Orchardgrass Production as Affected by Irrigation and Shade Regimes in Agrivoltaics

Orchardgrass Production in Agrivoltaics

Abstract

With the growing interest and research into agrivoltaic systems, new designs simultaneously emerge. This study focuses on one of these emerging designs in Oregon, USA and the effects that differing shade and irrigation regimes may have on plant productivity, nitrogen and water use efficiency (WUE), nutritive value parameters and seasonality within the array of an orchardgrass (Dactylis glomerata) crop. Three irrigation regimes were selected and names based on replacement of daily evapotranspiration values (ET): 100% daily ET replacement (I₁₀₀), 50% daily ET replacement (I₅₀), and no irrigation (I₀). Additionally, three distinct shade zones were identified within the agrivoltaics array: eastern, western, and center. Full irrigation (I₁₀₀) resulted in increased yields (P<0.01) while shade regime had no impact (P=0.21) on overall yield. Additionally, all irrigation regimes resulted in a decrease in WUE (P<0.01) when compared to no irrigation application. Total annual crude protein production was also affected by irrigation application with the highest crude protein produced in I₁₀₀ and lowest produced in I₀ (P<0.001). On a seasonal basis, both I₁₀₀ and I₅₀ irrigation regimes increased daily growth rates (P<0.01). These results indicate that alterations of microclimates [e.g. soil temp, moisture, PAR]may be occurring when shade and irrigation treatments are combined, causing effects on the plants that are grown with agrivoltaic systems. Further research may indicate which parameters are being affected most, leading to the results seen in this study.