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.
Seid ali Hoseini; Mansur Mesdaghi; Cerkis Pambokhchyan
Volume 18, Issue 4 , September 2012, , Pages 637-651
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 shrubland in Sar-Aliabad 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 shrubland in Sar-Aliabad summer rangelands of Golestan province. In representative stands of each vegetation type, eighty 1-m2 plots were clipped and weighed. In double sampling method, 16 plots were estimated and clipped. In comparative yield method, standard (reference) plots were used as the highest yield belonged to the reference plot 5 and the lowest yield belonged to the reference plot 1. A highcorrelation was found between estimated and clipped plot in double sampling method. There was also high correlation between reference plots and their weights, so estimation of double sampling and ranks of comparative yield method were corrected by using regression equations. There were no significant differences among 3 methods, but time consumption of double sampling was better than the other methods. So, because of extensive application of double sampling method in grasslands and shrublands and its high accuracy and precision this method of yield estimation is recommended for the study area.