Agrivoltaics, or solar sharing, is more than just generating electricity. By carefully selecting crops and optimizing cultivation techniques beneath the panels, you can maximize "dual revenue" from both agricultural and power generation activities. Here, we delve into understanding the unique environment beneath the panels and practical strategies for crop selection and cultivation.1. Understanding the Microclimate Beneath Solar PanelsFarmland with solar panels installed above creates a unique environment—a "microclimate"—different from conventional open-field cultivation. Understanding these characteristics is the first step towards optimizing cultivation.Sunlight: The amount of sunlight is reduced by the panels' shading rate and arrangement. However, this isn't merely a "lack of light." The partial shading can also offer the benefit of reducing stress on crops from intense midday sun.Temperature: Panels block sunlight, suppressing the rise of ground and air temperatures, especially in summer. This can improve root growth environments or alleviate physiological disorders in crops caused by high temperatures.Humidity: Panels block rain, which can help retain soil moisture and maintain humidity levels. While this is advantageous for drought-sensitive crops, caution is needed for crops that dislike excessive humidity.2. Optimal Crop Selection for Maximizing Profit: Suitability and ExamplesGiven the unique microclimate beneath the panels, choosing suitable crops is essential for maximizing profitability. There are generally three types of crops to consider:Type 1: Shade-Loving or Shade-Tolerant CropsThese are crops that do not require direct sunlight or may even fare worse under it.Leafy Vegetables: Spinach, Japanese honewort (mitsuba), garland chrysanthemum (shungiku), lettuce, mizuna, wasabina (mustard greens), etc. They tend to grow softer leaves and improve in quality under partial shade.Mushrooms: Shiitake, wood ear mushrooms (kikurage), etc. They dislike direct sunlight and prefer humidity, making the environment beneath panels suitable.Medicinal Plants/Herbs: Ginseng, ginger, Japanese ginger (myoga), Japanese spikenard (udo), fiddlehead ferns (kogomi), etc.Type 2: Crops Whose Quality Tends to Improve with Partial ShadeSome crops may show improved quality (color, texture, sweetness, etc.) or yield with moderate shading.Root Vegetables: Potatoes, taro (satoimo), sweet potatoes, ebi-imo (a type of taro, successfully cultivated in a Kyoto case study). Suppressing ground temperature increases can promote root enlargement.Certain Fruits: Blueberries, strawberries, etc. Moderate shading can prevent sunburn and help regulate sugar content and coloring.Legumes: Soybeans, green beans, etc.Type 3: Forage Crops and Pastures Suitable for Renewable Energy GenerationThis option not only balances power generation with direct food production but also deepens collaboration with livestock farming.Forage Grasses: Italian ryegrass, orchardgrass, etc. They grow well with consistent sunlight and moderate humidity beneath the panels and can be used for grazing or feed production (e.g., Minami Aso Village, Kumamoto case).Feed Corn, Buckwheat, Barley: While yields might be lower, these can be viable options for demonstrating continuous land use.3. Optimal Cultivation Techniques and Equipment UtilizationTo maximize the benefits of the microclimate beneath panels and stabilize yields, implementing innovative cultivation techniques and utilizing modern equipment is effective.Optimizing Water Management:Since panels block rain, rainwater supply decreases. Automated irrigation systems or drip tubes should be used to provide efficient watering based on crop type and soil moisture levels.Soil beneath panels tends to retain moisture, so caution against over-watering leading to root rot is important, and drainage measures should be considered.Soil Management:To prevent continuous cropping obstacles, implement crop rotation and systematic soil improvement through compost application.Considering the impact of panel installation on the soil, regular deep plowing and soil analysis can be effective.Environmental Monitoring:By introducing IoT sensors to monitor sunlight, temperature, humidity, and soil moisture beneath the panels in real-time, precise management tailored to crop growth stages becomes possible. Systems that detect abnormalities early and automatically initiate irrigation or ventilation are also being introduced.Panel Design Innovations:Adjusting Shading Rate: It's crucial to adjust panel density (shading rate) according to crop type and growth stage. A shading rate of about 30% to 50% is generally recommended.Panel Height and Arrangement: Height (2m to 4m) and row spacing/arrangement must allow for agricultural machinery and sufficient light for crops. Innovative designs like vertical panels or tracking systems that dynamically adjust light transmission and angles are also being researched and implemented.Pest and Disease Control:Environments with higher humidity can be more susceptible to pests and diseases. Regular inspection and early detection/countermeasures are crucial. Consider appropriate pesticide use plans or biological control methods using natural enemies.4. Learning from Success: The Ebi-imo Cultivation in KyotoIn a large 2.4MW agrivoltaics plant introduced in Kyoto Prefecture, Ebi-imo (a type of taro), a regional specialty, is being cultivated. Ebi-imo prefers partial shade, and in this project, the partial shade provided by the panels helps reduce heat stress during intense sunlight periods and suppresses soil moisture evaporation. This has improved the growing environment for Ebi-imo, ensuring stable yields and quality. This case demonstrates how skillfully combining crop characteristics with the panel-covered environment can enhance the quality of agricultural production.Conclusion: Pioneering the Future of Agrivoltaics with Technology and WisdomAgrivoltaics is a venture where the true value lies not just in installing solar panels, but in how effectively agriculture can be sustained and developed beneath them. By deeply understanding the microclimate beneath the panels, choosing suitable crops, optimizing cultivation techniques, and utilizing the latest equipment, it's possible to achieve "coexistence and co-prosperity" for both agriculture and energy production, contributing to sustainable food supply and energy self-sufficiency.