Irrigation of Controlled Environment Crops—Part 4: Balancing Light, Water, and Nutrients
Are you unwittingly compromising your plants? In a controlled environment many variables affect production. But if any one of those variables gets out of balance, it can undermine your whole operation. For example, if you apply enough nutrients for high production but only enough light for low production, you’ll increase costs and limit yield. To get the most out of your crop, you’ll need to measure and balance environmental inputs correctly to get the most efficient use out of them. If you’re not measuring the right variables, fixing problems that keep you from your goals will be a shot in the dark, because you won’t know what the real problem is. Amplify your production and efficiency In part 4 of our popular controlled-environment webinar series, world-renowned soil physicist, Dr. Gaylon Campbell, teaches what is required to ensure all environmental variables remain balanced for the highest possible efficiency and production. Discover: - How to model biomass production from light, water, and nutrient resources - Relationships between biomass production, light, and CO2 - Relationships between biomass production and water use - Relationships between biomass production and nutrient uptake - Limiting factors in the balance equations - Examples and monitoring applications
Recommended
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Irrigation of Controlled Environment Crops—Part 4: Balancing Light, Water, and Nutrients
Similar to Irrigation of Controlled Environment Crops—Part 4: Balancing Light, Water, and Nutrients (20)
More from METER Group, Inc. USA
More from METER Group, Inc. USA (20)
Recently uploaded
Recently uploaded (20)
Irrigation of Controlled Environment Crops—Part 4: Balancing Light, Water, and Nutrients
- 2. IRRIGATION OF CONTROLLED ENVIRONMENT CROPS BALANCING LIGHT, WATER, AND NUTRIENTS Gaylon S. Campbell, PhD METER Group, Inc. USA
- 5. WHERE DID ALL THAT BIOMASS COME FROM? • 4 kg/m2 biomass after 8 weeks • 70% water, so around 1.2 kg/m2 dry biomass • 10% of dry matter is nutrients, so 1.1 kg/m2 of new stuff
- 6. Assimilation Growth Development RESOURCE CAPTURE BY PLANTS • Temperature, Daylength, Water Stress • CO2 + H2O + Light → Carbohydrate • Assimilate + Nutrients + Water → Plants
- 7. LIEBIG’S LAW OF THE MINIMUM
- 8. MODELS TO CONSIDER • Photons to biomass • Water to biomass • Nutrients to biomass
- 10. ASSIMILATION VS. LIGHT AMBIENT CO2 Higher CO2 concentration increases light use efficiency
- 11. PHOTONS TO BIOMASS 𝑫𝑫𝑫𝑫𝑫𝑫𝑫𝑫𝑫𝑫 𝑳𝑳𝑳𝑳𝑳𝑳𝑳𝑳𝑳𝑳 𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰𝑰 𝑫𝑫𝑫𝑫𝑫𝑫 : 1000 𝜇𝜇𝜇𝜇𝜇𝜇𝜇𝜇 𝑚𝑚2𝑠𝑠 × 3600 𝑠𝑠 ℎ𝑟𝑟 × 12 ℎ𝑟𝑟 𝑑𝑑𝑑𝑑𝑑𝑑 = 43.2 𝑚𝑚𝑚𝑚𝑚𝑚 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩𝑩 𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑𝒑: 1 𝑔𝑔 𝑚𝑚𝑚𝑚𝑚𝑚 × 43.2 𝑚𝑚𝑚𝑚𝑚𝑚 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 × 60 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑 = 2.6 𝑘𝑘𝑘𝑘 𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 𝑚𝑚2 Losses and Inefficiencies • Respiration • Fractional light interception < 1 • Inefficiencies in photosynthesis
- 12. WATER TO BIOMASS Dry matter-water ratio is 3 to 6 g dm/kg water g water/g dry matter 0.6 2.4 150 - 300 Assimilation Hydration Transpiration
