Effects of foliar application of a byproduct of the two-step olive oil mill process on rice yield

The main objective of this work is to study the effects of foliar fertilization with a byproduct of the two-step olive oil mill process at different dose on rice (Oriza sativa cv. Puntal) production and quality in Villafranco del Guadalquivir, near to Sevilla city (Andalusia, Spain). The obtained results show that the foliar fertilization with a byproduct rich in humic substances (but also containing macro- and micronutrients) increased the leaf concentration of micronutrients Fe, Cu, Zn and Mn, and macronutrients N and K uptake by plants. Highest values of chlorophyll A, B and carotenoids were found in the plots foliar fertilized, which presumably favoured photosynthesis. Foliar application of the byproduct gave significant increases in grain protein concentration of about 22%, grain starch concentration of about 5%, grain yield of about 4% and a significant rice yield of about 6%. (C) 2003 Elsevier B.V. All rights reserved.