Physiology: towards more precise agriculture

Cenicaña advances in the knowledge of some physiological processes of sugarcane: how it accumulates sucrose and absorbs nutrients, how it responds to photosynthesis, and its efficiency in the use of water.

Four years ago Cenicaña began to deepen the study of the processes involved in the production of biomass and sucrose in the cultivation of sugar cane.

The research model is based on a comprehensive approach that aims to improve the knowledge of some processes of the soil-plant-environment relationship, to refine agronomic practices.

Miguel Angel López, a physiologist at the Center, explains what is being done and what practical implications these investigations will have in the medium and long term.

Plant-soil interaction

Nutrient accumulation is currently being studied in the varieties most used in agribusiness and in some potential varieties for semi-dry, humid and piedmont environments.

The results obtained so far are complementary to the research on soils and nutrition carried out in Cenicaña, and their importance lies in the fact that they define the amount of nutrients accumulated in the crop for a given productivity, as well as their way of absorption over time. .

In this sense, these results will be useful to fine-tune the dose and time of application of fertilizers in conventional management and fertigation systems.

Plant

Regarding the plant, progress is being made in characterizing the form and quantity of the production of dry matter (fiber and sucrose) and fresh matter (tons of cane per hectare) of different varieties. This characterization will allow to establish critical growth periods, that is, moments in the crop cycle in which the gain in tonnage, fiber and sucrose is maximum.

With regard to the accumulation of sucrose, the preliminary results with the varieties CC 85-92, CC 93-4418, CC 01-1940 and CC 06-791 show that the accumulation of this carbohydrate is a gradual process, in which the first They “fill” the internodes in the lower third of the stem, then those in the middle third, and so on. Although at the end of the crop cycle all thirds show sucrose gain, the upper third reports the highest accumulation rates, followed by the middle and lower thirds, respectively.

Similarly, the dynamics of sucrose accumulation over time suggests that when the harvest periods of the aforementioned varieties extend beyond 13 months after emergence, there is no difference in the percentage content of sucrose. along the stem.

Eventual harvest cycles less than or equal to twelve months would apparently favor the CC 85 -92 and CC 93-4418 varieties due to their higher percentage concentration of sucrose. However, CC 01-1940, even at this age, presents better productive performance, evaluated through the variable ton of sugar per hectare, cycle or month.

These types of studies support the analyzes on the quantification of the effect of cutting age on sugar production and tonnage and are useful tools to determine critical periods of the crop during its growth and production cycle.

Knowing these critical periods is key to establishing the optimal time to carry out agronomic tasks such as irrigation, fertilization and weed management.

Plant-environment interaction

Regarding the effect of environmental conditions (light, water, CO2 and temperature, for example) in the behavior of the crop, investigations on the influence of radiation on photosynthesis of sugarcane indicate that there is a positive relationship between these two parameters; thus, the greater the capture of light from the sun, the greater the fixation of carbon to produce tonnage and sucrose.

On the other hand, the results of the study of the relationship between radiation and efficiency in the use of water (amount of CO2 that enters the leaf with respect to the amount of water that leaves it in the form of vapor) indicate that the leaves of the crop show a better response when solar radiation is high.

The results obtained recall the importance of the integral approach in crop management. Agronomic practices such as irrigation and nutrition favor the growth of the canopy (group of leaves), which in turn increases the capture of radiation and photosynthesis. However, individual management tasks are not enough, since crop growth and CO2 capture are processes that require the convergence of several production factors.

 

Information letter
3 Year / 2 Number / July of 2015

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