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Satchithanantham S.,ASABE | Sri Ranjan R.,University of Manitoba | Bullock P.,University of Manitoba
Transactions of the ASABE | Year: 2014

Subsurface drainage is used for removing excess water from agricultural lands to improve productivity, although it can cause water quality problems downstream. Agricultural drainage is identified as one of the contributing factors to Lake Winnipeg's nutrient enrichment and subsequent water quality deterioration. It has been suggested that controlled drainage in the Lake Winnipeg watershed could be a potential best management practice (BMP). The objective of the study was to evaluate the flow and nutrient export through subsurface drainage by comparing free drainage with overhead irrigation (FDIR) and controlled drainage with subirrigation (CDSI) under potato crop. The experiment was carried out in southern Manitoba in a potato field with sandy loam soil using the same irrigation water source. Subsurface drainage was installed in 2009 at an average design depth of 0.9 m. Controlled drainage was accomplished by using drainage control structures at drainage outlets. Subirrigation was carried out by pumping water back through the subsurface drainage network. Drainage flow, nutrient export, and weather parameters were monitored during the growing seasons of 2010 and 2011. On average, controlled drainage reduced the flow volume by 91% in 2010 and 54% in 2011 compared to free drainage. The drainage volume from FDIR plots ranged from 13% to 53% of the rainfall received, while for CDSI plots it varied from 0% to 8%. In both years, average nitrate concentrations were lower in CDSI compared to FDIR plots. However, average phosphate concentrations were lower in 2010 and higher in 2011 under CDSI compared to FDIR. Compared to FDIR plots, average nitrate-N export from CDSI plots was reduced by 98% in 2010 and 67% in 2011. Average phosphate export was reduced by 94% in 2010; however, in 2011, it was 15% higher than FDIR. The majority of the export happened during the period dominated by heavy drainage outflow, which coincided with spring snowmelt. The nutrient export reduction by CDSI is attributed mainly to the drainage volume reduction by controlled drainage. © 2014 American Society of Agricultural and Biological Engineers.

Vadas P.A.,U.S. Department of Agriculture | Good L.W.,University of Wisconsin - Madison | Panuska J.C.,University of Wisconsin - Madison | Busch D.L.,ASABE | Larson R.A.,University of Wisconsin - Madison
Transactions of the ASABE | Year: 2015

Phosphorus (P) loss from agriculture can compromise the quality of receiving water bodies. For cattle farms, P can be lost from cropland, pastures, and outdoor animal lots. We developed a new model that predicts annual runoff, total solids loss, and total and dissolved P loss from cattle lots. The model requires input for annual precipitation, lot surface type, soil test P for earthen lots, cattle number and type, frequency of cleaning, and percent vegetative cover. The model estimates annual runoff using a precipitation dataset and curve number, annual solids loss based on annual runoff, annual particulate P loss based on solid loss and manure and soil P content, and annual dissolved P loss for each runoff event. Testing showed that the model reliably estimated runoff, solids loss, and P loss from a wide variety of lots and was more accurate than other, currently used models. The new model provides a valuable tool for developing whole-farm estimates of P loss and more effectively targeting P loss mitigation practices.

Campbell C.M.,Amec Foster Wheeler | Fulton J.P.,ASABE | McDonald T.P.,Auburn University | Wood C.W.,Auburn University | And 2 more authors.
Applied Engineering in Agriculture | Year: 2010

As technology advances for application equipment, it is assumed that control and distribution of material should improve. Therefore, an investigation was conducted to evaluate if spinner disc-control technology improves the distribution of poultry litter. A typical litter spreader equipped with an electronically adjustable hydraulic flow control (proportional) valve was used to test a closed-loop system (CLS) providing spinner-disc control and compare these results to a traditional open-loop system (OLS), using a manual valve. Three application rates of 2242, 4483, and 6725 kg/ha were selected for applying broiler litter. Litter was collected based on ASABE S341.3 testing protocol but was modified to assess pattern uniformity using a two-dimensional pan matrix. Results indicated that the CLS was able to maintain more consistent spinner-disc speeds only allowing 1- to 6-rpm differences between the individual spinner-discs whereas the OLS allowed 1-to 12-rpm differences. Further, the CLS generated spinner-disc speeds near the desired 600 rpm regardless of the application rate and also consistently provided smaller CVs (23.0% to 27.6%) over the range of application rates. Overlap pattern comparisons revealed no pattern shifts for either control system. However, significant differences were found between the systems (p = 0.0524) thus recommending the CLS when performing variable-rate application (VRA) or if changing rates regularly when moving between fields. Finally, results suggested that pattern uniformity can be improved when using the CLS over the OLS. © 2010 American Society of Agricultural and Biological Engineers.

