Agrivoltaics is the practice of using the same land for both farming and solar power generation. It’s also known as dual-use solar or agrisolar.
Benefits
1. Diversified income: Farmers can earn money from both agriculture and solar power.
2. Reduced carbon footprint: Solar power reduces reliance on fossil fuels.
3. Energy resilience: Solar power provides an alternative. energy source.
4. Ecological benefits: Solar panels can help cool crops and reduce water evaporation.
5. Reduced land use competition: Solar panels can be integrated into existing agricultural practices.
Types of agrivoltaic systems
1. Elevated: Solar panels are placed above vegetation.
2. Inter-row: Vegetation is grown between rows of solar panels.
Applications
Crop cultivation, Livestock grazing, Pollinator habitats, Aquaculture, Greenhouses, and Tea plantations.
Examples
• China has had over 500 agrivoltaic projects since 2011
. In India, start-ups like SunSeed Pvt. Ltd. are working on agrivoltaics projects.
Introduction To LI-COR 6800 Portable Photosynthesis System
INTRODUCTION:
•The LI-COR 6800 is a instrument used to measure gas exchange in plants.specially Photosynthesis
• It is a Infrared Gas Analyzers (IRGA)which give accurate measure of CO2 and H2O conc. in leaf gas exchange.
• The LI-COR 6800 provides complete, real-time information about both the light reactions and the carbon reaction of Photosynthesis.
• The instrument measures uptake of carbon dioxide (CO2) and release of water vapor (H2O) by the leaf with high precision infrared gas analyzers.
The gas exchange system
• The LI-6800 is an open gas exchange system, which means that the measurements of photosynthesis and transpiration are based on the differences in CO2 and H2O in an air stream that is entering and exiting the leaf.
1.CONSOLE:
The console provides the operating system, interface, air conditioning, and data logging.1.power button 2.head and fluorometer cable connectors 3.air supply to head connector 4.power cable connector.
The back of the console has :
1. Auxiliary Air Inlet
2. Air Inlet and filter cover
3. USB ports
4. Ethernet port
5. CO2 cartridge Holder
6. Desiccant H2O(The desiccant column holds Sorbead® . The desiccant removes water vapor from the air)
7. Humidifier H2O scrub(The LI-6800 humidifies the air stream by drawing air through wet Stuttgarter Masse (Pall Corporation). Stuttgarter Masse is a porous ceramic substrate that holds liquid water.)
8. Soda Lime CO2 scrub(The CO2scrub column holds soda lime(Ca(OH)2, H2O, NaOH, and KOH).
9. USB Host Port
Sensor head
LI-6800 The sensor head includes the sample and reference gas analyzers, flow meters, a spring-loaded latching mechanism, a Peltier thermoelectric cooler, and a system ofvalves. A leaf chamber and optional light source connect to the head. The chambers feature independently-articulated hinges to help form a good seal around unevenly-shaped leaves.
Chambers also have three positions
1. Open: The lower chamber is all the way open, ready to accept a leaf.
2. Parked: The first stop on the way to closed. Squeeze the handle until it clicks,then release. This is to adjust the position of a leaf before clamping down on it.Store and ship the head with the chamber in this position.
3. Closed: This is the position for making measurements. Squeeze the handle firmly and then release it. The chamber will close, compressing the gaskets.
To measure photosynthesis using the LI-COR 6800
IRGA, you need to provide five key environmental parameters that affect gas exchange measurements.
1. CO₂ Concentration (ppm)
• Specifies the level of carbon dioxide available for photosynthesis.
• Common setting: 400 ppm (ambient) or controlled levels (e.g., 200–1000 ppm for response curves).
2. Photo-synthetically Active Radiation (PAR) – Light Intensity (µmol m⁻² s⁻¹)
• Determines the amount of light reaching the leaf.• Common setting: 1000–2000 µmol m⁻² s⁻¹ for saturating photosynthesis or lower for light response curves.
3. Leaf Temperature (°C)
• Maintains the desired leaf temperature for accurate physiological responses.
• Common setting: 25°C (standard) but adjustable based on environmental studies.
4. Relative Humidity (%) or Vapor Pressure Deficit (VPD)
• Controls stomatal behavior and transpiration.• Common setting: 50–70% RH or VPD of 1–2 kPa for normal conditions.
5. Flow Rate (mol s⁻¹)
• Regulates the airflow through the leaf chamber to ensure proper gas exchange.
What data we get from machineFrom photosynthesis machine we get three curves as follows:
1. ACI curve (photosynthesis vs conc. CO2 in leaf)
2. AQI curve (photosynthesis vs light)
3. VPD (vapour pressure deficit) OR stomatal conductance
What those curves indicates ?
1. ACI curve
The A-Ci curve represents the relationship between net photosynthesis (A, µmol CO₂ m⁻² s⁻¹) and intercellular CO₂ concentration (Ci, ppm).
What It Shows:
• This curve demonstrates how net photosynthesis (A) changes as the internal leaf CO₂ concentration (Ci) increases.
• At low Ci values, photosynthesis is limited by Rubisco activity (enzyme-limited phase).
• As Ci increases, photosynthesis also increases until it reaches a saturation point. Beyond this point, additional CO₂ does not significantly boost photosynthesis.
• The saturation phase indicates that the regeneration of RuBP (Ribulose-1,5-bisphosphate) becomes the limiting factor instead of Rubisco.Key points :
• A steep initial increase at low Ci suggests that Rubisco is efficiently fixing CO₂.
• The plateau at higher Ci values shows that photosynthesis becomes limited by other factors (e.g., RuBP regeneration or electron transport rate).
• This curve helps estimate (maximum carboxylation rate) and (maximum electron transport rate), which are crucial for photosynthetic efficiency.
2. AQI Curve
The A-Ci curve represents the relationship between photosynthesis verses light
What It Shows
• This graph illustrates how photosynthesis (A) responds to varying light intensities (PAR, Photosynthetically Active Radiation).
• At low PAR, photosynthesis increases linearly because the process is light-limited (light is the main energy source for carbon fixation).
• As PAR increases, photosynthesis starts to slow down because other factors (such as CO₂ availability or enzyme capacity) become limiting.
• Eventually, photosynthesis reaches a maximum rate (Amax), meaning additional light does not increase photosynthesis further.
Key points:
• The Light Compensation Point (LCP) is where photosynthesis equals respiration, meaning net CO₂ uptake is zero.
• The Light Saturation Point (LSP) is where adding more light no longer increases photosynthesis.
• This curve helps determine the efficiency of light use (quantum yield, Φ) and the light saturation level of a plant
3. VPD OR Stomatal conductanceWhat It Shows:
What It Shows:
• This graph explains how stomatal conductance (gs) changes in response to increasing Vapor Pressure Deficit (VPD).
• VPD represents the difference between leaf water vapor pressure and air water vapor pressure higher VPD means drier air.
• As VPD increases, gs decreases, meaning the plant closes stomata to prevent excessive water loss.
• Lower gs reduces CO₂ uptake, which can limit photosynthesis at high VPD levels.
Why we are doing this ?
• We are using LI-COR 6800 Photosynthesis system to collect ACI, AQI and VPD readings.
• These measurements are crucial for understanding how plants respond to varying CO2 concentrations, light intensities, and vapor pressure deficits. By analyzing these parameters, we can gain insights to plant behavior and photosynthetic performance under different environmental conditions.
Specifically:
• ACI data will inform the optimal CO2 concentration for the plant allowing to adjust CO2 supplementation accordingly.
• By analyzing AQ data the light saturation point can be determined where photosynthesis reaches its maximum rate. It informs photosynthetic efficiency i.e how effectively plant uses light energy.
• VPD data will guide the optimization of the poly-house humidity and temperature control system, ensuring that the plant experiences optimal water stress and transpiration conditions.
Using HELIOS Software plant model will be created by inputting plant architecture measurements and photosynthesis data. This model will unable to simulate or predict how plant will behave in terms of photosynthesis, allowing us to optimize growing conditions and improve crop productivity.
Outcomes
This project aims to provide insights for optimizing agri-voltaic system design .
Key outcomes includes:
1. Optimal solar panel height:
Determining the ideal height for solar panels to maximize energy production while minimizing shading effects on crops.
2. Crop spacing : Identifying the optimal spacing between crops to ensure adequate sunlight penetration, promote healthy growth.
3. Crop selection and layout: Informing the selection of suitable crop species and layouts to maximize interaction between agriculture and photovoltaic energy production.
25 February – 28 February 2025
1. On 25 Feb I visited Vigyan Ashram campus to meet Mr. Ranjeet sir he explained the project regarding agrivoltaic.
2. This project allotted to Tejaswini with her I join this project further,
3. On 26 Feb Tejaswini explained and give me training of operating the LI -COR 6800 Photosynthesis instrument.
4. Tejaswini give me training how to handle instrument.
How to measure leaf area. Console setting,logsetup,environment parameters.)
1 March – 3 March 2025
- With Tejaswini we started photosynthetic rate measurements of ACi,AQi and VPD curve.
- Recently Tejaswini completed strawberry, cucumber, turmeric, fenugreek Rose.
- Total 30 curve collect from single crop.
5 March 2025
On 5 March Nimish sir from SunSeed Pvt. Ltd visited to our campus to discuss about project and tell next work on project .
6 March -7 March 2025
we started Chrysanthemum reading
