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Fertiliser management for the pros

Due to the fertiliser ordinance, the subject of "fertilisation" is more present than ever, and that far beyond the roundtables.  Everyone is talking about it, but not everyone bases what they say on facts, and on a political level there are indications of further restrictions. That's reason enough to approach fertilisation from a technical standpoint and to point out practical solutions. When looking at the world's agricultural regions, it becomes apparent how different the natural conditions and the respective requirements of the producers are.

Shortage and surplus
"When they assume operations at farms later, our students would like to have simple documentation of the entire fertilizer management process", assures Prof. Hans-Werner Olfs. The expert on plant nutrition from the University of Osnabrück, Germany limits his statement by saying that the kind of simple, comprehensive documentation IT-savvy agriculture students want is not possible (yet). "However, some manufacturers are working hard on developing this system and there will probably soon be applications suitable for practical use - even for smart phones."

While farmers in Central Europe usually have to deal with an excess of nutrients, in the Sub-Sahara region there is a shortage for crop production, especially of phosphorous. In South America the soil in many regions bonds the nutrients.  This means that some phosphate is present in the soil, however it is so firmly bonded that it is not or hardly available for crop plants.

With a view to the legal specifications in Germany, scientist Olfs finds that in some points the 2017 fertiliser ordinance "was too lax from a technical standpoint and farmers should recognise this and develop an awareness for the fact that now something needs to change".


Apply mineral fertilisers exactly
A great deal is possible from a technological standpoint - sometimes even with less effort and expense than expected. In Olfs' opinion, there are two basic problems with classic mineral fertiliser.  For example, fertiliser is often not applied exactly, especially perpendicular to the driving lane. If the fertiliser applied overlaps too heavily, then for example, too much nitrogen (N) enters the soil in some areas. Grain can go into storage later if the coefficient of variation, i.e. the measure of the accuracy in lateral distribution, exceeds 30 percent.  The second problem concerns the physical properties such as the particle sizes of mineral fertiliser. If it is frequently reloaded as "bulk product“, pressure and abrasion crush the fertiliser pellets.  The fertiliser pellets become a kind of powder that is difficult to distribute.  As a result, fertiliser management expert Olfs sees mineral fertiliser in big bags as more complex and expensive, but with regard to distribution accuracy considers it to be a more sustainable alternative to "bulk product".

Check manure first 

If the livestock density is (too) high, the valuable raw material manure becomes a problem. Bringing manure from surplus regions with intensive animal husbandry into regions with less livestock enables at least a partial compensation in the course of several years. The specifications of the new fertiliser ordinance have made farmers in the consumption areas uncertain and they are now hardly accepting any farm fertiliser.

In addition to basic considerations on the intensity of animal husbandry, those who have delivered manure in the past now have to come up with new ideas. Knowing farm fertiliser stocks exactly is a first important step. Olfs advocates simple measuring methods that farmers can use themselves on their farms. Methods that take measurements using near infrared (NIR) sensors directly at the pump of the liquid manure tank before the fertiliser is spread, or on the spreading equipment, are on the verge of becoming suitable for use in practice. Initial DLG test reports are available and show the direction for Olfs.  Manure is not always the same - not on a farm and especially not on different farming operations. If the farmer knows the quality of the manure, it can be used more exactly and efficiently on the farmer's own fields or provided to other farms. Not only the nitrogen content should be measured, but also additional value-determining constituents and the pH value.

Whenever the cultivated crop allows, Olfs advocates manure under-root fertilisation, which he considers superior to drag hoses. Fertilising under-root means: Manure is not spread on the surface of the field, but is instead applied in the soil using an injection cultivator.  

This technology will certainly be present at AGRITECHNICA 2019. With its diversity, the world's leading trade fair for agricultural machinery offers the complete overview farmers need the world over so that the guiding theme of AGRITECHNICA catches on in practice: "Global Farming - Local Responsibility".

At a glance

  • Supply/availability of nutrients very heterogeneous worldwide
  • Europe: Technological answers to social requirements
  • Manure: Check constituents and use efficiently
  • Mineral fertiliser: Spread more exactly and protect pellets
  • Under-root fertilisation reduces losses and protects the environment

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