Gupta S.K.,University of Florida | Ehsani R.,ASABE | Ehsani R.,University of Florida | Kim N.-H.,University of Florida
Transactions of the ASABE | Year: 2015

This article presents a part of the research work for the design and optimization of a fruit tree harvesting system using numerical methods. The analytical framework for the optimization is formulated based on a continuous canopy shaker that harvests citrus crops, primarily Valencia oranges (Citrus sinensis). Tree limbs are modeled analytically in the numerical based design optimization of a shaker that requires information regarding the limb configuration and properties. The objective of this study is to formulate a mathematical model to predict the configuration of primary limbs and to determine the properties of citrus wood. The tree limbs, thus proposed, are statistical prototypes or representations that account for the 5th, 25th, 50th, 75th, and 95th percentiles of actual tree limbs from random individual citrus trees. Polynomial response surface models were developed to predict sectional properties of the statistical model of the tree limbs. The distributions of the secondary branches and fruits were also predicted to model their effect on the dynamic response of the tree limbs. A three-point bending test, specific gravity test, moisture content test, and damping test were conducted on freshly cut samples of citrus wood. An elastic modulus of 8.5 GPa and modulus of rupture of 67.3 MPa were calculated from a load-deflection curve, and a density of 1450.8 kg m-3, moisture content of 42%, and damping ratio of 10.78 were measured. Although the proposed methodology was developed for a canopy shaker, it could be easily implemented for other vibratory harvesters, such as limb shakers, foliage shakers, and over-the-row harvesters. © 2015 American Society of Agricultural and Biological Engineers.

Samani Majd A.M.,Texas A&M University | Ashtari A.K.,Texas A&M University | Ashtari A.K.,University of Tehran | Riskowski G.L.,Texas A&M University | And 5 more authors.
Transactions of the ASABE | Year: 2015

Ammonia (NH3) emissions from animal feeding operations (AFOs) are the source of a number of environmental issues. Wet spray scrubbers using non-acidic solutions might be a new approach for NH3 mitigation from AFOs. A lab-scale spray scrubber was built to clean 0.024 m3 s-1 of an NH3/air mixture with an average NH3 concentration of 20 ppmv. Three variables including contact time, nozzle type, and scrubbing solution were investigated to evaluate their effects on the ammonia removal efficiency of the scrubber. The contact times were set to 0.3, 0.6, and 0.9 s, which were achieved by changing the elevation of the spray nozzle. Two types of spray nozzles were studied. The nozzles had full-cone spray patterns with different spray angles and different droplet sizes. Reverse osmosis (RO) water and two types of electrolyzed water (50 mg L-1 of free available chlorine, FAC) with pH = 9.0 and pH = 6.5 were tested as scrubbing solutions. The parameters were evaluated in 54 experiments, which included 18 treatments with three replications, to determine the effectiveness of the treatments in scrubbing NH3 gas from air. The maximum removal efficiency of 56% was achieved with the narrow-angle nozzle, 0.9 s contact time, and electrolyzed water with pH = 6.5. Therefore, within the ranges studied, increasing the contact time, decreasing the pH of the electrolyzed water, and using the narrow-angle nozzle increased the efficiency of the scrubber. The RO water captured more of the NH3 in the form of total ammoniacal nitrogen (TAN) than did the EW, which may indicate that EW forms chloramines in the scrubbing process. TAN is a desirable by-product because it can be used as fertilizer. EW may need to be used at pH levels lower than 6.5 to maintain FAC/TAN mass ratios lower than 7.6 in order to avoid N2, Cl2, and NH3 gas losses from the scrubbing solution. © 2015 American Society of Agricultural and Biological Engineers.

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