scholarly journals The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. W. McDowell ◽  
Z. P. Simpson ◽  
A. G. Ausseil ◽  
Z. Etheridge ◽  
R. Law
Keyword(s):  
Water Quality ◽  
Mean Transit Time ◽  
Lag Time ◽  
Practice Change ◽  
N Leaching ◽  
N Losses ◽  
Leaching Losses ◽  
Nitrate N ◽  
The Mean ◽  
Lag Times

AbstractUnderstanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.

scholarly journals Reducing nitrate leaching losses from a Taupo pumice soil using a nitrification inhibitor eco-n

2007 ◽  
pp. 131-135 ◽  
Author(s):  
K.C. Cameron ◽  
H.J. Di ◽  
J.L. Moir ◽  
A.H.C. Roberts
Keyword(s):  
Water Quality ◽  
Nitrate Leaching ◽  
Nitrification Inhibitor ◽  
N Leaching ◽  
N Transfer ◽  
Management Options ◽  
N Losses ◽  
Leaching Losses ◽  
Significant Contributor ◽  
Annual Loss

The decline in water quality in Lake Taupo has been attributed to nitrogen (N) leaching from surrounding land areas. Pastoral agriculture has been identified as a significant contributor to this N transfer to the lake through animal urine deposition. There is therefore an immediate need for new management options to reduce N losses. The objective of this study was to measure the effectiveness of using a nitrification inhibitor (eco-n) to reduce nitrate leaching losses from a pasture soil of the Taupo region. A 3-year study was conducted using 20 lysimeters on Landcorp's 'Waihora' sheep and beef farm, within 10 km of Lake Taupo. The results show that animal urine patches were the main source of nitrate leaching (>95% of the total annual loss) and that eco-n significantly (P

scholarly journals Nutrient losses in drainage and surface runoff from a cattle-grazed pasture in Southland

2000 ◽  
pp. 99-104 ◽  
Author(s):  
R.M. Monaghan ◽  
R.J. Paton ◽  
L.C. Smith ◽  
C. Binet
Keyword(s):  
Surface Runoff ◽  
Dairy Herd ◽  
Drainage Water ◽  
Primary Objective ◽  
Stocking Rate ◽  
N Losses ◽  
Pasture Production ◽  
Leaching Losses ◽  
Drinking Water Standard ◽  
Nitrate N

In response to local concerns about the expanding Southland dairy herd, a 4-year study was initiated in 1995 with the primary objective of quantifying nitrate-N losses to waterways from intensively grazed cattle pastures. Treatments were annual N fertiliser inputs of 0, 100, 200 or 400 kg N/ha. Stocking rate was set according to the pasture production on each of these four treatments, and over the 4 years of study ranged between the equivalent of 2.0 cows/ha for the 0N treatment, to 3.0 cows/ha for the treatment receiving 400 kg N/ ha/year. Mean annual losses of nitrate-N in drainage were 30, 34, 46 and 56 kg N/ha for the 0, 100, 200 and 400 kg N/ha/year treatments, respectively. Corresponding mean nitrate-N concentrations in drainage waters were 8.3, 9.2, 12.5 and 15.4 mg/ l, respectively. Very little direct leaching of fertiliser N was observed, even for drainage events in early spring, shortly after urea fertiliser application. The increased nitrate-N losses at higher rates of N fertiliser addition were instead owing to the indirect effect of increasing returns of urine and dung N to pasture. In Years 2 and 3, leaching losses of Ca, Mg, K, Na and sulphate-S averaged 61, 9, 11, 28 and 17 kg/ha/year, respectively, in the 0N fertiliser treatment. Increasing fertiliser N inputs significantly increased calcium and, to a lesser extent, potassium leaching losses but had no effect on losses of other plant nutrients. Surface runoff losses of Total-P, nitrate-N and ammonium- N were less than 0.5 kg/ha/year. For this well-drained Fleming soil, surface runoff was a relatively minor contributor of N to surface water, even for plots receiving high rates of fertiliser N and at a stocking rate of 3.0 cows/ha. Extrapolating these results to a 'typical' dairy pasture in Eastern Southland would suggest that the safe upper limit for annual fertiliser N additions to this site to achieve nitrate in drainage water below the drinking water standard is approximately 170 kg N/ha. Although losses of Ca in drainage were large, returns of this nutrient in maintenance applications of superphosphate-based products and lime should ensure Ca deficiencies are avoided in Southland dairy pastures. Keywords: cation-anion balances, dairy, N fertiliser, nitrate leaching, surface runoff, Southland

scholarly journals Influence of Stress on Individual Lag Time Distributions of Listeria monocytogenes

