Efficient nitrogen fertilisation is gaining importance due to the current scarcity of fertilisers, the ‘red areas’ and increasing production costs. Patrick Riek, Account Manager at Royal Avebe, tells us more about it.
Patrick has every confidence in the nitrogen-reduced fertilisation strategy for good cultivation and fertilisation advice. “Years of research on our trial and demo fields show that we achieve significantly higher starch yields with our fertiliser recommendation of 120 kg of nitrogen per hectare, instead of the generally maintained 160 to 180 kg. This can be explained as follows based on plant physiology: a high N (nitrogen) dose at the beginning of the growing season ensures that the potato plant’s foliage mass grows better. The additional advantage of a larger foliage mass falls sharply above a certain foliage mass due to self-shading and the greater need for maintenance. Therefore, fertilisers that only stimulate foliage growth, but do not lead to higher yields, can be saved.”
From foliage growth to tuber setting – the decisive moment
To maximise yields, the timing of fertiliser application is crucial in reducing the amount of nitrogen. “The plants must have sufficient nutrients and energy to achieve the desired yield around the time between crop conclusion and flowering.” The plant needs the most nitrogen in this transition period.
Added value for the grower
By reducing the amount of nitrogen fertilisers, the nitrogen efficiency (i.e. the proportion of the total N-intake that the plant actually uses) can be significantly increased. “Based on our
fertiliser advice, growers can save up to 100 euros per hectare with current fertiliser prices,” Patrick explains. “Together with the resulting higher starch yield, which at one tonne per hectare means about 350 to 400 euros more yield for the grower, that means considerable added value for the grower.” According to Patrick, Avebe has developed a future-proof fertilisation strategy that could be the solution to today’s nitrogen problems.
Good prospects for starch crops
The increase in added value for the grower results from years of research conducted by Avebe on its numerous trial and demo fields. And not without success! The result is a sound fertilisation recommendation with a lower N-intake. Patrick is confident about the future and has particularly high expectations of developing sustainable and efficient cultivation methods and breeding both disease-tolerant and virus- and pest-resistant varieties.
Sustainable potato growing is all about doing more with less: more yield with a lower footprint. Avebe helps its growers with low-input varieties with higher nitrogen efficiency. Knowledge Coordinator Jans Klok sees good opportunities for the future.
Sustainable cultivation methods start with the right choice of variety. Avebe compares old and new starch varieties on test and demo fields. At our own breeding company Averis and from external parties. There has been an increasing supply of new varieties for a few years now. Varieties with a broader resistance to diseases such as phytophthora, a higher starch yield or better nitrogen efficiency. According to Klok, there is a big difference between varieties regarding the amount of nitrogen that remains in the soil after cultivation. “So far, the new varieties seem to be coming out of the trials well, but they will have to prove themselves in practice.”
Reduction of CO2 emissions
The standard variety Seresta will be compared with the varieties Adelinde and Avenger at the special durability demo. Seresta is sensitive to phytophthora and needs a lot of nitrogen, says Klok. “If we want to reduce carbon emissions, the nitrogen intake can influence this. Both Adelinde and Avenger can manage with 60 kg less nitrogen/ha than Seresta. Applying 10 kg less nitrogen reduces carbon emission by 3 per cent. Nitrogen efficiency is also at the heart of the 7th Nitrates Action Programme.” A significant advantage of Avenger over Adelinde is that the variety has better phytophthora resistance. Avenger therefore needs fewer treatments against phytophthora than the other two varieties. Compared to Seresta, Avenger scores 45 per cent less environmental impact on aquatic life and 67 per cent less on soil life. Jans Klok: “If we convert the use of nitrogen and the improved phytophthora resistance into money, the cost of growing Avenger this year is 500 euros per hectare lower than Seresta.”
Practice versus politics
The way Klok sees it, sustainable potato cultivation and political developments do not always go hand in hand. The first draft of the 7th Nitrates Action Programme stated that growers must sow a catch crop before 1 October, while almost 9 tonnes of starch potatoes per hectare grow after 1 September. “It is known that 1 tonne of potatoes contains 4 kg of nitrogen. So with 9 tonnes, you remove 36 kg of nitrogen per hectare from the soil. A catch crop in this area can retain up to 22 kg of nitrogen per hectare. Avebe raised this issue with the Dutch Ministery of Agriculture, Nature and Food Quality and the rule was relaxed in the final 7th Nitrate Action Programme.”