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24 June 2026 13 minutos

Productive Optimum vs. Economic Optimum: Why Seeking Maximum Yield May Be Costing You Money

For years, we were taught that proper fertilization meant achieving the maximum possible yield. But with current fertilizer prices, that goal may be just what leaves you with no margin. There is a point, before maximum yield, where your money works harder.

Productive Optimum vs. Economic Optimum: Why Seeking Maximum Yield May Be Costing You Money

Every season, the same tension repeats on your farm. The bag of fertilizer costs more than last year, while the price at which you sell your harvest goes up, down, or stays still without you being able to do anything about it. You're caught between a cost you can't control and an income you can't either. And in the midst of that tension, you make a decision that defines a large part of your profitability: how much fertilizer to apply.

The traditional answer has been to apply what is necessary to achieve maximum yield, fill the tree, ensure it lacks nothing, extract all the production the crop can give. That logic made sense when fertilizer was cheap. But today, with inputs at historically high levels, chasing the last kilo of harvest may cost you more than that kilo is worth. You are spending on fertilizer to produce fruit that does not pay for what it cost to produce it.

There is a difference that almost no one explained to you, and that in the current context is worth its weight in gold: the difference between the productive optimum, the dose that maximizes biological yield, and the economic optimum, the dose that maximizes your profit; they are not the same point, and learning to seek the second, instead of the first, is one of the most profitable mindset shifts you can make. To understand it, you first need to be clear about what your crop consumes, what it truly takes, and when it needs it.

Total Absorption vs. Export: What Your Crop Consumes and What You Really Need to Replace

Let's start with a distinction that completely changes how fertilization is calculated, and that mixes two concepts that are often confused.

Total absorption is the complete nutritional demand of your crop throughout its cycle, all the nitrogen, phosphorus, potassium, calcium, and other nutrients that the plant takes from the soil to build roots, trunk, branches, leaves, flowers, and fruits. It is the complete picture of what the crop "eats" in a cycle. But what many overlook is that not everything the plant absorbs leaves your farm. The leaves that fall, the branches you prune, the plant residues… all of that stays in the lot and, as it decomposes, returns a good part of those nutrients to the soil. It is a loan that the crop makes to itself, not a loss.

Export, or extraction by harvest, is something else, and it is what really matters for your pocket; it is the minerals that physically leave the lot within the fruits you harvest and sell; that nitrogen, that potassium, that calcium that travels inside the avocado or coffee bean to the truck and never returns. That is the real loss, the non-negotiable bill that the soil presents to you and that you must necessarily replenish if you don't want your land to become impoverished with each harvest. Export is the real cost of the system.

Let's look at it with concrete numbers. In Hass avocado, a production of 20 tons per hectare exports from the lot about 52 kg of nitrogen, 21 of P₂O₅, and 94 of K₂O within the fruit. There is something revealing about potassium, it almost doubles nitrogen, because the avocado fruit is a great demander of potassium. In coffee, although the logic is the same, the crop extracts very different amounts of each nutrient depending on what the harvested beans take. Knowing that export figure is the starting point for any rational fertilization, because it defines the minimum floor you must return.

Fertilizing based on total absorption overestimates what your crop really needs you to provide. If you calculate your dose thinking about everything the plant absorbs, including what will return to the soil via leaf litter and prunings, you will be applying too much, paying for nutrients that the system was already recycling. Intelligent fertilization starts from the real export, adds what is lost along the way (leaching, fixation, volatilization, as we saw in previous blogs), subtracts what the soil already provides and what is recycled, and only then defines how much to buy. Everything else is waste.

Absorption Curves: Your Crop Doesn't Eat the Same Every Day

Knowing how much your crop exports in a complete cycle is half the story. The other half is when it needs it. And here comes a concept that separates calendar fertilization from precision fertilization, which is the absorption curves.

An absorption curve is the graphical representation of how many nutrients the plant extracts at each stage of its development; this reveals that your crop does not consume the same amount of nutrients every day. The speed and volume of absorption per hectare change drastically throughout the phenological cycle. There are moments of calm, when the plant takes little, and moments of explosive demand, when it needs large amounts in a few weeks.

In avocado, after harvest and pruning, the tree needs nitrogen to regenerate foliage and build the structure that will support the next load. During flowering and fruit set, the protagonists are calcium, boron, and zinc, which define how many flowers turn into fruits and prevent physiological drop. And during the fruit filling, those months from fruit set to harvest, the demand for potassium skyrockets, which is the nutrient responsible for transporting sugars and defining the final size that the market pays you for. Applying potassium abundantly during flowering, when what the tree needs is calcium, is wasting money and, worse yet, risking the harvest.

Here is the economic consequence that almost no one calculates, a nutrient applied outside its demand window is a nutrient exposed to being lost. If you put nitrogen when the absorption curve is low, the plant does not take it at a sufficient speed, and that nitrogen is left at the mercy of the rain that washes it away or the soil that transforms it. You paid for it, but your crop did not take advantage of it. The absorption curves are the map that tells you when each peso invested in fertilizer has the highest probability of becoming a harvest, and when it will slip away. Synchronizing the application with the curve is, in practice, fertilizing fewer times in vain.

The Productive Optimum is Not the Economic Optimum

Now we have the two ingredients, how much the crop exports and when it demands it, to understand the heart of this article, and the concept that can transform your profitability.

