Comparison of plant litter quality in three range plant species and its relationship with soil characteristics

Despite the importance of litter quality in soil conservation and stability, improvement of soil chemical properties, and increasing forage production in the rangeland ecosystem, very few studies have been carried out on the litter quality of range plant species and most studies on plant quality are limited to forage quality of plants in rangeland. This study aimed to measure and compare the litter quality of three range plant species, i.e., Artemisia aucheri, Centaurea virgata and Scariola orientalis and its relationship with some physico-chemical characteristics of soils in Hajibeyggi rangeland, Torbat Heidarieh, eastern Iran. Plant litter was sampled through systematic-randomize sampling method on three transects with a length of 200 meters and 1 m2 quadrat. One litter sample of plant species along with one soil sample was collected from 0-15 cm depth in each plot. Parameters related to litter quality including phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), phenol and lignin were measured by standard methods. Also, soil characteristics including texture, lime percentage, EC, bulk density, pH, phosphorus (P), potassium (K) and organic carbon were measured by standard methods. One-way ANOVA was used to compare the litter quality of species and Duncan test was used to separate means with significant difference. The relationship between litter quality and soil characteristics was investigated using Pearson correlation. The highest amount of P was in litter and dead materials of C. virgata, the highest amount of K was in A. aucheri and the highest amount of lignin was in S. orientalis. The highest amount of soil P, lime, silt, clay, clay+silt, pH, organic carbon and bulk density was found under A. aucheri canopy and the highest amount of K and gravel under S. orientalis canopy. The amount of calcium in A. aucheri litter was significantly correlated with soil lime, and its Mg content was related to soil EC and pH. The amount of P in C. virgata litter was significantly correlated with soil pH, and its K content was related with soil gravel, silt and clay + soil silt. The amount of P in S. orientalis litter was significantly correlated with soil K, organic carbon, lime, clay, silt, sand and silt. Lignin and phenol are anti-quality chemical consitituents in plant litter and dead materials. Mean values of lignin in all plant species were similar, but the quantity of phenol in the litter of A. aucheri was higher than that in other two species. The amount of Mg and Ca were also similar in all plant species, but mean value of P in C. virgate was greater than that in other two species. It was not found clear relationships between litter quality and soil physico-chemical variables in this study.