Response of root production to different restoration measures in a degraded meadow

Belowground parameters, e.g. root production and dynamics, play a pivotal role in evaluating the restoration degree of degraded grasslands. However, it remains unclear how roots respond to the combined restoration measures. To investigate root responses to different restoration treatments, a field experiment was conducted in a degraded Songnen meadow from 2013 to 2014. The treatments included: free grazing (FG), no ploughing (NP), only ploughing (OP), ploughing and fertilizer (PF), ploughing and mulching (PM), ploughing with fertilizer and mulching (PFM). Our results showed the seasonal dynamics pattern of roots was a unimodal pattern, which mainly was influenced by precipitation rather than restoration measures. The impacts of different restoration measures on root production were dependent on precipitation. In 2013, compared with FG, only PFM significantly increased root production by 242.34% (0–10 cm) and 90.8% (10–20 cm), which was mainly attributed to the increase of aboveground net primary production, soil moisture and root numbers. However, restoration measures had minor effects on root production in 2014. Root turnover ranged from 0.47 to 0.78 yr−1 and was not significantly changed by different restored measures. This is because the dominant annual species, Chloris virgata, exhibited relatively small changes in root turnover across different plots. Moreover, PFM improved soil conditions, leading to increased root lifespan and survival rate. Our results suggest that the combined measures are an effective way to accelerate belowground restoration in the degraded Songnen meadow.