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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.

Toderich, K. N., Shuyskaya, E. V., Taha, F. K., Matsuo, N., Ismail, S., Aralova, D. B., Radjabov, T. F.
Publication type: 
Scientific Paper
Publication Source: 
Developments in Soil Salinity Assessment and Reclamation
Page Number: 

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