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07.04.2021 - Peer Leithold (Send email to Peer Leithold)

The Restrictions on N-Fertilization in Red Areas

Criticism of the fertilizer regulation

I would like to start with some principles. The Fertilizer Ordinance, which was adopted in 2017 and revised, i.e. tightened, in 2020, is now in full effect and poses major problems for all agricultural businesses.

First and foremost, this regulation clutters us up with new obligations to provide proof, imposes controls on us and increases the bureaucratic burden of farm management. Have you ever wondered how much time you have spent unproductively on this in recent years? What if you had put that time into bonusing your crops and optimizing N fertilization?

Secondly, from a scientific, i.e. agronomic point of view, the regulation is a technical nonsense. Every well-educated agronomist knows that drawing in fixed guideline values and fixed fertilizer requirement values does not correspond to nature. If it were really the wish of those who govern us to reduce the N surpluses, some of which are too high, the only thing that would be done would be to push for compliance with site-specific N balances and to invest in the continuing education of farmers or the training of the next generation. It has been known for decades that fertilizing at the optimum leads to low N balances and optimal economic results in the long run.

The Fertilizer Ordinance requires us farmers to fertilize according to so-called fertilizer requirement values. The basic formula here is essentially: Yield times removal factor minus Nmin = fertilizer requirement value. In the red areas, another 20% is then deducted across the board. And this is supposed to apply to ALL fields in Germany. This is a procedure from the stone age of agronomy. As we will see in a moment, this procedure does not even work on a single field.

Solution approaches

But let's move on to what is currently necessary. And that is the question of how we deal with it.

Solution No. 1: We try to deal with the legislator in a logical way and change the law. There have been many serious attempts to do this. Individual farmers as well as associations and federations have courageously and enthusiastically fought against this. The belief in factual logic, solid evidence and expert opinions went unheard in politics and were ultimately ground by the mills of the courts. There may even be a stage victory here and there, but the battle has been lost across the board.

Solution No. 2: One circumvents the regulations by not complying with them, but filling out the paper proofs as legally compliant as possible. This is certainly a quite pragmatic solution, but it does not eliminate the problem in the long run.

Solution No. 3: Try to take the economic edge off the regulations as far as possible by reacting cleverly in terms of crop cultivation. Right away, in areas with extremely high animal concentration, it will not go off without economic damage.

Crop production basics

On the basis of a 20-year N-increase trial (loess site, Saxony) in winter wheat by Dr. Albert, I will give you an example of the absurdity of the fertilizer regulation. First the bare data:

Deductions from this

1. There is no fixed relationship over time between the optimum yield and the corresponding fertilization level. The assessment of the fertilization level via a balancing scheme is demonstrably incorrect. The deviation of the optimal fertilization level from a theoretical fixed mean value is on average +-70 kg N/ha. In our example, the absolute variations of the annual N optima are between 60 and 245 kg N/ha. This is not a new finding. The knowledge about this has been known for 50 years.

2. The yield to be expected in one year is not known for the field or for the subplot at the time of fertilization. In our example, the optimal yield is between 65 and 121 dt/ha. All approaches to yield estimation based on historical yield data and additional information were not useful. There is no method in the world that can predict yield with sufficient accuracy. We balance with fictitious figures when calculating fertilizer requirements.

→ It follows: If you follow the DVO and fertilize according to rigid specifications, you will either waste fertilizer or lose yield. Whether you are more on the side of wasting fertilizer or losing yield always depends on the individual case and cannot be predicted. The fact is, the good sites suffer less from yield loss than the weak sites. A less favorable site and red area is the worst combination.

3. There is no fixed relationship between Nmin and the level of optimal fertilization. The optimal N fertilization level as a function of Nmin values varies between +/- 50 kg N/ha, i.e. a 100 kg corridor, around a theoretical mean value. Apart from this, the theoretical mean value is field-specific and cannot be determined at all in practice.

→ It follows from this: Nmin investigations for optimal fertilization are wasted money. This effort should be saved.

There is no relationship between the Nmin supply of the soil after winter and the subsequent mineralization (basic yield times 2.5 kg N/dt minus Nmin). So you cannot conclude from Nmin to mineralization. And last but not least, Nmin values are extremely variable over small areas. A composite sample of 10 ha may calm the inspector or the conscience, but it has nothing to do with crop production and fertilization.

In summary, the fertilizer ordinance has no scientific basis. It is a purely arbitrary regulation.

Obvious effects

1. Farms with organic fertilizers are generally worse off in the N-balance than pure cash crop farms. The area-independent animal husbandry from about 1.5 GM/ha must drive the accruing nutrients out of the region. This means the end for many smaller farms. Farms with livestock numbers between 0.5 and 1.5 GM/ha are increasingly unable to achieve optimal yields. This is due to the restrictive management of the N-balance and the lower N-efficiency of organic versus mineral fertilizers.

2. Pure arable farms on better sites can manage if they are able to ensure high N-utilization of the supplied fertilizer. The balances tend to go towards zero and into the negative range. On weak sites, the balances become negative more quickly. A downward spiral sets in over the short or medium term.

3. In the red areas, this process is faster and more radical.

4. The red areas in particular are at a crossroads. Either one extensifies, if necessary up to ecological agriculture, with the danger of losing one's economic independence at the current prices. One becomes even more dependent on state subsidies than before. Or, one goes the way into a new (old) form of agriculture.

New form of arable farming under strict N-restrictions

1. Get used to fertilizing only according to actual N-demand, instead of a rigid recipe! For this you need above all fast-acting and low-loss forms of fertilizer.

2. Be sure to divide the total amounts! Each gift division brings a few percent higher N-efficiency. Rule of thumb: splitting a total amount into two gifts gives about 10% more N efficiency. With limited total N amounts, the amount of yield gain is definitely greater than the cost of the additional pass.

3. Fertilize the partial areas with the N-sensor from now on! Thus you bring the fertilizer where it can produce the highest yield increase per kg N. Especially if you generally have to stay below the N-optimum of the field. Use the N-Sensor also for summer crops! Divide the total fertilizer quantity into two applications for corn, potatoes, sugar beets and summer cereals.

With these measures alone, you will gain about 20-30% additional N efficiency!

4. If possible, do not apply more than 50% of the required total N-quantity as organic fertilizer constantly! The remaining 50% must be followed up with mineral and fast-acting fertilizer forms on the subplots.

5. Try, if possible, to continue the crop rotation! Avoid the cultivation of wheat after wheat!

6. Plow wherever possible! Shallow and reduced tillage leads to higher lodging density on most sites, thus higher root penetration resistance, decrease in coarse pore volume, slower spring warming, lower and later N mineralization and thus higher N mineral fertilizer requirements.

7. Increase N efficiency by fertilizing lime, phosphorus, potassium and magnesium site-specifically and keeping them at the optimum!

If you implement these suggestions consistently, you can compensate most of the economic losses under the conditions of the DVO and especially in the red areas.