JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2021, Vol. 45 ›› Issue (6): 127-134.doi: 10.12302/j.issn.1000-2006.202101035

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Effects of interplanting herbage on surface runoff associated with nitrogen and phosphorus losses in Camellia oleifera plantations

CHEN Longsheng1(), MEI Li2,*(), CHEN Yongzhong1, ZHAO Zeyao2, XU Yanming1, ZHANG Zhen1, HU Yajun3, LIU Caixia1, SU Yirong3   

  1. 1. National Engineering Research Center for Oil-tea Camellia, Hunan Academy of Forestry, Changsha 410004,China
    2. College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Hubei Engineering Technology Research Center for Forestry Information, Wuhan 430070, China
    3. Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125,China
  • Received:2021-01-29 Accepted:2021-07-30 Online:2021-11-30 Published:2021-12-02
  • Contact: MEI Li E-mail:clongsheng@163.com;meili@mail.hzau.edu.cn

Abstract:

【Objective】 This study investigated the effects of interplanting herbaceous plants on surface runoff associated with nitrogen and phosphorus losses in the Camellia oleifera plantation to reduce agricultural non-point source pollution risk and improve downstream water environments. These findings would provide solutions for the efficient ecological management of this economic orchard system.【Method】 Three treatments with three replicates were designed for this experiment: ① non-interplanting as the control (CK), ② interplanting Paspalum notatum (T1), and ③ interplanting Coreopsis basalis (T2). A 5-year-old Camellia oleifera plantation was selected as the study site, which had a high risk of soil erosion because of the low coverage of inter-row grasses. Nine independent 600 m 2 plots were randomly arranged for this experiment. In each plot, a standard runoff monitoring unit with horizontally projected areas (16 m × 7 m) was established. After two years’s growth of sown grass in the C. oleifera plantation, the coverage of inter-row for P. notatum and C. basalis increased to 90.47% and 80.40%, respectively, compared with 31.13% coverage in the control treatment. Based on this background, the soil physical and chemical properties, including soil organic carbon, total nitrogen, and phosphorus, were determined. The surface runoff associated with nitrogen and phosphorus content in each plot from June to July in 2020 was monitored. The variations in surface runoff, soil erosion, runoff dissolved nitrogen (DN), and DN loss in different treatments were compared to determine which grass could provide a better protection from soil erosion and decrease the nitrogen and phosphorus loss.【Result】 After two years of sowing grasses, increasing trends in soil organic carbon, total nitrogen and phosphorus were found both in interplanting P. notatum and C. basalis treatments. Five erosive rainfall events were observed in the study area, from June to July 2020. Compared to the control treatment, both interplanting P. notatum and Coreopsis basalis significantly reduced surface runoff and soil erosion (P<0.05), with the total surface runoff decreasing by 35.04% and 33.56%, and the total soil erosion decreasing by 83.89% and 79.85%, respectively. The variation trends of DN and dissolved phosphorus (DP) concentrations in the different runoff events were not consistent. In the first and second runoff events, the concentration of DN was low and the concentration of DP was high, while in the fourth and fifth runoff events, the opposite results were observed, with high concentrations of DN and low concentrations of DP. The average values of DN and DP concentrations in all observed runoff events exceeded the Class V level of nitrogen and phosphorus in surface water according to the GB 3838-2002 Environmental Quality Standard for Surface Water. Compared with the control treatment, interplanting P. notatum significantly reduced the concentration of DN and DP by 4.67% and 16.88%, respectively (P<0.05). Interplanting C. basalis significantly reduced DP concentration by 16.88% (P<0.05), whereas DN concentration increased by 5.14% (P<0.05). In total, interplanting P. notatum and C. basalis reduced the loss of DN by 26.66% and 21.49% and DP by 63.06% and 50.57%, respectively.【Conclusion】 Both interplanting P. notatum and C. basalis significantly reduced surface runoff, soil erosion, DN and DP loss. Interplanting P. notatum was better than C. basalis for the protection from soil erosion in C. oleifera plantations.

Key words: Camellia oleifera plantation, Coreopsis basalis, Paspalum notatum, nitrogen and phosphorus loss, surface runoff

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