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Anatomy of a field trial: Wood-based biochar and compost influences a Pacific Northwest soil
Get PDFBiochar land application research in elevated rainfall areas (980 millimeters of annual rainfall) of the U.S. Pacific Northwest is lacking. A proof-of-concept field study examined the effects of spruce-pine-fir wood chip biochar (slow pyrolysis; 450-500 degrees Celsius; 35 megagrams per hectare), dairy manure compost (105 megagrams per hectare), compost + biochar (35 and 105 megagrams per hectare, respectively), and a control (no biochar or compost) on glacially altered soil (sandy or loamy skeletal, isotonic, mesic humic or aquic Dystroxerepts) chemical properties and growth characteristics of vetch and sweet corn over a growing season. In-season liming (5.4 megagrams per hectare) occurred to raise the soil pH for adequate crop growth. Biochar, alone or applied with compost, maintained a greater amount of soil organic carbon and, when combined with lime, acted more effectively than control conditions. Biochar and compost + biochar treatments reduced plant-available zinc and copper concentrations, although the concentrations were still an order of magnitude greater than those considered minimal for crop growth. There was no difference in vetch or corn yield among treatments. However, the compost + biochar treatment increased vetch total nitrogen and magnesium content, as well as corn copper content. Overall observations suggest that co-applying biochar with an organically-rich material like compost could be beneficial without compromising environmental quality
Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam
Get PDFResearcher’s seek a more renewable and natural alternative for water soluble anionic polyacrylamide (PAM), a highly-effective, petroleum-derived polymer used in agriculture to control erosion and reduce water seepage from unlined irrigation structures. This study evaluated two anionic polymers: a bacteria-produced polysaccharide (biopolymer) with 10-20 Mg/mol molecular weight (MW) and 30% charge density, and a PAM (12-15 Mg/mol MW, 30% charge density) to compare their ability to flocculate soil colloids, stabilize soil aggregates, and influence effective hydraulic conductivity (seepage loss). The biopolymer most effectively flocculated the colloids at a concentration of 1 mg/L, but was still 30% less effective than PAM at 1 mg/L and 50% less effective than 10 mg/L PAM treatments. The aggregate stability test included the polymers listed above as well as lower-MW representatives of each type (MW = 0.2 to 0.5 Mg/mol). Overall, both polymers increased the stability of 1- to 2-mm-diam., silt loam aggregates, though PAM was 1.35x more effective than the biopolymer, 88.7% vs. 65.5%. These results suggested that the biopolymer’s bulkier molecular conformation limited the extension and flexibility of the molecule in solution, compared to PAM. After 140 hr, the biopolymer reduced seepage loss rates 21%, while PAM increased loss rates 1.6-fold, compared to controls. These data suggest that the biopolymer would be less effective than PAM for reducing water erosion owing to its lesser flocculation and aggregate-stabilizing potential. However, the biopolymer could be a more desirable alternative to PAM for controlling seepage from unlined irrigation canals and reservoirs; it (i) can be used effectively at lower concentrations, (ii) is considered more environmentally friendly, and (iii) is produced from a renewable resource
Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2014
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 30 experimental cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2014 growing season in a randomized complete block design with 6 replications. At harvest on 24-25 September 2014, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. After 138 days in storage, samples were evaluated for surface rot, weight loss, and sucrose loss. Surface root rot ranged from 6 to 82%, weight loss ranged from 9.1 to 17.5%, sucrose losses ranged from 22 to 85%, and estimated recoverable sucrose ranged from 1,008 to 8,292 lb/A. Given these response ranges, selecting cultivars for rhizomania resistance and combining this resistance with storability will lead to considerable economic benefit for the sugar beet industry
Influence of harvest timing, fungicides, and Beet Necrotic Yellow Vein Virus on sugar beet storage
Get PDFRoot rots in sugar beet storage can lead to million dollar losses because of reduced sucrose recovery. Thus, studies were conducted to establish better chemical control options and a better understanding of the fungi involved in the rot complex. A water check and three fungicides (Mertect, Propulse, and Stadium) were investigated for their ability to control fungal rot on sugar beet roots held in long term storage during both the 2012 and 2013 storage seasons. At the end of September into October, roots were collected on five subsequent weeks, treated, and placed on top of a commercial indoor storage pile until early February. Both Propulse and Stadium performed well, by reducing fungal growth and rot on roots versus the check by an average of 84 to 100% for roots collected the first three weeks both years. When compared to the check and Mertect, both Propulse and Stadium reduced sucrose loss by 22 to 34% when differences could be statistically proven. The predominant fungal pathogens were an Athelia-like sp., Botrytis cinerea, Penicillium spp., and Phoma betae. Propulse and Stadium should be considered further for root rot control in commercial sugar beet storage and on roots being held for seed production
