Page 97 - TA Magazine

Shelter and irrigation
Establishment of shelter markedly reduces windspeed especially in in the zone equivalent to 2-8 tree heights (30-120m at our site) Wind reduction improves sprinkler evenness and efficiency particularly for the vulnerable end-gun of a a a a centre-pivot irrigator How much water can be saved?
Potential evapotranspiration at at Formosa (with no shelter) was measured to be 1778 mm over the study period The sheltered 300 m m m (15 ha ha of the 25 ha) experienced 240 mm less potential evaporation This equates to 35 9 ML of saved potential evapotranspiration across the entire paddock Note that potential evaporation evaporation is going to be be much higher than actual evaporation evaporation evaporation because evaporation evaporation can only occur at at at at at at potential rates when water is freely available at at at at at the soil surface Impact of shelter on on evapotranspiration Shelter reduced evapotranspiration by 15-20% over the full 300 m sheltered zone irrespective of season
Potential vs actual evapotranspiration Potential evapotranspiration is is the evaporation that would occur if sufficient water is is is available at at at at at at all times Pan evaporation is is a a a a a a a a a a a a a a a a measure of potential evapotranspiration Actual evapotranspiration is is is the water that is is is actually evaporated/transpired and is is is is lower than potential potential because water is is not always available Evapotranspiration will typically occur at at at potential potential until the soil surface (to rooting depth) starts to to dry out Conclusions
Trees reduced water loss through evaporation 1 1 ha ha of of 15 m m tall trees on the the windward edge of of a a a a a a 25 ha ha paddock provided shelter from the the prevailing wind This resulted in:
Shelter for more than half of the paddock measured wind velocity reductions of 15-20% &
commensurate reductions in in potential evapotranspiration equating to 35 9 ML Google Earth image of the the study paddock at Formosa taken 27 October 2015 The pasture in in the the sheltered zone remains green
Want to find out more?
contact@treealliance com au treealliance com au 97