Seyed Ali Hossaini; Mansour Mesdaghi
Volume 20, Issue 1 , June 2013, , Pages 23-37
Abstract
To find an accurate and rapid method of estimating herbage standing crop, clipping and weighing, double sampling, and comparative yield methods were compared in two vegetation types of grasslands and one cushion shrub land in Sar-Ali abad summer rangelands of Golestan province. In representative stands ...
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To find an accurate and rapid method of estimating herbage standing crop, clipping and weighing, double sampling, and comparative yield methods were compared in two vegetation types of grasslands and one cushion shrub land in Sar-Ali abad summer rangelands of Golestan province. In representative stands of each vegetation type, eighty 1-m2 plots were clipped and weighted. In double sampling, 16 plots were estimated and clipped. In comparative yield method, standard (reference) plots were used as the highest and the lowest yield were recorded for the reference plot 5 and reference plot 1, respectively. There was high correlation between estimated and clipped plots in double sampling. There was also high correlation between reference plots and their weights; therefore, the estimation of double sampling and the ranks of comparative yield method were corrected by using regression equations. There were no significant differences among 3 methods, but the time consumption of double sampling was better than the other methods. Given the widespread use of double sampling method in grasslands and shrub lands and also its high accuracy and precision, this method is recommended for the study area.
Najmeh Faryabi; Mansour Mesdaghi; Gholam ali Heshmati; Nemat alah Madadi Zadeh
Volume 19, Issue 3 , December 2012, , Pages 421-431
Abstract
Knowledge on floristic composition is one of the most important factors in management of rangeland utilization. Improper utilization of rangelands and lack of attention to the ecological potential of range habitats is the main reason for rangeland degradation. In this study, floristic composition and ...
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Knowledge on floristic composition is one of the most important factors in management of rangeland utilization. Improper utilization of rangelands and lack of attention to the ecological potential of range habitats is the main reason for rangeland degradation. In this study, floristic composition and canopy cover of the species of reference area (exclosure), key area (with mid grazing) and critical area (with over grazing) were considered and three areas were compared together. Ranking of the canopy cover percentage was performed through Van-der-Maarel
method and counting the number of the species was carried out using a systematic-random method. According to the obtained results, three relations were obtained as follows: Major biological forms: Therophyte> Hemicriptophyt> Chamophyte> Geophyte> Phanerophyte; Dominant growth form: Herb> shrub> grass> tree; Vegetation ranking based on canopy coverer: reference> key> critical area. In the critical area, due to over grazing and out of grazing season, canopy cover was strongly reduced and plant palatability decreased.