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Nutrient loads and sediment losses in sprinkler irrigation runoff affected by compost and manure
Get PDFHigh water application rates beneath the outer spans of center pivot sprinkler systems can cause runoff, erosion, and nutrient losses, particularly from sloping fields. This study determined runoff, sediment losses, and loads of nutrients (dissolved organic C, Nitrate-N, ammonium-N, total phosphorus [TP], ferric-oxide strip phosphorus [FeO P], dissolved reactive phosphorus [DRP], K, Ca, Mg, and Na) in sprinkler runoff for two years after a single application of either stockpiled or composted dairy manure. The two-year field investigation studied five treatments, including a non-amended control, in each of six blocks, with each block situated under a different span of a moving-lateral sprinkler system. In October 1999, we incorporated 29.1 or 71.7 Mg/ha of dry manure or 22.4 or 47.0 Mg/ha of dry compost into a calcareous silt loam soil on slopes from 0.8% to 4.4%. In spring of 2000 and 2001, we collected surface soil (0 to 5 mm) from bed tops to determine aggregate stability by wet-sieving field-moist aggregates and surface soil (0 to 30 mm) from furrows to determine soil test phosphorus (STP). We applied 21 to 46 mm of water at an average application intensity of 28 mm/h (peak intensity of 40 mm/h) to 6.4- x 36.6-m field plots six times in 2000 and twice in 2001. Additional non-monitored irrigations were made as needed to produce corn (Zea mays L.) silage each year. We measured runoff rates and collected 1-L runoff samples at 15- to 30-minute intervals to determine sediment and constituent losses for each monitored irrigation. None of the amendment treatments significantly affected runoff, sediment losses, or loads of dissolved organic C, ammonium-N, or TP. Without exception, runoff, sediment losses, and loads of every measured constituent varied among irrigations, after accounting for differences in water applied. Treatments influenced DRP, K, and Ca runoff loads, with DRP loads being 5 to 6 times greater from the manure treatments than the control. Loads of Nitrate-N, DRP, and Na were 2- to 4-fold greater from plots amended with manure rather than compost
Manure and fertilizer effects on carbon balance and losses for irrigated corn
Get PDFLittle is known about inorganic fertilizer or manure effects on organic carbon (OC) and inorganic C (IC) losses from a furrow irrigated field, particularly in the context of other system C gains or losses. In 2003 and 2004, we measured dissolved organic and inorganic C (DOC, DIC), particulate OC and IC (POC, PIC) concentrations in irrigation inflow, runoff, and percolation waters (6-7 irrigations/y); C inputs from soil amendments and crop biomass; harvested C; and gaseous C emissions from field plots cropped to silage corn (Zea mays L.) in southern Idaho. Annual treatments included: (M) 13 (y 1) and 34 Mg/ha (y 2) stockpiled dairy manure; (F) 78 (yr 1) and 195 kg N/ha (y 2) inorganic N fertilizer; or (NA) no amendment--control. The mean annual total C input into M plots averaged 16.1 Mg/ha, 1.4-times greater than that for NA (11.5 Mg/ha) or F (11.1 Mg/ha), while total C outputs for the three treatments were similar, averaging 11.8 Mg/ha. Thus, the manure plots ended each growing season with an average net gain of 3.8 Mg C/ha (a positive net C flux), while the control (-0.5 Mg C/ha) and fertilizer (-0.4 Mg C/ha) treatments finished the season with a net C loss. Atmospheric CO2 incorporated into the crop biomass contributed 96% of the mean annual C input to NA and F plots but only 68% to M plots. We conclude that nutrient amendments substantially influence the short-term carbon balance of our furrow-irrigated system. Amendments had both direct and indirect influences on individual C components, such as the losses of DIC and POC in runoff and DOC in percolation water, producing temporally complex outcomes which may depend on environmental conditions external to the field
Copper and zinc speciation in a biosolids-amended semiarid grassland soil
Get PDFPredicting trace metal solid phase speciation changes associated with long-term biosolids land application is important for understanding and improving environmental quality. Biosolids were surface-applied (no incorporation; 0, 1, 2, 5, 10, and 15 tons per acre) to a semi-arid grassland in 1991 (single) or again in 2002 (repeated). In July 2003, soils were obtained from the 0-3, 3-6, and 6-12-inch depths in all plots. Using soil pH, soluble anion and cation concentrations from 0.01 moles per liter calcium chloride extractions, and dissolved organic carbon content, copper and zinc associated with minerals, hydrous ferric oxide, or dissolved organic phases was modeled using Visual Minteq. Scanning electron microscopy and energy dispersive x-ray analysis was also utilized to identify solid phase metal associations present in single and repeated biosolids-amended soils. Based on soil solution chemistry and verified using Visual Minteq, greater than 89 and 96 percent of copper and zinc, and greater than 99 percent of zinc were adsorbed to hydrous ferric oxides in all single or repeated biosolids-applied soils, respectively. However, when detected in the repeated biosolids treatments, only 59-79 percent of copper was adsorbed to hydrous ferric oxides while 21-41 percent was associated with dissolved organic carbon; downward copper movement was associated with dissolved organic carbon. The scanning electron microscopy and energy dispersive x-ray analysis of clay-sized separates from all soil depths led to direct observation of iron-zinc, aluminum-zinc, and aluminum-copper associations. Results implied that even after surface-applying biosolids either once or twice of up to 15 tons per acre, soil solution concentrations, Visual Minteq predictions, and scanning electron microscopy and energy dispersive x-ray analysis suggested minimal shifts occur in phases controlling long-term copper and zinc solubility
