was noticed that P. turgidum grains are very easy to thresh and to clean. Accordingly, P. turgidum grains could be considered as a poten- tial crop, and it may serve as a supplementary food, alongside the common cereals. This might help to alleviate the current food gap in the arid regions. The quality of forage can be expressed in several parameters, such as total digestible nutrients, digestible crude protein and caloric value (DUIVENBOODEN 1985). The total di- gestible nutrients (TDN) is an appropriate measure of the food energy available to animals only after the digestion losses have been deducted (LOFGREEN 1951). Therefore, TDN is a measure of energy requirement of animals and energy value of feeds (HENEIDY 2002). The mean value of TDN (64.03%; Tab. 7) of the grazeable parts of the studied wild P. turgidum ACTA BOT. CROAT. 68 (1), 2009 139 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Tab. 6. Ash, crude protein (CP), fat (EE) contents (%) and gross energy (GE) in Mcal kg –1 DM of P. turgidum grains compared to some common cereals and to grain-producing species. Species Determined by (%) (Mcal/kgDM) Ash CP EE GE Panicum turgidum Present study 18,1 10,92 7,31 4,01 Panicum antidotale KEARL et al. (1979) 12,3 10,9 1,9 – Panicum miliaceum 7,2 10,4 3,2 – Echinochloa crusgalli 19,7 7,6 2,2 – Zea mays 3,21 8,06 13,84 4,94 Triticum vulgare 4,73 9,5 8,69 4,63 Hordeum vulgare 4,38 9,92 2,02 4,13 U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees populations was lower than that obtained by HENEIDY (1996). However, it meets the re- quirements for sheep diet (61.7%; NRC 1975) and breeding cattle diet (50.0%; NRC 1984). And it is higher than that of the common fodder crops (Barseem (clover) and barley, Tab. 7) recorded by SOLIMAN and EL-SHAZLY (1978). The TDN value of P. turgidum in the four studied phytogeographical regions can be considered fair for grazing animals compared with common fodder crops. The feeding value of forage depends primarily on the magni- tude of its contribution to the energy need of an animal. Difference in this respect between forages is almost completely a consequence of the relative amounts in which they are vol- untarily consumed (PETRUSEWICZ 1976). Energy contained in food is called gross energy (GE), energy intake or consumption. After subtracting the caloric value of the feces (F) 140 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Tab. 7. The nutritive variables (DCP: digestible crude protein, TDN: Total digestible nutrients (%), GE: Gross energy, DE: Digestible energy and NE: Net energy in MJ kg –1 DM) of the studied wild P. turgidum populations compared to other related studies, rangelands, common fodder crops and to cultivated P. turgidum. Panicum turgidum Determined by (%) (MJ kg –1 DM) DCP TDN GE DE NE Mean of the studied wild populations Present Study 2.73 64.03 17.6 11.79 5.02 Mean of cultivated populations 5.05 63.48 18.06 11.7 4.97 Gulf of Aqaba (Sinai) HENEIDY (1996) 2.65 65.67 17.51 11.83 5.04 Rangelands (Western Mediterranean coastal region) EL Omayed ABDEL-RAZIK et al. (1988a) 5.4 75 – – – 4.9 72 15.09 10.91 4.77 Common fodder crops SOLIMAN and EL-SHAZLY (1978) Barseem – 56 – – – Barley – 64 – – – Corn – 68 – – – Tab. 8. Simple correlation coefficient between the soil parameters, the chemical composition (Ca/P, Ca/Mg, CF: % crude fiber and CP: % crude protein) and the nutritive variables (DCP: digest- ible crude protein, DE: digestible energy and ME: metabolized energy) of the aboveground parts of the studied wild P. turgidum populations; · significant, P < 0.05; ·· very significant, P < 0.01; and ··· highly significant, P < 0.001. Plant materials Soil parameters pH OM CaCO3 Silt Mg K HCO3 P Chemical composition Ca/P –0.31 0.50 · –0.08 0.47 · 0.24 0.4 0.34 0.34 Ca/Mg –0.5 · 0.15 –0.06 0.02 0.45 · 0.45 · 0.17 0.27 CF 0.09 –0.03 –0.74 ·· –0.27 0.19 0.1 0.2 0.23 CP 0.3 –0.24 0.4 0.04 –0.41 –0.4 –0.51 · –0.4 Nutritive variables DCP 0.3 –0.24 0.4 0.04 –0.41 –0.4 –0.51 · –0.4 DE –0.09 0.15 –0.26 0.07 0.3 0.33 0.29 0.46 · ME –0.09 0.15 –0.26 0.07 0.3 0.33 0.29 0.46 · U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:36 Color profile: Disabled Composite 150 lpi at 45 degrees from the food energy and the losses through urine and methane, the reminder is called me- tabolized energy (ME) or assimilation energy (DRODZ 1975). The mean of gross energy (GE), digestible energy (DE) and the metabolized energy (ME) of the studied wild popula- tions of P. turgidum (Tab. 7) was higher than mean of the natural forage in the western Med- iterranean coastal rangelands (HENEIDY not published). The principal components analysis (PCA) applied to the chemical composition and nu- tritive variables data of the studied P. turgidum populations showed that the first three vec- tors accounted for 92.7% of the total variance (14.98). The contribution of the investigated variables in the variation accounted for by the first three vectors was limited to a number of variables including ash, crude protein, carbohydrate contents (NFE), total digestible nutri- ents (TDN) and Ca/P ratio content of the plant materials (Tab. 9). PC1 expressed the great- est proportion of variation (42.8% of the total variance) with an eigenvalue of 6.41. It was related to ash, carbohydrate contents, organic matter, total digestible nutrients and Ca/P ra- tio content of the plant materials (Tab. 9). PC2 accounted for 32.8% of the variation with an eigenvalue of 4.91. It was related to crude protein, carbohydrate contents and Ca/P ratio content of the plant materials. PC3 accounted for 17.1% of the variation with an eigenvalue of 2.56. This PC corresponded to the crude protein, total carbohydrates, total digestible nu- trients and Ca/P ratio content of the plant materials. When these three vectors were used as axes for the scatter diagram (Fig. 5) of the examined populations the same grouping was obtained as that of the cluster analysis of the P. turgidum studied populations using the chemical composition and nutritive variables data exemplified by the dendrogram result- ing from the complete linkage method of sorting (Fig. 6). The studied populations were ACTA BOT. CROAT. 68 (1), 2009 141 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Tab. 9. The loadings of the chemical composition and nutritive variables of the studied wild P. turgidum populations on the first three eigenvectors of the PCA analysis (*Values of the character with major contribution in the three vectors). Character Eigen vectors PC1 PC2 PC3 Ash *–0.50 0.2 –0.21 CF 0.02 –0.02 –0.02 CP 0.05 *0.29 *0.74 EE 0.04 –0.036 –0.12 NFE *0.39 *–0.43 *–0.39 OM *0.50 –0.2 *0.21 TDN *0.34 –0.1 *0.25 DCP 0.02 0 0.01 GE 0.02 –0.01 0.01 DE 0.04 –0.03 –0.11 ME 0.02 0 0.01 NE 0.01 0 0.01 NR 0 0 0 Ca/Mg 0.02 0 0.02 Ca/P *0.48 *0.80 *–0.36 U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:37 Color profile: Disabled Composite 150 lpi at 45 degrees separated into two main groups »I« and »II« at 0.97 dissimilarity distance. Group »I« in- cluded populations 2, 3, 4, 5, 6, 7, 8, 9, 11, 16, 17, 18 and 19, while group »II« included populations 1, 10, 12, 13, 14 and 15. Group »I« was split into two subgroups »A« and »B« at 0.81 dissimilarity distance. Subgroup »A« included populations 2, 3, 4, 5 and 6, while subgroup »B« included populations 7, 8, 9, 11, 16, 17, 18 and 19. The results obtained from applying both classification and ordination numerical analyses separated the studied wild P. turgidum populations into two major groups (I and II) on the basis of eight characters (the ash, crude fiber, crude protein, total carbohydrates, organic matter and digestible crude pro- tein content and Ca/P ratio). While group »II« included six populations (five populations 142 ACTA BOT. CROAT. 