Sugarcane success is related to correct boron management

We know that boron is an extremely important micronutrient for plants, participating in physiological processes, such as: growth regulation (regulates the synthesis of AIA oxidase), correct formation of floral buds, formation of fibers (cotton) and carbohydrates (soy ), synthesis and transport of sucrose through the phloem (sugar cane), among others. However, the difficulty of nutritional management of this nutrient is also known, mainly due to the high potential for leaching of boric acid and sodium octaborate in the soil.

An important characteristic of this nutrient is its low mobility, especially in species that do not produce polyols as primary metabolites (natural boron complexes). As a consequence, in addition to the deficiency frequently observed in soil boron fertilization, excessive foliar supplementation can cause boron accumulation on the leaf surface, causing phytotoxicity, whose symptoms can even be confused with fungal diseases.

With the aim of proposing a solution to the aforementioned problem, Agrotechnica, for example, developed the Octabor foliar fertilizer, a product with 8,5% m/m of soluble boron (110,5 g/L), fluid, for applications via leaf. It is composed of a true complex between borate anions and a mixture of polyols, the exact composition of which led to the company's recent filing of a patent.

To prove its effectiveness, the performance of Octabor was evaluated in sugarcane cultivation, applying the fertilizer together with the ripener, against other sources of boron: boric acid, sodium octaborate and boron neutralized with monoethanolamine, in commercial areas . Furthermore, research was carried out only with application of the product in pre-ripening, 60 days before harvest, to compare with applications from different ripeners, in the same area. The main parameters evaluated were: Total Recoverable Sugars (ATR) and/or productivity via Tonne of Sugarcane per Hectare (TCH). The commercial areas where the experiments were conducted included alcohol and sugar plants and sugarcane suppliers in the States of São Paulo and Goiás.

The results showed that the Octabor product performed better than other boron sources, when applied together with ripeners. Even with a smaller amount of nutrient applied, the response was superior in all cases, being the most significant against boric acid, where the final difference in ATR was 6,9 kg/t.

It was also possible to observe that the application of Octabor in pre-ripening achieved higher TCH and ATR values ​​than conventional treatments with ripeners. These results are consistent with current studies on ripeners and boron in pre-ripening, where it is possible to conclude that the function of boron is different from the mode of action of ripeners. While the former actively participates in the biochemical processes of sucrose synthesis and transport in the plant, the latter act on the plant's hormonal metabolism, regulating the chemical energy it produces for storage in the form of sugars to the detriment of its use for growth. vegetative.

Thus, it is possible to conclude that the boron-based fertilizer complexed with polyols presented more relevant indices compared to the other sources of boron usually used in sugarcane cultivation, in relation to the ATR. Furthermore, the experiments carried out with Octabor in pre-ripening (60 A.D.C.) indicate that the supply of a source of boron with a different formulation can be an important tool for the nutritional management of the nutrient in sugarcane cultivation, enabling significant gains in both TCH and ATR, regardless of the application of ripeners or in joint applications, depending on the farmer's objective and the time of application of the products.