Manure and fertilizer effects on carbon balance and organic and inorganic carbon losses for an irrigated corn field
Get PDFData collected from both artificially and field (naturally) weathered biochar suggest that a potentially significant pathway of biochar disappearance is through physical breakdown of the biochar structure. Through scanning electron microscopy (SEM) we characterized this physical weathering which increased structural fractures and possessed higher numbers of liberated biochar fragments. This was hypothesized to be due to the graphitic sheet expansion accompanying water sorption coupled with comminution. These fragments can be on the micro and nano-scale, but are still carbon-rich particles with no detectable alteration in the oxygen to carbon ratio of the original biochar. However, these particles are now easily dissolved and could be moved by infiltration. There is a need to understand how to produce biochars that are resistant to physical degradation in order to maximize long-term biochar C-sequestration potential within soil systems
Root rot in sugar beet piles at harvest
Get PDFSugar beet root rots are not only a concern because of reduced yields, but can also be associated with losses in storage. Our primary sugar beet root rot disease problem in the Amalgamated production area is Rhizoctonia root rot. However, this rot frequently only penetrates a short distance past the surface of the root before a bacterial complex stops the fungus and continues the rot process. This rot complex leads to direct yield loss at harvest time along with additional costs in factory processing. When rotted roots make it into storage piles, they have been shown to compromise surrounding healthy roots. A recent end-of-harvest storage pile survey of 74 to 76% of the piles at receiving stations in Treasure Valley and Magic Valley has identified rotted roots entering storage. In Treasure Valley, the number of piles in the High category was almost cut in half, while the number of piles in the Low category was more than doubled. In the Magic Valley, the number on piles in the High category was eliminated and those in the Intermediate category were reduced by 66%. Thus, it appears that the efforts at harvest to keep rotted roots out of piles were successful. Controlling root rots in the field improves yield, but keeping rotted roots out of storage should increase profits as well
Evaluation of neural network modeing to calculate well-watered leaf temperature of wine grape
Get PDFMild to moderate water stress is desirable in wine grape for controlling vine vigor and optimizing fruit yield and quality, but precision irrigation management is hindered by the lack of a reliable method to easily quantify and monitor vine water status. The crop water stress index (CWSI) that effectively monitors plant water status has not been widely adopted in wine grape because of the need to measure well-watered and non-transpiring leaf temperature under identical environmental conditions. In this study, a daily CWSI for the wine grape cultivar Syrah was calculated by estimating well-watered leaf temperature with an artificial neural network (NN) model and non-transpiring leaf temperature based on the cumulative probability of the measured difference between ambient air and deficit-irrigated grapevine leaf temperature. The reliability of this methodology was evaluated by comparing the calculated CWSI with irrigation amounts in replicated plots of vines provided with 30, 70 or 100% of their estimated evapotranspiration demand. The input variables for the NN model were 15-minute average values for air temperature, relative humidity, solar radiation and wind speed collected between 13:00 and 15:00 MDT. Model efficiency of predicted well-watered leaf temperature was 0.91 in 2013 and 0.78 in 2014. Daily CWSI consistently differentiated between deficit irrigation amounts and irrigation events. The methodology used to calculate a daily CWSI for wine grape in this study provided a real-time indicator of vine water status that could potentially be automated for use as a decision-support tool in a precision irrigation system
Sustainable manure management
