Academia.eduAcademia.edu

Figure 3 – uploaded by Daniel Andersen

See full PDFdownloadDownload figure
Table 3. Average surface soil (0-30 cm) Melich-3 phosphorus concentration (mg P/kg soil) for Central lowa 1 (CN IA 1), Central lowa 2 (CN IA 2), Northwest lowa 1 (NW IA 1), Northwest lowa 2 (NW IA 2), Southwest lowa 1 (SW IA 1), and Southwest lowa 2 (SW IA 2). Values within a column that do not share the same letter are significantly different at the 0.05 level.

Table 3 Average surface soil (0-30 cm) Melich-3 phosphorus concentration (mg P/kg soil) for Central lowa 1 (CN IA 1), Central lowa 2 (CN IA 2), Northwest lowa 1 (NW IA 1), Northwest lowa 2 (NW IA 2), Southwest lowa 1 (SW IA 1), and Southwest lowa 2 (SW IA 2). Values within a column that do not share the same letter are significantly different at the 0.05 level.

Related Figures (6)

Central lowa 1 (CN IA 1) was a 3.09 ha feedlot permitted for 1,000 head of cattle. Runoff effluent drained into a solid settling basin designed to hold 4,290 m* of effluent. The VTA consisted of two channels operated in parallel; each channel was 24 m wide and averaged 311 m long. Central IA 1 VTA soil consisted of Clarion loam, Cylinder loam, and Wadena loam (Soil Survey Staff, NRCS USDA, 2010). The VTS at Central lowa 2 consisted of a SSB, VIB, and VTA. Runoff from the 1.07 ha feedlot drained into a concrete SSB which released effluent into a 0.32 ha VIB. Effluent captured in VIB tiles was pumped onto VTA. Soils in the VIB consisted of Nicollet loam and Webster clay loam and the VTA was Harps loam (Soil Survey Staff, NRCS USDA, 2010). Northwest lowa 1 (NW IA 1) consisted of a 2.91 ha feedlot permitted to hold 1,400 head of cattle. Feedlot runoff was collected in a SSB with a volume of 3,700 m®. The SSB outlet pipe discharged onto VTA consisting of Galva silty clay and Radford silt loam soils (Soil Survey Staff, NRCS USDA, 2010). Northwest lowa 2 (NW IA 2) had an SSB-VIB-VTA system designed to control runoff from a 2.96 ha concrete feedlot. A settling basin collected the feedlot runoff and released it to a 1.01 ha VIB drained by 15 cm diameter perforated tiles installed 1.2 m deep and spaced 4.6 m apart. Flow from the tile lines was collected in a sump and pumped onto the VTA divided into two 27 m wide channels. The channel receiving effluent was switched manually by the producer. Northwest IA 2 consisted of Moody silty clay loam (Soil Survey Staff, NRCS USDA, 2010). Southwest lowa 1 (SW IA 1) was a 7.49 ha feedlot with an 11,550 m?® solid settling basin that released effluent to a 4.05 ha VTA was divided into ten channels. Tile lines, installed to control water table depth below the system and enhance infiltration of effluent into the soil, surrounded each of the VTA channels. Soils in the VTA consisted of mostly Judson silty clay loam and smaller areas of Colo-Ely complex (Soil Survey Staff, NRCS USDA, 2010). Southwest lowa 2 (SW IA 2) was a 3.72 ha feedlot. Runoff drained into a solid settling basin and was released to a 3.44 ha VTA constructed with earthen berm spreaders along the length. The spreaders slowed the flow of effluent through the system, increasing the time for infiltration. Southwest IA 2 VTA soil consisted of Kennebec silt loam (Soil Survey Staff, NRCS USDA, 2010) Table 1. Summary of the feedlot capacity, system configuration, and component sizes for vegetative treatment systems at each of the six sites.
Central lowa 1 (CN IA 1) was a 3.09 ha feedlot permitted for 1,000 head of cattle. Runoff effluent drained into a solid settling basin designed to hold 4,290 m* of effluent. The VTA consisted of two channels operated in parallel; each channel was 24 m wide and averaged 311 m long. Central IA 1 VTA soil consisted of Clarion loam, Cylinder loam, and Wadena loam (Soil Survey Staff, NRCS USDA, 2010). The VTS at Central lowa 2 consisted of a SSB, VIB, and VTA. Runoff from the 1.07 ha feedlot drained into a concrete SSB which released effluent into a 0.32 ha VIB. Effluent captured in VIB tiles was pumped onto VTA. Soils in the VIB consisted of Nicollet loam and Webster clay loam and the VTA was Harps loam (Soil Survey Staff, NRCS USDA, 2010). Northwest lowa 1 (NW IA 1) consisted of a 2.91 ha feedlot permitted to hold 1,400 head of cattle. Feedlot runoff was collected in a SSB with a volume of 3,700 m®. The SSB outlet pipe discharged onto VTA consisting of Galva silty clay and Radford silt loam soils (Soil Survey Staff, NRCS USDA, 2010). Northwest lowa 2 (NW IA 2) had an SSB-VIB-VTA system designed to control runoff from a 2.96 ha concrete feedlot. A settling basin collected the feedlot runoff and released it to a 1.01 ha VIB drained by 15 cm diameter perforated tiles installed 1.2 m deep and spaced 4.6 m apart. Flow from the tile lines was collected in a sump and pumped onto the VTA divided into two 27 m wide channels. The channel receiving effluent was switched manually by the producer. Northwest IA 2 consisted of Moody silty clay loam (Soil Survey Staff, NRCS USDA, 2010). Southwest lowa 1 (SW IA 1) was a 7.49 ha feedlot with an 11,550 m?® solid settling basin that released effluent to a 4.05 ha VTA was divided into ten channels. Tile lines, installed to control water table depth below the system and enhance infiltration of effluent into the soil, surrounded each of the VTA channels. Soils in the VTA consisted of mostly Judson silty clay loam and smaller areas of Colo-Ely complex (Soil Survey Staff, NRCS USDA, 2010). Southwest lowa 2 (SW IA 2) was a 3.72 ha feedlot. Runoff drained into a solid settling basin and was released to a 3.44 ha VTA constructed with earthen berm spreaders along the length. The spreaders slowed the flow of effluent through the system, increasing the time for infiltration. Southwest IA 2 VTA soil consisted of Kennebec silt loam (Soil Survey Staff, NRCS USDA, 2010) Table 1. Summary of the feedlot capacity, system configuration, and component sizes for vegetative treatment systems at each of the six sites.
Table 2. Yields and phosphorus removal from harvesting vegetative treatment area vegetation for Central lowa 1 (CN IA 1), Central lowa 2 (CN IA 2), Northwest lowa 1 (NW IA 1), Northwest lowa 2 (NW IA 2), Southwest lowa 1 (SW IA 1), and Southwest lowa 2 (SW IA 2). In a second experiment, Sheaffer et al. (2008) found that phosphorus uptake could be greatly enhanced by increasing the yield of the canarygrass through supplemental addition of nitrogen fertilizer. By adding supplemental nitrogen they were able to increase phosphorus uptake to 72 kg P/ha. Their results for phosphorus uptake are similar to those found in this study without supplemental nitrogen application as we monitored phosphorus uptake of up to 61 kg P/ha. The feedlot runoff vegetative treatment areas received substantially higher nitrogen application rates
Table 2. Yields and phosphorus removal from harvesting vegetative treatment area vegetation for Central lowa 1 (CN IA 1), Central lowa 2 (CN IA 2), Northwest lowa 1 (NW IA 1), Northwest lowa 2 (NW IA 2), Southwest lowa 1 (SW IA 1), and Southwest lowa 2 (SW IA 2). In a second experiment, Sheaffer et al. (2008) found that phosphorus uptake could be greatly enhanced by increasing the yield of the canarygrass through supplemental addition of nitrogen fertilizer. By adding supplemental nitrogen they were able to increase phosphorus uptake to 72 kg P/ha. Their results for phosphorus uptake are similar to those found in this study without supplemental nitrogen application as we monitored phosphorus uptake of up to 61 kg P/ha. The feedlot runoff vegetative treatment areas received substantially higher nitrogen application rates
Figure 1. Illustration of how soil Melich-3 phosphorus increases along the length of the Northwest lowa 1 vegetative treatment area. (a) Increases in soil phosphorus and (b) percent increase in soil Melich-3 phosphorus concentration as compared to initial sample. Along with the average phosphorus concentrations it is also important to consider how the phosphorus is distributed down the length of the VTA. This is illustrated for the Northwest lowa 1 VTA (figure 1). The plots show (a) the absolute change in soil phosphorus concentration (as compared to the initial soil sample) and (b) the relative change normalized as the percent change in soil concentration. Both plots showed a general pattern of greater accumulation within the upper portion (near the inlet) of the VTA which was expected since this would be the area where solids eroded from the feedlot and escaping the settling basin would