American Journal of Agricultural Research

  • Modelling of unsteady spatially distributed drying parameters assessed non-destructively in a small industrial food dryer

    Modelling of unsteady moisture diffusion in relation of product temperature become complex due to complexity involve in solving complex numerical equations. In this study, a simplified methodology (determination of drying parameters: lag factor and drying constant) used to model change in food quality with its temperature in an industrial dryer using potato slices (6mm thick, 60°C). A shiftable real time data acquisition box was developed. Linear and exponential models were developed to estimate product quality as a function of dimensionless moisture ratio, linked with change in product temperature. The experimental and models predicted color kinetics using variable values of lag factor and drying constant revealed good correlation coefficients (R2 = 0.88-0.99, P ˂ 0.0001). The change in spatially distributed quality parameter with product weight loss was successfully assessed and modelled unsteadily, providing a better way to optimize the design process as a function of food physiognomies in an industrial dryer.

  • Estimation of Yield Advantage and Competitiveness of Onion-Rosemary Intercropping over Sole Cropping at Wondo Genet

    Different cropping system and planting patterns of onion and rosemary evaluated to estimate yield advantage and their competitiveness during 2013-14 and 2014-15 growing seasons under irrigated condition at wondo genet Sidama zone, Southern Ethiopia. The experiment comprised of six treatments: sole Onion (250,000 plants ha-1), sole Rosemary (83,333plants ha-1) and four onion-rosemary intercropping mix proportion: 100 onion: 80 rosemary, 100 onion: 60 rosemary, 100 onion: 40 rosemary and 100 onion: 20 rosemary, using randomized complete block design with three replications. Analysis of variance revealed that; intercropping of onion with different population densities of rosemary significantly affected dry bulb yield; highest dry bulb yield was recorded at solitary cropping than that of intercropped. Similarly; essential oil yield of rosemary significantly influenced by cropping system; highest essential oil yield obtained in sole planted than intercropped. The highest value of land equivalent ratio (1.52), land equivalent coefficient (0.57) and relative crowding coefficient (6.07) obtained when onion intercropped with 80 % rosemary population density. However, positive values of actual yield loss and maximum intercropping advantage obtained in treatments where onion intercropped with rosemary at 20 and 40 % population density. Generally, these finding suggest that intercropping of onion with rosemary at 80 % population density enhanced yield advantage and Competitiveness as indicated by higher land equivalent ratio and relative crowding coefficient. Therefore, the inclusion of onion with 80% a rosemary population density elevated yield advantage and competitiveness over sole planted crop per unit area as indicated by higher LER and relative crowding coefficient.

  • Evaluations of faba bean (Vicia faba L.) Genotypes for agronomic traits and crude protein content across seven faba bean

    Faba bean (Vicia faba L.) is an important cool season protein rich food and feed legume belongs to fabaceae family. Twelve faba bean genotypes were evaluated in 2018/2019 cropping season across seven environments in Ethiopia using randomized complete block design with four replications. The combined analysis of variance showed highly significance difference among genotypes, environments and genotype by environment interaction effects (P

  • Nitrogen Nutrition, Yield, and Quality of Cotton under Varying Nitrogen Application Timings and Planting Dates

    Nitrogen (N) management may need to be different for cotton planted at different dates. The objective of this research was to determine the optimal N application timing for cotton under different planting dates. A field trial was conducted on the University of Tennessee West Tennessee Research and Education Center at Jackson, TN in 2011 and 2012 in a split plot randomized complete block design with four replicates. Three cotton planting dates of early planting, standard planting, and late planting and four N application timings of pre-plant, at-planting, early side-dress, and late side-dress were assigned to the whole plots and subplots, respectively. Although the interactions of planting date by N application timing, year by N application timing, and year by planting date were significant on leaf N at early bloom and late bloom; cotton plants received adequate N nutrition for optimal yield under different N application timings and varying planting dates in both years. No significant difference in lint yield was observed among the four N application timings regardless of planting date in 2011 that was wet in the early season but dry in the late season. In 2012 that was dry in the early season but wet in the late season, however, lint yield was higher with late side-dress of N than pre-plant at standard planting; the yield did not differ among the four N application timings at early planting or late planting. Higher fiber micronaire but lower fiber strength was obtained under early planting and standard planting than late planting. In 2011, the length and uniformity of fiber were not affected by the planting date. In 2012, however, the length and uniformity of fiber were greater at late planting than early planting and standard planting. The fiber length and fiber uniformity were greater with late side-dress of N than…

