Let's talk about the growth of grasses

Dear readers, it is known that all plants in their growth dynamics, describes a sigmoid curve of growth, the organs of any organism in their growth also exhibit these characteristics. Likewise, it is important to emphasize that the curve occurs for any type of plant independent of the characteristics of its biological cycle, having to vary the unit of time that it is necessary to assume to be able to describe them, that is why Herrera (2006), points out that the corn growth curve can be expressed in 16 weeks, those of erect tropical grasses in 10-12 weeks, that of the regrowth of a temperate grass in 28-35 days.

In the growth curve of the pastures 3 periods can be distinguished and that Del Pozo et al., (2011) describes as follows:

Slow growth period: its duration depends on the species and the degree of intensity with which it was defoliated (by cutting or by grazing with animals), this period is related to the capacity to use the accumulated reserve in the roots and at the base of the stems, the development of the assimilative system and the distribution of the photoasimilates in the different organs. In this period the photosynthesis rate is high, therefore, there may be an increase in the accumulation of dry mass, with predominance in the leaves.

Intermediate period of very rapid growth: in this period there is a remarkable increase in the leaf area with a positive balance of the photosynthetic capacity until maximum production is reached, the growth of the plant becomes relatively constant, which is expressed in the maximum growth rate of the crop and accumulation of reserves in its root system.

This period is also characterized by the delay of the death rate of the morphological structures of the plant, in connection with the corresponding increase in the growth rate of the stems, which causes a high rate of tissue production and a small rate of death of the various components of the pasture to be expressed. Therefore, the maximum grassland production per hectare may not correspond to the maximum photosynthesis, since it will depend on how the rate of tissue loss by death behaves.

Final period of low growth: when this stage is reached the plant slows down its growth, the plant begins to age, there is a greater accumulation in stems, inflorescences and of dead material in the pastures.

Taking into account the aforementioned, when a pasture is left with approximately 10 cm of remnant height after being cut by the animal, these plants continue to develop and mature and tries to replenish the affected tissues, for this reason they begin to produce regrowths from the knots present on the stems, it could be said that they are aerial regrowths occupying for this the nutrient reserves that are at the base of the stem and the ungrazed foliage.

Dear readers, when a pasture begins to grow it is important to give it proper management, because every time it is cut by the animal it will require a high demand for nutrients for it to regrow, that is why it is important that once the animals leave the paddock to make uniformization in the area because some grasses are cut above 10 cm in height leaving a large remnant which could cause the regrowth to be little vigorous because the supply of reserves in the stems and foliage is lower than those present in the meristems., a situation that can lead to the grass plant producing a regrowth with less biomass than if it could germinate, grow and develop from the root system.

Bibliographic references

Herrera, R. (2006). Growth and development. In Institute of animal science, Physiology, biomass production and silvopastoral systems in tropical pastures (pp. 53-70). Havana: Institute of Animal science.
Del Pozo, P.; Herrera, R.; Blanco, F. (2014). Ecophysiological bases of pasture management in André Voisin (pp. 371-397). Hatuey Indian pasture and forage Experimental Station.

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