The 2019 season will be the second year the Provisia® Rice System is available to rice farmers in the Southern United States. Horizon Ag variety PVL01 is the only variety available that is tolerant to Provisia herbicide.
In 2018, despite the system being new to most farmers and it being launched in a particularly challenging growing season, the Provisia Rice System performed remarkably well. The growing environment last year posed significant weed control challenges. In many cases, the herbicide bill for rice farmers exceeded $150 per acre, and weed control was still less than desirable. However, the Provisia Rice System provided the cleanest fields in the South and came with a much lower price tag. Overall, field yield performance of PVL01 was much better than expected for a launch variety. The worst yields tended to correspond with Newpath herbicide carryover, but even in those situations, yields were better than expected.
PVL01 was fast-tracked from the initial cross to commercial launch because of the tremendous need for this new technology, and we have been learning on the go with this variety. As we consider how to maximize the potential for success with this variety moving forward, a few management tips should be employed.
PVL01 Variety: The ideal plant population centers around 15 plants per square foot. Depending on the soil type, weather conditions at planting and ability to protect against pests like birds and seedling disease, survival rate for drilled seeds should range from 50 percent to 70 percent. Based on seed size of PVL01, our seeding rate recommendation is 50 pounds to 70 pounds per acre. Yields can fall off significantly when the population falls below 15 plants per square foot. Furthermore, if PVL01 is planted too thick (> 20 plants per square foot), competition and mutual shading can also reduce grain yields. Nitrogen requirements for PVL01 are similar to other Southern U.S. long grain varieties. To manage PVL01 for the best opportunity of reaching its top-end yield potential, apply nitrogen in a single preflood application or in a split application where approximately 70 percent is applied to dry soil at the five-leaf stage and incorporated with the flood within seven days after application, with the remaining 30 percent being applied between green ring and ½ inch internode elongation.
PVL01 is susceptible to blast. Alternate irrigation methods are not recommended for PVL01. If PVL01 is planted on blast-prone fields and/or conditions are prevalent for blast, flooded water depth should be increased to help mitigate rotten neck blast. A minimum of one fungicide application is recommended. Because timing is critical to protect PVL01 from blast, two fungicide applications may be warranted. When applying fungicides, be sure spray volume is adequate. More and more people promote low-volume spraying. We do not recommend fungicides being applied at less than 5 GPA, and we prefer as close to 10 GPA as possible. Here are two examples of 2.5 GPA and 10 GPA.
Herbicide Program: Sequential applications of Provisia herbicide must be made in the rate range of 13 fl oz to 18 fl oz per acre, not to exceed 31 fl oz per acre for the year. Rice must be at least one true leaf and not beyond panicle initiation. Sequential applications should be made at least 10 days apart. To maximize weed control, as well as yield potential, start clean with tillage and/or a burndown herbicide treatment. Residual grass and broadleaf herbicides should be applied as a pre-emergence. Provisia can be tank mixed with a few herbicides (read the label to check for approved tank mixes) but works best when applied alone, especially in the second application. Do not tank mix with propanil or propanil- containing products. Starting clean with an application of clomazone and/or Sharpen herbicide PRE ensures the weed pressure is under control going into the first application of Provisia early-postemerge with Prowl H2O or another approved residual herbicide. It is recommended that the second application of Provisia be applied immediately before permanent flood.