Crop management of maize should be well-thought-out
High mass yields, good quality while, at the same time, not placing stress on the nutrient balance: reconciling these wishes expressed by a maize farmer is not always easy – but it is possible. One thing is clear: selecting a variety that is suitable for the intended use and location lays the foundation for a good yield. However, to realise the full yield potential of the variety, this is far from sufficient on its own. With well-thought-out crop management, it is possible to positively influence other key factors that affect the yield. The AGRAVIS experts provide valuable tips on this subject.
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- Experiments have shown that yield increases of 10 percent or more can be achieved with site-specific maize sowing compared to standard sowing.
Much yield is lost due to an "incorrect" choice of sowing density, i.e. one that is not suited to the location. But what is the "correct" crop density? How can it be calculated? And what factors need to be known for this? To answer these questions, AGRAVIS Raiffeisen AG has been carrying out precise experiments on crop density of maize since 2014.
Practical system from AGRAVIS NetFarming
Based on the findings from these experiments, AGRAVIS NetFarming GmbH has developed a practical system to calculate the optimum crop density and link this to site-specific approaches. Remote sensing data gathered over a number of years has been evaluated in order to identify different yield zones at field level. Combined with knowledge about the availability of water for maize sowing, the water retaining capacity of the location and assessment of the expected amount of precipitation, a sowing map can be created on the NetFarming portal.
Important: variety-specific properties
Properties that are specific to the variety are also taken into account in this process. These can sometimes represent enormous differences. The variety Niklas, for example, is more suited to higher sowing densities than the variety DKC 3507. In practice, therefore, the recommended sowing densities can vary between 5.4 and 12 plants per square metre within very heterogeneous areas. Experiments have shown that yield increases of 10 percent or more can be achieved with this process compared to standard sowing. Improved values have also been identified in several quality parameters. It therefore makes sense to address this issue.
Info on site-specific maize sowing
Further information on site-specific maize sowing and the maize starter pack for beginners can be found at www.netfarming.de or in AGRAVIS Aktuell 1/2017. As well as making a well-considered choice of sowing density, crop management of maize plants also includes nutrition in accordance with the plants' needs. However, the fertilisation strategy is not determined solely by the wish to maximise the yield. The legal framework often plays a key role here, because where maize is cultivated, livestock – and therefore ample manure – is usually not far away. At the same time, because of the pressure on agricultural space, many farms in cattle-intensive regions have to deal with tight nitrogen and phosphorus balances.
New German Fertiliser Ordinance
This problem will be exacerbated by the new German Fertiliser Ordinance and a new approach is needed in all areas where fertilisation is used. Efficient use of mineral and organic fertilisers must be the top priority in the long term. With organic fertilisation in particular, losses can be minimised. One of the most important levers for this is optimisation of the spreading technology. The more contact with the ground that can be achieved, the lower the probability of gaseous N losses. Fertilisation of maize with manure usually takes place on unworked arable land. The legally prescribed incorporation period of four hours is supposed to ensure that losses into the air are minimised. However, N losses amounting to up to 30 percent of the applied ammonium content can occur during this period if conditions are unfavourable. It is therefore extremely important to aim for the fastest possible incorporation.
As well as the machinery, weather conditions during spreading play a key role. The frequent practice of fertilising mature maize crops with manure needs to be particularly called into question, because at this time, high temperatures combined with sunshine can usually be reckoned on. Both these factors favour the release of ammonia gas to a high degree, which means that these times should definitely be avoided. To further improve the efficiency of the manure, it is advisable to add nitrification inhibitors such as Entec FL or Piadin, particularly when fertilising maize. These ensure that the ammoniacal nitrogen in the manure transforms more slowly into nitrate which reduces the leaching risk.
Risk of nitrate leaching
For maize, the main nutrition period and the fertilisation time are far apart, so with this crop, the risk of nitrate leaching is particularly high. The ammonium fraction remains "in situ" for longer and also has further positive effects with regard to plant nutrition, so the availability of micronutrients is improved, for example. With the classic approach, the next step is to use mineral side-dressing during sowing. For many farms, DAP is still the standard fertiliser, but not always the best choice for farms with a tight phosphorus balance due to its very high phosphorus content. There is a lot of experimentation in this area, and sometimes phosphorus is completely omitted from the side-dressing. In the short term, this works without any notable loss of yield, but there can be problems in the long run, and if conditions are difficult while the maize is still young.
Administering phosphorus in maize
So, how can maize be more efficiently fertilised with phosphorus? New systems can help to reduce the amount of phosphorus without having to reckon on loss of yield. With the seed band fertilisation process, fine microgranules are distributed into the seed furrow directly when sowing. The idea behind this is simple: the nutrients are closer to the grain. This enables the maize plant to access them more quickly and effectively. With this type of application, only 10 to 15 kilogrammes of phosphorus are distributed per hectare. Technically, this is possible by using microgranule spreaders which can be easily retrofitted to maize drills. AGRAVIS has carried out experiments with Phytavis Microgran P granules at several locations over a number of years.
Nitrogen, sulphur and zinc
Results consistently show that this type of fertilisation reduces the use of phosphorus without negatively affecting the yield. In addition to phosphorus, small quantities of nitrogen, sulphur and zinc are also applied via the microgranules. However, the nitrogen requirement cannot be covered by this means alone. In classic side-dressing, for example, stabilised nitrogen-sulphur fertilisers (such as Entec 26) can then be used. A seed dressing brings the nutrients even closer to the grain than the microgranules. Particularly in cold locations and unfavourable conditions, using the product Trailer for the application of nutrients such as nitrogen, phosphorus and zinc to the maize grain can be beneficial for the development of young plants.
Fertilisation with Korn-Kali
In addition to balanced nitrogen and phosphorus fertilisation, it is important to check the availability of the other nutrients. Potash in particular is removed in large quantities by the silage maize harvest. It is sensible to replace these quantities with Korn-Kali fertiliser prior to sowing. Although fertilisation with manure does provide a certain amount of potash, this amount is often overestimated. Current nutrient analyses of organic fertilisers in combination with soil analyses offer a good guide to bridging gaps in supply. If symptoms appear during the season which show, for example, a lack of boron and zinc in the maize, foliar fertilisers can cover short-term shortfalls.
For more information, please contact Stefan Hanebrink, Tel. +49 (0)251- 682 2067, firstname.lastname@example.org, www.netfarming.de.