Organo-mineral fertilizers for optimal nitrogen nutrition of rice

Proper nitrogen nutrition of rice is essential to guarantee appreciable results from the cultivation of this cereal.
Nitrogen supports the vegetative growth of plants and increases yield and quality of production, favouring tillering, the development of the leaf area, the formation and filling of caryoxides and, last but not least, the synthesis of proteins, which increase resistance to cooking.

The chemical forms of nitrogen absorbed by rice are mainly ammonia in submersion and nitric nitrogen in dry phases (with a decidedly greater energy expenditure), to a lesser extent urea and amino acid.

The quantity and chemical forms of Nitrogen present in the circulating soil solution strongly depend not only on the composition of the soil itself (especially in terms of organic substance) but also on the submersion/dry alternation. In particular, dryness (i.e. the condition of aerobiosis) favors nitrification, with the transformation of ammonia into nitrates (more subject to leaching), while submersion favors the presence of ammonium ions.   The fractionation of the total annual dose of Nitrogen on rice is always to be expected, but it is not possible to generalize the scheme, as it varies depending on the cultivation context (including water management: dry seeding, round irrigation, continuous submersion) and the cultivated varieties (cycle length), being able to provide from two (pre-seeding and corn differentiation) to three interventions (pre-sowing, tillering and differentiation of the cob).

Both the deficiency and the excess of Nitrogen can have negative effects on rice and possibly on the environment.

In case of insufficient availability, rice shows chlorosis, stunted growth and abnormal development of the root system, with fewer and more elongated roots. Production is affected in qualitative terms (due to the lower accumulation of proteins in the caryoxides) and quantitative (due to the decrease in the number of culms and spikelets). Nitrogen deficiency, more common in soils with a low organic matter content and low CSC, can however also occur when the fertilizer units are applied at the wrong time or improperly.

On the other hand, an excess of nitrogen fertilization can increase the chalkiness of rice and negatively affect its aesthetic qualities, as well as making the tissues more tender and sensitive to attacks of diseases and parasites. Incorrect and/or excessive nitrogen fertilization can finally have negative repercussions on the environment due to the heavy losses of fertilizer units due to leaching or volatilization. The excess of Nitrogen also leads to the undesirable proliferation of algae in the water during the submersion phases, as well as to a greater risk of eutrophication of the water itself and of the receiving reservoirs when the chambers are emptied.

It is therefore essential to ensure that the Nitrogen distributed in each application is made available to the plant gradually. In fact, it is estimated that the efficiency of using fertilized nitrogen units by rice is very low, between 30 and 50%, due to losses due to washing and denitrification (nitric nitrogen), volatilization (ammonium nitrogen) and immobilization (both chemical forms).

To promote this gradual release of Nitrogen, it is possible to resort to so-called “controlled release” fertilizers, that is, added with inhibitors – nitrification or urease – capable of slowing down the processes of transformation of Nitrogen from one chemical form to another. Calciocyanamide is also used, which, in addition to Nitrogen, provides calcium, a fundamental element in rice nutrition and important for counteracting soil acidification in rice fields, linked to prolonged submersion.

The alternative to these products is represented by organo–mineral fertilizers, which by virtue of their formulation release nitrogen both in a ready release (mineral fraction) and in a slow and prolonged manner over time, following the mineralization processes that the organic matrix undergoes by the microorganisms present in the soil. For these performances to be guaranteed, the quality of the organic substance used in the formulation of the products is fundamental, in particular its level of humification. The presence of high quantities of humic substances is in fact the basis of the cation exchange capacity of organo-mineral fertilizers and, consequently, the protective effect against the nutrients – which are therefore released gradually and with a significant reduction in losses – as well as their buffering capacity.

Agriazoto 300 is a high-strength nitrogen-based organo-mineral fertilizer, designed for the optimal fertilization of nitrogen-hungry crops. The specific composition of the organic matter and the forms of nitrogen contained determine a prompt and gradual transfer of Nitrogen, to better accompany the development and needs of the crop. The organic atter contained in Agriazoto 300 promotes the maintenance of soil fertility and ensures the  Nitrogen is protected from losses due to evaporation and washout, thus benefitting the crop, the environment and business revenue.