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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (1): 26-35.DOI: 10.11686/cyxb2020517

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Effects of different restorative measures on soil carbon and nitrogen and their component fractions in a degraded desert steppe

Xing WANG1(), Shuang YU1, Dong-mei XU1,2(), Ke-chen SONG1   

  1. 1.Agricultural School of Ningxia University,Yinchuan 750021,China
    2.State Key Laboratory Breeding Base of Land Degradation and Ecological Restoration of Northwest China,Ningxia University,Yinchuan 750021,China
  • Received:2020-11-24 Revised:2021-01-12 Online:2021-12-01 Published:2021-12-01
  • Contact: Dong-mei XU

Abstract:

This research investigated the impact of three restorative measures on soil carbon and nitrogen fractions in historically overgrazed desert steppe grassland in Yanchi County, Ningxia. The restorative measures investigated were deep tillage+reseeding (SR), shallow tillage+reseeding (QR) and grazing exclusion (i.e. enclosure) (F). Traditional grazing was taken as the control (CK). Measurements made included soil organic carbon (SOC), total nitrogen (TN), particulate organic carbon (POC), readily oxidizable organic carbon (ROC), microbial biomass carbon (MBC), nitrate nitrogen (NO3--N), ammonium nitrogen (NH4+-N) and microbial biomass nitrogen (MBN) for the 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm soil layers. It was found that: 1) For the QR treatment, soil SOC content (5.50-9.93 g·kg-1), soil TN content (0.17-0.23 g·kg-1), soil ROC content (0.53-0.99 g·kg-1) and soil MBN content (62.82-73.20 mg·kg-1) were generally higher than in other treatments. 2) Soil MBC content (386.00-481.80 mg·kg-1) and the proportions of each component of carbon and nitrogen in SOC and TN were generally higher in the F treatment. 3) Soil POC, NH4+-N and NO3-N contents were decreased under the various restorative treatments compared with the CK treatment. 4) The contents of POC, NH4+-N and NO3--N in each soil horizon were also decreased under the various restorative measures, compared with the CK treatment. Correlation analysis showed that SOC content was significantly positively correlated with TN and ROC content (P<0.01), and significantly negatively correlated with MBC content (P<0.05). Based on soil carbon and nitrogen fixation and preservation data, shallow tillage+reseeding was the most effective restorative measure for the degraded desert steppes in this study.

Key words: restoration measurements, soil organic carbon, soil total nitrogen, soil carbon and nitrogen fractions