Research has been conducted on post- harvest stubble manipulation in ratoon rice production for many years. In general, post- harvest flail mowing or bush hogging to approximately 8-inches or post-harvest rolling the stubble increases ratoon rice yields. Both practices encourage the ratoon regrowth to come from the crown node of the plant.
Panicles that derive from the crown tend to have more grains per panicle and more filled grains per panicle.
Disease pressure, especially cercospora, which tends to be the dominant disease in the ratoon crop, is also reduced. The ratoon crop also matures more uniformly and typically increases quality. Stubble management practices do delay maturity by two weeks and is not recommended when first crop is harvested after Aug. 15th.
Typically, 90 pounds of nitrogen (N) per acre is recommended for ratoon rice production regardless if stubble management is used or not. Maturity of rice is delayed as rates of N increase. Therefore, the rate of N should be reduced when the rice is harvested after August 15.
This is done to reduce the potential of losing the crop prior to maturity due to cold weather.
AmistarTop is the only fungicide registered for use in the ratoon rice crop. It has shown good activity on cercospora in our research. The labeled application rate is 10 to 15 fluid ounces per acre and 5 gallons of water (10 is better) is required to provide adequate coverage.
Recent research suggests that the fungicide should be applied 5- to 6-weeks after the first crop is harvested.