Effects of land preparation and fertilization as soil management on corn yield grown on Lopburi soil series

Split plot design was employed to study effects of growing mungbean as green manure (non-growing and growing mungbean as green manure), land preparation practices (no-tillage, conventional tillage and deep tillage) and rates of chemical fertilizer (0-0-0, 5-5-0, 5-5-0 + top dressing 5-0-0, 10-5-0 and 10-10-10 kg/rai) as a method of soil management on soil properties, yield and nutrients uptake of corn on Lopburi soil series at Nakhon Sawan Field Crops Research Center during 1987 growing season. Green manure was acting as main plot, land preparation as subplot and fertilization as sub-subplot. Bulk density of the soil was slightly different either when growing mungbean as green manure or no growing before growing corn of among land preparation practices. Soil moisture content was increased when growing mungbean as green manure and also on deep cultivation. Corn yield was increased from 519 to 652 kg/rai on land previously incorporated mungbean as green manure when compared with no green manure but yields were not affected by three different land preparation practices. Corn yields were significantly increased when chemical fertilizers were applied. The chemical fertilizer rate of 5-5-0 + 5-0-0 as top dressing produced the highest corn yield (621 kg/rai) while the rate of 10-10-0 produced the next best yield of 619 kg/rai and no fertilization (0-0-0) produced the lowest yield (527 kg/rai). Nitrogen and potassium uptake in corn grain were significantly increased when mungbean was used as green manure, but phosphorus uptake was not significantly different. Nitrogen uptake in corn grain was significantly different among three different land preparation practices, but phosphorus and potassium uptake were not significantly different. Nitrogen, phosphorus and potassium uptake in corn grain were not significantly different among rates of chemical fertilizer