2005 ◽  
Vol 71 (6) ◽  
pp. 2940-2948 ◽  
Author(s):  
L. Guillier ◽  
P. Pardon ◽  
J.-C. Augustin
Keyword(s):  
Listeria Monocytogenes ◽  
Food Industry ◽  
Single Cells ◽  
Lag Time ◽  
Exponential Growth Phase ◽  
The Mean ◽  
Stressed Cells ◽  
Lag Times ◽  
The Times ◽  
Applied Stresses

ABSTRACT The effects of nine common food industry stresses on the times to the turbidity (T d) distribution of Listeria monocytogenes were determined. It was established that the main source of the variability of T d for stressed cells was the variability of individual lag times. The distributions of T d revealed that there was a noticeable difference in response to the stresses encountered by the L. monocytogenes cells. The applied stresses led to significant changes of the shape, the mean, and the variance of the distributions. The variance of T d of wells inoculated with single cells issued from a culture in the exponential growth phase was multiplied by at least 6 and up to 355 for wells inoculated with stressed cells. These results suggest stress-induced variability may be important in determining the reliability of predictive microbiological models.

scholarly journals Effectiveness of Nutrient Management on Water Quality Improvement: A Synthesis on Nitrate-Nitrogen Loss from Subsurface Drainage

2021 ◽  
Vol 64 (2) ◽  
pp. 675-689
Author(s):  
Wenlong Liu ◽  
Yongping Yuan ◽  
Lydia Koropeckyj-Cox
Keyword(s):  
Water Quality ◽  
Nutrient Management ◽  
Fertilizer Application ◽  
Organic Fertilizers ◽  
Corn Yield ◽  
Fertilizer Rate ◽  
N Losses ◽  
Nitrate N ◽  
Management Plans ◽  
Fertilizer Rates

HighlightsFertilizer rate was found to be the most important factor controlling flow-weighted nitrate-N concentrations.Organic fertilizer may significantly increase nitrate-N losses, but N content of manures can be variable.We did not find significant differences in nitrate-N export among fertilizer application methods or timing.Split fertilization reduced nitrate-N export at lower fertilizer rates (<167 kg N ha-1) but not at higher rates.Fertilizer N recommendations need re-evaluation to consider both environmental and economic effects.Abstract. Nutrient management, as described in NRCS Code 590, has been intensively investigated, with research largely focused on crop yields and water quality. Yet, due to complex processes and mechanisms in nutrient cycling (especially the nitrogen (N) cycle), there are many challenges in evaluating the effectiveness of nutrient management practices across site conditions. We therefore synthesized data from peer-reviewed publications on subsurface-drained agricultural fields in the Midwest U.S. with corn yield and drainage nitrate-N (NO3-N) export data published from 1980 to 2019. Through literature screening and data extraction from 43 publications, we obtained 577 site-years of data with detailed information on fertilization, corn yields, precipitation, drainage volume, and drainage NO3-N load/concentration or both. In addition, we estimated flow-weighted NO3-N concentrations ([NO3-N]) in drainage for those site-years where only load and volume were reported. Furthermore, we conducted a cost analysis using synthesized and surveyed corn yield data to evaluate the cost-effectiveness of different nutrient management plans. Results from the synthesis showed that N fertilizer rate was strongly positively correlated with corn yields, NO3-N loads, and flow-weighted [NO3-N]. Reducing N fertilizer rates can effectively mitigate NO3-N losses from agricultural fields; however, our cost analysis showed negative economic returns for continuous corn production at lower N rates. In addition, organic fertilizers significantly boosted corn yields and NO3-N losses compared to inorganic fertilizers at comparable rates; however, accurate quantification of plant-available N in organic fertilizers is necessary to guide appropriate nutrient management plans because the nutrient content may be highly variable. In terms of fertilizer application methods, we did not find significant differences in NO3-N export in drainage discharge. Lastly, impact of fertilization timing on NO3-N export varied depending on other factors such as fertilizer rate, source, and weather. According to these results, we suggest that further efforts are still required to produce effective local nutrient management plans. Furthermore, government agencies such as USDA-NRCS need to work with other agencies such as USEPA to address the potential economic losses due to implementation of lower fertilizer rates for water quality improvement. Keywords: Conservation practice, Corn yields, Cost-effectiveness, NO3-N loss, Nutrient management, Subsurface drainage, Midwest U.S.