  • Development status and trend of high efficiency grain air-and-screen cleaning device

    The cleaning device in modern agricultural equipment is an important part of the reference of the grain combine harvester. The loss rate of the grain and other factors are directly affected by the cleaning device. In this paper, the development status of the current cleaning equipment and the research and analysis are described in three aspects: the distribution of the airflow field in the cleaning device, the movement law of the exudate, and the research on the centrifugal fan. The loss rate and the impurity ratio of the grain harvest are reduced. Objectives, reviewed the research status and trends of domestic and foreign grain combine harvester cleaning equipment, and put forward new ideas for the future development prospects and prospects of grain combine harvester, and provide reference for improving the research and design of grain harvester cleaning equipment. experiments.

  • Soil Nutrient Levels after Corn Harvest under NPSFe Biofertilizer and NPKZn Briquettes

    Interest in the use of alternate fertilizers has increased in recent years for improving crop nutrition and soil health. The efficacy of these fertilizers on corn (Zea mays L.) production has not been well documented. Alternate fertilizers organically enhanced NPSFe biofertilizer (NPSFe) manufactured from sterilized organic additives extracted from municipal wastewater biosolids and NPKZn briquettes (briquettes) produced by compacting commercially available solid fertilizers into a super-granule between 1-3 grams were evaluated for nutrient concentrations in the soil relative to common fertilizers ammonium sulfate (+P+K) and urea (+P+K) at Jackson and Grand Junction, TN from 2011 to 2013. NPSFe, the briquettes, ammonium sulfate, and urea and four N application rates of 0, 85, 128/170, and 170/255 kg ha-1 were assigned to the main and sub plots, respectively, in a split plot randomized complete block design with four replicates. Soil at a 0-15 cm depth was analyzed for Bray P, NO3–N, NH4+-N, SO42–S, and organic C concentrations after corn harvest. The briquettes produced lower soil NO3–N concentrations than the other fertilizers particularly under wet soil conditions. NPSFe sometimes had higher post-harvest soil NH4+-N than the briquettes and ammonium sulfate. NPSFe sometimes tended to be higher than the other fertilizers in post-harvest soil P concentrations after corn harvest, thus the P provided by NPSFe may be less available than TSP. NPSFe and ammonium sulfate both increased post-harvest soil SO42–S levels compared to the briquettes and urea, particularly at higher application rates. NPSFe had greater soil organic C level than the other fertilizers. In conclusion, NPSFe consistently increases soil organic C level, particularly at the higher N rates, within three years of experimentation, which may promote microbial activities and health of the soil.

  • Corn Mineral Nutrition Responses to NPSFe Biofertilizer and NPKZn Briquettes

    Alternative fertilizers have been increasingly developed during recent years in order to improve crop nutrition. The efficacy of these fertilizers on corn (Zea mays L.) production has not been well examined. Alternative fertilizers of organically enhanced NPSFe biofertilizer (NPSFe) manufactured from sterilized organic additives extracted from municipal wastewater biosolids and NPKZn briquettes (briquettes) produced by compacting commercially available solid fertilizers into a super-granule between 1-3 grams were evaluated for nutrient concentrations in plant biomass and grain of corn compared to commonly used N fertilizers ammonium sulfate and urea at Jackson and Grand Junction, TN during 2011-2013. NPSFe, the briquettes, ammonium sulfate, and urea and four N application rates of 0, 85, 128/170, and 170/255 kg ha-1 were assigned to the main and sub plots, respectively, in a split plot randomized complete block design with four replicates. Aboveground plant biomass at the silking growth stage (R1) and physiological maturity stage (R6) and grain at harvest were analyzed for N, P, K, S, Fe, and Zn concentrations. NPSFe resulted in similar or lower plant N concentrations relative to the conventional fertilizers ammonium sulfate and urea. The briquettes performed equally or better in terms of plant N concentrations compared to ammonium sulfate and urea. In excessive spring precipitation, the briquettes had higher biomass N concentrations at R1. NPSFe tended to have lower P concentrations in plant biomass at R1 and R6. The briquettes had similar or higher plant P levels relative to ammonium sulfate and urea. Both NPSFe and ammonium sulfate increased S concentrations in plant biomass compared to the briquettes and urea. In conclusion, the briquettes do not consistently improve corn N, P, K, and Zn nutrition compared to the conventional fertilizers ammonium sulfate and urea. NPSFe sometimes seems to reduce corn N and P nutrition but increase Zn nutrition relative to…