be expected to settle. Additionally, smaller settling basin release events would not distribute the applied effluent over the entire VTA, but instead only load the effluent over a fraction of the total treatment area. This trend is present in all years, but becomes especially evident in 2009. Although this appears true as a general trend, exceptions occurred; most notably the 365-m point in 2008 which exhibited a significant increase in phosphorus concentration. The VTA experienced heavy hydraulic and phosphorus loading during this year which may have created concentrated flows paths and greater phosphorus transport and accumulation at this sampling location. Corrective actions by the producer to level and reduce channeling appear to have alleviated this in 2009, although remnants of the 2008 accumulation remain. This illustrates two things, first it is critical for the producer to watch for concentrated flow and to take corrective action as soon as possible to correct the situation, and second higher hydraulic loadings are prone to creating concentrated flows.
Figure 1. Illustration of how soil Melich-3 phosphorus increases along the length of the Northwest lowa 1 vegetative treatment area. (a) Increases in soil phosphorus and (b) percent increase in soil Melich-3 phosphorus concentration as compared to initial sample. Along with the average phosphorus concentrations it is also important to consider how the phosphorus is distributed down the length of the VTA. This is illustrated for the Northwest lowa 1 VTA (figure 1). The plots show (a) the absolute change in soil phosphorus concentration (as compared to the initial soil sample) and (b) the relative change normalized as the percent change in soil concentration. Both plots showed a general pattern of greater accumulation within the upper portion (near the inlet) of the VTA which was expected since this would be the area where solids eroded from the feedlot and escaping the settling basin would be expected to settle. Additionally, smaller settling basin release events would not distribute the applied effluent over the entire VTA, but instead only load the effluent over a fraction of the total treatment area. This trend is present in all years, but becomes especially evident in 2009. Although this appears true as a general trend, exceptions occurred; most notably the 365-m point in 2008 which exhibited a significant increase in phosphorus concentration. The VTA experienced heavy hydraulic and phosphorus loading during this year which may have created concentrated flows paths and greater phosphorus transport and accumulation at this sampling location. Corrective actions by the producer to level and reduce channeling appear to have alleviated this in 2009, although remnants of the 2008 accumulation remain. This illustrates two things, first it is critical for the producer to watch for concentrated flow and to take corrective action as soon as possible to correct the situation, and second higher hydraulic loadings are prone to creating concentrated flows.
Figure 2. Comparison of soil phosphorus accumulation predicted using the mass balance approach and the phosphorus accumulation monitored shown on (a) annual basis and (b) cumulative basis.
Figure 2. Comparison of soil phosphorus accumulation predicted using the mass balance approach and the phosphorus accumulation monitored shown on (a) annual basis and (b) cumulative basis.
Figure 3. Melich-3 phosphorus concentration profiles from the surface to a depth of 1.2 m at (a) Central lowa 1, (b) Northwest lowa 1, (c) Northwest lowa 2, and (d) Southwest lowa 1.
Figure 3. Melich-3 phosphorus concentration profiles from the surface to a depth of 1.2 m at (a) Central lowa 1, (b) Northwest lowa 1, (c) Northwest lowa 2, and (d) Southwest lowa 1.
Figure 4. Comparison of Melich-3 phosphorus concentration profiles at vegetative treatment area inlets and outlets at Central lowa 1 after four years of use.
Figure 4. Comparison of Melich-3 phosphorus concentration profiles at vegetative treatment area inlets and outlets at Central lowa 1 after four years of use.
Related topics:
Environmental ScienceAgricultureSoil phosphorusAgricultural and Bioresource Engineering
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved