Forage‐Corn Response to Rice‐Mill Wastes and Fertilizer

A method for disposing of rice‐mill wastes is needed to avoid their pollution and fire‐hazard potential. Two greenhouse experiments were conducted to determine the effects of rice shavings and rice husks on forage‐corn (Zea maysL.) production in two soils. In Experiment I, rice (Oryza sativaL.) shavings were applied at rates of 0, 75 000, and 150 000 kg/ha with or without additions of nitrogen (N), nitrogen and potassium (NK), nitrogen, phosphorus, and potassium (NPK), or poultry droppings (PD). The residual effects of these treatments, involving in some cases a further application of N, were also evaluated. Corn top and root yields were at least doubled with rice shavings application. Highest yields were obtained with rice shavings plus NPK or PD applied at a rate equivalent to 100 kg/ha. Additions of either N or K only did not affect yield. Although yields differed on the two soils, the responses to treatments were similar. In Experiment II, rice husks and shavings were compared in the presence or absence of Nand NPK fertilizers. In the absence of fertilizer, there were no yield differences between the two; otherwise, rice husks at 150 000 kg/ha were superior to rice shavings. These results suggest that under the conditions of this study, the rice waste‐soil system had enough N to support an initial cropping to corn, and P was the major limiting nutrient. Poultry droppings were as good as any of the feritlizer combinations used. Although not investigated, a significant component in the yield improvement may have resulted from the effects of these wastes on the soils' physical properties. The use of these wastes for corn production would, in addition to increasing yield, eliminate waste disposal problems without creating environmental hazards.