Efficiency of Some Selected Organic Wastes as Nitrogen Source for Sweet Corn Grown on Kamphaeng Saen Soil

Abstract

Four kinds of organic waste material (OWM) and inorganic fertilizer (IF) namely castor meal (CM), activated sludge cake (AS) from whisky factory, rice straw compost (RSC), effluent from biogas production (EFB) of liquid swine wastes, and ammonium sulfate were tested as nitrogen source for sweet corn planted in Kamphaeng Saen soil series. The amount of application was equivalent to 15 kg N/rai (93.75 kg N/ha). The field trails were conducted consecutively 3 times in the dry seasons. The results at the first crop showed that except the RSC, the corn yield in the sole OWM treated plots was more or less as high as that in the IF plot. With continual application of the OWMs, the tendency of the corn yield was expected to show the result at the decreasing order: AS ≥ EFB ≥ IF ≥ CM >RSC > check (Ch). There were not significantly different in yield between the combination treatments of 1/2OWM + 1/2IF and the sole OWM treatment except in the RSC case. The corn yield in the RSC treated plot could be increased effectively as high as that in the IF if the RSC was used in combination with the IF as 1/2RSC + 1/2IF, In terms of plant nutrients, the contents of total N in grain and straw could be ranked in the following order: IF = EFB = AS = CM > RSC > Ch. In terms of tasseling and silking, application of the OWMs, either by itself or combined with IF, enhanced tasseling and silking dates to become 1-3 days earlier than usual. With three consecutive applications of the organic wastes, there was no change in the soil properties in terms of pH, Eh, and Na content. However, continual application of RSC or EFB, either single or combined with IF, tended to increase K and Mg in the soil whereas the AS slightly increased soil P and soil Ca. For the EFB case, it could be used effectively not only as the N source for the sweet corn, but also it could substitute irrigation water as much as 28,000 1/rai/wk (175,000 1/ha/wk) or 196,000 1/rai/crop (1,225,000 1/ha/crop).