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Evaluation of different mulch materials for reducing soil surface evaporation in semi‐arid region

Farzi, R., Gholami, M., Baninasab, B., Gheysari, M.
Soil use and management 2017 v.33 no.1 pp. 120-128
Olea europaea, arid zones, drying, emulsions, evaporation, gravel, leaves, mulching, olive pomace, olives, photochemistry, photosystem II, physiological response, pistachios, semiarid zones, soil water, soil water content, stomatal conductance, straw mulches, super absorbent polymers, water conservation, water potential, water stress, wheat straw, wood chips
In recent years, the use of new mulches for soil water conservation in arid regions has been introduced as an alternative to conventional (plastic) mulches. However, systematic studies concerning the effects of different organic [pistachio shell mulch (PSM), wheat straw mulch, de‐oiled olive pomace mulch (DOM) or wood chips mulch], chemical [superabsorbent polymer (HM) or organic‐based emulsion polymer (PEM)] and mineral [gravel mulch (GM)] covers on soil and water conservation are scarce. Therefore, two experiments were carried out. Experiment 1 was aimed at evaluating the effects of mulches of different composition on soil surface evaporation, whereas in experiment 2 we investigated the effects of this decrease in soil evaporation due to different mulch materials on some olive tree physiological responses to soil drying. We analysed stem water potential, transpiration rate, stomatal conductance, leaf density and maximum efficiency of photosystem II photochemistry (Fv/Fm) of 2‐yr‐old plants of ‘Konservalia’ olive, grown in pots in open field. The results showed that different mulch materials had different efficiency on soil water conservation and DOM and pistachio shell mulch PSM – as new mulch materials – seems more favourable for conserving soil water. Water stress caused reductions in all parameters measured and increment in leaf density compared with unstressed treatment. Olive plants grown using different soil mulch presented higher values of stem water potential, transpiration rate, stomatal conductance and Fv/Fm ratio compared to control plants. Although all the mulch treatments improved the water content of soil, DOM and PSM were found to be superior in maintaining optimum soil water content for olive use.