Gerbera Breeding & Consulting Dr. Yoseph Shoub
58, Savionim St., Ganey Am 45905, Israel, Tel/Fax: 972-9-7406731
Some notes about Irrigation and feeding gerbera
Report on visit to India, on behalf of ‘Selecta’ 6 - 14th September 2006
Feeding of intensive agricultural crops is based technically on supplying fertilizers through the irrigation lines. The term used for such method is ‘Fertigation’ (irrigation + fertilizers).
In general, most of the feeding formulas include the same basic Elements the N P K, with only some reasonable variations within the Elements ratios. Growers today are able to choose for different crops, common commercial mixed fertilizers, usually enriched with Microelements.
Different formulas are used elsewhere for gerbera culture that produces good results.
A simple example for such used satisfactory feeding formula, for soil gerberas is a mixture of 2 common fertilizers and Nitric acid, injected into 1000 Liter of the irrigation water:
300 gr. “19 19 19” (enriched with Microelements),
300 gr. “13 0 46” (Potassium Nitrate),
100cc Nitric acid (60%).
(Ca and Mg fertilizers can be added if required).
The formula achieved in this example is: N 110 ppm, P 25 ppm, K 160 ppm + Micro Elements.
This simple balanced formula is only one of other practical possibilities that are used in gerbera culture with other fertilizers, and with some variations within the Elements ratios.
How to use the above example, using 3 tanks system:
Tank A (500 liter): The 2 fertilizers (100kg) are mixed in the tank, 50 kg. for fertilizer.
3 Liters of this solution is injected into 1000 liter of the irrigation water.
Tank B (500 liter) is used for the acids: in our example, a volume of 12.5 liter of Nitric acid is added. 4 Liter of this acid solution is injected into 1000 liter of the irrigation water.
Tank c (if required) is used for Ca and Mg fertilizers.
Fertigating with low pH (6.7 – 5.5) keeps clean the irrigation lines, helps to avoid blocking of the drippers and improves the availability and the absorption of the minerals by the plants.
One good feeding formula can cover the whole growth cycles -
Here is the place to note, that for gerbera (and may be for other crops too), the same feeding formula can be used all along the growth period, from planting to the end of the crop. And the reason is - That all along the gerbera plant’s growth, new branches, new roots, new flowers and new buds are developing continuously at the same time.
Thus, one good balanced feeding formula will cover all the gerbera plants needs.
Therefore, it was strange to notice that the Indian gerbera growers are advised, to use separately, at least 3 different fertilizers during the week, and about 7 different formulas for different periods of growth, that are not exist in gerberas at all.
Generally speaking, the daily fertilizers quantities, absorbed and used by the plants are small, as related to the plants’ limited daily growth-rates and their daily production abilities. Therefore, the minerals’ quantities supplied daily by the fertigation are used only partly by the plants.
Traditionally, most of the growers everywhere, tend to exaggerate with fertilizers quantities. Therefore, in practice we simply rinse to the ground water, parts of the unused minerals of yesterday by today’s irrigation, along with contaminating our drinking water.
In fact, as we do not measure continuously the soil solution at the root zone, we do not have accurate information, about the minerals that haven’t been used and haven’t been washed.
Therefore we are not able to react on time for avoiding the process of salts accumulation.
The accumulation of salts is even more stressed if we do not supply on time the amount of water used by the plants. And most of the Indian gerbera growers I met, didn’t irrigate according to the water consumption of their plants, in soil as well as in containers.
Time and again we have to remind the gerbera growers in hot countries that in summer, the
minimal daily amount of water per gerbera plant grown in soil, should be not less than 500cc per day. Less water than this minimal daily amount opens the gate for salinity problems.
Without shading the amount of water should be increased up to 20%, or according to the daily water consumption.*
In case of salinity occurrence in Soil beds, the growers have to wash the soil media without fertilizers, in a continuous one long irrigation, as needed for washout the excess salts. The common used quantities of water for washing the soil beds are at least 3 to 4 times of the normal daily irrigation quantity. A useful method used by gerbera growers, is to wash regularly the soil beds every 4 to 6 weeks, without any hesitation.
The right way to wash the soil beds is to use the present dripping lines, and not by sprinkling or by shower hose. Washing with the dripping lines will correctly remove the salty fronts from the root zone. Washing by shower hose, will dissolve the salty fronts, and rinse it into the root zone.
Reducing the fertilizers quantities requires accurate automatic irrigation control system. **
Experiments with different crops including gerberas, show that with accurate automatic irrigation control system, it is possible to reduce the concentration of the feeding formulas (without changing the balance of the formula’s ingredients), and yet to have the high quality of growth and production. Reducing the fertilizers rates decreases the danger of salinity.
Leaves analysis also show that the chemical composition of our gerbera plants’ leaves, fed by low fertilizers concentrations did not change, in compare to the composition of our gerbera leaves fed by ‘normal’ feeding solutions.
* Information regarding the relations of Shading / Watering is found in our website in the Report on gerbera growing conditions in Colombia - February 2006
** Printed down is a summary, describing the profitable usage of the new ‘Auto Agronom irrigation control system’ in our gerbera breeding farm in Israel.