Nutrient Solutions |
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Solution Management |
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Laboratory Analysis Fertiliser Quality |
Optimising hydroponic crop nutrient uptake.
Regular analyses of recirculating hydroponic solutions and adjustments of the stock solution recipes allows crop nutrient uptake to be optimised for both yield and product quality. Estimating crop nutrient uptake rates provides a better control than adjusting recipes according to set target concentrations in the solution.
Adjusting Stock solution recipes according to analysis results
Nutrient uptake calculationsCalculating nutrient uptake rates is basically an accounting operation but with amounts of nutrients instead of amounts of money. Two solution analyses are like two bank statements, when nutrient concentrations multiplied by the solution volume equals the amount of each nutrient in the system at the times of the first and second solution analysis. Records of water use, A & B stock solution and acid or alkali added show how much of each nutrient has put into the system (how much has been paid into the bank) in the time between the two analyses. The difference between the amount of each nutrient in the first analysis plus the amount of all the additions and minus the amount at the final analysis must equal the withdrawls from the system. In a well run recirculating nutrient solution, the only withdrawls will be the uptake of nutrients by the crop. Leaky systems have uncontrolled withdrawls, but it is sometimes possible to estimate the volume of solution leaked and hence the loss of nutrients.
Excel spreadsheets for making the uptake calculations have been used and continuously improved in this practice over the past 16 years. Greenhouse tomato, pepper, cucumber and lettuce growers in New Zealand have been using our services for many years to calculate uptake rates and revise nutrient solutions and a few growers are now using our software to make their own calculations and adjustments to their recipes. We can make uptake calculations and suggest recipe adjustments for growers in New Zealand and overseas, if they are able to get quality analyses of nutrient solutions and keep proper records and can send and receive data in comma separated value (.CSV) files. Use the form below if you would like a quote for the cost of this service. Spreadsheets for uptake calculations can be supplied in Microsoft Excel workbooks for growers who would prefer to make their own calculations. The cost of this workbook is $152 including Nutricalc spreadsheet. Subscribers to this website who have already downloaded Nutricalc from the website can purchase the Uptake workbook for only $117.00. The workbook can be emailed to you as an Excel File attachment. The Uptake workbook contains the following pages: - Advice Note data base; this is information on water, stock solution and acid use.
- Crop data base: this data includes the crop area, planting date and variety
- Laboratory analysis results data base
- Uptake calculation worksheet
- Uptake history data base: stores the uptake rates
Use the form below if you would like to receive more details by email (Office Word documents) or use the GHVI subscription form to order and pay for the Uptake calculation work book. | |