Under semi-arid Mediterranean conditions, limited moisture is the main constraint to rainfed cropping with wheat (Triticum
aestivum), barley (Hordeum vulgare), and food and forage legumes. With increasing land-use pressure, moisture-conserving
fallowing is being replaced by continuous cropping, which is considered an unsustainable practice. Thus, a long-term trial with
durum wheat (T. turgidum var. durum) was established in 1983 at Tel Hadya, Aleppo, Syria (mean annual rainfall 330 mm) to
assess alternative rotation options to fallow and continuous cropping. Nitrogen (N) and grazing/residue management were
secondary factors. Soil aggregation, infiltration, hydraulic conductivity, and total soil organic matter and component fractions
(fulvic and humic acids and polysaccharides) were determined at the end of 12 years. Some rotations, e.g., medic (Medicago
sativa) and vetch (Vicia faba), significantly increased soil organic matter (12.5–13.8 g kg1 versus 10.9–11 g kg1 for
continuous wheat and wheat/fallow). All measurements, or indices, indicated parallel trends with increasing organic matter,
e.g., coefficients of macro-structure, micro-aggregation, and water-stable aggregates, and decreasing dispersion. Similarly,
legume rotations had higher infiltration rates (16.2–21.8 cm h1 versus 13.9–14.4 cm h1 with continuous wheat and wheat/
fallow) and hydraulic conductivity rates (8.7–12.4 cm h1 versus 6.2–7.4 cm h1 with continuous wheat and wheat/fallow).We
conclude that cereal/legume rotations, in addition to being biologically and economically attractive, also enhance soil quality
and thus promote soil use sustainability in fragile semi-arid areas as in the Mediterranean zone.
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