Abstract: Plants can be used for animal grazing in wind erosion control to reduce water flow rates and to increase evaporation and transpiration. In the NW of Iran (East Azerbaijan province), rangelands previously used to animal grazing were changed to agricultural land use; this vegetation is unsuitable vegetation coverage. Researchers studied Chenopodium album to determine its stem biomass characteristics. Data were collected using an accidental sampling methodology (1x1 m). In total, 6 plots were identify and 30 samples were collected for this research. In the minimum, maximum and mean stem biomass for this plant were found to me 1.4, 3.8 and 2.2 g, respectively.

INTRODUCTION

Rangeland ecosystem stabilizing, optimum and continual utilization of the range without studding and knowing the influencing factors on its segments and animal pasturage are of special importance (Bibalani et al., 2011a, b; Mozaffarian, 2007; Shadkami and Bibalani, 2010, 2011). There are different methods of evaluating rangelands and all of them have advantages and disadvantages. Factors such as vegetation species composition, annual production, area coverage, plant density, soil surface coverage, constitution and presence of succulence plants were used (Bidlock et al., 1999; Mogaaddam, 2001) but estimation of these parameters are time consuming and expensive. Fresquez et al. (1990) reported an increase in vegetative production and forage quality of Blue Grama (Mata-Gonzalez et al., 2002). Benton and Wester (1998) reported an increase in Tobosagrass (Hilaria mutica) yield following applications of biosolids at levels of 7, 18 and 34 dry Mg ha^-1 in the Chihuahuan desert. Although, dormant season applications of biosolids seem to be more beneficial for plant growth than growing season applications during the year of biosolids application (Benton and Wester, 1998), explanations for this phenomenon have not been documented (Mata-Gonzalez et al., 2002).

Fig. 1:	Part of Shanjan rangeland in Shabestar district, East Azerbaijan province, Iran

Most evidence is related to its negative effect on aboveground vegetative and reproductive plant biomass (Day et al., 2003; Milchunas and Lauenroth, 1993), changes in the spatial patterning of plant canopies and soil resources (Adler et al., 2001; Bertiller and Coronato, 1994; Callaway, 1995; Schlesinger et al., 1990), the reduction of soil seed banks (Bertiller, 1996, 1998), the decrease in the availability of safe micro-sites for plant re-establishment (Oesterheld and Sala, 1990) and the invasion of woody plants (Milchunas and Lauenroth, 1993; Rodriguez et al., 2007; Schlesinger et al., 1990). Above-ground defoliation can modify the partitioning of assimilates between below- and above-ground organs and consequently the root growth of defoliated plants (Belsky, 1986; Richards and Caldwell, 1985; Rodriguez et al., 2007; Snyder and Williams, 2003). In this research, we have studied the amount of above ground biomass and occurrence of Chenopodium album (Gharaman, 2003) (Fig. 1) at the rangeland area of Shanjan village, Shabestar district, NW Iran. This parameter needs more attention but it is one of the determining factors of rangeland ecosystem.

MATERIALS AND METHODS

The research area is part of Shanjan rangeland in Shabestar district with distance about 5 km from Shabestar city.

Table 1:	Scientific name for Chenopodium album classification report (USDA, 2011)

Fig. 2:	Chenopodium album species

Fig. 3:	Sampling design in 1x1 m plot (Ping et al., 2010); 1-5 is sub-sample in each main sample

The terrain in this area is hilly and researchers carried out the study on a site with a northerly aspect (Bibalani et al., 2011a, b) (Fig. 1). This region is component of Iran-Turan Flora with elevation between 1700-1850 m (Bibalani et al., 2011b). Chenopodium album is a fast-growing weedy annual plant in the genus Chenopodium (Table 1, Fig. 2). It tends to grow upright at first but typically becomes recumbent after flowering (due to the weight of the foliage and seeds) unless supported by other plants. The leaves are alternate and can be varied in appearance. The first leaves near the base of the plant are toothed and roughly diamond-shaped, 3-7 cm long and 3-6 cm broad. The leaves on the upper part of the flowering stems are entire and lanceolate-rhomboid, 1-5 cm long and 0.4-2 cm broad; they are waxy-coated, un-wettable and mealy in appearance with a whitish coat on the underside. The small flowers are radially symmetrical and grow in small cymes on a dense branched inflorescence 10-40 cm long.

In this research, stem biomass has been sampled in May and June, 2010. For sampling, there was used an accidental sampling methodology (1x1 m plot) in this research and selected 30 (6 plots with 5 sub-sample for each of them) samples in total (Ping et al., 2010) (Fig. 3). After sapling from studding area, they have been scaled fresh weight of above ground part of plant with sensitive scale then dried by Avon set in 80°C during 24 h (Ping et al., 2010) and scaled dried weight separately. This study have been research in Shanjan rangeland at Shabestar district in East Azerbaijan, Iran in Summer 2010.

RESULTS AND DISCUSSION

Results from this study showed that the maximum, minimum and medium stem biomass of Chenopodium album in the study area were 1.4, 3.8 and 2.2 g, respectively (Fig. 4). Stem height Chenopodium album was unsteady from 200-800 mm that average of it is about 450 mm.

Fig. 4:	Chenopodium album stem weight (fresh and dried weight)

In total of 6 plots were identified and 30 samples were studied in this research. From 30 samples about 69.44% of stem weight was lost when samples were dried. Vegetation species can have an effect on soil chemical and physical properties (Ardekani, 2003). Increasing Chenopodium album species in the study area could cause specific biological qualification and as this species increasing density of aboveground biomass will increase and also the amount of soil protection and stabling will increase specially protection with wind erosion and soil lost with runoff (Bibalani et al., 2011a, b; Shadkami and Bibalani, 2010, 2011). Study on this plant over ground biomass is so much important information, especially for medicinal plant. Bibalani et al. (2010) have been studied and recognized some medicinal plant of Ilkhji region, Eastern Azerbaijan province (Northwestern Iran).

In this study, researchers examined the biomass of this plant and results suggest that changes in the above-ground cover of this plant affect by grazing or soil compaction with animal at this area as found in other studies (Bibalani, 2011a-c; Rodriguez et al., 2007; Shadkami and Bibalani, 2010, 2011) and the difference of wet weight and biomass of this plant would be expected in this area (Bibalani, 2011a-c; Shadkami and Bibalani, 2010, 2011).

CONCLUSION

This study has revealed and quantified the stem biomass of the Chenopodium album in the Shanjan rangelands, the plant has good biomass in this research area and probably also in other areas where the Chenopodium album is growing that need studding separately in another areas. It is a pioneer study and the results have given estimations of the stem biomass of the Chenopodium album for the 1st time in Shanjan rangeland.

It is needed for studying this and other shrub species in the area and could be used in identifying plants best suited for rangeland ecosystem stability and specifically for stabilizing surface soil layers, especially from water and wind erosion.

ACKNOWLEDGEMENTS

The researchers greatly acknowledge the scientific support from the Islamic Azad University-Shabestar Branch to the first researcher in this study. This study is a part of a project entitled Study on Root Development Forbs and Shrubs on Shanjan Range of the Shabestar area and their effects on soil surface and sub-surface erosion with Project No. 51955880630001. The researchers also express their sincere appreciation to the anonymous reviewer(s) for their help to improve the study quality.