Corn and Soybean Production As Affected By Application of Swine Manure and Synthetic Fertilizer at Different Rates in Indiana.

Seven treatments were implemented within each crop to total 14 treatments. Swine manure (Sus Scrofa L.) was applied in the preceding fall at three N levels (112, 224, 336.kg N ha-1). Prior to planting, UAN (28% N) fertilizer was applied at rates that closely mirrored the swine manure rates. An untreated control was the seventh treatment within each crop. Deep soil samples (0 to 30 and 30 to 60 cm) were taken early in crop development and after harvest to monitor nitrate and ammonium content and movement. Whole plant biomass was taken at V4 and R6 (full seed) for soybean and V6 and R6 (physiological maturity) for corn. Mid-season nutritional content was determined with most recent mature trifoliate leaves at R4 (full pod) for soybean and ear leaves at R1 (silking) for corn. Yield of both studies was also collected using yield monitors. Results showed significant differences in early season growth of both corn and soybean as a result of increased N rates, early growth was enhanced by higher N rates. N content in biomass and tissue was increased as a result of higher N rates. At one site of study (ACRE) yield ofsoybean was reduced for the control (0 lb. kg N ha-1), but not for all other treatments. At another site (DPAC) soybeanyield was significantly lower for the low UAN treatment (112 kg N ha-1) but not for the rest of treatments. Corn yields increased as N rate increased at ACRE with better yields in the manure N rates compared to UAN. At DPAC corn yields were also significantly higher at 224 kg N ha-1 336 kg N ha-1 of N manure treatments and also at the 336 kg N ha-1 UAN treatment when compared to all other treatments. Overall the effect of fertilizer N source and rate were more evident on corn than in soybean as expected due to biological Nfixation. Early differences in plant growth, biomass and N content due to higher N application and source did not directly relate to final yields.