Honestly, it’s mostly historical and practical. As agronomists, we’re trained to tackle what’s visibly limiting in the field: pests, diseases, nutrient deficiencies, weeds, irrigation. Photosynthesis rarely looks like the “problem,” so it gets sidelined. Also, until recently, we couldn’t measure photosynthesis or canopy light capture efficiently at the field scale. It was almost a black box.

Thank you Arturo, your analysis and comment are very accurate.

I would like to add the following:

Photosynthesis research has not been and is not in the hands of agronomists, because biochemistry itself is a great science that could not be the majority of the academic training of agronomists, for the same reasons you point out.

The explanation of C3 photosynthesis was given in 1950 (my mom is older than that explanation!). That is, it is a “relatively new knowledge”, which was summarized to be understood by agronomists at some point in the following years probably by a plant physiologist (Agronomist!) And it seems (as you say about the story) that it was not reviewed or updated again. C4 metabolism was deciphered in 1966 by Hatch and Slack and CAM metabolism consisted of many papers that Osmond summarized in 4 phases in 1978 in a CAM state of the art trying to join all the findings up to that date that seemed quite confusing or at least disordered.

On the other hand, the existing technology to measure photosynthesis and its subthreads in situ only offers a partial resolution of the photosynthetic process, perhaps that's why you found as you say a "black box" in your measurements (I have found similar things with that type of technology and measurements in situ). This leads me to talk about the quantifications of the photosyntate. These are more objective and agronomically useful evaluations, because they are not only an image of partial resolution but they allow to evaluate the photosynthetic performance of an entire day and in this way they help to learn to interpret and thus to agronomically manipulate photosynthesis to maximize the production of the biomass of interest.

Unfortunately, as I mentioned, the study of photosynthesis is not in the hands of agronomists and the study of photosyntate (as a daily photosynthetic yield) seems to have little or no interest to biochemists who have the know-how for this.

All this seems to indicate that if we want more and better data for a better understanding of photosynthesis for agronomic purposes we will have to look for a way to make a space in the transnational research of photosynthesis.

Today we have much more technology and methodologies than in 1950 while the interests of biochemists in photosynthesis research have moved far from our agronomic way.

Las discusiones y comentarios de Morales y Vásquez concuerdan ampliamente con los procesos fisiológicos los que han sido ampliamente estudiados en los claustros universitarios

That's an insightful observation, and scientifically, there are clear reasons for this imbalance in academic focus. Although carbon, hydrogen, and oxygen account for 92% of a plant’s biomass—with carbon alone contributing nearly 50%—these elements are typically not limiting in the natural or agricultural environment. Carbon is obtained from atmospheric CO₂, while hydrogen and oxygen come from water (H₂O), both of which are generally abundant and accessible to plants.

On the other hand, the remaining 8% of biomass, comprising essential mineral nutrients like nitrogen, phosphorus, potassium, magnesium, sulfur, and trace elements, often limit plant growth and productivity in agricultural systems. These nutrients directly influence critical physiological functions, such as:

• Nitrogen: Key for amino acids, proteins, and chlorophyll synthesis.
• Phosphorus: Essential for ATP production and energy transfer.
• Potassium: Regulates osmotic balance and enzyme activation.

Since these nutrients must be absorbed from the soil or nutrient solutions (in hydroponics), their availability, mobility, and interaction with the soil environment become central topics in agronomy.

Furthermore, while photosynthesis is the core process for biomass accumulation, it is an autonomous and highly conserved mechanism in plants that does not vary as much between species compared to responses to nutrition, water, and stress factors. For example:

• Drought stress limits photosynthesis by closing stomata to conserve water, yet agronomy focuses more on irrigation management than directly manipulating photosynthetic pathways.
• Nutrient deficiencies, such as nitrogen shortage, reduce chlorophyll content and thus photosynthesis, but the focus is on fertilization strategies rather than photosynthetic biochemistry.

Additionally, directly enhancing photosynthesis (like increasing Rubisco efficiency or engineering C4 traits into C3 plants like rice) is highly complex and still largely confined to genetic engineering and advanced research, rather than practical field solutions.

