effect of wheat straw biochar and lignite on nutritional value of nitraria schoberi and astragalus podolobus in greenhouse condition

Most of rangeland soils are limited in their ability to supply adequate nutrients to plants. soil conditioners have shown to alter soil fertility and plant characteristics. this investigation aims to evaluate the influence of two soil conditioners on nutrition value of n. schoberi and a. podolobus. for this, two separate experiments for each species were carried out in a greenhouse using a completely randomized design with three replications during 2018 and 2019. treatments had four levels of wheat straw biochar (wsb) as well as lignite at rates of 0, 1.25%. 2.5% and 3.75% w/w added to clay loam soil. in the end of vegetative stage and before flowering, plant samples were taken and their crude protein (cp) and acid detergent fiber (adf) content were measured and then, dry matter digestibility (dmd) and metabolizable energy (me) were calculated. data were analyzed by one-way analysis of variance (anova) and the means were compared using duncan's test. the results demonstrated that wsb addition had no effect on nutrition value of both species. by application of lignite, cp content of n. schoberi enhanced up to 44.45% more than that for control. the effect of lignite addition on nutrition value traits was high for n. schoberi. but this material had no effect on a. podolobus quality traits. based on our findings, application of lignite at 3.75 (w/w) was recommended to improve soils of rangeland for cultivation of n. schoberi in dry-land plantation projects or the conversion of dry lands to arable pastures.