Zinc Fertilization of Rice Grown on Clay Soils in Arkansas

Zinc (Zn) fertilizer is not currently recommended for rice grown on clay or clay loam soils in Arkansas. In 2003, eight field sites were established to evaluate the response of rice grown on clay soils to Zn fertilization. Shortly before or after seeding, granular Zn fertilizer was applied to the soil surface at rates of 0, 5, 10, and 20 lb Zn/acre. Tissue Zn concentration 10 to 14 days after flooding and grain yield response to Zn fertilization rate were evaluated. At the eight sites, the mean soil pH ranged from 6.0 to 8.0 and Mehlich-3-extractable Zn ranged from 2.0 to 11.4 lb Zn/acre. Seven of the eight sites had soil pH >7.0 and Mehlich-3 Zn >5.6 lb Zn/acre. Rice grain yield and dry matter accumulation at midtillering were not significantly affected by Zn fertilization rate, averaged across locations. Midtillering tissue Zn concentrations increased as Zn rate increased, but showed that only one site had mean tissue Zn concentrations that could be considered low to deficient. Zinc does not appear to be a major yield-limiting factor for rice grown on clay soils.