Green foliage decomposition in tree plantations on degraded, irrigated croplands in Uzbekistan, Central Asia

J. P.A. Lamers, C. Martius, A. Khamzina, M. Matkarimova, D. Djumaeva, R. Eshchanov

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Afforestation is a prospective strategy to improve soil fertility of salt-affected, irrigated croplands in Central Asia. The effect of macro- and mesofauna and microflora on the decomposition of tree leaves, collected ca. 2 weeks before natural fall, was monitored during 367 days. The three-year-old tree plantations consisted of Elaeagnus angustifolia L., Ulmus pumila L., and Populus euphratica Oliv. The leaf decay rate was determined in 25 × 25 cm sized polyester litterbags with mesh sizes of 10,000 μm (coarse), 250 μm (medium), and 20 μm (fine). Decomposition in the coarse litterbags, allowing access by the entire decomposer community, was highest in P. euphratica at 61% weight loss after 367 days. In the same period, the weight loss in E. angustifolia was 51% and in U. pumila 52%. Combined correlation and multiple regression analyses revealed that decomposability was determined by mesh size, initial C/N ratio, crude fiber-to-N (CF/N) ratio, leaf area, and specific leaf area. A high correlation existed between traits impacting decomposition by the entire decomposer population and the digestibility of leaves by animals as measured in the laboratory (the in vitro digestibility). Initial leaf N (34 g N kg-1 DM) content was highest in E. angustifolia, followed by 23 g N kg-1 DM in U. pumila and 22 g N kg-1 DM in P. euphratica. The C/N ratio followed the order of P. euphratica (21.8) > U. pumila (19.4) > E. angustifolia (13.1). The CF/N ratio followed the order P. euphratica (5.2) > E. angustifolia (3.9) > U. pumila (2.9). Despite a lower decay rate and a higher N content remaining in leaves after 367 days in comparison to both other species, E. angustifolia had the highest potential for soil bio-amelioration. This was due to its foliage production (6 t ha-1 on average), which was about 2.5 times higher than that of the other species, giving a total leaf N loss of about 97 kg N ha-1 in coarse mesh bags. The N loss from U. pumila and P. euphratica leaves amounted to 33 and 23 kg N ha-1, respectively. The potential of leaf decomposition for supplementing soil N in the region depends on the decay rate, the initial leaf N content, the annual leaf biomass production, and differences between N contents over the course of the decomposition period. These can be additional criteria for selecting tree species suitable for afforestation of the degraded, irrigated croplands in Central Asia.

Original languageEnglish
Pages (from-to)249-260
Number of pages12
JournalNutrient Cycling in Agroecosystems
Volume87
Issue number2
DOIs
Publication statusPublished - 2010 Jun

Keywords

  • Decomposition rate
  • Digestibility
  • Leaf nitrogen content
  • Litterbag technique
  • Multipurpose trees
  • Specific leaf area
  • Tree foliage

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Soil Science

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