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Surfactant effects on soil aggregate tensile strength
Get PDFLittle is known regarding a soil aggregate's tensile strength response to surfactants that may be applied to alleviate soil water repellency. Two laboratory investigations were performed to determine surfactant effects on the tensile strength of 1) Ap horizons of nine wettable, agricultural soils collected from across the continental U.S., and 2) two of the nine soils (Latahco and Rad silt loams from the Pacific Northwest) that were sampled at two depths (5 and 15 mm) after being sprinkler irrigated. Along with an untreated control, three surfactants (an alkyl polyglycoside, an ethylene oxide/propylene oxide block copolymer, and a blend of the two) were spray applied by hand at rates of 0, 1, 1.63, 3.35, 4.79, or 8.14 kg active ingredient ha1 to 1) air-dry, loose soil in Study 1 and 2) field-moist, tamped soil in Study 2 before being irrigated with surfactant-free water at 88 mm h/1 twice, once for 0.33 h, then about 8 d later for 0.25 h. Tensile strength was measured on oven-dry, 4- to 6.35-mm-diameter aggregates (18=n=37) of known mass for each treatment using a load cell with an attached flat-tip probe moving at a constant 0.27-mm s-1 rate that applied continuous strain to each aggregate until it failed. In Study 1, tensile strength ranged widely, from 27 kPa for Adkins loamy sand to 486 kPa for Bolfar loam, averaged across surfactant treatments. Tensile strength for all nine surfactant-treated soils averaged 164 kPa, 7% greater (P=0.099) than the control. In Study 2, surfactants significantly affected the tensile strength of Latahco but not Rad aggregates, when averaged across irrigations and sampling depths. After irrigation, aggregate tensile strength averaged 26% less (Pb0.001) at the 5- than 15-mm depth, likely due to droplet kinetic energy fracturing near-surface, intra-aggregate bonds or surfactant leaching. All told, tensile strength varied more by soil series and depth than by surfactants
Influence of sugarbeet tillage systems on rhizoctonia-bacterial root rot complex
Get PDFThe Rhizoctonia-bacterial root rot complex on sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventional and strip tillage as main plot treatments were arranged in a randomized complete block design with four replications. Within main plots, there were seven treatments (non-inoculated check and six R. solani AG 2-2 IIIB strains). Regardless of tillage, the roots responded in a similar manner for fungal rot (conventional 8% versus strip 7%), bacterial rot (26% versus 34%), total rot (33% versus 41%), neighboring roots infected (1.7 roots versus 1.5 roots), distance spread (157 mm versus 150 mm), and the number of dead plants (12% versus 14%). Strip tillage resulted in 6% more root yield in 2009 (P = 0.087), while conventional tillage resulted in 7% and 27% more root yield in 2010 (P = 0.063) and 2011 (P = 0.012), respectively. The tillage systems influenced disease variables in a similar manner but more studies will be needed to determine their impact on yield. Control for the rot complex should focus on typical Rhizoctonia root rot control measures (crop rotation, in-furrow fungicide applications, irrigation management, and host resistance) while a better understanding of the complex continues to be developed
Using extension phosphorus uptake research to improve Idaho's nutrient management planning program.
Get PDFIrrigated silage corn is the main crop used for phosphorus removal; however little is known about the actual amounts of phosphorus removed under southern Idaho growing conditions. The purpose of this study was to survey phosphorus removal by irrigated corn grown for silage in southern Idaho under variable soil test phosphorus concentrations. In this survey whole plant corn tissue phosphorus concentrations ranged from 0.116 to 0.307% total phosphorus and averaged 0.208%, which is lower than Natural Resources Conservation Services estimates used prior to 2007 (0.26% phosphorus) but higher than estimates used since 2007 (0.185%). The study was used by NRCS to update nutrient management planning software used by planners in Idaho
Wood chip mulch thickness effects on soil water, soil temperature, weed growth and landscape plant growth.
Get PDFWood chip mulches are used in landscapes to reduce soil water evaporation and competition from weeds. A study was conducted over a three-year period to determine soil water content at various depths under four wood chip mulch treatments and to evaluate the effects of wood chip thickness on growth of 'Husker Red' Penstemon digitalis Nutt. plants. The effects of four wood chip thicknesses (depth of application: 0, 2.5, 5, and 10 cm) on soil water content, weed numbers, soil temperature, and height, width, stalk number, and first flower date of 'Husker Red' Penstemon were investigated. The addition of mulch, at all mulch thicknesses, conserved soil water compared to when no mulch was used. The differences in soil water content likely influenced some of the plant growth factors measured. Weed numbers were significantly higher at the 0 and 2.5 cm mulch thickness compared to the 5 and 10 cm thickness In general, mid-day soil temperatures were highest at the shallower soil depths in the unmulched plots. Flowering plants in 2008 in the unmulched treatment were slightly shorter than in the mulched treatments. There were no significant differences in the number of flower stalks per plant although there was a trend for a lower number of stalks with the mulched treatment. The time of first flower was, on the average, about 2 days earlier for the unmulched treatment compared to the 10 cm mulch thickness. Wood chip mulch helped conserve soil water, which in turn had some effects on plant growth
Biochar and Manure Affect Calcareous Soil and Corn Silage Nutrient Concentrations and Uptake.
Get PDFWhen added to soils, carbon-rich biochar derived from the pyrolysis of woody materials can sequester atmospheric carbon dioxide, mitigate climate change, and potentially increase crop productivity. However, research is needed to confirm the suitability and sustainability of biochar application to different soils. We applied four treatments (dry wt.) to an irrigated calcareous soil in Nov. 2008: control; stockpiled dairy manure, 18.8 Mg/ha; hardwood-derived biochar, 22.4 Mg/ha; and manure + biochar using previous rates. Nitrogen fertilizer was applied when needed (based on pre-season soil test N and crop requirements) in all plots and years with N mineralized from added manure included in this determination. Available soil nutrients (NH4-N, NO3-N, Olsen P, diethylenetriaminepentaacetic acid (DTPA)-extractable K, Mg, Na, Cu, Mn, Zn, Fe), total C and N (TC, TN), total organic C (TOC), and pH were determined periodically, and silage corn nutrient concentration, yield, and uptake were measured over two growing seasons. Biochar treatment resulted in a 1.5-fold increase in available soil Mn and 1.4-fold increase in TC and TOC, where manure produced a 1.2- to 1.7-fold increase in soil macro- and micro-nutrients (except Fe), compared to controls. In 2009, biochar increased corn silage B concentration but produced no yield increase; and in 2010, biochar decreased corn silage TN (33%), S (7%) concentrations, and yield (36%) relative to controls. Manure produced a 1.3-fold increase in corn silage Cu, Mn, S, Mg, K, and TN concentrations and yield compared to the control in 2010. The combined biochar-manure effects were not synergistic, except in the case of available soil Mn. In these calcareous soils biochar did not alter pH or availability of P and cations, as is typically observed for acidic soils. If the second year results are indicative of future effects, they suggest that biochar applications lead to reduced N availability in calcareous soils and may need to be accompanied by additional N inputs if yield targets are to be maintained
Environmental Benefits of Biochar
Get PDFUnderstanding and improving environmental quality by reducing soil nutrient leaching losses, reducing bioavailability of environmental contaminants, sequestering C, reducing greenhouse gas emissions, and enhancing crop productivity in highly weathered or degraded soils, has been the goal of agroecosystem researchers and producers for years. Biochar, produced by pyrolysis of biomass, may help attain these goals. The desire to advance understanding of the environmental and agronomic implication of biochar utilization led to the organization of the 2010 ASA-CSSA-SSSA Environmental Quality Division session entitled Biochar Effects on the Environment and Agricultural Productivity (Long Beach, CA; Oct. 31-Nov. 3). Twenty-five presentations from this session, and sessions at the 2010 U.S. Biochar Initiative Conference (Ames, IA; June 27-30) and Biochar Symposium 2010 (organized by Dr. Bruno Glaser; University of Bayreuth, Bayreuth, Germany, July 8-9), make up a special collection of review and technical research papers focused on biochar creation and utilization. Individual contributions deal with improvement of the biochar knowledge base, current information gaps, and future biochar research needs. The prospect of biochar utilization is promising, as biochars may be custom designed for specific environmental applications
Emissions of Ammonia, Methane, Carbon Dioxide and Nitrous Oxide From Dairy Cattle Housing and Manure Management Systems
Get PDFConcentrated animal feeding operations emit trace gases such as ammonia (NH3), methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) to the atmosphere. The implementation of air quality regulations in livestock-producing states increases the need for accurate on-farm determination of emission rates. The objective of this study was to determine the emission rates of NH3, CH4, CO2, and N2O from three source areas (open-lots, lagoon, compost) on a commercial dairy located in southern Idaho. Average emissions per cow per day from the open-lots were 0.12 kg NH3, 0.49 kg CH4, 26.9 kg CO2, and 0.01 kg N2O. Average emissions from the lagoon (g per m square per day) were 1.5 g NH3, 132 g CH4, 391 g CO2, and 0.36 g N2O. Average emissions from the compost facility (g per m square per day) were 1.7 g NH3, 14.8 g CH4, 547 g, and 0.93 g N2O. The combined emissions of NH3, CH4, CO2, and N2O from the lots, lagoon and compost averaged 0.13, 1.5, 33.4, and 0.02 kg per cow per day, respectively. The open lot areas generated the greatest emissions of NH3, CO2, and N2O contributing 76, 75, and 53% to total farm emissions. Methane emissions were greatest from the lots in the spring (71% of total) after which the lagoon became the largest source of emissions (64% of total) for the remainder of the year. Data from this study can be used to develop trace gas emissions factors from open-lot dairies in southern Idaho and potentially other open-lot production systems in similar climatic regions
Ethanol production of semi-simultaneous saccharification and fermentation from mixture of cotton gin waste and recycled paper sludge
Get PDFEthanol production from the steam-exploded mixture of 75% cotton gin waste and 25% recycled paper sludge in various conditions was investigated by semisimultaneous saccharification and fermentation (SSSF) consisting of a pre-hydrolysis and a simultaneous saccharification and fermentation (SSF). Four cases were studied: 24-h pre-hydrolysis + 48-h SSF (SSSF 24), 12-h pre-hydrolysis + 60-h SSF (SSSF 12), 72-h SSF, and 48-h
hydrolysis + 24-h fermentation (SHF). The ethanol concentration, yield, and productivity of SSSF 24 were higher than those of the other operations. A model of SSF was used to simulate the data for four components in SSF. The analysis of the reaction rates of cellobiose, glucose, cell, and ethanol using the model and the parameters from the experiments showed that there was a transition point of the rate-controlling step at which the cell growth control in the initial 2 h was changed to the cellobiose reaction control in later period during ethanol production of SSF
from the mixture
Evaluation of Potential Runoff and Erosion of Four Center Pivot Irrigation Sprinklers
Get PDFThe operational characteristics of center pivot sprinklers are well documented but few studies have been conducted to evaluate the effects that operating characteristics of a particular sprinkler have on infiltration, runoff, and erosion for specific soil types. The objective of this study was to evaluate potential runoff and erosion from four commercial center pivot sprinklers on three widely distributed, south central Idaho soils. A modified commercial irrigation boom system was used to emulate center pivot irrigation on experimental runoff plots. Sprinklers used in the study were: 1) Nelson R3000 with brown plate, 2) Nelson R3000 with red plate, 3) Nelson S3000 with purple plate, and 4) Senninger I-Wob with standard 9-groove plate. Based on manufacturer’s published sprinkler nozzle flow rates, up to 12% variation in applied water was measured between sprinkler types. Testing of sprinkler nozzle flow rates revealed up to an 8.6% difference between measured nozzle flow rate and manufacturer’s published data. Significant differences in runoff and erosion between sprinkler types were observed but were not consistent across all runoff tests or soil types. In general, sprinkler types that visually appear to more uniformly distribute sprinkler droplets over the wetted area with respect to time exhibited the greatest measured erosion rates. This functional difference in water application may cause sediment to remain in suspension in overland flow for a longer duration allowing sediment to be more readily transported down slope. A 50% reduction in sprinkler flow rate reduced runoff and soil erosion 60 to 80% for the same volume of water applied over six irrigations. Reducing sprinkler flow rate early in the growing season prior to crop canopy development could be an effective management tool for reducing sprinkler runoff and erosion
Planting System Effect on Yield Response of Russet Norkotah to Irrigation and Nitrogen under High Intensity Sprinkler Irrigation
Get PDFConversion of potato ridged-row planting systems to wide bed planting systems may increase water and nitrogen use efficiency in commercial irrigated potato production systems by reducing the amount of irrigation water and water applied nitrogen fertilizer bypassing the potato root zone. Wide bed planting systems consist of planting multiple rows on a wide bed with 20 to 35% higher plant population than found in conventional ridgedrow planting systems. The objective of this study was to evaluate the effect planting system has on yield response of ‘Russet Norkotah’ potato to irrigation and nitrogen. Planting systems evaluated were (1) conventional ridgedrow with dammer-diking; (2) 3.7 m wide bed with five potato rows spaced 66 cm between adjacent rows centered on the bed and; (3) 3.7 m wide bed with seven potato rows spaced 46 cm between adjacent rows. Six irrigation amounts, 50, 70, 85, 100, 115, and 130%, of estimated evapotranspiration after tuber initiation and four nitrogen rates, <20, 50, 100, and 150%, of conventional recommendations were applied to the three planting systems. Interactions between irrigation amounts and nitrogen rate were significant for total and U.S. No. 1 yield, irrigation
water use efficiency, and gross return in one or both study years. Interactions between nitrogen rate and planting system were significant for total and U.S. No. 1 yield, irrigation water use efficiency and gross return in the first year of the study. Interactions between irrigation amount and planting system were not significant. In the first study year, total and U.S. No. 1 yields were significantly increased 12 and 19 percent, respectively, under the 7-row bed planting system compared to ridged-row planting system. Comparison of ridged-row planting system and 5-row bed planting system on 31 commercial potato fields in eastern Idaho representing a combined area of 2,800 ha over 5 years resulted in significantly higher total yield and irrigation water use efficiency with the bed planting system. The 5-row bed planting system averaged 6% higher total yield, 5% less water application and an 11% increase in irrigation water use efficiency. The results of this study demonstrate that under high intensity rate sprinkler irrigation in the soil and climatic conditions prevalent in eastern Idaho, bed planting systems provide viable production alternatives for irrigated potato production that may increase total yield, gross return, and irrigation water use efficiency