Aluminum-based water treatment residual use in a constructed wetland for capturing urban runoff phosphorus: Column study
Get PDFAluminum-based water treatment residuals (Al-WTR) have a strong affinity to sorb phosphorus. In a proof-of-concept greenhouse column study, Al-WTR was surface-applied at 0, 62, 124, and 248 Mg/ha to 15 cm of soil on top of 46 cm of sand; Al-WTR rates were estimated to capture 0, 10, 20, and 40 years of phosphorus from an urban watershed entering an engineered wetland in Boise, Idaho, USA. Creeping red fescue (Festuca rubra) was established in all columns; one set of columns received no Al-WTR or plants. After plant establishment, once per week over a 12-week period, ~1.0 pore volumes of ~0.20 mg phosphorus/L was added to each column. Infiltration rates were measured, leachate was collected and analyzed for soluble phosphorus, and fescue yield, phosphorus concentration and uptake were determined. After plant harvest the sand, soil, and the Al-WTR layer were collected and analyzed for Olsen phosphorus, amorphous aluminum, iron, and phosphorus storage capacity (PSC), and soluble+aluminum+iron-bound, occluded, and calcium-bound phosphorus phases. Infiltration rate increased only due to the presence of plants. Leached phosphorus decreased (50%) with plants present; Al-WTR further reduced soluble phosphorus leaching losses (60%). Fescue yield, phosphorus concentration and uptake increased with increasing Al-WTR rate, due to Al-WTR sorbing and potentially making phosphorus more plant available; Olsen-extractable phosphorus increased with increasing Al-WTR rate, supporting this contention. The PSC was reduced with the 62 Mg/ha Al-WTR rate but maintained with greater Al-WTR rates. The 124 and 248 Mg/ha Al-WTR rates also contained greater phosphorus associated with the soluble+aluminum+iron and occluded phases which should be stable over the long-term (e.g., decadal). It was recommended to apply Al-WTR near the 124 and 248 Mg/ha rates in the future to capture urban runoff soluble phosphorus in the Boise, Idaho engineered wetland
Biochar can positively influence soil moisture relations
Get PDFOne major issue related to climate change is the potential to improve soil water relations in light of changes in future precipitation patterns or reductions in water availability in drier portions of the world (such as the western US). It appears that biochar may play a positive role, but that role may be soil texture related. We performed a study with a sandy (Wolverine sand from Shelley, ID), silty (Portneuf silt loam from Kimberly, ID), and clay loam soil (Danville clay loam from a subsurface horizon, from near Oakland, CA) that received either 5 or 10% by volume of lodgepole biochar in either chipped (0.25-0.63”) or fine (0-0.25”) form; a control (no biochar) was also included. Soil-biochar treatments were evenly mixed and placed into containers, volumetric moisture sensors were inserted into the soil, and then 150 mL of water were evenly applied to the soil surface. Sensor measurements were collected every 2 minutes over a 14 day drying period. Results showed that after applying the same volume of water and allowing the mixtures to dry for 14 days, the control soils always contained less volumetric water than soils receiving biochars regardless of soil texture. Specifically, the volumetric water content was between 31 and 41%, 16 and 18%, and 15 to 18% greater than the control when chipped biochar was applied to the sandy, silty, or clay loam soils, respectively. In addition, differences between the 5% and 10% rates were not always considerable to warrant the greater application rate. It is important to note that the volumetric water content still increased when fine biochar was added to the soils, but the increase was not as dramatic as with the chipped biochar. It is speculated that at the applied rates, finer biochar particles could increase connectivity between the soil surface and subsurface and increase evaporative losses as compared to larger sized biochars. Additional research is needed to prove or disprove this hypothesis, but improvements in soil water content via biochar application may be of value to arid region crop producers and producers in areas where precipitation events are variable and lacking over relatively long time periods
Phosphorus losses from an irrigated watershed in the Northwestern U.S.: Case study of the Upper Snake Rock Watershed
