Managing pastures well is always a great challenge, as it involves nature’s great dilemma: making plants produce leaves to grow vigorously and, at the same time, providing leaves in quantity and quality so that the animals can feed well and convert them into more meat. , milk, wool and etc. Knowing this dilemma and managing pastures well, it is essential that you master two processes: understanding how plants grow and what animals’ strategies are to meet their daily challenge, which is to arrive at the end of the day with a full belly.
Plants need leaves to grow, which work like large solar panels. They capture radiation and, added to water, nutrients from the soil and carbon dioxide from the atmosphere, carry out photosynthesis and generate energy to produce. Herbivores (cattle, sheep, goats and horses) in their grazing process preferably consume leaves, as they contain the greatest amount of nutrients, extremely important for the nutrition and performance of these animals. If you hadn’t noticed this, now, I believe it has become clearer where the whole challenge lies.
As this story is a bit long, I decided to divide it into three parts (almost a cinema trilogy). In today’s text, we are going to talk about the growth of grass plants. Next, how herbivores feed and, finally, how to manage this dilemma and manage pastures well. In all of them we will try to explain it in a very simple way, without too much “technique”, so that a greater number of people understand all this logic of the processes and can apply it in their daily work, seeking to eliminate errors in pasture management.
So let’s start!
Tillers, our soldiers of pasture growth
Before talking specifically about the growth of real pasture, it is necessary to talk a little about what the so-called tiller is formed. The tiller, if we were to compare it to an army, is the equivalent of a soldier. A pasture is made up of a series of “soldiers”: the army of tillers. Each soldier is a new plant that appears and can emerge from the base (from the ground) or aerially, when leaves are inserted into the culms. As each soldier is important in the army, the growth of each tiller is fundamental to the growth and production of the pasture as a whole.
Our plant soldier, the tiller, is made up of roots, culms (many people call them stalks), leaves and dead material. The dead or senescent material is basically the dry leaves that appear on the underside of the tillers. As the pasture grows, these leaves become shaded, are no longer able to carry out photosynthesis, lose their function and, without strength, end up dying. The higher the pastures, the more leaves. Even entire tillers end up being shaded at the base of the canopy (a pile of tillers, stems and leaves), stop producing and end up dying (the competition for light is fierce).
Figure 1. Our soldier, the tiller, on the left and the canopy (tangle of tillers) on the right.
All production of roots, leaves and stems comes from a tiller growth point, the so-called “apical meristem” (I know this name is difficult, but don’t be alarmed). When the tillers are small, the apical meristem is very close to the ground and protected from being eaten by cattle – a “new soldier, still well-rounded”. If the meristem is eaten, it means that the soldier was killed and that tiller is gone. It no longer has new leaves to grow from and it dies, so it is important to protect it. As the situation becomes calm, without much fighting, the tillers (our soldiers) start to grow, the culms start to lengthen, the apical meristem becomes more courageous, takes the risk and loses its fear, climbs inside the culm and if it is not eaten midway, it emerges at the top, in the form of an inflorescence (structure that supports the flowers) and then produces seeds, fulfilling its mission.
You understand, once the inflorescence appears, that tiller no longer produces leaves and stops growing. Our job as pasture managers is to ensure that the tillers’ mission of producing seeds is fulfilled as long as possible.
Troop evolution: the pasture growth curve
Well, now that you understand what they are made of and what the dynamics of the growth of each soldier, the tillers, is like, let’s talk a little about the evolution of the growth of the entire troop, the so-called “pasture growth curve”. To make it easier to explain this entire journey, let’s imagine that people have an area of pasture that is already well fertilized and on a certain night a large batch of cattle escaped, entered this paddock and in the morning, when you went to look, the area and the pasture was on the ground, completely shaved. You quickly open the gate and remove the animals from the area, leave this paddock closed and reinforce the fence to avoid having this unpleasant surprise again.
Now, follow me and try to imagine this pasture growing over the days, okay? The figure below will illustrate the growth curve and will help us to better understand this entire process.
Figura 2. A curva de crescimento do pasto.
In the curve, the initial phase of the pasture called “snap”, the pasture is still very low, practically the tillers are made up of leaves, but very small leaves. Therefore, it has a low capacity to capture light and produce energy, so its growth is very slow. As the soldiers (profilers) grow, they reach the exponential phase. This is considered the period of maximum pasture growth, where the plants reach an average height, we have a considerable area of leaves with a high photosynthetic rate and the pasture explodes in growth. We call it the “pasture jumping” phase and it comes with that phrase we always hear: “my pasture last week seemed like it wouldn’t leave the ground and in a few days it jumped up”. At this stage, in addition to the larger leaves, we have a little more culms, but they are still controlled. Some weaker, smaller leaves and tillers begin to shade out and die.
Then comes the third and final phase, called “there is pasture left”. For those who think this is a good phase, I’m sorry to inform you that it’s not and I’ll explain. At this stage, the pasture is already very high and to provide support for all this gain in height, the tillers had to greatly increase the quantity and mass of stalks. The same process happens with the leaves, which are now quite large (they capture a lot of light), but are much harder to hold all that size. The number of tillers is also much smaller, a good part of our soldiers ended up in the shade and died along with a good part of the leaves at the bottom of the canopy.
You can already see that all this coarse structure of the pasture and all the mortality of leaves and tillers is not desirable. The pasture continues to grow, but much of what is produced from leaves above, losses increase below, as more leaves and tillers are shaded. Finally, at this stage the soldiers carry out their mission of emitting inflorescences and then seeds more easily.
Not too low, not too high
This entire process of pasture growth in the imaginary paddock that was left without cattle and went from the “scraper” phase to the “there is pasture left” phase (Figure 3), takes place under good temperature and rainfall conditions, in approximately 45 days in tropical pastures. and 60 days in winter pastures, a relatively short time between lack and excessive surplus.
Figure 3. Not too low (left), not too high (right)
Our goal, as pasture managers, is to adjust the animal load to control tiller growth and keep the pastures always in the “jump” phase, where growth is maximum, with many tender leaves and losses, with the appearance of dead leaves. and presence of small culms. For this to happen, in addition to mastering pasture growth and why we can’t lose our hand (don’t leave it too low or too high), we have to understand how the animals feed. But, this is a topic that we will talk about in the next text. Until then!
Text: Armindo Barth Neto
Business and Relationship Consultant and Coordinator – SIA
Images: SIA Image Bank
