Cal Poly 12 th annual conference: Sustainable water strategy management in precision growing by Niels van Rooyen Welcome to Priva Headquarter: Priva Campus, Netherlands: 1
Organization Workplace for 400 employees. Using green current and no gas makes Priva Campus CO 2 -neutral. Market groups Agro Business Building Intelligence Offices Company headquarters in De Lier, Netherlands. Local offices are located in Germany, United Kingdom, Sweden, Canada, Mexico and China. Agenda Plant processes Overview sensors Micro irrigation Reasons Pretreatment Conditions Time Sunlight accumulation Plant evaporation Plant in control Recirculation Disinfection EC pre-control Full cycle 2
Plant processes Light (Radiation) Humidity (%) Temperature ( C) CO₂ Water and nutrients Plant processes In formula: + 6 CO 2 + 6 H 2 0 Energy C 6 H 12 O 6 + 6 O 2 Which means: CO 2 + Water + Light Sugars + Oxygen 3
Plant processes Water Nutrients Water and nutrient consumption GROWTH Humidity Radiation Temperature Trans piration Cooling Temperature Radiation CO₂ Photosynthesis Humidity Radiation Temperature Development QUALITY Monitoring plant processes; Sensors Sensor overview Outside (weather station) Climate compartment Water system Other Temperature Temperature EC Portable analysers Rain detection Relative humidity ph Wind speed CO₂ Flow Wind direction Light (PAR) Moisture Radiation Plant temperature Pressure Humidity Heating temperature Level Snow detection (not on mast) Vent position Drain 4
Greenhouse measurements Vent position Snow detection Wind speed Temperature Wind direction Rain (yes/no) Light CO₂ Plant temperature Inside light measurement Temperature Humidity Outside humidity Screen position (running time) Pipe temperature EC ph Flow Drain Tensio measurement EC ph Flow Outside measurements Wind direction sensor Wind speed sensor Temperature sensor Rain sensor (yes/no intensity-volume) Light sensor Outside humidity sensor 5
Climate sensors Measuring box Temperature ( C) Humidity (%) Infra red plant temperature sensor ( C) CO₂ monitor 0 3000 ppm Heating pipe temperature sensor ( C) Inside light Measurement (PAR) Vent position indicator ( degrees) Irrigation sensors EC sensor Pressure level sensor ph sensor Paddlewheel flow sensor (liters/min) Soil moisture sensor Moisture / Drain measurement Portable sensors -EC only -ph only -EC & ph 6
Reasons micro irrigation Physical water scarcity More than 75% of the river flows are withdrawn for agriculture industry and domestic purposes. Accounting for recycling of return flows. Approaching water scarcity 60% of the river flows are withdrawn Economic Water scarcity World resources institute nov 2007 Reasons micro irrigation See current Water use Worldwide! With overhead irrigation 60% of the water (or more) disappears in the soil or evaporates With drip irrigation over 5 x more water efficiency Source: Australian Academy of technological sciences and engineering 7
Reasons micro irrigation Open field GH Micro irrigation 60 liters/kg tomato 5 liters/kg tomato Example: From Pivot Irrigation towards Greenhouse Irrigation 8
Closed greenhouse highest water efficiency Van Kooten, Heuvelink and Stanghellini, 2008 Micro irrigation Micro irrigation is on providing the plant the right amount of water at the right time, resulting in maximizing output (growth/quality) whilst minimizing input (water/fertilizer) The basic steps to optimize fertigation: (fertigation; irrigation + well mixed nutrients) 1) Start with good quality of supply water 2) Correct dosing of water including nutrients 3) Recirculate drain water 9
Micro irrigation 1) Start with good quality of supply water Disinfected With as less sodium as possible With low bi-carbonate levels < 0.5 mmol/l With higher bicarbonate values not all acid will be able to react and let C02 escape. The ph will rise at the roots of the crop to a higher value than the original set point ph A correct and a stable ph and EC level at the root zone is essential, for optimal up take of nutrients to prevent deficiencies and diseases. Micro irrigation 2) Correct dosing Irrigation conditions Irrigation conditions are those conditions that determine when and for how long irrigation takes place Irrigation conditions Traditional Clock Modern Sunlight accumulation Advanced Plant evaporation Future Plant in control 10
Traditional: clock irrigation Advantages: Easy to operate Simple installation Disadvantages: Preset irrigation starts with fixed running time per cycle Fixed amount of irrigation water No weather influence Sunny or cloudy No influence on amount Traditional: clock irrigation Irrigation amount Duration of irrigation cycle Irrigation amount (fixed) 0 Irrigation based on clock starts Time 11
Modern: sunlight accumulation Light accumulation When a light sensor is connected to the system the controller can start the irrigation based on how much sunlight the plant receives over a period of time Advantages Relatively simple to install Can be connected directly to an irrigation unit Irrigation based upon plant requirements Light equals energy equals (calculated) plant activity equals (calculated) evaporation Weather influence Number of starts adjust automatically based on sunny/cloudy days Disadvantages No influence on amount Modern: sunlight accumulation Sunlight accumulation Sun rises and the computer starts to count the amount of sunlight Sunlight accumulation set point reached start irrigation Sunlight accumulation set point 0 Time 12
Modern: sunlight accumulation Light accumulation with minimum rest time When there is a high sunlight intensity, the sunlight accumulation set point is reached too fast resulting in the fact that the plants receive too much water. A minimum rest time period set point is added which indicates the minimum time between two irrigation cycles for the same valve, to avoid the plants receiving too much water Modern: sunlight accumulation Sunlight accumulation Sunlight accumulation set point Sunlight accumulation set point reached start irrigation With high intensity sunlight, the set point might be reached too fast. Min rest period set point Sunlight accumulation set point reached and the minimum rest time has passed start irrigation 0 Minimum rest period is the minimum amount of time that needs to pass between two irrigation cycles of the same valve. The minimum rest time avoids that the plant receives too much water Time 13
Modern: sunlight accumulation Light accumulation with maximum rest time When there is a low sunlight intensity, the sunlight accumulation set point is reached too slow resulting in the fact that the plants receive too little water. A maximum rest time period set point is added which indicates the maximum time between two irrigation cycles for the same valve, to avoid the plants receiving too little water Modern: sunlight accumulation Sunlight accumulation Sunlight accumulation set point Sunlight accumulation set point reached start irrigation With low intensity sunlight (cloud cover), the set point might be reached too late. Max rest period set point Sunlight accumulation set point reached and the maximum rest time has passed start irrigation 0 Maximum rest period is the maximum amount of time that can to pass between two irrigation cycles of the same valve. The maximum rest time avoids that the plant receives too little water Time 14
Advanced: plant evaporation PLANT is more in control When an irrigation cycle is started based on evaporation, the water of the previous cycle has been evaporated by the plant (including drain requirements) the water content of the substrate can be kept in optimal conditions Root Optimizer Drain system Priva Root optimizer 30 15
Root Optimizer Drain system Priva Root optimizer 31 Actual evaporation Humidity content substrate 4 3 5 = Evaporation! 2 Weight reduction 6 Time 1 7 1 Time 16
Working of the Root Optimizer (24h) Day Maximum humidity content Night Last drain Irrigation cycle during night period Measured Weight Substrate Measured dry-out level First start; Measured dry-out level is higher dan maximum dry-out level Maximum dry-out level Measured dry-out level First drain after 3 starts 8:00 16:00 22:00 8:00 time Example (sunny day) Measured Dry out level Radiation Drain Start moment 17
Advantages Root Optimizer Substrate type independent Completely integrated in water management program Always optimal humidity content of the substrate Optimal root growth resulting from healthy root environment Desired drain is always accomplished Adapts automatically on actual weather conditions Actual evaporation shown in graphical interface First irrigation cycle easily determined Upon necessity, extra starts during the night Future: TopCrop The future of process automation in horticulture: The plant in the control loop: Direct control instead of indirect control by environment Continuous measurement and direct correction of crop status: Crop activity Suppression of diseases Water absorption 18
Recirculation 3) Recirculate - Recirculation is the recycling of the excess irrigation water (drain is necessary to keep substrate environment healthy) - The principle is to re-mix the disinfected drain water with fresh water and inject it into the fertilizer unit - Recycling brings increased risk of the spread of diseases and is why recycled water needs to be treated (disinfected) removing all types of harmful pathogens Recirculation & disinfection Imidacloprid 0.2 µ g / 0.1 l 0 0 250 UV mj/cm2 0 25 H2O2 ppm Principle: Damaging the DNA structure of micro-organisms by using UV-C radiation Capacities depending on: - Transmission value (T10) of the water to be treated - UV-C dosing (mj/cm 2 ) Selective: 60-100 mj/cm2 (bacteria's, fungi) Total: 150-250 mj/cm2 (diseases, including viruses) UV-oxidation: The combination of peroxide an UV gives a more effective disinfection. Because of the oxidizing, growth inhibitors and pesticides are decomposed. 12/11/2013 38 19
Basic system design 1. Irrigation into the greenhouse 2. Small drain collection pits 3. Central drain tank 4. Priva Vialux disinfection unit 5. Central disinfected tank 6. Fresh water tank (well/rain) 7. EC-precontrol Mixing of fresh water with drain water 8. Irrigation/fertilization unit 2. 1 & 9. 5. 3. 8. 7. 6. 4. Complete irrigation overview 20