Nitrogen leaching from sheep-, cattle- and deer-grazed pastures in the Lake Taupo catchment in New Zealand

2011 ◽  
Vol 51 (5) ◽  
pp. 416 ◽  
Author(s):  
C. J. Hoogendoorn ◽  
K. Betteridge ◽  
S. F. Ledgard ◽  
D. A. Costall ◽  
Z. A. Park ◽  
...  
Keyword(s):  
New Zealand ◽  
Animal Species ◽  
Organic N ◽  
N Leaching ◽  
Mineral N ◽  
Leaching Losses ◽  
Grazed Pastures ◽  
Nitrate N ◽  
Ammonium N ◽  
The Impact

A replicated grazing study measuring nitrogen (N) leaching from cattle-, sheep- and deer-grazed pastures was conducted to investigate the impact of different animal species on N leaching in the Lake Taupo catchment in New Zealand. Leaching losses of nitrate N from intensively grazed pastures on a highly porous pumice soil in the catchment averaged 37, 26 and 25 kg N/ha.year for cattle-, sheep- and deer-grazed areas, respectively, over the 3-year study and were not significantly different (P > 0.05). Leaching losses of ammonium N were much lower (3 kg N/ha.year for all three species of grazer; P > 0.05). Amounts of dissolved organic N leached were significantly higher than that of mineral N (nitrate N + ammonium N), and over the 3-year study averaged 44, 43 and 39 kg N/ha.year for cattle-, sheep- and deer-grazed areas, respectively (P > 0.05). On a stock unit equivalence basis (1 stock unit is equivalent to 550 kg DM consumed/year), cattle-grazed areas leached significantly more mineral N than sheep- or deer-grazed areas (5.5, 2.9 and 3.4 g mineral N leached/24 h grazing by 1 stock unit, for cattle, sheep and deer, respectively) (P < 0.001). Likewise, based on the amount of N apparently consumed (estimated by difference in mass of herbage N pre- and post-grazing), cattle-grazed pastures leached more mineral N than sheep- or deer-grazed pastures (123, 75 and 75 g mineral N/kg N apparently consumed for cattle, sheep and deer, respectively) (P < 0.01). This study gives valuable information on mineral N leaching in a high-rainfall environment on this free-draining pumice soil, and provides new data to assist in developing strategies to mitigate mineral N leaching losses from grazed pastures using different animal species.

scholarly journals Lag Time as an Indicator of the Link between Agricultural Pressure and Drinking Water Quality State

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2385 ◽  
Author(s):  
Hyojin Kim ◽  
Nicolas Surdyk ◽  
Ingelise Møller ◽  
Morten Graversgaard ◽  
Gitte Blicher-Mathiesen ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Land Surface ◽  
Soil Surface ◽  
Lag Time ◽  
Mitigation Measures ◽  
Successful Implementation ◽  
Water Protection ◽  
Cross Correlation Analysis ◽  
Lag Times

