The 2006 rice production season will be a difficult one for Louisiana producers. Projected low cash prices for the crop, coupled with historically high input costs, will make it imperative that producers do an excellent job in managing the crop. Rice is a crop with high input costs. Variable costs include (but are not limited to) labor, seedbed preparation, levee construction, seed, fertilizer, herbicides, insecticides, fungicides, fuel for irrigation, application expenses (either aerial or ground application), harvest costs (including transportation), drying and sometimes storage. Many of these input costs are directly influenced by the price of fossil fuels, which partially explains why rice production input costs are so high today. Producers must do everything possible to minimize input costs while optimizing yields and quality. Following are just a few early season considerations for the 2006 crop.

Timely, effective weed control

This is a must in rice production. Be absolutely sure you know what weeds you are trying to control and make sure your herbicide program will effectively control the weeds in question. A number of newer herbicides have been registered for use in rice in recent years – all with strengths and weaknesses. Herbicide timing is also critical in rice production. Certain herbicides will do an excellent job on 2-3 leaf grasses, but a very poor job on 4 leaf grasses. Certain herbicides perform poorly when fields are very dry, and flushing before application may be necessary. If it takes a long time to flood a field after an herbicide application, one may encounter re-infestation in the last portion of the field to be flooded. Under these conditions an herbicide with residual activity may be cost-effective.

The introduction of Clearfield technology several years ago dramatically expanded our weed control options as well as overall cultural practices. However, if one is using this technology, and dry seeding for the first time, this presents different options and challenges from those typically encountered in a water-seeded, pinpoint flood system. Make sure you are well aware of these differences and take advantage of that knowledge.

Fertilizer, a costly input

The most frequently limiting nutrients in Louisiana rice in order of importance are nitrogen, phosphorus, potassium and zinc. Make sure fertilizer is applied in proper quantities and at the most effective timings based on the management system in use. Phosphorus, potassium and some micronutrients should be applied based on soil sampling. Nitrogen rates, however, are dependent on variables such as variety (or hybrid), field soil type and cropping history, disease pressure and numerous other factors such as flooding capacity.

One should always try to apply the bulk (65%-70%) of the nitrogen rate to a dry soil surface just before applying the permanent flood. This normally occurs when rice is in the 4-5 leaf stage in dry seeded or water seeded, delayed flood (non-pinpoint) fields. One should always avoid the application of large volumes of nitrogen into a flooded field on very small rice, as well as avoid draining a field shortly after the field has been permanently flooded. Both of these situations will lead to loss of considerable amounts of the applied nitrogen.

The use of Agrotain urease inhibitor has sometimes shown cost-effective potential in research conducted by the Rice Research Station. This is especially true where it will require more than five days to completely flood a field after the nitrogen application has been made.

Insect control

While many different insects can damage rice, the most injurious is the larvae of the rice water weevil. Methods of control of this insect have changed over the years. For many years, the insecticide of choice was Furadan, which was applied into the flood after a threshold of larvae was detected feeding on the root system. After the loss of Furadan, Icon was used for several years as a seed treatment.

Today, we use primarily pyrethroid insecticides to control adult weevils. This application is made just before or shortly after the permanent flood is applied. This timing is critical as these insecticides are essentially ineffective in controlling these pests once the adults have laid eggs. Eggs are typically laid in the leaf sheath at or below the waterline, which make a foliar insecticide application essentially ineffective.

In some cases, fields must be drained to attempt to control the rice water weevil. This is often the case where the use of a pyrethroid is avoided because the field will be used later for crawfish production or a pyrethroid can’t be used because of the potential for drift onto an adjacent crawfish production pond. If this is the case, this should be factored into nitrogen timing and rate decisions as mentioned earlier.

Get more information

Additional information is available on these and other rice production topics in two LSU AgCenter rice publications available at your parish extension office or at the Rice Research Station: Louisiana Rice Production Handbook and Rice Varieties and Management Tips-2006. You can also obtain these publications on-line by going to the Rice Research Station website. Also, do not hesitate to contact your parish extension agent or any Rice Research Station researcher for information on any aspect of rice production.

Permission granted 03/22/06 by B. Leonards (LA Farm & Ranch Magazine) to republish article on www.lsuagcenter.com.