Dryness during the last week in central Brazil has put stress to second-season (safrinha) corn that is still young and vulnerable with shallow root systems. This coincided with heat, with temperatures in the middle to upper 30s Celsius (90s Fahrenheit), leading to increased evapotranspiration and depleting topsoil moisture.
The news is not all bad. The dryness has allowed safrinha corn planting to become nearly complete in Mato Grosso, Brazil's largest corn producer, though it is several weeks behind the normal pace. These later-planted seeds will unfortunately risk the start of the dry season as they go through pollination and fill. The dry season in Brazil usually starts late April or early May.
Though it has been dry during the previous week, that will not be the case for the following week. Scattered showers will redevelop from Mato Grosso to Minas Gerais this weekend, largely continuing through next week as well. Seven-day precipitation totals of 1 to 3 inches seems likely across a good portion of this region, being very timely for new plants.
Southern areas have enjoyed more bountiful showers during the last week, increasing soil moisture from Rio Grande do Sul to Parana and setting up safrinha corn in these areas very well.
It will be dry during the weekend, but showers may return with a system early next week. Overall, these plants are in good shape.
In between, however, Mato Grosso do Sul is having a rough go. Delayed like everyone else in the region for the start of the safrinha season, the dryness has caused stress.
But unlike their neighbors to the north, widespread showers are not expected to form this weekend into next week. And unlike the neighbors to the south, the showers with the system next week may be brief and underwhelming.
After next week, models suggest that the rest of the month will continue to be on the dry side of normal, across almost the entirety of Brazil, and significantly so over the central region. A couple of inches of rainfall in one week of April will not be enough to stave off temperatures that will continue to be in the middle to upper 30s Celsius (90s Fahrenheit). The demand for subsoil moisture will only increase with time.
Luckily, subsoils have been filled by above-normal precipitation from January through mid-March. However, plants will use this moisture quicker than normal under the current dry April forecast. There may not be much left to draw from as plants pollinate in May, a month where average rainfall drops dramatically but temperatures do not.
Record yields being forecast by many agencies are in danger of being too optimistic for the current situation. May rainfall, even if above normal, will be needed but may not provide enough moisture to fulfill this potential.
John Baranick can be reached at firstname.lastname@example.org
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