- 13. CALCULATING TRANSPIRATION 𝐸𝐸 = 𝑔𝑔𝑣𝑣 𝑒𝑒𝑠𝑠 𝑇𝑇𝑐𝑐 −𝑒𝑒𝑎𝑎 𝑝𝑝𝑎𝑎 [ml/m2/day] gv - vapor conductance (stomatal and boundary) [ml/m2/day] es(Tc ) - saturation vapor pressure at canopy temperature [kPa] ea , pa - vapor pressure of air and atmospheric pressure [kPa]
- 14. HOW VAPOR DEFICIT AFFECTS TRANSPIRATION 𝐸𝐸 = 𝑔𝑔𝑣𝑣 𝑒𝑒𝑠𝑠 𝑇𝑇𝑐𝑐 − 𝑒𝑒𝑎𝑎 𝑝𝑝𝑎𝑎
- 15. Fraction of mineral nutrients in dry biomass of tomato (from Bruce Bugbee, Acta Horticulturae, February 2004) % Leaves Stems Fruits Roots N 4 1.5 3 3 P 0.5 0.2 0.5 0.2 K 4 3 4 2 Ca 2 0.5 0.2 0.2 Mg 0.6 0.1 0.2 0.2 S 0.4 0.3 0.2 0.2 NUTRIENTS TO BIOMASS
- 16. ARE THE RESOURCES BALANCED? Photons to biomass 43 𝑚𝑚𝑚𝑚𝑚𝑚 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 × 0.7 × 0.6 𝑔𝑔 𝑑𝑑𝑑𝑑 𝑚𝑚𝑚𝑚𝑚𝑚 = 18 𝑔𝑔 𝑑𝑑𝑑𝑑 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 Water to biomass 3.2 𝑘𝑘𝑘𝑘 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 × 5 𝑔𝑔 𝑑𝑑𝑑𝑑 𝑘𝑘𝑘𝑘 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 = 16 𝑔𝑔 𝑑𝑑𝑑𝑑 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 Nutrients to biomass 16 𝑔𝑔 𝑑𝑑𝑑𝑑 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 × 0.1 𝑔𝑔 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛. 𝑔𝑔 𝑑𝑑𝑑𝑑 = 1.6 𝑔𝑔 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛. 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 3.2 𝑘𝑘𝑘𝑘 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑 × 2.5 𝑔𝑔 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓. 𝑘𝑘𝑘𝑘 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤 × 0.4 𝑔𝑔 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛. 𝑔𝑔 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓. = 3.2 𝑔𝑔 𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛. 𝑚𝑚2 𝑑𝑑𝑑𝑑𝑑𝑑
- 17. WHAT DOES THIS MEAN? • If we know daily light integral, fractional interception, and light conversion efficiency we can estimate light-limited dry matter production • If we know, or can compute, transpiration rate, fractional cover, and water use efficiency we can estimate water-limited dry matter production • Since nutrients are supplied with the water, all factors that affect transpiration rate will also affect plant nutrition • Nutrient levels high enough to allow crop steering are likely in excess of those needed for the biomass being produced
- 18. MEASURE TO KNOW AROYA Nose Fractional interception AROYA DLI Quantum Sensor Kit Light (PPFD, DLI, Rabs) ATMOS 22 Wind AROYA Climate Station Air temp, CO2, Vapor deficit SC-1 Stomatal conductance TEROS 12 Water, Nutrients, Root temp
- 19. AROYA The information you need to manage the plant environment
- 22. CONCLUSIONS 22 • Yield is determined by the most limiting resource in the plant environment • Potential conversions rate of photons to biomass is determined by PPFD, [CO2], and light use efficiency • Potential conversion rate of water to biomass is determined by radiation, vapor deficit, and water use efficiency • Nutrients are supplied by fertigation and must be balanced with each other, and with light and water use • The AROYA tools are designed to help growers maximize production, minimize waste, and continuously improve
- 23. QUESTIONS Gaylon S. Campbell, PhD Senior Scientist METER Group, Inc. 2365 NE Hopkins Ct, Pullman, WA 99163 T 509.332.2756 E support.environment@metergroup.com W www.metergroup.com