EFFECTS OF HYBRID AND GRAIN DAMAGE ON ESTIMATED DRY MATTER LOSS FOR HIGH-MOISTURE SHELLED CORN

Abstract

ABSTRACT NMR imaging was used to nondestructively measure transient moisture profiles during the drying of an ear of sweet com. Two-dimensional proton density images were measured, transient moisture profiles were determined, and shrinkage was measured from the proton densitiesAn interactive computer program was used to examine the effect of physical damage, hybrid, and weather conditions on dry matter loss during drying of 22% m.c. (wet basis) shelled corn with air at ambient conditions. Simulations used official weather data for October and November of 1969, 1975, and 1977 for locations in southwest, central, and northeast Indiana. Multipliers corrected allowable storage time for differences in grain damage and hybrid resistance to storage mold. Regardless of location or physical damage level, dry matter losses (DMLs) of the hybrids resistant to mold growth were con-sistently 30 to 40% lower than DMLs for susceptible hybrids. When 45% of the kernels had damage to the pericarp or were broken, there was 2.0 to 2.3 times the DML in the top layer of com as there was when 15% had damage. The effect of damage was slightly greater in hybrids susceptible to mold invasion. Hybrid storage mold resistance had approximately the same effect as changing the percentage of damaged kernels from 45% to 30%. Allowable storage time was influenced by both corn temperature and drying time. For the location-year combinations studied, average wet bulb depression during the drying period was a good indicator of time required to dry and average wet bulb temperature was a good indicator of potential for DML. These two factors can be used to interpret the influence of weather on differences in damage and hybrid resistance. Minimum deterioration of the top layer occurred when the average wet bulb temperature was relatively low and the average wet bulb depression was large. The increase in DML for a good year versus a bad year was equivalent to changing kernel damage from 30% to 45%..