scholarly journals Vegetation and Residence Time Interact to Influence Metabolism and Net Nutrient Uptake in Experimental Agricultural Drainage Systems

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1416
Author(s):  
Rachel L. Nifong ◽  
Jason M. Taylor
Keyword(s):  
Nutrient Uptake ◽  
Residence Time ◽  
Best Management Practices ◽  
Ecosystem Respiration ◽  
N Uptake ◽  
Agricultural Drainage ◽  
Residence Times ◽  
Hydraulic Residence Time ◽  
Uptake Rates ◽  
Lower Mississippi River

Agricultural drainage networks within the Lower Mississippi River Basin (LMRB) have potential to attenuate nutrient loading to downstream aquatic ecosystems through best management practices. Nutrient uptake (nitrogen, phosphorus), gross primary production (GPP), ecosystem respiration (ER), and denitrification rates were estimated using a combination of sensor measurements and hourly discrete samples for dissolved nutrients and gases at three hydraulic residence times (2, 4, and 6 h) in three vegetated and three unvegetated ditches. We also measured vegetation and soil nutrient content. GPP and ER were significantly higher in vegetated drainages and increasing hydraulic residence time increased respiration rates. Shorter hydraulic residence times were associated with increased uptake rates for both N and P, and vegetation increased N uptake rates in all hydraulic residence time (HRT) treatments. Vegetation and sediment assimilated N and P over the course of the experiment. Overall, our experimental results demonstrate the strong role of emergent vegetation in nutrient retention and removal processes in agricultural drainage ditch networks.

scholarly journals Nutrient uptake in a simplified stream channel: Experimental manipulation of hydraulic residence time and transient storage

Ecohydrology ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. e2012 ◽  
Author(s):  
Davi Gasparini Fernandes Cunha ◽  
Nícolas Reinaldo Finkler ◽  
Maria do Carmo Calijuri ◽  
Timothy P. Covino ◽  
Flavia Tromboni ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Residence Time ◽  
Experimental Manipulation ◽  
Transient Storage ◽  
Stream Channel ◽  
Hydraulic Residence Time

Utilization of Semi-Continuous Algae Culture for the Treatment of Recycled Dairy Lagoon Wash Water

2021 ◽  
Vol 07 ◽  
Author(s):  
Gregory Schwartz ◽  
Mark Ibekwe ◽  
Trygve Lundquist ◽  
Shelton Murinda ◽  
Marcia Murry
Keyword(s):  
Wastewater Treatment ◽  
Business Models ◽  
N Uptake ◽  
Algal Species ◽  
Dairy Wastewater ◽  
Wash Water ◽  
Algal Culture ◽  
Hydraulic Residence Time ◽  
Uptake Rates ◽  
The Impact

Background: The utilization of animal wastes in algal culture has proven to be challenging. The utilization of “free” nutrients has drawn many researchers and industries to developing business models that call for the use of these free nutrients, which comes at a cost. Some of these costs include reduced productivity, increased contamination, lower-value target markets, and lower treatment capabilities (for wastewater treatment applications). This paper evaluates the impact of dairy lagoon effluent on productivity and wastewater treatment ability. Methods: Screened dairy lagoon wash water was fed to four three square meter outdoor open paddlewheel algal cultivation reactors. The units were operated semi-continuously for one and a half years. Seasonal productivity and nutrient uptake rates for nitrogen (N) and phosphorous (N) were measured against wastewater dilution requirements. Seasonal algal species dominance was also recorded. Wastewater was added at two levels, and the lower level was supplemented with synthetic fertilizer. Results: Seasonal N uptake rates ranged from 0.5 to 1.2 grams of N uptake per square meter per day, while P uptake ranged from 0.17 to 0.3 grams of P per square meter per day depending on season and hydraulic residence time (HRT). N removal efficiency ranged at 40 to 70% for semicontinuous operation, depending on HRT, season, and dilution of influent wastewater, which was made up from 1.5% to 13% of the daily water exchange. Conclusion: Algal reactors tended to be N limited due to the inability to add enough dairy wastewater to mitigate the high turbidity and dark color. Treatments with lower levels of added dairy wastewater tended to show higher nutrient removal. Algal culture from dairy wash water could benefit from a pretreatment step to reduce turbidity and color, promoting algal growth and productivity.

