Tree Wind Breaks in Central Asia and Their Effects on Agricultural Water Consumption

Thevs, N., et al., 2019. Land

Original research (primary data)
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Abstract

Across Central Asia, agriculture largely depends on irrigation due to arid and semi-arid climatic conditions. Water is abstracted from rivers, which are largely fed by glacier melt. In the course of climate change, glaciers melt down so that a reduced glacier volume and reduced water runoffs are expected to be available for irrigation. Tree wind breaks are one option to reduce water consumption in irrigated agriculture and build resilience against climate change. This paper therefore assesses the water consumption of major crops in Kyrgyzstan and adjacent areas, i.e., cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.), corn (Zea mays L.), rice (Oryza sativa L.), potato (Solanum tuberosum L.), and barley (Hordeum vulgare L.) in combination with tree wind breaks. Crop water consumption was assessed through the Penman Monteith approach. Tree wind break types investigated were single rows from poplars (Populus spec.) and multiple rows with understory vegetation by elm (Ulmus minor L.) and poplar, respectively. Tree water consumption was determined through sapflow measurements. The seasonal reference evapotranspiration (ETo) for field crops was 876-995 mm without wind breaks and dropped to less than half through multiple row wind breaks with understory vegetation (50 m spacing). Tree water consumption was 1125-1558 mm for poplar and 435 mm for elm. Among the wind break crop systems, elm wind breaks resulted in the highest reductions of water consumption, followed by single row poplars, at spacing of 50 and 100 m, respectively. However, elm grows much slower than poplar, so poplars might be more attractive for farmers. Furthermore, single row wind breaks might by much easier to be integrated into the agrarian landscape as they consume less space.

Case studies

Basic information

  • Case ID: INT-255-1
  • Intervention type: Created habitats
  • Intervention description:

    "The tree wind break was composed of elm (Ulmus minor) and Acacia spec., with berry shrubs as understory vegetation (Figure 2). The tree wind in the 81◦–261◦ direction in order to shelter against the prevailing south winds, which come down from the nearby Tianshan Mountains (Figure 1). The average tree height of the shelterbelt was 10 m. Its crown area was 15 m wide. also looked at multiple rows of poplar (Populus spec. L.) "

  • Landscape/sea scape ecosystem management: No
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Reduced water availability  Mixed results Water availability: Water consumption (evapotranspiration - mm) of agricultural landscape: wind break plantations + cropland. Measure other factors such as changes in wind speed, evapotranspiration, temperature but these are used to elucidate how exactly the wind breaks may contribute to altering the water consumption of the system (e.g. by reducing wind speeds, evapotranspiration decreases).  Mixed effectiveness
  • Approach implemented in the field: Yes
  • Specific location:

    Temen Suu [village] is located on an elevation of 941 m in the plain north of the Tianshan Mountains.

  • Country: Kyrgyz Republic
  • Habitat/Biome type: Created forest |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: "Effectiveness determined by comparing to reference sites that do not have the intervention (wind breaks) acting as a control Mixed effectiveness because varies depending on species and size of the plantations (e.g. the 50 × 50 m grid of the poplar multiple row wind break consumed so much water that the overall water consumption of barley, potato, or wheat combined with such a multiple row poplar wind break system was higher than water consumption of the crops without a wind break ... The water consumption of elm trees is much lower than that of poplars, which explains the low water consumption of elm tree wind break systems. In particular, with small grid sizes (up to 200 × 200 m) the substantial reduction wind speed in combination with low water consumption of elm trees resulted in an overall low water consumption of these systems.)"
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Other non-NbS approach(s)
  • 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: Please select
  • 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: