The effect of transparent agri-photovoltaics and multifunctional netting system on raspberry yield and quality

Agri-photovoltaic (AgriPV) systems integrate solar energy generation with crop production, offering dual land-use benefits in regions that are facing land scarcity and climate challenges due to temperature extremes. This study assessed the impact of an AgriPV installation on the performance of a primocane red raspberry (Rubus idaeus L.) cultivar under Mediterranean conditions. Specifically, three production systems were assessed: (1) AgriPV and white net, (2) white net alone, and (3) open field (unprotected cultivation). Yield, plant growth parameters, and microclimate conditions were monitored throughout the primo-cane production season, spanning from early August until mid-November. In addition, fruit from three distinct harvestings were monitored for polyphenolic composition and aroma profile. Results indicated a substantial yield increase of 65% under AgriPV and white net combination compared to open field. The yield increase was less pronounced when white net alone was placed above the plantation. The increase was particularly evident when excessive air temperatures were monitored and is attributed to the favourable microclimate created by plant shading during temperature extrêmes that additionally resulted in enhanced water use efficiency. A significant impact of the different production systems was recorded mainly in sugar-related fruit attributes, while limited variation on other secondary metabolites was monitored. In particular, total soluble sugars (TSS) content was generally higher under the AgriPV and netting system at all harvest points. Liquid Chromatography–Mass Spectrometry (LC-MS) analysis led to the identification and quantification of 16 polyphenolic compounds in raspberry fruits. The most prevalent compounds in all timepoints were cyanidin's derivatives. Volatile organic compounds (VOCs) composition was more strongly affected by the harvest period than by the cultivation conditions, indicating a developmentally driven aroma evolution. Overall, results reported herein demonstrate an evident advantage of AgriPV's viability under harsh environmental conditions for raspberry production, without any trade-offs in qualitative and/or sensorial attributes.