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When does maize need nutrients?

The first part of the series “Solid & Liquid Fertilisers” deals with the question of how to ensure the best possible nutrient supply for maize to secure yields. 

The traditional underground fertilisation has mostly become a standard in Europe. Because of new climate challenges, the fertilisation strategies for maize have already been undergoing a change process for several years. The objective is to better establish the crops and to supply them earlier to compensate for the weather conditions and to influence the population development in a positive way – always with the aim of approximately maintaining the yield level.

Challenges with maize

After seeding, maize has to emerge quickly and evenly. The maximally possible yield level is determined at an early stage (approx. 4-8 leaves) by the formation of the cobs. This is why in this stage, the quick and early availability of nutrients is essential for the plant. At the same time, it still is cool at that time and in many parts of Europe the soil temperature is below 15° C. This means that mineralization does not yet take place and thus nutrients are not yet additionally delivered from the soil. Moreover, the underground fertiliser depot cannot yet take effect as it has only been opened up by the plant to a limited extent. In this stage, warm and cold temperatures phases often alternate making the nutrient uptake more difficult the more so as the maize at that time has only formed a rudimentary root system and thus, its nutrient utilisation ability is rather poor.

The nutrient demand of maize varies enormously in the course of the different development stages. At the same time, the parameters nutrient availability and nutrient uptake change, too. In the youth development, from the switch from grain to root nutrition, the supply of N and P is crucial. During this period, the demand of maize for N and P is highest – while the uptake rate in relation to the dry matter formed is lowest.
After the youth development, the requirement for nitrogen and phosphorus continuously increases until the blossoming stage. During this phase, the underground fertiliser depot already is fully developed, and the soil gets warmer and warmer, i.e. mineralisation and additional supply from the soil or from organic fertilisers also increase continuously. Therefore, in some regions, liquid manure is applied in the population at the time of stem extention to secure the nutrient supply in this phase – with the largest possible daily nutrient quantities.

Trend toward starter nutrient application

To counteract the core problem that nutrients are not fully available after seeding and to use this time more efficiently, the trend in Europe at the moment is towards a concentrated input of starter nutrients. It depends on the type of soil and the general supply of the soil as well as of the specific climatic site. When sowing early and with rather colder temperatures, the starter nutrient application is more important than in regions where the soil heats faster due to the climate or where seeding is carried out later. The general supply situation of the soil also is very important. On soils where the supply is excellent for example due to the longtime use of organic fertilisers, a placed starter fertiliser input plays a rather minor role. On poorly supplied soils, a targeted nutrient input and a nutrient input close to the grain make sense to supply the plants as early as possible in an optimum way.

The starter nutrient input can be applied in the form of fertiliser granules or liquid fertiliser which are placed directly at the seed in the seed furrow. This ensures an efficient nutrient utilisation as already the first roots can absorb the concentrated fertiliser.
Liquid fertiliser is comparatively low priced and available in high capacities. On dry soils, its advantage is that it is available to the plant in a concentrated way what argues for an efficient nutrient utilisation. As a contact fertilisation directly at the grain, even small quantities of liquid fertiliser are sufficient to ensure an ideal supply of the plant with starter nutrients.

The big advantage of solid fertiliser is that it can be mixed for different variants and compositions. Logistics and market availability, too, play an important role. Anyone who can handle seed, normally can also handle solid fertiliser. Thus, granulated starter fertiliser in the form of microgranular compound in general is easier to handle and currently also more widespread in many markets.
Both starter nutrient methods (solid and liquid) are not about applying high quantities of nutrients in the field. The objective is to concentrate low nutrient quantities and make them available to the plant close to the primary and secondary root system to encourage youth development. The main nutrient supply still comes from the underground depot, organic fertilisation or the additional nutrient from the soil.
In the next terraHORSCH, we will take the Maestro line as an example to take a closer look at the technical aspects of the application of solid and liquid fertiliser.