RS will have quarter with above-average rainfall

The next three months will be marked by rainfall between normal and slightly above average in Rio Grande do Sul. This is what the Climate Forecast Bulletin for the April-May-June 2025 quarter, prepared by the Permanent Council for Applied Agrometeorology of the State of Rio Grande do Sul (Copaaergs), indicates. 

Forecasts indicate that more frequent rainfall will resume and the drought will end during the fall and winter of this year. In addition, the weakening of the La Niña phenomenon is expected, as well as a transition to a period of normal weather conditions in April, May and June, with a probability of over 70%, and the persistence of neutral conditions during the winter of 2025. 

Forecast for April 

During the month, irregular rainfall is expected to predominate. The highest rainfall levels are expected to occur from the center to the north of the state. While below-average rainfall may be recorded in the south. 

Loana Cardoso, coordinator of Copaaergs, highlights that the normal rainfall is not expected to occur in April. “The rains return in May and June and the period of replenishment of water in the soil and springs begins,” she says. 

Temperatures are expected to be slightly above average, especially in the northern part of the state, and closer to average in the southern part of the state, in border regions. A thermal contrast is also expected due to the much warmer air mass that should predominate in Central Brazil, and the air masses of polar origin that come from the south of the continent. 

Storms and hail

The state of Rio Grande do Sul is expected to experience storms, strong wind gusts and hail. These phenomena will occur mainly due to extratropical cyclones and areas of instability that are forming between Argentina, Uruguay and Paraguay, reinforced by the thermal contrast observed in the region of the Río de la Plata, which is hot near the coast of the state of Rio Grande do Sul and cold south of the coast of the Province of Buenos Aires.

Technical recommendations for agriculture

The Copaaergs bulletin indicates technical recommendations for the fall/winter period, which consist of investing in irrigation and water storage systems. It is time to establish autumn management as a strategy for maintaining soil cover, aiming to increase dry matter, improve soil quality and structure, and increase soil water storage capacity, using annual or perennial fall-winter materials. 

Specific guidelines for different cultures

Summer culture at the end of its cycle

• Harvest and store the grain as soon as it reaches maturity (harvest point);
• Use strategies to maintain soil cover.

Winter grain producing crops

• Planning actions for installing winter crops;
• Stagger the sowing season within the period indicated by agricultural zoning;
• In cereals, preferably use disease-resistant cultivars;
• Plan plant protection, paying special attention to Gibberella;
• Avoid sowing in excessively moist soils and soils with a history of cereal mosaic virus.

Irrigated rice

• Due to the increased frequency of rain typical of autumn, be sure to harvest when it reaches the ideal time;
• Anticipate the adaptation of areas intended for cultivation for the next harvest, especially soil preparation and systematization and drainage activities, to enable sowing at the recommended time;
• In regions where reservoir levels are low due to the use of water for crop irrigation, and where the forecast for the next quarter (April, May and June) indicates a tendency for rainfall to be slightly above average, it is recommended that producers invest in capturing and storing water for the next harvest.

fruit growing

• Implement or maintain plant cover in orchards, aiming to protect and retain water in the soil;
• Avoid excessive organic fertilization of cover crops to prevent early sprouting of fruit trees;
• When carrying out pre-pruning or cleaning pruning, pay attention to the use of phytosanitary products to prevent fungal wood diseases, which may be favored by the higher temperatures and air humidity expected for the period;
• Due to the forecast of above-normal average temperatures, pay attention to monitoring the accumulation of cold hours during the period in order to correctly manage dormancy breaking for the next cycle, especially for varieties with lower cold requirements.

Vegetables

• Although there is a forecast of above-average rainfall in the quarter, attention should still be paid to the need for irrigation at certain times, which should preferably be carried out via a drip system, which offers better water use efficiency;
• Emphasize disease monitoring, especially those caused by wetting of the aerial part or excess humidity in the air or soil;
• Manage the opening and closing of protected environments to maintain thermal and air humidity conditions.

foragers 

• Sow long-cycle winter forage crops, whether annual or perennial, as early as possible, if there are soil moisture conditions, taking advantage of the greater availability of solar radiation at the beginning of autumn.

Access the full bulletin at the link below: