As the number of challenges related to climate change, weeds, and other economic issues increases, crop rotation may become an important practice for California rice growers. Rice growers rotate from one crop to another to disrupt pest lifecycles, prevent pesticide resistance, and broaden the toolbox of pesticides that can be used in their field beyond what is available when growing rice. Crop rotation can also improve soil structure and nutrient uptake by the crop. The decision to rotate from rice to another crop depends on potential profitability, which is calculated based on chosen production practices and their associated costs. The calculations that inform this decision are complex and time-consuming.
To assist growers in their decision-making process, Sara Rosenberg, a UC Davis graduate student, and UC Cooperative Extension Advisor Whitney Brim-DeForest developed the Rice Rotation Calculator. “To support rice growers and other interested persons in understanding the possible profitability of rotating out of rice, we have developed a crop rotation calculator to explore how different production decisions may impact profitability in the year following rice,” says Rosenberg. The online tool compares the profits of rotating from rice to tomato, sunflower, safflower, or beans. Users adjust values based on their own farm costs to calculate the costs and benefits of switching over to a rotational crop compared to staying with rice production.
Brim-DeForest adds, “This calculator has been developed for the context of rotations with California flooded rice within the Sacramento Valley regions. Therefore, it is particularly useful for continuous rice growers who produce in these regions and who may be interested in trying to integrate rotations into their operation. However, the tool can be useful for anyone who is interested in understanding short-term financial impacts of crop rotations.”
Rosenberg and Brim-DeForest caution that the tool shouldn’t be used to predict the return on investment over the long term. “This calculator shows a cost-benefit analysis of a short-term switch from rice to another crop,” says Rosenberg. More study is needed to see if the initial positive long-term observations made by Rosenberg and Brim-DeForest continue to be an outcome from using the calculator. “While crop rotations may not be profitable when looked at on a one-year basis, some growers who rotate state that they experience an increase in rice yields and a decrease in rice input costs over time. Some growers have reported a 5 to 10% increase in rice yields, savings in nitrogen inputs, and benefits for weed control, that led to decreased herbicide applications in the following rice crop after rotation. Under these parameters, even if you lose money one year, you may experience an increase in income over the long term.”
UC Davis Department of Agricultural and Resource Economics and UC Cooperative Extension cost and return studies and focus group interviews formed the foundation for the Rice Rotation Calculator.
It is anticipated that users of the Rice Rotation Calculator will make personalized decisions on whether to rotate from rice. Using the Calculator can help growers understand how certain crop production variables inform their decision to rotate or not. Increased crop rotation can prevent invertebrates, vertebrates, diseases, and weeds from reducing crop yields. Crop rotation changes the chemicals used against pests and mitigates the development of pesticide resistance.
The Western Integrated Pest Management Center partially funded the development of the Rice Rotation Calculator.
Brim-DeForest’s rice cost production study: Espino LA, Brim-DeForest W, Leinfelder-Miles M, Linquist BA, Buttner P, Murdock J. Stewart D, Sumner DA. Sample Costs to Produce Rice Sacramento Valley – 2021.
An overall look at crop rotation in California rice: Rosenberg, S, Brim-DeForest W, Crump A, Linquist B, Espino L, Al-Khatib K, Leinfelder-Miles M, Pittelkow C. 2021. Crop rotation in California Rice Systems: Assessment of Barriers and Opportunities feasibility study. https://doi.org/10.3389/fagro.2022.806572
