A novel application method of dung in restoring a degraded meadow steppe of Northern China

Abstract The rapid increase in amount of dung by intensive livestock feeding has caused serious environmental problems. Natural grasslands are limited by nutrients’ availability while the dung contains nutrients that cannot be directly used by plants. The lack of effective way to release the plant available nutrients from dung greatly limits the use of dung in an environmentally friendly way. We developed a novel methodology to effectively use dung in restoration of degraded grasslands by applying dung with urea and decomposition inducer in a field experiment. We further explored the mechanisms underlying the positive effect of the combined application of dung, urea and the inducer on a degraded grassland by monitoring changes in soil, plant and community characteristics for three consecutive years under combined application of urea and dung (UD), urea, dung and decomposition inducer (UDI), and no application as control (CK) in a degraded meadow steppe in Northern China. Application of UD and UDI significantly increased soil moisture, soil total nutrients, available macronutrients, and vegetation indexes. Soil nutrients and vegetation indexes were significantly higher by application of UDI than that of UD. Soil moisture was found to be a main driving factor in aboveground biomass for each treatment. In contrast, aboveground biomass was positively related to both soil moisture and soil nutrients in each experimental year, regardless of treatments. When all data were pooled as a whole, structural equation modeling analysis indicated that the UDI-induced increase in aboveground biomass was achieved by both increasing soil moisture, and soil total nutrients and available nutrients. The inducer can accelerate dung decomposition and enhance release of nutrients from dung to soil, thus contributing to restoration of degraded grasslands. Our results demonstrate a novel way to directly use dung by combining application of urea, dung and decomposition inducer in restoration of degraded meadow steppe.