The 2015 rice season in Louisiana has been a challenging one up to this point. The predominant theme in this year’s crop, so far, has been precipitation. Since March 1, which marks the beginning of rice planting in southwest Louisiana, the Rice Research Station has received more than 24 inches of rain. While this is above average for these three months, the total amount of rainfall has probably been less of an issue than the frequency with which the rainfall events have occurred. The Rice Research Station recorded measurable rainfall on 13 days in March, 14 days in April and 14 days in May (thus far). This means that the station received rain on slightly less than half the days in this three month period.
These rainy conditions have certainly affected the rice crop this season. Initially, the early rain in March delayed seeding. Most southwest Louisiana rice producers normally begin planting in early March. This year, very little rice was planted until the third week of March. Actually, we were fortunate to have a brief window of dry weather in late March-early April that allowed most producers to get the bulk of their dry-seeded crop in the ground. The amount of water-seeding was up this year as well. This was a result of the wet conditions early on as well as an overall increase in the amount of non-Clearfield rice planted this season. The increase in the acreage of non-Clearfield rice was due to a couple of factors. First, the price producers will receive for their crop this year is down. This caused many farmers to attempt to decrease their cost of production, and non-Clearfield rice typically has lower input costs than Clearfield rice. Also, the amount of acreage planted to the medium-grain variety Jupiter has been up the past two growing seasons. Primarily, this is due to the acreage reductions in California because of water shortages. Many producers planted Jupiter with the expectation that medium-grain prices would be up because of medium-grain shortages in California. Typically when planting a non-Clearfield variety, most producers will use a water-seeded pinpoint flood system. This technique provides suppression of the noxious weed red rice, which is found in most of our rice fields. However, much of the water-seeding was delayed as well because the approval for the use of AV-1011 seed treatment bird repellant was not granted by the EPA until March 20. Many producers did not want to water-seed until they could use the bird repellant because of the potential of bird depredation in water-seeded rice. Therefore, all of these factors combined to get the majority of the crop off to a later-than-normal start.
The excessive rainfall in April and May continued to cause complications even after the crop was planted. These conditions have made it difficult for many producers to put out herbicides with ground rigs, which need dry fields. This has certainly caused issues where Clearfield fields are in close proximity to non-Clearfield fields. It is essential to avoid drift of the herbicides used in Clearfield fields to non-Clearfield fields. Typically, there is less potential for drift with a ground rig than an airplane. In some situations, this has led to only one application of NewPath herbicide, which certainly leads to less-than-optimum weed control with this system.
Wet conditions have interfered with nitrogen fertilizer applications in many fields. Ideally, the bulk of nitrogen is applied on dry soil just before the permanent flood is brought onto the field. Because the fields never dried in many cases, much of this nitrogen went out on muddy fields or after the flood was applied to the field. This is a much less efficient way to apply nitrogen and causes more nitrogen to be lost. Furthermore, this will also make it more difficult for producers to decide on timing and rates of midseason nitrogen applications, since the inefficiency of the early nitrogen applications will lead to earlier-than-normal deficiency occurring in many fields. Another issue with the wet conditions is the distance that that some of the aerial applicators have to fly to put out midseason nitrogen. Most rice fields have a grass landing strip nearby that can be used to refill the plane with nitrogen a number of times during the fertilizer application process. Many of the strips are unusable because of the wet conditions, and the aerial applicators have to fly from strips much farther from a field. This can increase the time and expense of fertilization.
The excessive rainfall has also exacerbated disease issues in rice, especially in relation to blast disease. Blast is a fungal disease in rice that can cause symptoms in both the vegetative as well as reproductive stages of growth. We are currently seeing a significant amount of leaf blast (vegetative stage) in the variety Jupiter and to a lesser extent in the variety CL151. The disease has been severe enough in a few fields to necessitate the application of a fungicide. These conditions may also lead to a more significant problem with this disease during the reproductive stages of growth later on. We are also observing significant sheath blight disease infections at earlier growth stages than normal.
These wet conditions are also troublesome with soybeans, which are the main rotation crop with rice in southwest Louisiana. The wet fields are preventing planting as well as creating unfavorable conditions in fields that have been planted. It appears that a third to half the fields in southwest Louisiana that have been planted will need to be replanted because of stand loss from excessive moisture.
Bottom line is – we need some dry weather!
This project was partially supported by USDA National Institute of Food and Agriculture.
Permission granted June 15, 2015 by B. Leonards (LA Farm & Ranch) to republish article on www.lsuagcenter.com