Benefits of fertilizer efficiency on sugarcane yield and longevity

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Sugarcane is, without a doubt, a crop of great relevance and importance in the Brazilian agricultural scenario. According to Conab, the area harvested in the 2020/21 harvest was more than 8,6 million hectares, generating, through the conversion of more than 654 million tons of harvested stalks, around 41 million tons of sugar and 29 billion of liters of ethanol for the national economy.

An important difference between sugar cane and other crops is its cultivation cycle. As it is considered a semi-perennial crop, there are particularities regarding the practices adopted at the time of planting and, in subsequent years, the regrowth of sugarcane that occurs after harvesting and which are known as “ratoons”. One of the biggest challenges for sugarcane production is how to extend the useful life of the sugarcane field to allow, in a sustainable and economic way, the greatest possible number of cutting and regrowth cycles (ratoons).

Among several practices used to enable this extension of the sugarcane cycle, fertilization management is an extremely efficient strategy that, both from a technical and operational point of view, has proven to be increasingly important in the production results of sugar cane ratoons and, mainly, when fertilization is carried out in a complete and balanced way.

It is a fact that, for several years, sugarcane ratoon fertilization was always thought of as applications limited to the two macronutrients most extracted from the soil by crops, which are nitrogen and potassium. Those who are a little more familiar with the culture have certainly heard or even recommended the application of fertilizer formulas such as 16 00 30, 18 00 27 or 20 00 20. For a while, this practice worked and was consolidated, mainly because much of the sugar cane was cultivated in soils with better fertility, as well as due to average productivity which, until the mid-2000s, was at levels below 70 t/ha.

Even with all the challenges and difficulties faced by sugarcane in recent years, the production scenario has been changing in a positive and consistent way, driven mainly by the change in approach to how to fertilize and nourish crops and look at the efficiency of the products used.

As an example, and returning to the nutrients most used by sugarcane, nitrogen has always been a major concern in fertilization. As it is an extremely demanding crop in this element, applications of around 90 to 120 kg/ha of nitrogen are common in different situations. But, more than the dose, the understanding of the best source to supply nitrogen in sugarcane ratoon fertilizers has always been questioned by producers. And, in this topic, urea was considered for some time as an inferior source to the others for the sole reason that, in some situations, if applied to the soil surface, part of its nitrogen could be volatilized, that is, lost in the form of ammonia gas and not be used by plants.

But, on the other hand, among all the most used sources, urea, in addition to being the source with the widest availability on the market, is the one with the highest concentration of nitrogen (46%) as well as with the ideal physical characteristics for application and mixing with other fertilizers. In other words, once the issue of possible nitrogen loss has been resolved, urea becomes an extremely interesting fertilizer for fertilizing sugarcane ratoons and for field operations.

And, it is in cases like this that research, development and technology in fertilizers work to solve problems and bring highly efficient solutions to sugarcane fertilization. Mosaic Fertilizers, in its extensive portfolio, has the Excellen line, which are products with urea stabilized with NBPT additive, a technology that reduces losses due to nitrogen volatilization and allows the obtaining of products highly concentrated in nitrogen and other nutrients for ratoon fertilizers of cane. In addition to greater efficiency in the use of nitrogen by sugarcane, the use of Excellen generates gains through reduced storage costs, application time and greatly improves fertilization due to the great versatility of formulas and greater safety in the handling and application of products.

Another extremely important nutrient for the yield and longevity of ratoon crops is phosphorus. Phosphorus is an immobile nutrient in the soil, which is applied to sugarcane cultivation, basically, at the time of planting for estimates of 4 to 5 cuts. However, what happens is that with time and contact of this nutrient at the bottom of the furrow, part of the phosphorus applied during planting becomes fixed in the soil and loses its efficiency. In this way, more and more excellent results have been observed by applying doses of phosphorus to sugarcane ratoon. The application of P together with N and K in the ratoon crop, and always in accordance with the results of soil analysis, aims not only to increase productivity but also to improve the development of the root system, which contributes to increased longevity of the sugarcane field.

In general, it is recommended to apply phosphorus to ratoon crops when soil levels are below 15 mg/dm³ and in doses of 30 to 40 kg/ha of P₂O₅ depending on expected productivity. However, new scientific work and field observations have demonstrated responses to phosphorus in wider ranges of levels in the soil, as well as doses that can reach up to 60 kg/ha of P.₂O₅.

And, in the same way as nitrogen, Mosaic also brings innovation to other nutrients with a focus on increasing efficiency and productivity. As for phosphorus, Mosaic recommends its application in sugarcane ratoons as MicroEssentials, a product that has consistently shown average increases of 7 t/ha of sugarcane in relation to management with sources of traditional matches.

However, it is worth highlighting that not only productivity is a factor in the profitability of the crop, but also the quality of the harvested product. The amount of sugar contained in the stems (ATR) is important for the yield and industrial conversion of sucrose. And, to obtain better quality in sugarcane, that is, with greater ATR, the plant must transfer the sugar produced to the stalk, a point in which Magnesium plays a fundamental role. For efficient applications of this nutrient, Mosaic Fertilizers recommends K-Mag, a product that provides potassium, sulfur and magnesium with high solubility and rapid availability for the crop. The use of K-Mag in sugarcane ratoon fertilization, in addition to contributing to increased productivity, also improves sugarcane quality indices, demonstrating in several fields, TRS increases of more than 3 kg/t.

It is clear that, with the new levels of productivity and the need to increase the longevity of the sugarcane field, greater attention must be paid to the balance and efficiency of fertilization of sugarcane ratoons. The careful assessment of soil conditions and productivity expectations and the use of products with proven performance such as Excellen, MicroEssentials and K-Mag are determining factors so that the crop can convert, with greater efficiency, the nutrients provided in fertilizers, transforming them into greater production and better quality of sugar cane. And in the end, this translates into greater profitability and, without a doubt, increasing the productive sustainability of the crop.