Jäschke, Yun; Oyunbileg, Munkhzul; Uuganjargal, Khaliun; Oyuntsetseg, Batlai; Wesche, Karsten; Ritz, Christiane; Oyundelger, Khurelpurev (2026): Aboveground biomass amount, nitrogen content, digestibility of biomass in eastern Mongolian steppe in 2019 and 2020 [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.993583 (DOI registration in progress)

Seasonal aboveground biomass data was collected from non-fenced area using 1 m × 1 m sampling quadrat at 63 sites in central and eastern Mongolian steppes. In each quadrat, living and standing dead aboveground plant material was clipped at ground level. Summer sampling was conducted between mid-July and August and thus during the peak growing season. Autumn sampling was done from mid- to end of September in 2019 and 2020, while spring sampling was only conducted at end of May in 2020 for part of study sites. From each quadrat, we also recorded species vascular plant richness and estimated the total cover of vegetation and the proportion of cover of each functional group, i.e., graminoids (grasses and sedges), shrubs, subshrubs, forbs. Air dried biomass samples from different functional groups were further analyzed for N concentration using a CN analyzer, and community-weighted means of the plant N content were calculated by the share of the dry biomass weight. Crude protein content and yield were further calculated. Water content of total biomass was calculated based on the difference of fresh and oven-dried weight of the total aboveground biomass. Organic matter digestibility of forage ingested based on the fecal CP content was calculated based on equation which was established for sheep on similar steppe condition of Inner Mongolia (Wang et al., 2009). Top-soil samples (0-5cm) were measured for soil pH and EC in a soil water suspension (soil : water ratio = 1:5). Soil total carbon and nitrogen measured by a CN analyzer. We used the Olsen P method (Sims, 2000) to extract the amount of plant available phosphorus. Phosphorus contents in the soil extracts were measured by spectrometry. The content of inorganic C, i.e., carbonate, was first assessed with a quick test using 10 % HCl, and we further analyzed samples which showed significant reactions using a calcimeter following Scheibler's method. Contents of organic C contents were then calculated by deducting inorganic C contents from total C content. A subsample of approximately 1 g of air-dried soil was oven-dried at 105°C for 24 h to determine rest water in the soil. Contents of C, N and aP were corrected for rest water content, and expressed based on oven-dried soil. We aimed to reveal seasonal dynamics of forage availability (biomass amount, N content, CP content/ yield, digestibility, water content) and to evaluate the relative effects of climate, soil chemistry, and grazing on it.