Rotation crops
Based on United States Department of Agriculture figures, only 30 percent of California rice is grown in rotation with other crops, and 70 percent is in rice/rice or rice/fallow rotation. Improvements in surface drainage and better management strategies to solve nutritional problems may improve the performance of alternate crops, but rice remains one of only a few crops well adapted to the poorly drained soils of the Sacramento Valley. In the lighter-textured rice soils, rotation crops may include safflower, corn, cotton, oats, wheat, grain sorghum, dry beans, sugarbeets, vegetable seed crops, and tomatoes, depending on the soil and other land conditions.

Alternate crops grown after several successive rice crops may do poorly. One common problem is phosphorus (P) deficiency caused by alternate flooding and drying. This problem reverses over time, but P placed with the seed is often needed for the crop immediately following rice. Barley, corn, grain sorghum, safflower, and wheat have all shown benefits from P application following rice.
Secondary income from rice lands
The Sacramento Valley is an important overwintering ground for migrating ducks and geese of the Pacific Flyway. Rice fields provide food for overwintering birds as well as excellent habitat for pheasants and resident waterfowl. Rapid population growth in California has increased the demand for fee hunting, thus providing additional income to rice growers. Catfish and crayfish farming on soils adapted to rice may also provide secondary income, but these uses require special investment and management procedures.
Alternative Rice Cropping Systems
Conventional water-seeded rice, intensively managed with varying external inputs of farm equipment, fertilizers, and pesticides, is grown on most of the acreage and by most producers. Some notable alternative systems are in use because of cost, marketing, or philosophical considerations. Following is a brief description of the major variations from conventional California rice.
No-till or drill-seeded rice
Rice fields that have been fallowed the previous year are most commonly used for drill-seeded rice; land may or may not be tilled before planting. Winter annual weeds are controlled with a nonselective herbicide before planting in spring. Seed is sown directly with a triple-disc; no-till drill into uncultivated soil and ammonium phosphate fertilizer is banded with the seed. The field is intermittently irrigated one to three times, allowing the crop to germinate and grow as an upland crop. High rates of herbicides are often necessary to control grass weeds. Nitrogen fertilizer is applied just before permanently flooding the rice, usually in 3 to 5 weeks after planting. The principal goal of no-till rice is to reduce costs by eliminating tillage operations. Aquatic and broadleaf weeds, the rice water weevil, and other pests that infest water-seeded rice during stand establishment may be reduced in no-till rice.

No-till rice requires careful water management during stand establishment. Grass weeds, normally suppressed under water-seeded culture, may grow vigorously in drill-seeded rice. Yields are usually equal to those of conventional rice cropping systems.

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