68 (1), 2009 HENEIDY S. Z., HALMY M. W. Fig. 5. Three-dimensional scatter plot of the first three eigenvectors of the PCA analysis based on data of chemical composition and nutritive variables of the studied wild P. turgidum popula- tions. The solid line enclosed the main groups (I and II). The dashed line enclosed the two subgroups (A and B) differentiated within group I. Fig. 6. Dendrogram resulted from application of complete linkage method of sorting, using chem- ical composition and nutritive variables of the studied wild P. turgidum populations. U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:37 Color profile: Disabled Composite 150 lpi at 45 degrees collected from south Sinai-Gulf of Aqaba coastal plain and one population from north Si- nai) characterized by the lowest ash content, highest crude fiber, organic matter, total di- gestible nutrients content. Group »I« comprised the rest of the studied populations with rel- atively high nutritive value (higher protein, fat, carbohydrates and mineral content together with lower fiber content). Group »I« was further subdivided into two subgroups (»A« and »B«). Subgroup »B« was distinguished by having the highest values of carbohydrates, crude protein, digestible crude protein and energy content. Moreover it is characterized by low crude fiber contents and Ca/P ratio. This group included eight populations collected from Wady El-Natrun, Eastern desert, north Sinai and south Sinai. It is evident that sub- group »B« comprised populations posses the best nutritive characters concerning low fiber content, high crude protein, carbohydrates and ash content. The variation in the nutritive value among the studied populations may be attributed to the effect of some edaphic pa- rameters. The variations in EC, organic matter content, calcium, potassium, bicarbonate, chloride, and phosphorous content of the soil were significant among the three groups (Tab. 10). It worth noting that, the variation in the nutritive value among the cultivated popula- tions was insignificant. All the cultivated populations acquired high nutritive value, which in- dicate the effect of edaphic factors exerted on the wild population nutritive value as was illus- trated also from the correlation between some edaphic factors and some nutritive variable. Despite the variation in the edaphic, climatic and other factors such as grazing pressure factors among the studied phytogeographical regions, there was slight variation in the chemical composition and the nutritive variables of the studied populations, especially in the content of the organic constituents. However this did not significantly affect the nutri- tive value of the plant across the different studied populations. These relatively low varia- ACTA BOT. CROAT. 68 (1), 2009 143 PANICUM TURGIDUM IN THE EGYPTIAN DESERT Tab. 10. One way-ANOVA testing the significance of variation in the soil characteristics among the main groups resulting from the cluster analysis of the studied wild P. turgidum populations; ·significant, P < 0.05; ·· very significant, P < 0.01; and ··· highly significant, P < 0.001. Soil characters F-Value EC (mmohs cm –1 ) 4.5 · pH 2.1 (%) OM 4.4 · Sand 3.2 Silt 2.9 Clay 2.2 CaCO3 3 (mg/100g) Ca 3.9 · Mg 0.3 Na 3.5 K 8.4 ·· HCO3 7.3 ·· Cl 4.0 · SO4 1.0 P 11.2 ·· U:\ACTA BOTANICA\Acta-Botan 1-09\Heneidy.vp 16. travanj 2009 12:42:37 Color profile: Disabled Composite 150 lpi at 45 degrees tions in the nutritive value among the investigated populations indicate the considerable plasticity of the studied species to the environmental conditions. However, a notable differ- ence was recorded between the wild and cultivated P. turgidum populations, in the chemi- cal composition and the nutritive variables. The cultivated populations attained higher lev- els in crude protein, fats, carbohydrates, digestible crude protein and lower crude fiber content than the wild populations (Tab. 5 and 7). Based on the value of DCP and net energy, considering the scale suggested by BOUDET and RIVIERE (1968), P. turgidum has good or ex- cellent forage quality. 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