Thus, academic training in agriculture emphasizes controllable factors—soil fertility, water management, pest control, and crop protection—that have immediate, measurable impacts on crop yield and quality. While we acknowledge that plants are biomass producers driven by photosynthesis, the practical focus remains on factors that limit the realization of that potential in variable field conditions.

This is the direct and literal answer to the discussion prompt; it seems to be generated by AI. ResearchGate's idea with this space is to generate scientific discussion beyond what AI can find online to develop an answer.

Clearly, agronomy, being an applied science, utilizes developed scientific knowledge to propose management strategies. For this reason, agronomy effectively prioritizes production-limiting factors to focus its agronomic work. This has been the case for decades, and it is precisely this reason that we want to bring up with this discussion. AI has constructed the literal answer to the first question, and it is clearly evident how the original focus was on biomass production. Currently, in addition to biomass production, there are other quality parameters that go beyond this original agronomic focus on production-limiting factors. For example:

Coffee producers who once enjoyed a price distinction due to the "high-altitude coffee" designation have lost that quality distinction, and their solution has been to seek out farms at higher altitudes to achieve the same results they previously achieved on their lower-altitude farms. Clearly, this has nothing to do with biomass production, but rather with qualitative characteristics of aroma, flavor, etc., characteristic of a coffee produced under very specific conditions of temperature and solar radiation (directly related to photosynthesis) and vaguely summarized as "high-altitude coffee." Agronomy owes a great deal to these topics due to the limited knowledge available on photosynthate production. The argument that CO2 and H2O are not limiting factors might have been true a few decades ago, when the guidelines for agricultural science curricula were drawn up at universities, but they are not true today, and despite this, universities essentially have the same curricula constructed in light of the realities and needs of decades ago. There are even some papers that argue that the fact that atmospheric CO2 has increased from 330 ppm 50 years ago to 425 ppm currently, an increase in productivity is expected. These are very dangerous arguments because although phytotron tests show that an increase in CO2 concentration leads to an increase in biomass production, other factors such as temperature and natural water availability are not taken into account in the analysis, so such conclusions are very irresponsible in light of the effects of climate change.

Another example is that in pineapple, producers have a problem with natural flowering (natural flowering in pineapple cultivation is undesirable because, for logistical and market reasons, producers require artificial flowering when it is convenient for their commercial interests). When flowering occurs naturally, there is a production disorder coupled with a loss of fruit quality. Producers had noticed that in areas with very high temperatures and very high solar radiation, natural flowering did not occur, so they established projects in these areas, without limitations of economic investment to guarantee the success of the projects. However, in a few years they found that current agronomic knowledge could not decipher the management of pineapple for these places. Basically, the plants expressed a difference in the harvest index, mainly related to a change in the biometric plasticity of the pineapple plant. This demonstrates that the agronomic focus on the limiting factors of management and nutrient supply (fertility and nutrition) and that pest and disease management is not sufficient to address contemporary agricultural challenges. Similar situations are occurring in much older crops such as vineyards. Changes in temperature and solar radiation are leading to modifications in photosynthate production, specifically the quality or characteristics of photosynthate. These changes are influencing the quality of wine. It is no longer a question of biomass or production volume, but also of quality.

In short, this entire discussion has been raised with the goal of creating a healthy and objective discussion, to ensure more active participation by agricultural science professionals in the study of photosynthesis and photosynthate. This must go beyond viewing photosynthesis as a process limited to extracting CO2 from the atmosphere, considering it a non-limiting factor and forgetting about it. Instead, we must understand more details about the production of different types of photosynthate, combined with climatic conditions, in order to understand how we can practically direct photosynthate production to where it best suits us from an agronomic point of view.

We've already done this once, with nutrition and plant health management. We must maintain what we've achieved with that and continue improving it. But on the other hand, we can't continue to view photosynthesis as a process we can't do anything about, because that's not true. We can!.

I hope to eventually share my findings on CAM metabolism in pineapple and demonstrate how we can effectively control this biochemical process through specific agronomic practices to meet the needs of growers.

Agronomy spends less time on photosynthesis because the process itself is universal and well-understood, while real yield depends more on managing water, nutrients, pests, soil, and climate—factors that indirectly control photosynthesis efficiency.