How to use the “Law of the Minimum” to rationalize fertilizer investments – Part 1

When I started reflecting on this article, I decided to do an exercise to understand what the internet already offers on the subject. I opened the content search engine, typed “fertilization reduction” and more than 62 thousand results were displayed. But I didn't stop there, then I wrote “balanced fertilizer” and received 10 thousand results. I was curious and, at the same time, tempted to continue and, as a last step, I searched for “balanced fertilizer” and just over 4 thousand results came to the screen.

The existence of a lot of content addressing the reduction of fertilizer to the detriment of balance, in principle, may even make sense, given some intrinsic factors of agriculture. Fertilizers are essential for increasing productivity and sustainable production, but like other inputs, they are part of the production cost, and at times when the market puts pressure on margins, the first thought that comes to mind is cost reduction and , consequently, the use of these products.

By choosing to reduce fertilizer, the producer is reducing or suppressing the supply of nutrients to the plants, focusing only on cost as the driver and disregarding important aspects, such as the condition of the soil, plants or even the climate. In the short term, this option reduces the budget, but can considerably increase production risk and negatively impact the economic result of the harvest.

Yes, balance or balance fertilization It is a path that requires more information for decision-making, but allows the crop to better respond to the investment made in fertilization, reducing risk and the cost per product harvested. What changes in this option is the direction towards reducing or even increasing the supply of nutrients, considering the analysis of all the elements required by crops and how they are in the soil. In practical terms, it is possible to reduce the intake as long as an analysis is made of the reality of each nutrient, that is, identifying which ones are most limiting and which, if applied, will generate a greater return on investment.

To achieve this, it is possible to apply a law that, if followed and respected, provides greater security and predictability for fertilizer recommendations and results. The concept was created and put into practice in the mid-19th century, by the German inventor and chemist Justus von Liebig, and to this day, it is fundamental for the rational use of nutrients in fertilizers. When evaluating the availability of each element in the soil, he observed that the yield of a crop is limited by the nutrient that is least available to the plants.

“Liebig’s Law” or “Law of the Minimum” can be easily explained as shown in the figure below. On the left, the nutrient P (phosphorus) board defines the maximum water level in the barrel and even though all the other boards are higher, this one limits the water level. The moment this board is aligned with the others, representing fertilizer, the barrel's water capacity increases.

Expanding this concept to crops, limiting plant productivity is avoided with the balance of all nutrients. In other words, to guarantee healthy and productive soil, it is necessary to meet the nutrition needs that satisfy the needs of the crops. This means that, even if a large amount of nutrients are applied in fertilization, if the content of a single nutrient, which is more limiting in the soil, is not met, the efficiency of the fertilization will be very low.

For this reason, the most important step to starting the discussion about fertilization is to make a well-made diagnosis, identifying which nutrients may be limiting the productive potential. Powerful tools such as good sampling of areas, reliable soil analysis, knowledge of the management history and the culture to be implemented are essential to carry out a good diagnosis and recommend nutrients in accordance with the 4C's philosophy – Correct nutrient, dose Correct, Correct place, Correct time.

After the diagnosis has been made, the best way to reduce risk without reducing the productive potential of crops is to make rational use of nutrients and proven, high-efficiency products. These are the reasons why Mosaic Fertilizers develops and recommends products such as Performa, a line of high-performance fertilizers that combines the most advanced technologies to provide greater fertilization efficiency and increase productivity, profitability and sustainability of the production.

The Performa line has the best of Mosaic Fertilizers' technologies - MicroEssentials, Aspire and K-Mag - containing macro and micronutrients in balanced levels, with immediate and gradual availability of nutrients and high uniformity, providing high operational yield and effective distribution in the field. All these characteristics and benefits generate increases in nutrient absorption, better crop nutrition and result in increased productivity.

For soybean cultivation, for example, the use of the products can increase production by up to eight bags per hectare in relation to conventional fertilization. Performa was developed to nourish crops from the beginning to the end of the cycle and help build soil fertility, resulting in increasingly efficient and sustainable production systems.

By Flavio Bonini, Technical Services Manager at Mosaic Fertilizers

The second part of this article can be read here.