Estimation of the yield using plant dimensions in Artemisia sieberi and Dorema ammoniacum, (case study: Dare Baz Sarayan rangeland, South Khorasan province, Iran)

Abstract

Determining an appropriate method for measuring plant yield is useful in estimating the grazing capacity of rangelands. The method of determining yield through plant dimensions is a fast and low-cost method, but may not be used according to the vegetative  structure of the plant. Therefore, this research aimed to estimate the plant yield via linear regressions of canopy cover, height, and volume as (dependent variables) in two species of Artemisia sieberi and Dorema ammoniacum in Dare Baz rangelands of Sarayan, south Khorasan province in Iran in 2021. Six parallel transects 50 m long with 10 m distance from each other were established. Random sampling method was done along transects using 30 plants in all 6 transects. Plant height, plant diameter (small diameter perpendicular to the large diameter), canopy cover, canopy volume, and yield of each plant were measured. Data were entered into R software. The relationship between yield and the other variables was estimated using correlation and regression analysis. The results showed that there was a significant linear relationship between all three estimators and yield in both plant species (p < 0.01). Meanwhile, the best relationships between canopy volume and yield were obtained in both species. The R2 values between canopy volume and yield were 0.71 and 0.60 for A. sieberi and D. ammoniacum, respectively. On the other hand, based on the obtained R2 value, the estimation of the yield through the plant dimensions was an efficient method in A. sieberi than to D. ammoniacum.