Get PDFThe sustainability of modern manure management is far from certain, with many demonstrating significant limitations from the stand point of efficient use of manure resources and protection of environmental quality and human health. As demonstrated through this review, for manure management to be sustainable, a broad array of issues must be considered and addressed, all in the context of highly competitive modern livestock production systems that largely seek to minimize costs to the consumer. In the past decade there have been major innovations in the areas of land application, manure treatment and processing and in the science of understanding the impact of manure management. As a result, major opportunities exist to improve the components of manure management. To be sustainable, these optimized components must work within the constraints of the broader livestock production system
Biochar and manure effects on net nitrogen mineralization and greenhouse gas emissions from calcareous soil under corn
Get PDFFew multiyear field studies have examined the impacts of a one-time biochar application on net N mineralization and greenhouse gas emissions in an irrigated, calcareous soil; yet such applications are hypothesized as a means of sequestering atmospheric CO2 and improving soil quality. We fall-applied four treatments, stockpiled dairy manure (42 Mg/ha dry wt.); hardwood-derived biochar (22.4 Mg/ha); combined biochar and manure; and no amendments (control). Nitrogen fertilizer was applied in all plots and years based on treatment’s pre-season soil test N and crop requirements, and accounting for estimated N mineralized from added manure. From 2009 to 2011 we measured greenhouse gas fluxes using vented chambers, net N mineralization (NNM) using buried bags, corn yield, and N uptake, and in a succeeding year, root and shoot biomass and biomass C and N concentrations. Both amendments produced soil produced persistent soil effects. Manure increased seasonal and three year cumulative NNM, root biomass, and root:shoot ratio 1.6-fold, CO2-C gas flux 1.2-fold, and reduced soil NH4:NO3 ratio 58% relative to no-manure treatments. Relative to all other treatments on average, biochar-only produced 33% less cumulative NNM, 20% less CO2-C and 50% less N2O-N gas emissions, 35% less root biomass, and increased soil NH4:NO3 ratio 1.8-fold. These long-term effects suggest that biochar slightly impaired nitrification and N immobilization processes, and are likely caused by enduring biochar porosity and surface chemistry characteristics that influence N-transform-ation processes, alter microbial populations, and sequester soil ammonium. While the biochar-only treatment demonstrated a potential to increase corn yields and minimize CO2-C and N2O-N gas emissions in these calcareous soils; biochar also caused decreased corn yields under certain soil nutrient conditions. Combining biochar with manure effectively utilizes these soil amendments as it eliminated potential yield reductions and maximized manure net N mineralization potential
Soil phosphorus dynamics under sprinkler and furrow irrigation
Get PDFFurrow irrigation detaches and transports soil particles and subsequently nutrients such as phosphorus. To reduce the risk of erosion and offsite phosphorus movement, producers can convert from furrow to sprinkler irrigation. We completed research on soil phosphorus dynamics in furrow versus sprinkler irrigated soils from four paired fields in south central Idaho. Surface soils (0-2.5 inches) were obtained from fields in the fall following harvest. Furrow irrigated soils contained 38 parts per million of plant-available phosphorus (i.e. Olsen-extractable) on average, as compared to 20 parts per million under sprinkler irrigation. These results are important as 20 parts per million Olsen-extractable phosphorus may be considered the concentration where soil phosphorus is considered low to medium in soil testing; extractable phosphorus values over 40 parts per million limit sites to phosphorus application based on crop uptake only, based on the Idaho One Plan. Soils were additionally analyzed using a sequential extraction to identify inorganic soil phosphorus pools, and an amorphous aluminum and iron technique was used to help further explain differences in extractable soil phosphorus under furrow and sprinkler irrigation. Soils under furrow irrigation had greater concentrations of inorganic phosphorus in the soluble/aluminum-bound/iron-bound and occluded iron phases (i.e. iron coated phosphorus), and in the amorphous iron phases. These findings suggest that iron reduction chemistry plays a large role in phosphorus availability under furrow irrigation, even in calcareous soil systems
Erosion: Irrigation-induced
No full textSoil can be eroded by sprinkler or surface irrigation. Once sprinkler droplet kinetic energy detaches soil, overland flow transports the sediment downslope and off-site. Protecting the soil surface, increasing sprinkler wetted diameters, and tilling to increase infiltration and thereby lessen overland flow are effective control measures. Runoff minimization and management are key to reducing erosion induced by either sprinkler or surface irrigation. Slowing furrow stream velocities with mulch or crop residues reduces the flow’s hydraulic shear and, in turn, detachment of soil from furrow wetted perimeters. Stabilizing surface soil with, for example, polyacrylamide, bio-polymers, or whey keeps soil in place and helps maintains acceptable water quality in nearby surface wate