In the municipality of Soledade, the young couple of producers Bruna Miranda da Silva and Lucas Muniz invested in the production of pitaya as a way to diversify production and, with this, irrigation was necessary due to the low temperatures often recorded in the municipality.
In the area of 0.4 hectares, where the pitaya plantation is located, the young couple observed the need to invest in automated irrigation to ensure the cultivation of the fruit due to the occurrence of frequent frosts. In the winter of 2019, the couple made a significant investment in an anti-gee system through microsprinkler irrigation and drip irrigation equipment in the pitayas, also sizing the pump for the irrigation of other crops on the property.
"The low temperatures that Soledade records have always caused us fear. We researched and found that it was possible to produce. Last winter we tried to cover the plants, but it didn't work. So we invested in irrigation and the anti-gee system for this winter. We are curious to observe how the plants will behave during the season, because this was the first major frost that hit the plantation this year", comments Bruna, referring to the strong frost in the municipality on Friday (03/07). In addition to pitaya, the couple produces seasonings, cabbages, cabbage and broccoli, in addition to an area cultivated with pecan walnut that has not yet started production.
The rural extensionist Agropecuário da Emater/RS-Ascar, Roger Terra de Moraes, explains that pitaya is a kind of temperate climate and are not adapted to the intense cold. As a result, sub-zero temperatures cause severe damage and may result in the death of plants or part of them. "With a microsprinkler anti-frost system, the ice layer that forms on the surface of the plant creates a kind of capsule where the plant's internal temperature does not reach negative temperatures, maintaining the integrity of plant tissue," he explains.
According to the extensionist, the strategy can also be adopted in temperate fruit growing in general, cultivated in regions where frost is frequent. "Some species such as peach, plum, vine, among others cultivated in regions where late frosts often occur, this system is also efficient for preserving the integrity of flowering," moraes said.
Care should also be observed in crops such as vegetables and pastures. In vegetables, cultivation in partially modified environments such as greenhouses and tunnels partly protect plants from cold. However, in places where temperatures are excessively low, summer species can die, even if cultivated within these environments. Another orientation is not to cultivate species susceptible to low temperatures or that have their development affected with cold, such as tomatoes and peppers.
In the production of pastures, the extensionist guides the cultivation of frost-resistant species, such as oats and ryegrass. "The native pasture paralyzes its growth in these conditions of frost and intense cold, reducing the supply of fodder to animals," moraes said.
In wheat production, which is in the vegetative phase, frosts have little or no negative interference in the crop. "On the contrary, cold stimulates the tillering of plants, something that is desirable. The lethal temperature to the crop in the vegetative phase is below -9°C, and the rubber and spiking phase is the most sensitive", observes the extensionist.