Effects of tree windbreak on microclimate and wheat productivity in a Mediterranean environment

The presence of windbreaks is usually considered positive in mitigating the evapotranspiration (ET). For this reason, the windbreak barrier is included among the agro-techniques specific for the dry-farming systems. Objective of the study is to analyze the actual benefits of windbreaks on crop water requirements and yield. The 3-year field study has been carried integrating agronomic and microclimatic approaches. Study concerned durum wheat growing in open field, in a typical Mediterranean environment. A Cupressus arizonica L windbreak (3 m in height) bordered at North the experimental field. The analysis of the microclimatic observations shows that, when wind blew from the North direction, the windbreak presence influenced the wind speed until the distance 12.7H (H is the windbreak height), and temperature increased in a distance of 4.7H from the barrier. On the basis of the soil water content. continuously measured by TDR technique, evapotranspiration (ETd) was daily determined and season ET calculated. Windbreaks mitigated ET for a distance of 12.7 times the windbreak height. Out of this area, the ET was 16% higher than the ET measured near the windbreak belt (<4.7H). Yield performances changed accordingly the distance from the windbreak. Within the distance of 18 times the windbreak height, wheat productions were higher than those obtained in the zone not influenced by the windbreaks. Within the protected area, wheat water use efficiency (WUE, calculated as the ratio between yield and seasonal evapotranspiration) attained the maximum value of 1.15; out of the windbreak protection, WUE was 0.70 kg m(-3). Since windbreaks reduce ET, farms of the Mediterranean environments should be re-designed in order to consider the windbreaks as possible issue of sustainability. (C) 2008 Elsevier B.V. All rights reserved.