Cereals: focusing on nitrogen fertilization

Nitrogen plays a role of primary importance in the nutrition of plants: it is essential to their growth (plastic function), but also has a decisive influence on production performance, in quantitative and qualitative terms.

In the specific case of cereals, nitrogen deficiency is at the origin of stunted development, chlorotic spotting of leaves, reduction of photosynthetic efficiency and unbalanced composition of the grain.

On the other hand, excess nitrogen lengthens the plant cycle causing delays in the phenological phases, increasing sensitivity to biotic and abiotic adversity and favouring lodging in autumn-winter cereals.

Nitrogen is present in cultivated land in three forms:

• organic, part of the humus. It is provided to plants for absorption by mineralization processes, which release ammonia and nitric nitrogen;
• ammoniacal, scarcely available to plants since it is retained for adsorption by soil clays;
• nitric, very soluble in water, not retained by clays and highly available to plants.

Cultivated plants absorb Nitrogen mainly in the form of nitrates contained in the circulating solution, which, however, are also strongly subject to leaching, and therefore to the risk of percolation in ground water, and  risks to human health, since it is believed that nitrates may have carcinogenic effects. For this reason, the European Union in 1991 issued the so-called “Nitrates Directive” (Dir. EC 91/676), which requires all Member States to adopt good agricultural practices to contain the negative effects of the agricultural practice of nitrogen fertilization on the quality of groundwater.

In addition to leaching, the loss of nitrogen from soil layers explored by the roots of cultivated plants is also the phenomenon of:

– denitrification: reduction of nitrates and nitrites to gaseous forms, such as molecular nitrogen and nitrous oxide, and their dispersion in the atmosphere. Since this is a process favoured by anaerobiosis, it became a focus point in the paddy field;

– volatilization: nitrogen leaks in ammonia form, favoured by the basic pH of soil, humidity and high temperatures.

But where does the nitrogen that crops feed on come from? From two natural phenomena — biological nitrogen fixation, carried out in the soil by bacteria, and atmospheric nitrogen fixation, caused by electrical discharges that transform the Molecular nitrogen into nitrogen oxides and ammonia, which are then dragged ashore by rain — and from one anthropogenic phenomena: fertilization.

Just like with any other crops, cereals also need to establish an adequate nitrogen fertilization plan, which means identifying the dosage, the distribution times, the type of fertilizer and nitrogen form to be use and finally the distribution method;

The calculation of the nitrogen dose to be distributed over the entire crop cycle will have to take into account several factors:

• the cereal sowing time (autumn-winter cereal, spring cereal);
• the expected quantity and quality of production;
• the availability of nitrogen in the soil (also thanks to the crops that preceded the cereal in the rotation) and/or deriving from rains;
• possible losses due to leaching, volatilization, denitrification.

The distribution of nitrogen in cereals is more effective and efficient if its fractional, with variable timing depending on the cereal, but which normally contemplates a pre-fertilization sowing and another 1-2 interventions when the crop has high needs.

You can choose between:

• mineral, organo-mineral fertilizers (we spoke about it here) or organic ones, which provide a variety of Nitrogen for plants in terms of quantity and transfer times (fast release, controlled release). Knowing the peak needs of the crop, also in relation to the weather trend, allows you to choose the most suitable formulation to ensure the satisfaction of the nutritional needs of the plant without wasting fertilizer units;
• solid (granular/pelleted) or liquid fertilizers;
• distribution to the ground (also with fertigation) and leaf distribution (covered).

Nitrogen is essential for guaranteeing the good performance of any cereal crop, and thus plays a role of fundamental importance in the cultivation of corn, where the fertilization plan must therefore provide for adequate contributions not only in terms of quantities but also of periods of distribution and fractionation.

One hectare of corn that produces 130 quintals of dry grain requires approximately 290 units of Nitrogen which, without prejudice to all the above considerations concerning the balance of this element in a cultivated land, should be distributed as follows:

– 30% during pre-sowing (preferably through controlled transfer fertilizers);

– 35% within the growth phase

– 35% after about 30-35 days after the second application.

For the fertilization of cereals, Agribios offers a wide range of products, both pelleted and liquid, organic and organo-mineral, formulated for both integrated and organic cereals.

Some of the high-nitrogen products are:

AGRIAZOTO 300, high-titer nitrogen organo-mineral fertilizer, designed for the optimal fertilization of nitrogen-hungry crops. The specific composition of the organic substance and the forms of nitrogen contained determine a prompt and gradual transfer of the element, to better accompany the development and needs of the crop.

AGRIORGANICO 10%, nitrogen organic fertilizer obtained for cold pelleting from a mixture of partially hydrolyzed animal proteins and dried manure. The size of the natural organic molecules containing nitrogen allows it to be released gradually, remaining available to the plant for longer. Authorized for organic farming.

AGRICOMPLEX 10.5.15, AGRIOLIVO 12.5.5 and AGRISPRINT 10.5.8, which allow in a single step, to combine the mineral fraction containing gradual release nitrogen with phosphorus and potassium, along with a significant amount of highly humidified organic matrix and meso elements.

BIOCOMPLEX 5.15.5, produced from a mixture of organic fertilizers with a high nitrogen and phosphorus content with added potassium sulfate, to obtain an organo-mineral fertilizer complete with all the nutrients required by plants and an ideal ratio between the various nutrients. Authorized for organic farming.

SUPERORO, containing nitrogen and phosphorus which, being linked to protein molecules, are not directly usable by plants but are made available gradually and at a pace in tune with the nutritional needs of crops. Authorized for organic farming.

SUPERPRIMO 9.20, containing a mixture of manure (bovine and poultry) and processed and partially hydrolyzed animal proteins, maximizing the protection of nitrogen and phosphorus nutrients as well as calcium, sulfur and zinc. The natural substitute for nitrogen and phosphorus-based mineral fertilizers on the market.