How to use the “Law of the Minimum” to rationalize fertilizer investments – Part 2

In the first part of this article, I sought to contextualize how the lack of some or even a single nutrient can limit productivity and generate low returns on investment in fertilizers. Knowing the “Law of the Minimum”, my proposal for this second moment is to exercise this concept by applying fertilizer. But, to avoid technical terms and the need for in-depth knowledge in interpreting soil analysis and nutrition, we will facilitate the process with a “fertilization game”.

In the figures below, we present, in square format, both the nutrient content in the soil, in orange, and the doses that are contributed in fertilizers, in green.

The objective of the game is to use the green squares to level the soil nutrient columns (N, P, K, S and B) to obtain the highest possible score. But be careful: as in the Minimum Law, The column with the least number of colored squares (orange and green) will define the maximum score.

Having understood the objective of the game and the rules, it remains to define how many squares are available for use and these are given by the “RESOURCES” field containing eight green squares. Now let's put it into practice and, in three attempts, aim to achieve the highest score possible with the resources available.

Attempt 1: the eight green squares were used to raise the N, P and K columns with practically equal amounts for each nutrient. Note that even with the large increase in N, P and K, in the end, column S is the one that defines the score of 400 points.

Attempt 2: five green squares used to level the N, P and K columns and three used to adjust the S and B columns. Final result: 600 points.  

Attempt 3: As there are not enough resources to raise all the nutrients in the N level, the eight squares were used to adjust the other nutrients, generating 700 points.  

If you have come this far and understood the concept of the “Law of the Minimum”, you will notice that what this game illustrates is the reality of decision-making for fertilizer. In addition to the need to know soil fertility, there are several possibilities for combinations of fertilizers and scenarios that generally have limited resources. And the attempts in the game sought to illustrate the following scenarios:

Attempt 1 - cases in which fertilization is carried out based only on experience or with little information, with little consideration of the nutrient content of the soil or even the fertilization balance. It is usually a decision between using “more or less fertilizer” during the harvest without much attention to the needs of the plants or soil conditions.

Attempt 2 – fertilization already considering factors related to productivity expectations and the balance between nutrients. These are commonly situations in which there is concern about applying “points” or “kilos” of nutrients and these are more efficient processes than the previous one. What happens, however, is that the analysis tends to be very focused on primary macronutrients (NPK), and the other nutrients are applied incidentally because they are, in some way, contained in the products.

Attempt 3 – is the best example of how to rationally use fertilizer resources. Realize that, even though it is not possible to fully invest in all nutrients, understanding the soil situation and the importance of fertilization balance provide the best result among attempts. The restriction of resources may not have allowed reaching the maximum potential, however, the strategy of eliminating or minimizing the nutrients that are limiting made it possible, in this situation, to take advantage of the investment made in fertilizers and generate gains in productivity.

Both in the “fertilization game” and in real life, to use fertilizers rationally and obey basic agronomic concepts, such as the “Law of the Minimum”, we must always base ourselves on facts, data, information and, without a doubt, on our acquired experience to define the best strategy. Knowing in depth how the soil is, the culture to be implemented and using tools that provide better diagnoses, recommendations and nutrient use efficiency will certainly generate benefits in productivity and production sustainability.

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 the productivity, profitability and sustainability of crops. . The solution uses the best of the company's fertilizer technologies - MicroEssentials, Aspire and K-Mag - containing macro and micronutrients in balanced levels and with immediate and gradual availability, providing high operational performance and effective distribution in the field. All of these characteristics generate increases in nutrient absorption, better crop nutrition and result in productivity increases, for example, for soybean crops of up to eight bags per hectare in relation to conventional fertilization.

By Flavio Bonini, Technical Services Manager at Mosaic Fertilizers

The first part of this article can be read here.