Transpiration and early growth of tree plantations established on degraded cropland over shallow saline groundwater table in northwest Uzbekistan

Khamzina, A., et al., 2009. Agricultural and Forest Meteorology

Original research (primary data)
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Abstract

This study examined the early growth and water use of tree plantations established on a marginalized irrigated cropland in northwest Uzbekistan, where salinization of agricultural soils is widespread due to shallow saline groundwater tables. During the first two growing seasons in 2003-2004, the tree stands consisting of Elaeagnus angustifolia L., Populus euphratica Oliv., and Ulmus pumila L. were irrigated with 80 mm year(-1), and, in 2005, were left to rely on the shallow (0.9-2.0 m deep) groundwater with a salinity of 1-5 dS m(-1). Soil salinity increased but remained within the range of moderate-to-strong (4-14 dS m(-1)) during the three years. In the course of the growing season, plantations transpired 0.1-7 mm day(-1) in 2003 and 1-13 mm day(-1) in 2004-2005, as determined with the Penman-Monteith model. In the absence of irrigation, the annual stand transpiration averaged 1250, 1030, and 670 mm for E. angustifolia, P. euphratica and U. pumila, respectively. In 2005, the leaf area index of E. angustifolia ranged from 5 to 10, surpassing that of the other two species more than two-fold. Differences in canopy conductance and transpiration were significant among the tree species and the decoupling coefficient at no time exceeded 0.3, indicating strong physiological control of transpiration. The vigorous juvenile growth and high transpiration under deficit irrigation and after irrigation was terminated, suggested that afforestation with well-adapted tree species is a viable land use option for degraded cropland. The plantation responses to increasing soil salinity must be monitored to determine potential leaching demands in the long run.

Case studies

Basic information

  • Case ID: INT-204-1
  • Intervention type: Created habitats
  • Intervention description:

    experimental tree plantation established on degraded cropland The irrigation treatments included: (1) drip irrigation applied at a ‘‘deficit’’ rate (80 mm year 1), (2) drip irrigation applied at a ‘‘full’’ rate (160 mm year 1), and (3) traditional furrow irrigation applied at the deficit rate. The furrow irrigation was applied fortnightly whereas the deficit and full drip applications were scheduled respectively once and twice a week. The irrigation took place only during the first two growing seasons (2003–2004) and was ceased thereafter. The plantations consisted of two local species, Russian olive (Elaeagnus angustifolia L.) and Euphrates poplar (Populus euphratica Oliv.), both naturally occurring in the riparian forest of Amu Darya delta, and Siberian elm (Ulmus pumila L.), which was introduced during last century and has been widely planted within the irrigated area since.

  • Landscape/sea scape ecosystem management: No
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Biomass cover loss  Positive The growth parameters such as tree height and The leaf area index ... served as indicators of the tree performance during the first two years of plantation establishment
  • Approach implemented in the field: Yes
  • Specific location:

    Khorezm Region of Uzbekistan, at 418650 N latitude, 608620 E longitude (altitude 102 m a.s.l.). The region is an oasis within the transition zone of the Karakum and Kizylkum deserts and located in the lower reaches of the Amu Darya River, about 250 km south of the remainders of the Aral Sea (Fig. 1).

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

Evidence

  • Notes on intervention effectivness: effectiveness determined by assessing change over time - tree growth since the start of the experiment "The vigorous juvenile growth and high water consumption of three tree species first under limited irrigation and later entirely relying on the groundwater is evidence of the successful establish- ment of tree plantations on degraded agricultural land. The site conditions, including high evaporative demand and sufficient soil water content resulting from the slightly-to-moderately saline groundwater, are generally favorable for growth and transpiration by salt-tolerant tree species. "
  • 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:
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • 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: No
  • Experimental evalution done: Not applicable
  • Non-experimental evalution done: Empirical case study
  • Study is systematic: