Luca Incrocci ([email protected])
University of Pisa, Pisa, Italy
Euphoros Workshop – Szentes (HU), 28 June 2011
Chemistry of nutrient solution Chemistry of nutrient solution --
Use of a Nutrient Solution calculatorUse of a Nutrient Solution calculator
1) pH: 5.5 – 6.5
2) Electro-Conductivity (EC) : 1.5 – 4.0 dS/m
3) Recipe: concentration (milli- or micro-moles per liter) of 12 nutrients
2/19
Macronutrients
(mmol/l)
N
5-15
P
1-2
K
4-10
Ca
3-8
Mg
1-2
S
1-5
Micronutrients
(µµµµmol/l)
Fe
15-40
B
15-30
Zn
5-10
Mn
5-10
Cu
1-5
Mo
0.1-0.5
Main characteristics of NS Main characteristics of NS Main characteristics of NS Main characteristics of NS
Nutrient solution and pH: how much acid? Nutrient solution and pH: how much acid? Nutrient solution and pH: how much acid? Nutrient solution and pH: how much acid?
3/19
1) H2CO3 +H2O HCO3− + H3O
+pKa
H2CO3 = 6.35
2) [HA] [HCO3-]W - [HA]
[H2O] [H3O+]
3) [H3O+] = [HCO3
-]W- [HA]
[HA]
4) pH = pKa + log ([HCO3-]W-[HA])/[HA])
[HA] = [HCO3-]W/(1+10pH-pKa)
=[HCO3-]Water - [HA]= [HA]
Target pH
[HA]
6.35 0.50 [HCO3-]W
6.00 0.70 [HCO3-]W
5.60 0.85 [HCO3-]W
Contribution of different types of ions to the EC of nutrient solution (NS) in closed substrate culture of greenhouse tomato. The values refer to newly-prepared NS or NS that was recirculated for 1-2 weeks.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
Fresh NS Rec. NS (7 days) Rec. NS (14 days)
EC
level (d
S/m
)Ballast ions Micronutrients Macronutrients
Accumulation of ballast ions in recirculating nutrient solutionsEC and nutrient concentration
04/19
Nutrient Solution calculator v1.0
• Free tool (Excel spreadsheet) developed by University of Pisa with the collaboration of dr. Ombódi Attila of the Szent István University.
•Input:
�Water composition;
�Crop recipe (also pH and EC); (It contains a database with 15 standard crop recipes);
�Fertilizer and acid nutrient content (it contains a database with the most used products)
�Fertigation system specification; 05/19
Nutrient Solution calculator
OUTPUT:
�calculation of the nutrient solution and its cost;
�calculation of stock nutrient solution ;
�salt precipitation test.
06/19
START
Vízvizsgálat eredménye
Mértékegységátalakító
Teszt(vízminıségellenırzése)
Tápoldatozó adatai
Recept az adottnövényhez
Recept adatbázis
Mőtrágyákés savak
Mőtrágyaadatbázis
Recept kiválasztása
Igen
Recept az adottnövényhezNem
pH és EC
Tápoldatmódosítása
Mőtrágyákés savak
kiválasztása
EredmEredméényny((nyomtatnyomtatááss))
Csapadékteszt
Hígításiarány
változtatása
Nem
Igen
SzSzáámmííttááss
A Tápoldat Kalkulátor folyamatábrája
07/19
Nutrient Solution calculator:Start page
08/19
Nutrient Solution calculator:Fertilizer and acid database
Check data:1) price2) composition
09/19
Nutrient Solution calculator:Recipe database
User can modify or insert a new recipe
10/19
Nutrient Solution calculator:Unit Converter tool
14/1514/1514/1514/15
Insert here the water composition in mg/l
Click to acquire the water composition in mmol/l
Nutrient Solution calculator:Input sheet (1)
1) Insert here the water composition in mg/l
2) Insert the fertigator parameter
12/19
Nutrient Solution calculator:Input sheet (2)
3) Select the recipe,pH EC
4) Check the target nutrient solution
13/19
Nutrient Solution calculator:calculation
Automatic calculation:1) choose the acids and
salts that could be used2) click on calculate
The expert user, could insert manually the values using the advice in the light-blue cell
When the element is in correct concentration appear a green colour in the cell.
14/19
Nutrient Solution calculator:Report and print
1) Check the absence of salt precipitation in the stocks:2) You can apply a lower dilution
Summary of the input and output
15/19
Nutrient Solution calculator:stock NS precipitation test
14/15
NS ion concentration
1) user could identify the precipitated salt(s)
16/19
Nutrient Solution calculator:Report and print
Output: �salts to prepare the stock NS solutions (A+B);�Its cost
17/19
Conclusions
• In soilless culture the use of correct nutrient solution is important for the optimal plant growth and for maximizing its re-use;
• pH, EC and the nutrient ion concentrations are the main characteristics of a nutrient solution;
•Nutrient Solution calculator is a tool useful for the grower and the technician to manage and calculate the NS solution.
18/19
Thank you very muchThank you very much
for the attention!for the attention!
Dip. Biologia Piante Agrarie – Villa Victorine (Le Piagge, Pisa)19/19
