Production of corn masa-based products is flourishing in the United States, as is the generation of masa processing waste. Masa by-products have potential for value-added utilization, an option which could produce less pollution in the environment and economic benefits for masa processors. Physical and nutritional properties of these byproducts are needed for the proper design of processing operations and by-product applications, but information concerning masa byproducts is not currently available. Thus the objective of this study was to fully characterize typical masa by-product streams. The masa by-products studied had moisture contents between 88.15% and 89.29% (w.b.), water activity values between 0.999 and 1.000, densities between 1030.85 and 1047.32 kg/m3 , yield stress values between 1440.04 and 1618.08 N/m2 , pH values between 6.17 and 6.30, Hunter L values between 35.15 and 49.13, a values between 0.27 and 0.98, and b values between 6.85 and 9.38. Drying curves were developed to predict drying behavior. The dried by-products had protein contents between 4.76% and 4.90% (d.b.), crude fat contents from 0.74% to 5.76% (d.b.), ash contents between 17.41% and 19.09% (d.b.), and carbohydrate contents from 71.93% to 75.41% (d.b.), which was due primarily to fiber, with hemicellulose levels of 20.82% to 24.06% (d.b.) and cellulose between 30.55% and 31.83% (d.b.). Dry masa by-products also consisted of 4.68% (d.b.) calcium. Therefore, dehydrated masa by-products seem very suitable for use as livestock feed additives.

An automatic thresholding technique was developed to segment the background from the images of corn germplasm (ears of corn). The technique was a modification of Otsu’s algorithm using probability theory. Three different measures were used to evaluate the performance of the modified Otsu’s algorithm for background segmentation and subsequent dimensional measurement of corn germplasm. Modified Otsu’s algorithm was found to perform better than Otsu’s algorithm and was successful in automatic background segmentation of all 80 images of corn germplasm included in the study. This modified algorithm also eliminated the misclassification of exposed cob in the image as background which occurred with Otsu’s algorithm. Subsequent dimensional measurements based on the segmentation by the modified algorithm were also highly accurate.

Tractor noise exposure levels were measured for bystanders as described by the Nebraska Tractor Test Laboratory and for bean-bar riders on ground surfaces of concrete, grass, and bean field. The influence of ground configurations, engine speeds, and gear selections on noise exposure levels were determined. The average sound level decreased as the ground cover changed from concrete to grass and then to bean field. An increase of 3 dBA was measured for engine speed changes from 1200 to 1500 rev/min and 1500 to 2000 rev/min. Gear selection was determined not to be significant for bystander exposures but bean-bar exposures increased as gear selection changed from first to fourth. Noise exposure levels experienced at the bean-bar position were, on average, 10 dBA higher than those measured at the bystander position. Results of the noise exposure measurements indicate that a hearing conservation program according to the Occupational Safety and Health Administration Compliance Manual (Petersen, 1979) should be established for bean-bar riders.

Soil compaction can cause significant crop yield reductions. Effective management of soil compaction caused by tractors requires an understanding of the influence of the tractive system on soil compaction. Soil strain under tractors equipped with single rear wheels, dual rear wheels, or steel tracks was measured and compared. Tractors were of nearly equal mass. Strain was measured by using soil-strain transducers installed at 100-, 150-, 200-, and 300-mm depths beneath the soil surface. Soil strain was defined as the change in transducer length divided by the initial length of the transducer when installed in the soil. Soil strain at 100- to 245-mm depth was significantly greater for the tractor with single rear wheels than for the other tractors. The difference in soil strain caused by tractors with different tractive systems decreased with soil depth.

A study was undertaken to estimate energy use and CO2 release due to postharvest preservation of the 38.8 × 106-Mg (1.52 ×109-bu) Iowa corn crop. About 87% of the crop is artificially dried. Other preservation methods include cribbing ear corn (7%), oxygen-limiting storage (5%) and chemical preservative treatment (1%). Preservation of the corn crop requires, in total, 18 200 TJ of energy and releases 1614 Gg of CO2. Combustion of fuel (liquefied petroleum or natural gas) and electricity accounted for 77 and 10% of total energy use, respectively. CO2 from combustion of fuel and generation of electricity accounted for 57 and 32% of the CO2 release, respectively. Preservation methods varied in total energy use and CO2 release from farm natural-air drying at 1020 MJ/Mg corn and 262 kg CO2/Mg corn to chemical preservative treatment at 116 MJ/Mg corn and 9.3 kg CO2/Mg corn.

There are many opportunities for improvement in equipment used in the hay and forage industry. University and industry groups have listed and prioritized these opportunities. A project was undertaken to evaluate the level of satisfaction farmers in Allamakee and Mahaska counties in Iowa have with their hay and forage equipment, and to have them identify any needed changes in that equipment. The information was obtained through mailed surveys and follow-up phone interviews. The surveys included two evaluation matrices, which farmers used to rank their equipment on a satisfaction scale with respect to several criteria.

Two corn hybrids, one resistant (FR35 ¥ FR20) the other susceptible (DF20 ¥ DF12) to storage fungi, were harvested and hand-shelled at 22% moisture, wet basis, and stored at this moisture in aerated l-kg bin units. Four Rovral® fungicide treatments plus an untreated control were tested using carbon dioxide evolution as the index of grain-deterioration rate. Equations of carbon dioxide weight versus time were fitted. The resistant corn hybrid manifested a lower deterioration rate than did the susceptible hybrid. Samples treated with fungicide showed a reduction in grain-deterioration rate compared with untreated samples.

Laboratory tests were conducted to determine preservative effects of iprodione (Rovral®) fungicide on shelled corn. One-kilogram corn samples were held at 20°C, and 18.0, 22.5, and 23.5% moisture while being aerated at 0.45 m3/min-Mg (0.4 cfm/bu). Time required for the samples to lose 0.5% of original dry matter was used as the criterion of preservative effectiveness. Application of 20 ppm of iprodione extended this time 21% for 18% moisture corn and 13% for 22.5% corn. Effectiveness of iprodione increases with application rate up to 100 ppm where storage time is extended about 25%. A higher application rate had little added effect. The 3.29 mL/kg (3 oz/bu) fungicide solution rate is more effective than the 5.48 mL/kg (5 oz/bu) rate. Non-uniform application of iprodione did not decrease preservative effectiveness if the same total quantity of fungicide was applied. Damaged kernel totals after storage tests were higher for 22.5% moisture samples, compared to 13% moisture samples, but were not affected by iprodione treatment.

Twenty-six years of Des Moines, Iowa, weather data were used in a computer simulation of ambient air drying of fungi-resistant and fungi-susceptible corn hybrids treated with Rovral® fungicide. Drying of 20 and 24% moisture corn harvested 15 October was simulated. Compared with the susceptible corn hybrid (DF20¥DF12) under the same conditions, the resistant corn hybrid (FR35¥FR20) had lower airflow requirements and used less fan energy. Rovral fungicide-treated corn had a lower rate of grain deterioration, required lower airflow rates, and used less fan energy than untreated corn.

The pneumatic grain conveyor on a plot combine was evaluated and its crosstube grain injector redesigned to increase material throughput to a rate that would avoid plugging during operation in high-moisture corn. The new design allowed a throughput of 77 kg/min (169 lb/min) of high-moisture corn during tests.