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Integrating Agroforestry and Pastures for Soil Salinity Management in Dryland Ecosystems in Aral Sea Basin

Salt-affected lands in the Central Asian region demonstrate the most characteristic features of natural continental terrestrial salinization, sodication, and alkalinization. Low organic matter (<1.0%), high salt contents, and poor waterholding capacity render these soils unproductive. The predominant salinity type is sulfate-chloride. The Na + and 2 4 SO − are dominant ions. Total nitrogen and phosphorus ranged between 0.7–5.5 mg kg −1 and 10.0–18.26 mg kg −1 , respectively. Available potassium is low or moderate. Vegetation richness, botanic species diversity, and plant biomass were well integrated with soil moisture and soil salinity. A linear regression equation between apparent soil electrical conductivity (EM38) and quantitative Na + accumulation for 0–75 cm ( r 2 = 0.88) soil pro fi les allowed us to identify the proportional contribution and interactive effects of each plant community (calculated for C 3 /C 4 species abundance) at fi ne desert landscape scale. Foliar d 13 C (carbon discrimination ) indexes as an indicator of long-term water-use ef fi ciency in plants in a restored forest – pastures ecosystem showed that d 13 C of C 3 species increased with a decrease in soil water availability, suggesting that water-use ef fi ciency increased with decreasing soil moisture and salinity. The C 4 species’ occurrences were observed to be absent and/or scarce within relatively lower soil moisture microhabitats, whereas they occurred and/or even had a high abundance within relatively higher soil moisture microhabitats and salinity, suggesting limited moisture available was a key factor of limiting C 4 distribution in arid region. The suitable coexistence of C3/C4 into an integrated agroforestry – farming system comprising 12–15% of tree cover, 58% of alfalfa, and 27–30% of annual forage crops provides satisfactory drainage – control of these salt affected marginal lands preventing salts accumulation at the root zone area. Trees/shrub plantations were deeply planting (sticks tap into the water table) through seedlings transplanting in early spring or late autumn seasons. A limited irrigation with low-quality water has been applied during the initial stage of growth before sole reliance on available drainage water (EC 4.5–12.3 dS m −1 ) resource becomes possible. The most promising plants including stands of native rangeland halophytes grown alone, or mixed with various traditional salt-tolerant trees, and fodder crops are addressed in this chapter.

Authors: 
Toderich, K. N., Shuyskaya, E. V., Taha, F. K., Matsuo, N., Ismail, S., Aralova, D. B., Radjabov, T. F.
Year: 
2013
Publication type: 
Scientific Paper
Publication Source: 
Developments in Soil Salinity Assessment and Reclamation
Volume/Chapter/Issue: 
31
Page Number: 
579-602

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