Imagine plotting a graph of the relationship between the fertilizer dose you apply and the yield you obtain. At first, each additional kilo of fertilizer produces a big jump in the harvest: the nutrient is scarce and the plant responds strongly. But as you continue to increase the dose, each additional kilo produces less and less extra harvest. The curve flattens out. This is what agronomy calls the law of diminishing returns, and it is one of the most consistent laws of agricultural production.

The productive optimum is the peak of that curve, the dose with which you achieve the maximum yield that your crop and your soil can give, regardless of how much it costs to get there. It sounds good, but it has a trap; the last kilos of fertilizer needed to reach that peak are very expensive in relation to the little extra fruit they generate, you are paying full price for nutrients that barely move the yield needle.

The economic optimum is another point, and it is before the peak. It is the exact place where the value of the extra fruit produced by the last kilo of fertilizer equals what that kilo costs. One step beyond that point, each additional kilo of fertilizer costs more than it returns in harvest, and you start to lose money even though you continue to produce more fruit. The economic optimum does not maximize your harvest; it maximizes your profit.

The most important thing is that this point moves with prices; when fertilizer is cheap in relation to the price of your harvest, the economic optimum approaches the productive one, it is worth applying a lot. But when fertilizer becomes expensive, as it is now, the economic optimum retreats, and it is profitable to apply less. Data confirms this precisely; in nitrogen fertilization trials, when the price relationship between fertilizer and grain was favorable, the optimal economic dose was between 125 and 137 kg of nitrogen per hectare; but when fertilizer became more expensive to a price relationship four times higher, that optimal dose fell to between 83 and 93 kg. The same land, the same crop, the dose that suits you changed almost 35% just because the input price changed.

This explains why the "always formula" can ruin you in a year of expensive inputs. A dose that was optimal when urea was cheap becomes a waste when urea skyrockets. And the error goes in both directions: falling short sacrifices harvest that was profitable, but overshooting, the most common mistake, burns money on fertilizer that does not translate into income and, on top of that, is lost through leaching, contaminating. The exact point of the economic optimum is not fixed nor inherited: it changes every cycle, with each lot, with each price.

Do you know where on the curve your farm is fertilizing today? Most producers apply seeking maximum yield without knowing that the maximum profit is a few kilos before. Harvis helps you find that point, lot by lot. Talk to our team →

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Finding the Exact Intersection of the Economic Optimum

Calculating the economic optimum by hand is practically impossible for a producer because it requires crossing variables that change all the time. This is where technology does what no manual calculation can.

That would only solve half the problem. What I do with the information is cross three layers of information that move independently: the absorption curve of your crop, how much it demands and at what exact moment in its cycle, the fluctuating price of each fertilizer in the market that changes week by week, and the projected price of your harvest at the time you are going to sell. With those three variables, the problem stops being agronomic and becomes mathematical: finding the point where they intersect.

On that crossing, I always model where the intersection that defines your economic optimum is located; the precise dose, at the precise moment, where the last peso invested in fertilizer still generates a return, just before entering the zone of diminishing returns where you would start to lose. It is not the dose that fills the tree to the maximum; it is the dose that maximizes your margin. And since that point depends on changing prices, the model adjusts; if potassium becomes more expensive this season, the recommendation retreats; if your harvest projects a good price, it may make sense to invest a little more.

There is a second saving, equally important. By synchronizing the recommendation with the absorption curve, with the data shared with me, waste due to leaching is avoided; I do not suggest applying a nutrient when the plant is not demanding it and, therefore, when it would be lost. Each application falls within the window in which the crop can actually take it. The result is twofold: you stop overspending on unnecessary products, and you stop losing the product you do apply. Evidence supports this approach: nutrient management adjusted to the data of each site has shown profitability increases close to 15%, applying 10% less fertilizer than the producer's usual practice. Less input, more profit, less loss to the environment: the economic optimum and soil care point to the same place.

Stop Fertilizing to Show Off Your Harvest and Start Fertilizing to Win

For too long, the success of fertilization has been measured by the size of the harvest. But a loaded tree means nothing if the kilos that loaded it cost more than what that fruit is worth. In the current context, with expensive inputs and uncertain selling prices, the producer who survives and thrives is not the one who produces the most, but the one who best manages every peso they invest in nutrition.

The mindset shift is this: stop asking yourself "how much should I apply so that my crop lacks nothing?" and start asking yourself "what is the dose that leaves me the greatest profit this cycle, with these prices, on this lot?" The first question seeks the productive optimum and, today, often costs you money. The second seeks the economic optimum and is the one that protects your profitability. The difference between one and the other is not seen in the tree: it is seen in your pocket at the end of the season.

As we already addressed in our blog Do You Know How Much It Costs to Produce a Kilo of Coffee or a Liter of Milk?, which you can read here, knowing the real cost of production is the basis for any profitable decision. Fertilization is, almost always, one of the largest costs of that calculation, and that is why a good decision generates the greatest return.

You don't have to solve this equation alone. Send me the data and my system crosses the absorption curves of your crop with the real market prices to tell you exactly how much, when, and in what form to fertilize to reach your economic optimum, lot by lot and cycle by cycle.

Optimize your crop's nutrition and stop losing money on every bag. Write to us on WhatsApp and receive technical assistance to find the economic optimum of your farm. Talk to Sales

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