Diffuse nitrogen (N) pollution from agriculture in groundwater and surface water is a major challenge in terms of meeting drinking water targets in many parts of Europe. A bottom-up approach involving local stakeholders may be more effective than national- or European-level approaches for addressing local drinking water issues. Common understanding of the causal relationship between agricultural pressure and water quality state, e.g., nitrate pollution among the stakeholders, is necessary to define realistic goals of drinking water protection plans and to motivate the stakeholders; however, it is often challenging to obtain. Therefore, to link agricultural pressure and water quality state, we analyzed lag times between soil surface N surplus and groundwater chemistry using a cross correlation analysis method of three case study sites with groundwater-based drinking water abstraction: Tunø and Aalborg-Drastrup in Denmark and La Voulzie in France. At these sites, various mitigation measures have been implemented since the 1980s at local to national scales, resulting in a decrease of soil surface N surplus, with long-term monitoring data also being available to reveal the water quality responses. The lag times continuously increased with an increasing distance from the N source in Tunø (from 0 to 20 years between 1.2 and 24 m below the land surface; mbls) and La Voulzie (from 8 to 24 years along downstream), while in Aalborg-Drastrup, the lag times showed a greater variability with depth—for instance, 23-year lag time at 9–17 mbls and 4-year lag time at 21–23 mbls. These spatial patterns were interpreted, finding that in Tunø and La Voulzie, matrix flow is the dominant pathway of nitrate, whereas in Aalborg-Drastrup, both matrix and fracture flows are important pathways. The lag times estimated in this study were comparable to groundwater ages measured by chlorofluorocarbons (CFCs); however, they may provide different information to the stakeholders. The lag time may indicate a wait time for detecting the effects of an implemented protection plan while groundwater age, which is the mean residence time of a water body that is a mixture of significantly different ages, may be useful for planning the time scale of water protection programs. We conclude that the lag time may be a useful indicator to reveal the hydrogeological links between the agricultural pressure and water quality state, which is fundamental for a successful implementation of drinking water protection plans.

scholarly journals The effect of decreasing fertilization on agricultural nitrogen leaching: a model study

2008 ◽  
Vol 16 (4) ◽  
pp. 376 ◽  
Author(s):  
K. GRANLUND ◽  
I. BÄRLUND ◽  
T. SALO
Keyword(s):  
Root Zone ◽  
Weather Conditions ◽  
N Fertilization ◽  
Climatic Conditions ◽  
N Leaching ◽  
N Losses ◽  
Agricultural Catchments ◽  
Nitrate N ◽  
Model Study ◽  
Different Parts

In Finland, the use of agricultural nitrogen (N) fertilizers has decreased since the beginning of the 1990’s but there is not yet any clear response in observed water quality in the monitored agricultural catchments and river basins. It is therefore important to analyse how the reduction in N fertilization affects N leaching at the root zone scale. In this study the nutrient leaching model ICECREAM was used to demonstrate the effects of climatic conditions and decreased N input on N leaching. Ten years (1991–2000) of climatic input data from five stations located in different parts of the country were used as input to simulate nitrate N (NO3-N) leaching from barley cultivation with i) constant N fertilization (Baseline simulation, 90 kg N ha–1) and ii) decreasing N fertilization (N Reduction Scenario simulation: annual linear decrease from 110 to 90 kg N ha–1). The annual and regional variation of simulated N leaching was considerable in both the Baseline and N Reduction Scenario simulations. In the Baseline simulation the average annual NO3-N leaching was 24% of the N fertilization amount. From 1991 to 2000, the annual N leaching decreased close to Baseline leaching values in the N Reduction Scenario simulations, but the decrease was not linear due to high variability in N losses caused by changes in annual weather conditions. The model results indicate that it is possible to achieve a reduction in root zone N leaching by adjusting the fertilizer levels.;

Tillage Effects on Drainage Fluxes and Nitrate Leaching through Unsaturated Zone under Irrigated Corn-Soybean Rotation

2019 ◽  
Vol 35 (3) ◽  
pp. 293-300 ◽  
Author(s):  
J. D. Jabro ◽  
W. M. Iversen ◽  
W. B. Stevens ◽  
U. M. Sainju ◽  
B. L. Allen
Keyword(s):  
Management Practices ◽  
Nitrate Nitrogen ◽  
Sandy Loam ◽  
Irrigation Management ◽  
Northern Great Plains ◽  
N Leaching ◽  
N Losses ◽  
Leaching Losses ◽  
Drinking Water Standard ◽  
N Fluxes

