[Image: Ecrevisse Spring Regrowth]Louisiana Farm and Ranch 1(4):30-31.
Although much of the crawfish production in Louisiana occurs in rotational cropping systems with rice, substantial production also occurs in crawfish monocropping systems where crawfish is the sole crop harvested. Crawfish monocropping operations are usually carried out in permanent ponds year after year, and often produce the highest yields of crawfish. Rice is frequently the preferred forage crop used in those ponds and is planted strictly for its desirable forage characteristics. Grain is not harvested and, unless waterfowl management is also part of the overall goal, grain production is not desirable.
Until 2004, rice variety selection for use in crawfish-only ponds has been limited to those varieties developed for grain production. Rice breeders have consistently developed rice varieties for grain production that have high grain to forage ratios, are shorter in plant height, and are earlier maturing – characteristics that, while desirable for high-yielding grain crops, are less desirable in a crawfish forage crop. Desirable traits for rice used in crawfish ponds include high forage biomass production, cool tolerance, longer maturity cycle, high resistance to lodging, slow rate of decline, disease resistance, and tendency for plant regrowth in spring.
In 2004, the LSU AgCenter released the first rice cultivar developed specifically for use in crawfish ponds where rice will not be harvested. ‘Ecrevisse’ was the culmination of years of screening and evaluation of rice varieties originating from throughout the world, and selection of one line that was further improved (purified) under Louisiana’s growing conditions. This new variety exhibits much greater forage biomass production, better persistence under the extended flood conditions of a crawfish pond, and has a greater propensity for post-winter regrowth than the commonly used U.S. varieties.
Because of the selection criteria used and the methods employed for further development of this variety, there was an inherent selectivity for disease resistance and affinity for south Louisiana’s soil and environmental conditions; therefore, this new variety should be the premier choice for establishing a rice forage crop in crawfish monoculture ponds in Louisiana and surrounding states. Ecrevisse is almost certainly limited to crawfish-only or monocropping systems because it is of the short grain type and exhibits poor milling traits, making it less desirable for use in food markets.
Regardless of whether Ecrevisse or a “grain variety” is chosen for use in crawfish monocropping systems, time of planting is probably the most important management consideration. For best results, when waterfowl hunting is not a consideration, it is essential to plant early enough in the summer to achieve maximum vegetative growth, but not so early that the plant reaches full physiological maturity. A forage crop that matures or “fills grain” before onset of winter tends to deteriorate more rapidly, often resulting in premature depletion of the forage resource.
In south Louisiana, the most appropriate planting time for rice is within the first two weeks of August. Recommended planting dates tend to be earlier with significant increases in latitude. When waterfowl management is an important component of the farming practice and seed formation in the crawfish forage crop is desired, then species selection and/or planting date may need to be altered. However, in most situations it is difficult to management for maximum benefits in the crawfish crop while also managing for waterfowl hunting.
To achieve the greatest benefit from a forage crop in crawfish monocropping ponds, consideration should be given to planting Ecrevisse, the only rice variety developed specifically for this use, and follow proper recommendations for time of planting and other management factors.