Evaluation of Different Seed Mixtures for Grass Establishment to Mitigate Soil Erosion on Steep Slopes of Railway Batters

Fox, J. L., et al., 2011. Journal of Irrigation and Drainage Engineering

Original research (primary data)
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Abstract

Unpredictable rainstorms can pose greater risks of soil erosion on newly formed unprotected railway batters. A bioengineering approach consisting of revegetation can be an effective tool for soil-erosion control. Perennial species, such as buffel grass, are preferred for durability of vegetation cover in the arid and semiarid tropics. However, it takes a longer time to establish buffel than annual species such as Japanese millet (JM). A replicated plot-scale field trial consisting of different proportions of grass-seed mixtures of buffel and JM was conducted on railway-batters slope in the semiarid tropics of central Queensland, Australia. A supplementary automated drip irrigation system was set up to aid seed germination and early establishment of the grass cover. JM alone or JM-dominated seed mixtures significantly reduced soil erosion during the earlier stages. For example, during the second sampling interval (SI), which occurred 63 days after seeding, JM alone reduced soil erosion by 50% (20.2 versus 10.21 t/ha) in comparison to the sole buffel. This trend began to shift as the growth of buffel commenced at the latter stages. By the end of the 11 months, erosion from all seeded plots was not significantly different among the plots with more than 90% soil-loss reduction in comparison to the bare scenario, resulting in more than 60% grass cover. Results suggested that a monoculture of JM or JM-dominated seed mixture with buffel grass could be an effective bioengineering approach for revegetation of railway batters for protection against soil erosion. Quick establishment owing to faster seed germination, seedling establishments, and growth-producing sizable canopy cover developed by JM in the early stage of batter could reduce soil erosion in comparison to a sole crop of slow-growing perennial species buffel. The established vegetation self-regenerated and responded dynamically and naturally to changing conditions of the railway batter within a year, after which JM started to die back.

Case studies

Basic information

  • Case ID: INT-193-1
  • Intervention type: Created habitats
  • Intervention description:

    Seeds were uniformly sown (30gm 2) by hand spreading. Treatments consisted of monoculture (sole) or a mixture (by weight ratio) of Japanese Millet and buffel grass.

  • Landscape/sea scape ecosystem management: No
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Soil erosion  Mixed results Mean and cumulative soil erosion (t/ha)
  • Approach implemented in the field: Yes
  • Specific location:

    The experiment was conducted on the Gregory railway line located approximately 25 km west of Blackwater (23°32′10.31′′S; 148°41′ 52.15′′E, altitude 172 m), Central Queensland, Australia.

  • Country: Australia
  • Habitat/Biome type: Created grassland |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: Effectiveness compared to unplanted bare ground control Results mixed because in some of the plots with certain species, initially erosion was worse than the controls
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures: N/A
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures: N/A
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: