ABSTRACT We investigate the effects of three different restoration methods on key restoration success indicators in degraded desert steppe ecosystems in Northern China over a 5 years period. However, the relative contribution of physical stabilization versus combined organic amendments in restoring plant–soil interactions and overall ecosystem functioning in severely degraded desert steppes remains insufficiently understood. To address this knowledge gap, we compared restoration treatments with increasing levels of vegetative and organic inputs: (1) sand barriers alone (SB), (2) SB + Caragana korshinskii litter addition (SB + LA), and (3) SB + LA + organic fertilizer (SB + LA + OF). We show that plant cover and soil properties increased significantly in response to restoration treatments that used organic inputs into the soil, although the treatments differed in their specific effects. Most of the restoration indicators were unresponsive to the SB treatment though. By the end of the experiment, plant cover had increased by 103.42% and 58.75% with respect to initial values in SB + LA and SB + LA + OF respectively. Soil nutrients (carbon, nitrogen, phosphorous, and potassium) showed a similar pattern, increasing only in the treatments that included external inputs. SB + LA and SB + LA + OF differed in their effects on soil microbial populations, so that SB + LA + OF produced a considerably higher number of soil microbes than those observed in SB + LA. Our results show that physical stabilization of soils alone, in the harsh and poor‐nutrient conditions of our highly degraded ecosystems, is not enough to support a robust plant cover. They also show that addition of organic fertilizers together with litter does not enhance plant cover nor soil nutrient contents, so that the addition of organic fertilizers has to be evaluated in terms of site conditions and economic costs. A simple cost–benefit analysis shows that the combination of simple sand barriers and plant litter constitutes a feasible method for improving soil and plant cover in highly degraded desert steppe ecosystems.
Qu et al. (Thu,) studied this question.