Estimating nitrogen uptake of individual roots in container- and field-grown plants using a 15N-depletion approach

2009 ◽  
Vol 36 (7) ◽  
pp. 621 ◽  
Author(s):  
Astrid Volder ◽  
Laurel J. Anderson ◽  
David R. Smart ◽  
Arnold J. Bloom ◽  
Alan N. Lakso ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Fine Roots ◽  
N Uptake ◽  
Age Groups ◽  
Large Variability ◽  
Root Age ◽  
Nitrate N ◽  
Coefficients Of Variation ◽  
Uptake Rates ◽  
Age Dependent

We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming, the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study, we used a 15N depletion method that allowed for the measurement of nitrate-N uptake rates on intact, individual, fine roots of known age. We expected that N uptake would decline rapidly as fine roots aged, regardless of the environmental conditions and species used. We compared age dependent uptake patterns of young grape cuttings with those of mature vines and with those of tomato. Although patterns of declining uptake with increasing root age were similar for all species and conditions tested, large differences in maximum N uptake rates existed between young cuttings and mature vines, and between woody and herbaceous species. Maximum rates were 10-fold higher for tomato and 3-fold higher for the grape cuttings, when compared with uptake rates of fine roots of mature vines. Coefficients of variation ranged from 43 to 122% within root age groups. The large variability in physiological characteristics of fine roots of the same age, diameter and order suggests that there is a functional diversity within fine roots that is still poorly understood.

scholarly journals Nutrient uptake, use efficiency and productivity of bread wheat (Triticum aestivum L.) as affected by nitrogen and potassium fertilizer in Keddida Gamela Woreda, Southern Ethiopia

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Temesgen Godebo ◽  
Fanuel Laekemariam ◽  
Gobeze Loha
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Nutrient Uptake ◽  
Bread Wheat ◽  
Block Design ◽  
N Uptake ◽  
Fertilizer Application ◽  
Southern Ethiopia ◽  
K Fertilizer ◽  
Use Efficiency

AbstractBread wheat (Triticum aestivum L.) is one of the most important cereal crops in Ethiopia. The productivity of wheat is markedly constrained by nutrient depletion and inadequate fertilizer application. The experiment was conducted to study the effect of nitrogen (N) and potassium (K) fertilizer rates on growth, yield, nutrient uptake and use efficiency during 2019 cropping season on Kedida Gamela Woreda, Kembata Tembaro Zone Southern Ethiopia. Factorial combinations of four rates of N (0, 23, 46 and 69 kg Nha−1) and three rates of K2O (0, 30 and 60 kg Nha−1) in the form of urea (46–0-0) and murate of potash (KCl) (0-0-60) respectively, were laid out in a randomized complete block design with three replications. The results showed that most parameters viz yield, yield components, N uptake and use efficiency revealed significant differences (P < 0.05) due to interaction effects of N and K. Fertilizer application at the rate of 46 N and 30 kg K ha−1 resulted in high grain yield of 4392 kg ha− 1 and the lowest 1041 from control. The highest agronomic efficiency of N (52.5) obtained from the application of 46 kg N ha−1. Maximum physiological efficiency of N (86.6 kg kg−1) and use efficiency of K (58.6%) was recorded from the interaction of 46 and 30 kg K ha−1. Hence, it could be concluded that applying 46 and 30 kg K ha−1was resulted in high grain yield and economic return to wheat growing farmers of the area. Yet, in order to draw sound conclusion, repeating the experiment in over seasons and locations is recommended.

scholarly journals Agro-Environmental Sustainability of Anaerobic Digestate Fractions in Intensive Cropping Systems: Insights Regarding the Nitrogen Use Efficiency and Crop Performance

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 745
Author(s):  
Federico Grillo ◽  
Ilaria Piccoli ◽  
Ivan Furlanetto ◽  
Francesca Ragazzi ◽  
Silvia Obber ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Environmental Sustainability ◽  
Inorganic Nitrogen ◽  
Organic Fertilizer ◽  
N Uptake ◽  
Mineral Fertilizers ◽  
Veneto Region ◽  
Liquid Digestate ◽  
Crop Performance ◽  
Use Efficiency

Digestate is an anaerobic digestion by-product rich in inorganic-nitrogen (N) that can be used as an organic fertilizer. Digestate agronomic efficiency and its impact on the environment have not yet been studied in detail, therefore this study tries to fill this gap. The agro-environmental sustainability of digestate fractions was evaluated in a holistic way by comparing the best management practices available in the Veneto Region agroecosystem. A farm experiment involving mineral fertilizer and both liquid and solid digestate fractions was established involving silage winter wheat and silage maize as main crops. Agro-environmental sustainability was investigated coupling crop performance analysis (e.g., yield, N uptake and N use efficiency (NUE)) with a novel proposed agro-environmental sustainability index (AESI) (i.e., product of the dry yield and NUE). The results showed that the liquid digestate fraction gave agronomic performances comparable to mineral fertilizers and a satisfying AESI while solid digestate showed lower performances. In conclusion, liquid digestate fractions might be an effective substitute for mineral fertilizers in the Veneto region agroecosystem reaching encouraging levels of agro-environmental sustainability. On the contrary, longer-term experiments are requested to evaluate solid digestate fraction sustainability.

