Optimum Irrigation Loading Rates of Highly Saline Wastewater on a Montmorillonitic Soil

Annual applications of 125, 90, and 50 cm of secondary-treated municipal effluent were applied to a 0.76 cm/hr glaciated soil growing alfalfa for 3 years. All treatments had weekly applications with the depth of application varying from 1.5-3.2 cm for the low rate plot to 3.8-8 cm for the high plot. The amounts applied paralleled the evapotranspiration curve of the crop with weekly applications lowest in the spring and fall and highest during the summer. Water quality varied from 1500-3000 Siemens /cm for the electrolyte concentration, from 5-11 for the sodium adsorption ratio, and from 0.1-12. 4 ppm for nitrate nitrogen. A water table developed within 1.2 meters of the surface for the 90 cm plot (treatment 35G) and within 1.1 meters of the surface on the 125 cm plot (treatment 50) at the end of the second irrigation season. Treatment 50 had lost 1-2% of the plant population at the end of the second year and 15-20% by the end of the third year of irrigating. Leaching fractions of 0.08-0.10 for total moisture should not be exceeded to prevent water table problems from developing near the surface. Annual soil applications of gypsum were added to the 90 cm plot (treatment 35G) to determine the efficiency in removing exchangeable sodium from the soil colloid exchange sites. After two annual applications of powdered gypsum, no significant difference between the gypsum plot (treatment 35G) and the non-gypsum plot (treatment 35) was detected in the top 1.2 meters. However, the sodium level for 35G in observation wells at the center of the plot were 2-5 times higher than the non-gypsum plot with the same annual rate of effluent. Sulphate levels were 4-8 times higher on 35G versus 35 and magnesium was 4 times higher. Calcium was replacing magnesium and sodium on the exchange complex at depths below 1.2 meters. Nitrate levels in the soil varied according to the nitrate levels in the effluent. In situ soil water extracts were monitored with depth and time across treatments. There was no difference in the nitrate levels in the soil according to treatment. Nitrate nitrogen levels were the highest in the ground waters beneath the plot with the thickest sand layer in the subsoil. Soil dispersion caused by sodic irrigation water for the top 3 cm of soil was evident at the end of the three-year project on the 50 cm annual application plot (treatment 20). Concentrating effects of ET and low leaching caused high sodium adsorption ratios of the soil solution during the irrigation season on treatment 20. Treatments 50, 35, and 35G did not show signs of soil dispersion on the top 3 cm

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 2 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of Federal farm program are sufficient to induce Western Corn Belt/Northern Plains farmers in environmentally sensitive areas to adopt sustainable fa practices and systems. To attain this goal, four case farms were chosen involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No. 2 is located in Moody County and followed a corn-soybean oats rotation on the acres focused on in the analysis prior to enrollment the Integrated Crop Management (ICM) program. It is a dry-land operation used conventional tillage prior to enrollment in the ICM program. The total operation consists of 1,858 acres, with 710 acres under the ICM program focused on 299 of those ICM acres in our analyses. Lamo and Clamo soils up the majority of the ICM crop acres. These are medium to fine-textured soils overlying a shallow drinking water aquifer

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 4 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No. 4 is located in Brookings County and followed a continuous corn rotation prior to enrollment in the Water Quality Incentive Program (WQIP). It is an irrigated operation that uses a center-pivot system. Conventional tillage practices are used. The total operation consists of 838 acres, with 213 acres enrolled in the WQIP program. One hundred and fifty of those acres received irrigation management assistance. In one 73-acre field irrigated by a center-pivot system, 66 acres were assumed to be under the center-pivot system and the other 7 acres were assumed to be in the corners of the field where the center-pivot system could not reach. These 7 acres were designated as the set-aside acres for the baseline before scenario. This 73-acre field was focused on in our analyses. The majority of the soils in this field are a combination of coarse-textured (Fordville), and fine-textured (Marysland) soils. Both of these soils overlay a shallow drinking water aquife

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 3 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area. Case Farm No.3 is located in Minnehaha County and has corn, soybeans, oats, alfalfa, and clover. It is a dry-land operation that uses conventional tillage. The total operation consists of 168 acres, with 108 of the acres under the Water Quality Incentive program (WQIP) being focused on in the study. The acres are divided into two separate fields that are managed differently. A corn/soybean rotation is followed on the lower field and inorganic fertilizers were used. The upper field contains two different rotations. One rotation is a corn/oats,clover rotation and the other is a corn/oats,alf/alf/alf/alf/alf rotation. The majority of the soils on the lower field under WQIP are a combination of medium (Brandt), and coarse textured (La Prairie) soils. Both of these soils overlay a shallow drinking water aquifer. The upper field was mostly Moody soils (medium-textured). These soils don\u27t overlay an aquifer, but contribute to the runoff onto the lower field

Profitability and Nitrate Leaching Effects of Possible Farming Practice and System Changes Over South Dakota\u27s Big Sioux Aquifer: Case Farm No. 1 Summary

The overall goal of the SARE/Water Quality project was to determine whether economic incentives offered by recent environmental provisions of the Federal farm program are sufficient to induce Western Corn Belt/Northern Great Plains farmers in environmentally sensitive areas to adopt sustainable farming practices and systems. To attain this goal, four case farms were chosen to be involved in this study based on their size, soil types, cropping systems, topography, and management in the Big Sioux Aquifer study area

No significant effect on bone mineral density by high doses of vitamin D3 given to overweight subjects for one year

<p>Abstract</p> <p>Background</p> <p>In meta-analyses supplementation with vitamin D appears to reduce incidence of fractures, and in cross-sectional studies there is a positive association between serum 25-hydroxyvitamin D (25(OH)D) levels and bone mineral density (BMD). However, the effect of supplementation with high doses of vitamin D on BMD is more uncertain and could in theory have both positive and negative effects.</p> <p>Methods</p> <p>The study was a one year, double blind placebo-controlled intervention trial performed at the University Hospital of North Norway. 421 subjects, 21 - 70 years old, were included and 312 completed the study. The subjects were randomized to vitamin D₃40.000 IU per week (DD group), vitamin D₃20.000 IU per week (DP group), or placebo (PP group). All subjects were given 500 mg calcium daily. Serum 25(OH)D, osteoprotegrin (OPG), receptoractivator of nuclear factor-kappaB ligand (RANKL), and BMD at the lumbar spine and the hip were measured before and at the end of the study.</p> <p>Results</p> <p>At baseline the mean serum 25(OH)D levels were 58 nmol/L (all subjects) and increased to 141 and 100 nmol/L in the DD and DP groups, respectively. After one year, no significant differences were found between the three groups regarding change in BMD, serum OPG or RANKL.</p> <p>Conclusions</p> <p>Supplementation with high doses of vitamin D for one year does not appear to have a negative effect on BMD in healthy subjects. In order to disclose a positive effect, subjects with low BMD and/or low serum 25(OH)D levels need to be studied.</p> <p>Trial registration</p> <p>The trial was registered at ClinicalTrials.gov (NCT00243256).</p