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18.02.2019 - Martin Schneider (Send email to Martin Schneider)

How is it that base fertilization always comes second

If you attend winter events of the official advisory service, you will often be provided with statistics on the development of the basic nutrient supply or the pH value of our soils: The statement is then always that significant portions of the area with consentration of "A" and "B" are sometimes clearly undersupplied, while other parts are clearly oversupplied. Depending on the nutrient and livestock density of a region, 30-40 percent of the areas are often undersupplied.

We can still substantiate this somewhat rough statistics with our own investigation: We looked it up ourselves, evaluated the soil samples from an area of almost 476,000 ha (the majority of which is in the new federal states) and paid attention to the really badly supplied zones. Behind this total area are 23,223 individual fields. These were mathematically sampled on average in 3.7-ha increments (mostly in 3-ha increments, a few also in 5-ha increments). This is the result: on average, 51% of the areas have an "A" or "B" grade of content, i.e. a very clear nutrient deficiency, for at least one nutrient (P, K, Mg) or for the pH value.

Figure 1 shows the result once again as a function of the area size. On smaller areas it looks somewhat better: "only" 43 % of the investigated areas have at least one blatant lack. However, on the areas larger than 20 ha, 64% already have at least one blatant deficiency in the supply of basic nutrients or in the pH value. Thus, it can be generalised across the sample examined that at least one significant yield-relevant impairment exists in every second field. So with a growth factor that we can actually influence by fertilization we can improve the situation. Unfortunately, it has to be said again and again: Basic fertilisation and liming are still too often neglected!

Why is that?

Is it perhaps due to the fact that one does not trust the use of an optimal basic fertilization? Is the concentration system outdated with its fertiliser recommendation? Let us first deal with the question of where our concentration fertilization system comes from: Behind the system are countless individual field trials on basic fertilization, carried out by the official advisory service over many decades at numerous locations in Germany. The resulting yield effects from the fertilization with basic nutrients and lime were investigated and evaluated for various initial nutrient supplies. The recommendation of our current fertilizer system is now based on the fact that the recommended level of fertilization also provokes a corresponding yield reaction. So, on the surface, it is not a matter of "fertilizing" the soil - that is "only" the side effect. It is primarily a matter of using the yield effects that justify fertilization! The convenient thing about this is that we have a fact-based system here that has been tested under our cultivation conditions and which can also be further developed if necessary (for example, the new VDLUFA position on P fertilization).

There is no need to argue about whether, in the upper part of concentration "B", fertilization should also be applied "only" after extraction. The point is to follow the system on the whole. So we really have to do more in concentration class "A" than just fertilize after extraction (and then in the oversupplied areas also refrain from fertilizing...). Especially in years with extreme weather events (spring and pre-summer dryness, long frost periods, ...) the results of a professionally correct basic fertilization become visible.

Figure 2 shows the result of a fertilisation test for the last year of a winter wheat harvest, which was presented by Dr. Zorn (Thüringer institution for agriculture, Jena) at last year's fertilization and plant protection conference in Thuringia. It is shown that fertilization via extraction also has its justification in terms of yield.

Now no farm carries out exact field trials and can regularly check for itself that the fertilizer-based yield effects actually occur on average over the years. Karl-Heinz Mann presented an interesting evaluation of this at the DLG Winter Conference 2015 (DLG membership number required for Download ).

It shows that on a farm (weathering site with approx. 56 soil points, initial supply for phosphorus and potassium in content class "A" and "B", average pH value at 6.1) with long-term negative P and K balance balances, the yield difference to farms with a balanced or slightly positive long-term nutrient balance is very clear: after 12 years, this is 11 dt/ha for wheat and 13 dt/ha for barley (see Figure 3). I repeat: after 11 years, more than one tonne yield difference for wheat per hectare and year between those farms that have basic fertilization under control and those that suspend it for many years!

Is it due to the complex organisation of the basic fertilization?

Now, if you are convinced that the right basic fertilizer strategy makes sense (and I hope you finally), then you "only" have to get the excecution right. So: the correct amount of P, K, Mg and lime at the right time (for the right type of fruit in a crop rotation fertilization) and with the right sub-area-specific distribution. This is where it can quickly become complex. Because: The soil analysis, which happened two years ago and is neatly filed in the filing cabinet. The liquid manure tanks are full and urgently need to be emptied until closing time. Liming comes to your mind in the summer, when there is no time for thorough planning anyway. Moreover, in a 4-6 year planning period, you can no longer cope with rigid planning anyway. The system must be adapted at least once a year to the new situation (current crop rotation planning, actual harvested yields, new laboratory analyses for slurry, etc.). I am sure that there are a lot of pitfalls here which hinder, if not make impossible, the orderly, planned process of basic fertilisation. At least so far.

Here we have identified a job where digitalization in plant production causes real added value and makes absolute sense! The only prerequisite is that the results of the soil analysis are GPS-supported. The rest can be automated if the region-specific fertiliser rules (some federal states have slightly different approaches) are stored mathematically in software in the form of an algorithm. In addition, it is necessary to know the crop rotation including the yield targets. Then it can start and literally with a few clicks the entire basic fertilizer planning for a farm can be done, agronomically and technically clean and optimized for specific areas. The agriPORT contains this application for basic fertilization (check this video out: lime planning for 2,000 ha in one minute). Many farms are making good use of this system already.

Last but not least, the question of costs should be discussed, which must be taken into account in order to obtain precise fertilizer planning including application maps. From the sampling to the calculation program with access to all agronomic knowledge, a farm must invest between 2 and 4 €/ha/year*. Maybe an hour of computer work per year is needed to keep the data up to date (adjusting field boundaries and crop rotation, booking yield, ...). Everything else is done by the software. This gives you a precise shopping list of fertilizers, a precise overview of what is to be delivered when and where (including a distribution plan for organic materials and lime logistics) and of course the application maps (for all terminal formats). These costs then control the annual basic nutrient budget of 50 to 150 €/ha, which is the cost of obtaining basic nutrients..

In a nutshell, it can be said that precise basic fertilization is absolutely sensible and necessary in accordance with recognised fertilization rules. In addition, good tools exist today to simplify the organisation. Check it out - we will be happy to consult you!!

*Depending on the area, 200 up to 2,000 ha were assumed for the calculations.