Fertilization adapted to the weather – even when nutrients are scarce

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How fertilization becomes plant nutrition –
Holistic fertilization saves raw materials
The situation in the fertilizer market is unprecedented: Prices continue to rise, increases of 300% are no longer unusual for nitrogen fertilizers. At the same time, due to high energy costs, the first producers are cutting back their manufacture. With Russia’s attack on Ukraine, a de-escalation in the fertilizer market – in which Russia would have had to participate as a major producer – seems a distant prospect. In addition to nitrogen fertilizers, phosphate and potassium are also affected. As well as the price rises, delivery bottlenecks for raw materials and tense retail and supply chains are further exacerbating the situation.
As a result, The topic of fertilization is worrying farmers throughout the country. Because recent developments – starting with the designation of red and yellow areas by the legislation, followed by the acute price explosion due to increased prices for raw materials and energy, further fuelled by the war in Ukraine, and the effects of climate change – are all leaving the profession profoundly unsettled. Old certainties are crumbling like parched fields in the sun, the dwindling stocks of nutrients – if they still exist – are carefully eked out on the impoverished fields and crops. Reduced profit and loss of quality are in many places already being discussed as the result of this shortage of nutrients.
Efficiency rates up
Unsettling changes have always prompted us to consider how we can adapt under our own initiative. There is a justified concern that energy and raw materials prices will never return to the levels of past years. And it must be assumed that politicians will place further restrictions on fertilization and crop protection. Last but not least, climate change will not stop at Germany’s borders. However, now more than ever – in view of the geopolitically uncertain supply situation – we need a consistently good supply for our crops, to maintain yields and quality. So what can we do?
To those raising incredulous eyebrows: This target is much less utopian than it may at first appear: The key is to increase the efficiency rates. Currently these are between 50 and 60% for nitrogen fertilizers, around 40% for potassium, and a mere 11% for phosphorus (Williams 2016)! It doesn’t take much imagination to see how increasing these significantly could bring potential savings.
We need more biology!
To a large extent, a higher efficiency rate for nutrient use – in addition to more efficient spreading and avoidance of losses – is based on soil biology and root growth. In future, our agricultural system will have to address the processes under the earth’s surface much more intensively. How do we sustainably promote soil fertility and avoid compaction and erosion? What role will crop rotations, intercropping, humus content, mycorrhiza, a more balanced nutrient budget or the carbon cycle play? Soil fertility is the decisive factor for the correction of almost all the nutritional problems of our crop plants.
Plant-available nitrogen must be present
But even if the theoretical knowledge about healthy soil is in place, it is far from being quick and easy to implement. What’s more: In the foreseeable future, another problem could exacerbate the restricted availability of nitrogen – a lack of sulphur. Nowadays barely 10 kg/ha falls from the air onto the fields each year; which is why there is a requirement for fertilizer for all field crops. It is now feared that the reduced performance in parts of the chemical industry will lead to reduced supply of sulphur in the future. If this is followed by a price rise or lower availability, leading to less fertilization, this would be disastrous, because sulphur plays a large role in plant metabolism. It is responsible for the uninterrupted uptake of nitrogen in crops. To put it another way: Without sulphur, the available nitrogen cannot be completely utilized. Plants are completely dependent on finding a proper balance between nitrogen and sulphur in order to transform nitrogen efficiently into yield and quality.
Innovations from technology and breeding
Numerous technological innovations over the last few years are helping to increase the nitrogen efficiency rate. For example, digitalisation: Charts based on data collected before or during the operation allow every granule of nutrient to be precisely distributed according to the requirements of the crop.
Agricultural technology has also provided developments for the efficient and economical application of nutrients. Perhaps the latest example is the Rauch DeePot 25.1, a technology for deep injection, primarily in maize and vegetables. The airtight placement of ammonium fertilizer at a depth of up to 25 cm is environmentally friendly, avoids nitrogen and sulphur losses and according to the manufacturer can generate additional yield even with 20% less fertilizer.
The choice of variety, at least in cereals, could and should have a significantly greater effect on the fertilization regime in future. There is also work to be done here in the areas of advice and breeding, to provide information about the specific requirements of individual varieties. In winter wheat it is urgently recommended to use the sowing rate as a basis for calculating the quantity of nitrogen fertilizer, as well as the current crop density and not least the variety and its growth type.
Leave the third dose up to the weather
Finally there is also the possibility of being able to react flexibly to uncertain weather conditions when it comes to fertilization, a factor which is of considerable importance in terms of the efficiency rate. Because: If the entire quantity of nitrogen is applied early in stabilized form, later adjustment is no longer possible. A partial quantity could thus be applied when its complete absorption and utilization by vital crops is guaranteed. Particularly on areas prone to early summer dryness, trials show that in addition to an adjusted sowing rate, a late application adapted to the weather, using a higher proportion of ammonium, leads to higher yields.
Fertilization nowadays is more than just the application of nutrients to the current crop rotation element. It is a long-term task, which also involves the securing of optimal soil health and nutrient ratios as well as the use of modern technical and digital tools, the use of suitable varieties, taking account of legal requirements and – equally important – the maximum flexibility for the quality application.

Über den Autor

Thomas Loschen

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