Fusarium, Rhizoctonia, Pythium are all root diseases that are sometimes difficult to control. The preventive use of useful fungi and bacteria can create a more resilient plant growth. Groen Agro Control provides analysis to quantify these organisms in the supplied material, or in the substrate or water. This way you know what quantity is in the packaging and, for example, what is still alive in the substrate or in drain water. This way you can determine whether a new dose is already needed or whether there is still enough life.
We mainly measure bacterial counts, so with that we measure the real living values in colony-forming units per ml or gram. The sample is placed on culture medium and after a few days we can count how much Bacillus spp., Trichoderma spp., lactic acid bacteria and such are present. I also recommend having a count of general bacteria, fungi and yeasts done. And always the analysis for important root diseases. The use of useful organic must of course be measurable in a lower infection pressure of harmful root diseases. This way you can see from all sides in the root environment how the use of useful organisms for your crop works.
Suppliers can also contact us to check the material to be delivered for the correct numbers. Shelf life of such agents is not infinite. Our Microbial Count Resilient package is a broad analysis of many of the above parameters. Ask for tailor-made advice so that we map out the right thing for you.
Respiration provides a total picture of the microbiological activity in a measured value of the amount of oxygen consumption in the organic material per hour.
The values for different raw materials are very different, and of course during your cultivation the values will vary according to the greater microbial activity in the soil. A number of examples in raw materials are shown in the table. Which are not standard values but practical values.
In compost-like a high respiration is measured, so there is a high oxygen consumption (>5) because the activity of micro-organisms is high there. And with it the oxygen consumption. Respiration is the amount of oxygen consumed by microorganisms in the soil. In this way they can release nutrients from organic matter for the plant.
The organic matter content in the soil therefore also determines how much micro life is possible and how many nutrients can be released.
If you are interested in these provisions, request them from our lab or ask for more information. Please note that 3 liters of sample is required.
For more information, please contact Ines van Marrewijk.
ContactControl of microbiology in water is often done on the basis of counting bacteria and fungi, the so-called bacterial counts in colony forming units per ml. That is counting living micros in water. So even if it is disinfected water or if you dose a cleaning agent in the dripping water, the bacterial counts indicate the still living microbes.
Groen Agro Control developed packages with growers to get even more information from good irrigation water. The sooner you detect increased spore pressure from plant diseases, the better you can respond before it becomes too contagious. For clean irrigation water, we have therefore developed the ’Microbial Count Concentrated’ package. This is particularly suitable for monitoring the plant diseases Fusarium and Pythium/Phytophthora at the lowest level in addition to bacteria and fungi.
With this ‘concentrated’ method, the sample is partially concentrated in order for Fusarium spp., Pythium spp. and Phytophthora spp. to test as sharply as possible for live traces in the water. Deliver 250 ml of water in sterile bottle and we measure what you need to know.
’Microbial Count Extended’ is extremely suitable for determining the spore pressure on roots or on the leaf on young plant material. We often receive 10 plants from the propagation phase, which we then plate on Fusarium, Pythium and Pytophthora. In this way it can be ensured before delivery that no plant diseases are present. During propagation, the irrigation water should of course also be monitored for a healthy plant.
Sufficient oxygen in water and substrate is a challenge in summer, with higher temperatures. Prevent too much pollution in the storage to consume the oxygen. Normally we determine bacteria in water as aerobic bacteria at 30 degrees Celsius. Under anaerobic, ie slightly more oxygen-poor conditions, anaerobic bacteria develop more. If desired, request EXTRA, so Microbial count anaerobic bacteria in water.
For more information, please contact Ines van Marrewijk.
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Yeasts are unicellular fungi and we mainly know them from brewing beer. They then convert sugars into alcohol and CO2 under oxygen-free conditions. If oxygen were added, only CO2 would be formed and no alcohol. That’s too bad. But what do yeasts do in horticulture in the water system or for plants?
Yeasts are found in water, humans and animals, plants, soil and insects. They do particularly well on sugar, for example on nectar from flowers or in fruit juice they cause spoilage. Yeasts themselves are also a food source for bacteria and other soil life. Although little is known about yeasts that would be directly harmful to plant growth, large amounts of yeasts sometimes occur in horticultural water systems.
Yeasts occur in normal values in soils (approx. 20,000 cfu/g soil). Increased values of yeasts are often triggered by the conditions or additions in water (>20 cfu/ml) or substrate. Yeasts prefer slightly acidic conditions around pH 4.5-5.5. Furthermore, yeasts grow easily on alcohols, organic acids (including a residual product when peroxide is used) and on N-containing compounds such as amino acids and ammonia. The carbon in it is used as an energy source. Yeasts grow easily in water with a lot of dissolved oxygen and with a lot of dissolved organic material (Total Organic Carbon / TOC).
Yeasts grow quickly on organic contamination, making them an important indicator of organic contamination in water. Specific types of yeast help to solubilize phosphates so that they become available for plant uptake.
As a real growth enhancer, yeasts have not yet been sufficiently studied.
For more information, please contact Ines van Marrewijk.
ContactGroen Agro Control often uses its knowledge and analyzes for research in practice. What happens to the growth and development of ornamental or vegetable crops with more or less application of, for example, nitrogen? We often see that moderating with nitrogen does not directly affect the nutrient level in the dry matter of the plant. The plant is able to maintain the nitrogen content in the leaves. By making smaller leaves and less stem elongation, the nitrogen content is maintained. Valuable knowledge to keep plants in ornamental crops with less input of inhibitors. However, for maximum production in kg, it can be disadvantageous in fruit crops. On balance, the strategy to apply less nitrogen can best be adapted to the seasons and cultivation phase.
When the nitrate dose is reduced, more sulphate and/or chloride must be given. The absorption of sulphate hardly increases if more is given. In addition, part of the nitrate can be replaced by chloride. How much chloride can be given depends on the crop. For example, tomato and gerbera absorb a relatively large amount of chloride, while bell pepper, cucumber and amaryllis absorb much less chloride.
Figure 1 left, tomato grown with normal nitrogen in a summer crop and right with low nitrogen.
In other research links were investigated between more and less nitrogen application and the effect on the development of plant diseases and pests. It is remarkable that development in plant diseases does not appear to be the same for every crop at a lower nitrogen dose. For example, when the nitrogen dose is reduced, plants become less sensitive to Fusarium, but more sensitive to Botrytis.
In other research using LED grow light we see that uptake ratios are different than with SON-T. Caused by, among other things, a lower plant temperature with LED, the amount of evaporation is lower, so that spore and other elements are absorbed in different proportions.
For more information, please contact Ines van Marrewijk.
ContactIn order to have a better overview of numbers, we will soon be switching to a new layout for the reports of nutrients in water. The analysis itself and the historical overview have remained. To your liking we add the extra pages for ”Graphics”. Please ask if you wish. See an example of the new layout here…
For more information, please contact Ines van Marrewijk.
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Heavy metals affect plant growth and can occur in the soil/soil, in groundwater and well water. Or come along through fertilizers or released from the cultivation system. In our accredited analysis for heavy metals in ground drinking and surface water, 13 metals are reported at a very sensitive management level in micrograms per litre. But we also measure heavy metals in crops or soil. Meanwhile, many growers notice that heavy metals are part of water quality. Some heavy metals accumulate through recirculation, which hinder the absorption of essential trace elements. In part 1 we discussed aluminum and arsenic, in part 2 we discussed barium, cadmium and chromium. Here we discuss cobalt, tin and nickel.
We measure aluminium, arsenic, barium, cadmium, chromium, cobalt, mercury, lead, nickel, tin and silver in the heavy metals package. Chromium-6, selenium, fluorine and iodide are special metals that we can do as additional analysis. We take measurements in water, fertilizers, (potting) soil/compost, seeds and crops and in fruit and vegetables. There are even MRLs for arsenic, cadmium, copper, mercury, lead.
Chromium-6, selenium, fluorine and iodide are special metals that we can use as additional analysis.
Cobalt (Co)
Cobalt occurs naturally in clay-containing soils and rocks (basalt). In greenhouse cultivation, cobalt mainly comes with raw materials that we add. Or when material (metal, paint, rubber) weathers, cobalt can end up in water. Cobalt also occurs in fossil fuel exhaust, so the level is increased along highways. Cobalt can be absorbed by plants via leaves and roots and can even promote growth at normal values. Although it is a non-essential element. If the values are too high, it results in leaf fall, discoloration of veins, folding of leaves and reduced crack growth. Cobalt is almost never found in horticulture in toxic levels. In the presence of cobalt in the root zone, it competes with iron and other metals and through this route presents a risk of iron deficiency. In agriculture, cobalt salts are given as fertilizer in grass for animal feed.
Tin (Sn)
Tin is found in most soils. Most soils have been reported to contain about 1 to 4 mg/kg of tin. Much higher values are found in peat soil, 50-300 mg/kg is described. One speaks of contaminated soil from 900 mg/kg (d.s.). In Dutch groundwater about 2 µg/l of tin occurs, in seriously polluted groundwater up to 50 µg/l. In
About tin excess is only something described when waste water from a tin mine ended up at plants. Tin was virtually not absorbed by the plant, so that excess will not quickly be visible in the plant, at most it hinders the absorption of other metals.
Nickel (Ni)
In the soil, nickel occurs mainly in clay and iron-rich soils. Nickel can be absorbed by plants but can hinder the absorption of iron at the roots. Some crops can withstand higher levels and absorb a lot of them. Nickel is often found in higher levels specifically in seeds and fruit dishes. With too much nickel, roots develop poorly and iron deficiency occurs. Nickel, like copper and zinc, is widely used in building materials. Processing metal by galvanizing, chrome plating or nickel plating protects the metal. When weathering, these metals can enter the drainage water. Also, the fertilizer iron and rock flour (agriculture) often bring nickel. At low pH, acidification of the soil, nickel comes into solution and thus increased values of in groundwater occur. In groundwater the target value is less than 15 µg/l.
Aluminum and arsenic were mentioned in the Nieuwsmail Horticulture 2021-Q3. You can request that part again via this Contact button. And in the Nieuwsmail Tuinbouw 2021-Q4 a second part was offered with barium, cadmium and chromium. You can request that part again via this Contact button.
For more information, please contact Ines van Marrewijk.
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Due to the expansion of our lists, we have adapted the analysis lists for residues for Crop/Leaf, Grain, Soil, analyzes can be found. All current lists can always be found on our site.
Analysis listsOur core business is to provide our customers with fast and reliable analysis results and advice. Although we are continuously evaluating our services, we are open for improvement, feedback and additional questions. Your opinion matters. For all additional questions and remarks please contact us.
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