scholarly journals Effect of bathymetric changes on residence time in Buenaventura bay (Colombia)

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 241-248
Author(s):  
Francisco Fernando Garcia Renteria ◽  
Mariela Patricia Gonzalez Chirino
Keyword(s):  
Finite Elements ◽  
Residence Time ◽  
Particle Tracking ◽  
Hydrodynamic Model ◽  
Residence Times ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Bathymetric Changes

In order to study the effects of dredging on the residence time of the water in Buenaventura Bay, a 2D finite elements hydrodynamic model was coupled with a particle tracking model. After calibrating and validating the hydrodynamic model, two scenarios that represented the bathymetric changes generated by the dredging process were simulated. The results of the comparison of the simulated scenarios, showed an important reduction in the velocities fields that allow an increase of the residence time up to 12 days in some areas of the bay. In the scenario without dredging, that is, with original bathymetry, residence times of up to 89 days were found.

scholarly journals Nitrogen cycling in Sandusky Bay, Lake Erie: oscillations between strong and weak export and implications for harmful algal blooms

2018 ◽  
Vol 15 (9) ◽  
pp. 2891-2907 ◽  
Author(s):  
Kateri R. Salk ◽  
George S. Bullerjahn ◽  
Robert Michael L. McKay ◽  
Justin D. Chaffin ◽  
Nathaniel E. Ostrom
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
N Uptake ◽  
N Fixation ◽  
N Budget ◽  
N2o Production ◽  
N Removal ◽  
Uptake Rates ◽  
N Loading

Abstract. Recent global water quality crises point to an urgent need for greater understanding of cyanobacterial harmful algal blooms (cHABs) and their drivers. Nearshore areas of Lake Erie such as Sandusky Bay may become seasonally limited by nitrogen (N) and are characterized by distinct cHAB compositions (i.e., Planktothrix over Microcystis). This study investigated phytoplankton N uptake pathways, determined drivers of N depletion, and characterized the N budget in Sandusky Bay. Nitrate (NO3-) and ammonium (NH4+) uptake, N fixation, and N removal processes were quantified by stable isotopic approaches. Dissimilatory N reduction was a relatively modest N sink, with denitrification, anammox, and N2O production accounting for 84, 14, and 2 % of sediment N removal, respectively. Phytoplankton assimilation was the dominant N uptake mechanism, and NO3- uptake rates were higher than NH4+ uptake rates. Riverine N loading was sometimes insufficient to meet assimilatory and dissimilatory demands, but N fixation alleviated this deficit. N fixation made up 23.7–85.4 % of total phytoplankton N acquisition and indirectly supports Planktothrix blooms. However, N fixation rates were surprisingly uncorrelated with NO3- or NH4+ concentrations. Owing to temporal separation in sources and sinks of N to Lake Erie, Sandusky Bay oscillates between a conduit and a filter of downstream N loading to Lake Erie, delivering extensively recycled forms of N during periods of low export. Drowned river mouths such as Sandusky Bay are mediators of downstream N loading, but climate-change-induced increases in precipitation and N loading will likely intensify N export from these systems.

Flow pattern and residence time of conduit flow and diffuse flow in calcareous sandstones (Bohemian Cretaceous Basin, Czech Republic)

2021 ◽  
Author(s):  
Iva Kůrková ◽  
Jiří Bruthans
Keyword(s):  
Czech Republic ◽  
Groundwater Flow ◽  
Residence Time ◽  
Dispersion Model ◽  
Tracer Tests ◽  
Water Levels ◽  
Northwestern Part ◽  
Residence Times ◽  
Karst Springs ◽  
Bohemian Cretaceous Basin

