comparison of different methods to estimate forage production of two shrub species halocnemum strobilaceum (pall.) bieb and halostachys caspica c. a. mey (case study: winter rangelands of golestan province, iran)

Proper range management needs an accurate and updated method of rangelands production measurement. in range production measurements, selecting an accurate and low-cost method is very important. in the present study, three estimation methods including adelaide technique, and double sampling using the 20 and 30% of vegetation cover were compared with clipping and weighing method (as control) in two shrub species of halocnemum strobilaceum (pall.) bieb and halostachys caspica c. a. mey (in may 2017). in each vegetation area, two 300m length transects with 100m distance randomly were placed. data were collected from 15 quadrates 4m² along each transect systematically. in each plot, the vegetation cover and yield of two species were estimated and harvested. data were analyzed regarding variance for each species and means comparison was done using duncan method. regression analysis was performed for each method between the estimated and actual clipping rates. the result showed that in h. strobilaceum, there were no significant differences between both double sampling with 20% and 30% and control. but higher estimation was obtained by adelaide method than control. for h. caspica, there was no significant difference between both adelaide and double sampling 30% with control. but the yield estimation of double sampling 20% was significantly higher than control. also, the regression relationship was well matched to the data. it was concluded that the double sampling method was more suitable for h. strobilaceum species due to its symmetrical diameter of the canopy. the adelaide method was recommended for h. caspica, which has separate foliage.