Get PDFWatersheds utilizing surface water for irrigation often return a portion of the water to a water body. This irrigation return flow often includes sediment and nutrients that reduce the quality of the receiving water body. Research in the 82,000 ha Upper Snake Rock (USR) watershed from 2005 to 2008 showed that, on average, water diverted from the Snake River annually supplied 547 kg/ha of total suspended sediment (TSS), 1.1 kg/ha of total phosphorus (TP) and 0.50 kg/ha of dissolved phosphorus (DP) to the irrigation tract. Irrigation return flow from the USR watershed contributed 414 kg/ha of TSS, 0.71 kg/ha of TP and 0.32 kg/ha of DP back to the Snake River. Significantly more TP flowed into the watershed than returned to the Snake River while there was no significant difference between inflow and return flow loads for TSS and DP. Average TSS and TP concentrations in return flow were 71 and 0.12 mg/L, respectively, which exceeded the TMDL limits of 52 mg/L TSS and 0.075 mg/L TP set for this section of the Snake River. Monitoring inflow and outflow for five water quality ponds constructed to reduce sediment and phosphorus losses from the watershed showed that TSS concentrations were reduced 36 to 75%, but DP concentrations were reduced only 7 to 16%. This research showed that continued implementation of conservation practices should result in irrigation return flow from the USR watershed meeting the TMDL limits for the Snake River
Estimation of furrow irrigation sediment loss using an artificial neural network
Get PDFThe area irrigated by furrow irrigation in the U.S. has been steadily decreasing but still represents about 20% of the total irrigated area in the U.S. Furrow irrigation sediment loss is a major water quality issue and a method for estimating sediment loss is needed to quantify the environmental impacts and estimate effectiveness and economic value of conservation practices. Artificial neural network (NN) modeling was applied to furrow irrigation to predict sediment loss as a function of hydraulic and soil conditions. A data set consisting of 1926 furrow evaluations spanning three continents and a wide range of hydraulic and soil conditions was used to train and test a multilayer perceptron feed forward NN model. The final NN model consisted of 16 inputs, 19 hidden nodes in a single hidden layer and 1 output node. Prediction performance of the NN model was model efficiency (ME) = 0.66 for the training data set and ME = 0.80 for the testing data set. The prediction performance for the complete data set of 1926 furrow evaluations was ME= 0.70 with an absolute sediment loss prediction error of less than ±5, ±10, ±20, and ±30 kg per furrow for 35%, 53%, 72% and 85% of the data set values, respectively. The NN model is applicable to predicting sediment loss rates between 1 and 300 kg per furrow for furrow lengths between 30 m and 400 m, slopes between 0.1% and 4%, flow rates between 5 L/min-1 and 75 L/min-1, and silt or sand particle sized fractions between 0.1 and 0.75
Influence of soil properties and test conditions on sorption and desorption of testosterone
Get PDFIn this study, batch sorption and desorption experiments were conducted for testosterone using four agricultural soils and five clay minerals. Significant differences in sorption behavior were observed between abiotic and biotic systems. The Freundlich sorption coefficient Kf (µg per g)/(µg per mL) ranged from 8.53 to 74.46 for soils and from 35.28 to 1243 for clays. The maximum sorption capacity (µg per g) of soils ranged from 25.25 to 440.61 for soils and 168.46 to 499.84 for clays. Correlation of sorption model parameters with soil properties indicated that both clay content and soil organic matter are important variables in predicting testosterone sorption behavior. Observed testosterone desorption from agricultural soils ranged from approximately 14 to 100 percent after 3 desorption cycles, and the desorption percentage decreased as the initial testosterone concentration decreased. Temperature, ionic strength, the water/soil ratio and soil depth were determined to influence sorption and desorption of testosterone. Desorption significantly increase with the soil depth and with the increase in the water to soil ratio. Temperature had an inverse effect on the sorption capacity of the soils tested. Thermodynamic calculations showed that the enthalpy change of the soils tested were the range of 12.9-20.7 kJ per mol, indicating weak interaction between testosterone and soil. Our results suggest that additional studies on how soil particles with different size fractions affect hormones fate and transport are needed in order to determine the potential risk of testosterone leaching or runoff
Reducing sucrose loss in sugar beet storage with fungicides
Get PDFRoot rots in sugar beet storage can lead to multi-million dollar losses because of reduced sucrose recovery. Thus, studies were conducted to establish better chemical control options and a better understanding of the fungi involved in the rot complex. A water check and three fungicides (Mertect, Propulse, and Stadium) were investigated for their ability to control fungal rot on sugar beet roots held in long term storage during both the 2012 and 2013 storage seasons. At the end of September into October, roots were collected on 5 subsequent weeks, treated, and placed on top of a commercial indoor storage pile until early February. Differences (P <0.0001 to 0.0150) between spray treatments were evident with both Propulse and Stadium reducing fungal growth on roots versus the check by an average of 84 to 100% for roots collected the first three weeks both years. The treatments also reduced (P <0.0001 to 0.0146) sucrose loss with the reduction being 14-46% when compared to both the check and Mertect when significant differences were observed. The predominant fungal pathogens were an Athelia-like sp., Botrytis cinerea, Penicillium spp., and Phoma betae. Propulse and Stadium should be considered further for root rot control in commercial sugar beet storage and on roots being held for seed production