  • Research on screening performance of double layer vibrating screen for soybean harvester based on discrete element method

    In order to improve the screening effect of grain combine harvester, it is necessary to study the influence of different screening parameters on screening performance.In this paper, discrete element method was used to simulate the screening process of soybean and short stems by selecting different screening parameters, and dynamic screening efficiency and the number of short stems under screening were introduced as evaluation criteria.The results show that under certain other conditions, the vibration frequency, amplitude and direction angle have significant influence on the screening performance, while the inclination angle of the upper screen has little influence on the screening performance. With the increase of vibration frequency, amplitude and direction angle, screening efficiency increased first and then decreased, while the number of short stalks under screening increased first and then decreased. Considering the screening efficiency and the number of short stalks under the screening, it is concluded that the screening performance is better when the amplitude is 25 mm, the vibration frequency is 4 Hz, the vibration direction angle is 25 degrees and the upper screening angle is 3 degrees. The simulation results are verified by field experiments, and the simulation results meet the requirements of field experiments.

  • Development of Light Sensors to Measure Defoliation

    Sensors have become valuable tools in agriculture when decisions regarding inputs require precision and speed. For example, factors in estimating defoliation in row crops, such as intensive labor and, in particular, subjectivity, are greatly reduced with the use of sensors that can remove these limitations and biases. Estimates of defoliation are almost always overestimated due to human error and biased, unconscious efforts to locate injury. To address these issues, the accuracy and preciseness of a light-based sensor to detect defoliation was tested by measuring simulated levels of defoliation (0-100%) on paper “leaves” at seven light intensities. Results indicated that higher lux values were detected through thinner paper (filter paper) than through thicker paper (cardstock), demonstrating that leaf thickness could potentially affect accuracy of the light-sensor system. Despite some light penetrating the thinner paper with simulated defoliation levels, the two light sensors tested yielded accurate and precise predictions of defoliation (R2 > 0.95). This light-sensor approach could potentially be used in the field to report real-time measurements of defoliation in row crops, such as soybeans, or in other plant-based systems where losses of leaf area require monitoring in order to prevent economic injury.

  • The growth and nutrient utilization of Clarias gariepinus (Burchell 1822) fed Parkia biglobosa meal based diet

    The study investigated the growth and nutrient utilization of Clarias gariepinus fingerlings fed five iso-nitrogenus diets, containing fermented locust bean meal, at varying inclusion level (0%, 10%, 20%, 30%, 40%, 50%) as replacement for fishmeal. Eight weeks feeding trial was conducted using Clarias gariepinus fingerlings which were randomly distributed into 12 bowls at a stocking rate of 20 fish per bowl, in replicates per treatment. The experimental design was completely randomized. The fish were fed at 5% body weight, twice daily. Six isonitrogenous (35% crude protein) diets containing fermented locust beans meal at varying replacement level for fish meal designated as diet A0, B10, C20, D30, E40 and F50 were formulated and fed to the fish. All the experimental fish fed the various treatments showed increase in weight, carcass crude protein and lipid content, compared to the initial value indicating positive contribution of the various diets to growth of the fish. The results obtained indicated there was no significant difference (P>0.05) in the mean weight gain, percentage weight gain. Specific growth rate, food conversion ratio and protein efficiency ratio among the fish fed the various diets. The highest weight gain was recorded in the fish fed the control diet (2.47g) while the least was recorded for the fish fed the B20 diet (2.18g). This study revealed that locust bean seed if processed, as in fermentation, could replace fishmeal up to 50% level in the diet of C. fish. This level of inclusion would be a significant replacement for the expensive fishmeal in feed manufacturing.