&lt;p&gt;Localities containing karst features were studied in the northwestern part of Bohemian Cretaceous Basin. Namely Turnov area in facies transition between coarse-delta sandstones and marlstones (Jizera Formation, Turonian) and Miskovice area in limestones and sandy limestones - sandstones (Peruc-Korycany Formation, Cenomanian). Evolution of karst conduits is discussed elsewhere (K&amp;#367;rkov&amp;#225; et al. 2019).&lt;/p&gt;&lt;p&gt;In both localities, disappearing streams, caves and karst springs with maximum discharge up to 100 L/s were documented. Geology and hydrogeology of this area was studied from many points of view to describe formation of karst conduits and characterize groundwater flow. Tracer tests were performed using NaCl and Na-fluoresceine between sinkholes and springs under various flow rates to evaluate residence times of water in conduits and to describe geometry of conduits. Breatkthrough curves of tracer tests were evaluated by means of Qtracer2 program (Field 2002). Groundwater flow velocity in channels starts at 0.6 km/day during low water levels up to 15 km/day during maximum water levels, the velocity increases logarithmically as a function of discharge. Similar karst conduits probably occur in other parts of Bohemian Cretaceous Basin where lot of large springs can be found.&lt;/p&gt;&lt;p&gt;Mean residence time of difussed flow based on tritium, CFC and SF&lt;sub&gt;6&lt;/sub&gt; sampled at karst springs is 20 years for 75% of water and 100 years for remaining 25%, based on binary mixing dispersion model. This shows that most of the water drained by karst conduits is infiltrated through the soil and fractured environment with relatively high residence time. Residence times in different types of wells and springs were also measured in whole north-western part of Bohemian Cretaceous Basin. Results indicate long residence times in semi-stagnant zones represented by monitoring wells and short residence times in preferential zones represented by springs and water-supply wells.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Research was funded by the Czech Science Foundation (GA CR No. 19-14082S), Czech Geological Survey &amp;#8211; internal project 310250&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Field M. (2002): The QTRACER2 program for Tracer Breakthrough Curve Analysis for Tracer Tests in Karstic Aquifers and Other hydrologic Systems. &amp;#8211; U.S. Environmental protection agency hypertext multimedia publication in the Internet at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=54930.&lt;/p&gt;&lt;p&gt;K&amp;#367;rkov&amp;#225; I., Bruthans J., Bal&amp;#225;k F., Slav&amp;#237;k M., Schweigstillov&amp;#225; J., Bruthansov&amp;#225; J., Miku&amp;#353; P., Grundloch J. (2019): Factors controlling evolution of karst conduits in sandy limestone and calcareous sandstone (Turnov area, Czech Republic). Journal of Hydrology: 574: 1062-1073&lt;/p&gt;

scholarly journals Assessment of model estimates of land-atmosphere CO<sub>2</sub> exchange across Northern Eurasia

2015 ◽  
Vol 12 (14) ◽  
pp. 4385-4405 ◽  
Author(s):  
M. A. Rawlins ◽  
A. D. McGuire ◽  
J. S. Kimball ◽  
P. Dass ◽  
D. Lawrence ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Carbon ◽  
Residence Time ◽  
Primary Productivity ◽  
Ecosystem Respiration ◽  
Regional Scale ◽  
Northern Eurasia ◽  
Sink Strength ◽  
Vegetation Productivity ◽  
Co2 Sink

Abstract. A warming climate is altering land-atmosphere exchanges of carbon, with a potential for increased vegetation productivity as well as the mobilization of permafrost soil carbon stores. Here we investigate land-atmosphere carbon dioxide (CO2) cycling through analysis of net ecosystem productivity (NEP) and its component fluxes of gross primary productivity (GPP) and ecosystem respiration (ER) and soil carbon residence time, simulated by a set of land surface models (LSMs) over a region spanning the drainage basin of Northern Eurasia. The retrospective simulations cover the period 1960–2009 at 0.5° resolution, which is a scale common among many global carbon and climate model simulations. Model performance benchmarks were drawn from comparisons against both observed CO2 fluxes derived from site-based eddy covariance measurements as well as regional-scale GPP estimates based on satellite remote-sensing data. The site-based comparisons depict a tendency for overestimates in GPP and ER for several of the models, particularly at the two sites to the south. For several models the spatial pattern in GPP explains less than half the variance in the MODIS MOD17 GPP product. Across the models NEP increases by as little as 0.01 to as much as 0.79 g C m−2 yr−2, equivalent to 3 to 340 % of the respective model means, over the analysis period. For the multimodel average the increase is 135 % of the mean from the first to last 10 years of record (1960–1969 vs. 2000–2009), with a weakening CO2 sink over the latter decades. Vegetation net primary productivity increased by 8 to 30 % from the first to last 10 years, contributing to soil carbon storage gains. The range in regional mean NEP among the group is twice the multimodel mean, indicative of the uncertainty in CO2 sink strength. The models simulate that inputs to the soil carbon pool exceeded losses, resulting in a net soil carbon gain amid a decrease in residence time. Our analysis points to improvements in model elements controlling vegetation productivity and soil respiration as being needed for reducing uncertainty in land-atmosphere CO2 exchange. These advances will require collection of new field data on vegetation and soil dynamics, the development of benchmarking data sets from measurements and remote-sensing observations, and investments in future model development and intercomparison studies.

Sign in / Sign up

Export Citation Format

Share Document