Abstract. High levels of nitrate-nitrogen (NO3-N) in the nation’s groundwater are a significant environmental concern. To date no studies have yet evaluated the effects of various tillage practices on percolated drainage and NO3-N fluxes below the rootzone of cropping systems in the northern Great Plains. A field study was conducted to examine and compare the effect of no-tillage (NT) and conventional tillage (CT) practices on seasonal drainage fluxes and NO3-N leaching losses below the rootzone in irrigated corn ( L.) and soybean ( L.) on a Lihen sandy loam soil. Sixteen passive capillary lysimeters, PCAPs (75 cm long polyvinyl chloride pipe with a collecting surface area of 0.1 m2) were placed 90 cm below the soil surface to quantify percolated drainage water below the rootzone of corn-soybean rotation under NT and CT practices. The study was designed as a randomized complete block with four replications. Drainage and NO3-N fluxes were not significantly affected by the tillage in 2014, 2015, 2016, and 2017 due to substantial spatial variations among lysimeters within each treatment. Average cumulative seasonal drainage depths across 4 years were 22.26 and 34.46 mm for corn and 24.95 and 28.16 mm for soybean under NT and CT, respectively. Averaged 4-yr cumulative NO3-N losses were 17.61 and 26.74 kg ha-1 for corn and 25.47 and 23.56 kg ha-1 for soybean under NT and CT, respectively. Flow-weighted NO3-N concentrations over 4 years were 57.9 and 65.7 mg L-1 for corn while those for soybean were 74.8 and 67.0 mg L-1 under NT and CT, respectively. Nitrate-nitrogen concentrations generally exceed the safe drinking water standard of 10 mg L-1. Reducing N inputs in well-drained soils and using site specific N and irrigation management practices are required to lower input expenses, reduce N leaching losses and sustain environmental quality. Keywords: Drainage, Fluxes, Leaching, Lysimeter, Nitrate-nitrogen, Rootzone, Tillage.

scholarly journals Assessments of N leaching losses from six case study dairy farms using contrasting approaches to cow wintering

2012 ◽  
pp. 51-55 ◽  
Author(s):  
J.M. Chrystal ◽  
R.M.Monaghan D. Dalley ◽  
T. Styles
Keyword(s):  
Dairy Cow ◽  
N Uptake ◽  
Dairy Herd ◽  
High Potential ◽  
System Level ◽  
N Leaching ◽  
Forage Crops ◽  
N Losses ◽  
Total N ◽  
Leaching Losses

The expansion of the southern dairy herd in New Zealand has raised a number of concerns about the sustainability of grazing brassica forage crops. Here we provide an assessment of the contribution of these crops to the potential for N losses to water at a wholefarm system level, and compare these with metrics derived for systems that use alternative approaches for wintering cows. The risks of nutrient losses to water from six Monitor Farms that use contrasting approaches to dairy cow wintering were assessed using the Overseer® Nutrient budgets model (Overseer). This modelling assessment was supplemented with detailed information about the management of effluent generated from off-paddock cow wintering facilities such as wintering pads and covered housing. Predictions of N losses from individual farm blocks indicated that both winter- and summer-grazed brassica forage crops have a relatively high potential for N leaching losses. Expressed at a whole-system level (i.e. accounting for the milking platform, winter forage crop and other support land), the winter forage crops accounted for between 11 and 24% of total N leaching losses, despite representing only 4 to 9% of the area. The high N leaching losses predicted for summer-grazed forage crops were attributed to the limited opportunity for N uptake of excreted urinary N by the following new pasture. Another risk identified for some farms was the current practice of applying effluents collected from off-paddock facilities to land during winter. These assessments suggest that off-paddock cow wintering systems can help to minimise N losses from farms to water, although the storage and safe return to land of effluents and manures generated from the housing facilities is essential if this potential benefit is to be realised. Our assessments also suggest that summer crop paddocks have a relatively high potential for N leaching losses, although further research is needed to confirm this. Keywords: dairy cow wintering, Southland, nitrate leaching, grazed brassica forage crops.

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