Photovoltaic systems promote grassland restoration by coordinating water and nutrient uptake, transport and utilization

Abstract

The extensive use of fossil fuels puts ecological and economic coordinated development at risk. Photovoltaic systems relieve the pressure of resource extraction and energy generation on climate change, and their installation and module operation affect vegetation productivity and grassland restoration by changing the microenvironment and ecosystem processes. However, it is still unclear whether plants adapt to these changes in photovoltaic systems to sustain their growth. Here, combined stable isotope techniques with plant traits, plant adaptations to photovoltaic systems at different scales were analyzed from the perspectives of water and nutrient sources, uptake, transport, and utilization. The results showed that photovoltaic systems increased water uptake by the dominant species Leymus chinensis from the top 10 cm of the soil and the aboveground biomass. This was associated with strong plasticity of roots and conduction tissues, which improved resource uptake from the fertile surface soil and transport within the plant, and promoted photosynthesis and leaf water loss by inducing stomatal opening. Different from fixed photovoltaic systems, tracking photovoltaic systems improved ecosystem water use efficiency and surface soil nutrient availability by reducing soil temperature. Tilting tracking photovoltaic systems especially promoted biomass accumulation and grassland restoration. The study suggested that photovoltaic systems promoted vegetation restoration of grassland ecosystem in semi-arid region through the water and nutrient coordination and the carbon-water coupling, and provides a solution for reasonable planning of photovoltaic industry and sustainable socio-economic development.