Saving irrigation water by accounting for windbreaks

Abstract

Water for irrigation in the Canterbury region of New Zealand is becoming an increasingly precious commodity as it is in many other areas of the world. Adequate use of this resource will define the economical and environmental future of the region. Current irrigation systems, even under best management practices, over-apply water, as they do not account for spatial variability of crop water needs in fields. Over-application of water is wasteful and has environmental and economical repercussions. Water requirements are determined by crop evapotranspiration (ET). Key factors affecting ET in Canterbury are wind and solar radiation. Both of these are significantly affected by windbreaks, resulting in variability in ET and water requirements across a field. Understanding the variability in ET caused by windbreaks will enable for the correct application of water through precision irrigation systems.A theoretical model was developed to estimate savings in irrigation by accounting for windbreaks in the Canterbury region. Windbreaks reduce evapotranspiration and therefore crops/pasture behind windbreaks needs less water than those in other parts of the field. Results for a case study in Canterbury show that windbreaks can potentially reduce the annual on-farm water consumption by 10 to 20%, while still maintaining ideal crop/pasture yields. In the short term, the application of precision irrigation systems in fields with windbreaks can have farm level benefits of improved water use and reduced nitrogen/phosphorus leaching. In the long term this could translate directly into cost savings because of a potential decrease in energy used for irrigation (running pumps, etc.).

Tree contributions to climate change adaptation through reduced cattle heat stress and benefits to milk and beef production

“…The impacts of pastoral trees on wind speed and shade are relatively well established (de Oliveira et al., 2018; de Sousa et al., 2021; De Vries et al., 2010; Hawke & Dodd, 2003; Karvatte et al., 2016; Vigiak et al., 2003), but there remains considerable uncertainty about the impacts of pastoral trees on air temperature and humidity. There is potential to improve our understanding of pastoral tree impacts on air temperature and humidity by applying existing numerical models that have been developed and applied extensively to analyze urban heat stress in humans (Meili, Acero, et al., 2021; Mughal et al., 2021; Nazarian et al., 2023).…”

“…For the sensitivity analysis here, we assume that the possible impact of trees on relative humidity ranges between a reduction and an increase (Table 1). The impact of trees on wind speed is highly variable, depending on the size and orientation of the tree patch, and the vertical structure and leaf density of the tree canopy (De Vries et al., 2010; Vigiak et al., 2003). The effect of trees in attenuating wind is related to their optical porosity, which varied in a survey of UK hedgerows and tree patches between 0.08 and 0.73 (Vigiak et al., 2003).…”

Effect of Windbreaks and some Design Factors on Performance of Sprinkler Irrigation System

“…Rate of evapotranspiration for vegetation is a function of four critical factors: wind speed, vapour pressure, air temperature and solar radiation. Where, solar radiation and wind speed are the most important factors affecting evapotranspiration in the Canterbury region (de Vries et al, 2010). Windbreaks have used in many previous periods to defend against the damaging effects of wind and to modify wind profiles and therefore reduce soil erosion and increase crop yield (Guan et al, 2003).…”

“…In New Zealand, studies have also shown that windbreaks can have great benefits in terms of saving water resource use in agriculture. de Vries et al (2010) studied the effect of windbreaks on irrigation requirement and evapotranspiration in the field in the Canterbury region which was protected by a single windbreak using a modeling approach. Irrigation water requirements were estimated by calculating actual evapotranspiration for a pasture crop at different horizontal distances from a windbreak.…”

Circles of live buffer strips in a center pivot to improve multiple ecosystem services and sustainability of irrigated agriculture in the southern Great Plains

“…Increased use of real time kinematic global positioning systems (RTK-GPS) in agriculture has made circular planting very easy. Since it was not possible to plant alternate strips of perennial grass buffer strips and annual crop strips in a flood irrigated field a few decades back, to 20% reduction in water use with windbreaks under irrigated conditions (de Vries et al 2010). There is a need to understand how windbreaks affect water use and water use efficiency under center pivot irrigation systems in the semiarid SGP.…”