Nitrate Concentrations In Leachate Research Articles

Nutrient leaching potential following application of papermill lime-sludge to an acidic clay soil

This experiment was carried out under greenhouse conditions with soil pots during 210 days, to evaluate the effect of calcitic papermill lime-sludge application (at the rates 0, 773, 1.547, and 2.320 mg kg-1 or respective equivalents to control, 2, 4, and 6 t ha-1), on chemical composition of soil leachate and its effects on eucalypt growth and yield. Highest soil leachate pH, SO4, and Na concentrations occurred in the 4 and 6 t ha-1 treatments. Soil leachate nitrate concentrations decreased with increasing lime-sludge rate. Soil leachate phosphate remained low (below the detection limit) in all treatments until 120 days, while the concentration increased in the lime-sludge treatments at 210 days (last sampling) in about 600 mg L-1. Lime-sludge decreased leachate Mg concentration, but had no significant effect among rates. Soil leachate Ca, K, B, Cu, Fe, and Zn did not change significantly for any lime-sludge application rates. The maximum NO3, Ca, Mg, K, and Na concentrations in the soil leachate occurred at 60 days after lime-sludge application (leaching equivalent to 1 pore volume), but for pH and SO4, the maximum occurred at 210 days (leaching equivalent to 4 pore volumes). Lime-sludge application decreased the concentration of exchangeable Al in the soil. Plant diameter growth and dry matter yield were increased with increasing lime-sludge rate. Beneficial effects on mineral nutrition (P, K, Ca, B, and Zn) of eucalypts were also obtained by the application of 4 and 6 t ha-1 of lime-sludge.

Nitrogen and sulfate attenuation in simulated landfill bioreactors

The characteristics of leachate from landfills vary according to site-specific conditions. Leachates from old landfills are often rich in ammonia nitrogen, posing potential adverse environmental impacts in the case of uncontrolled discharge. At landfills where leachate recirculation is practiced, leachate ammonia concentrations may accumulate to higher levels than during the single pass leaching. Using leachate recirculation with system modifications, separate aerobic and anoxic zones for nitrification and both autotrophic and heterotrophic denitrification can be provided. Results from simulated landfill bioreactors indicated that both nitrogenous and sulfur compounds can be attenuated through autotrophic denitrification, and leachate nitrate concentrations of 750 mg/L reduced to less than 1 mg/L by denitrification to nitrogen gas promoting this very common process in a landfill environment results in the reduction of both leachate ammonia and sulfate concentrations.

The effect of autumn applied 15N-labelled fertilizer on nitrate leaching in a cultivated soil during winter

Nitrogen (N) fertilizer applied in autumn to arable farm land raises concerns over affects on ground water quality. The contribution of autumn 15N-labelled fertilizer (50 kg N ha-1) to nitrate leaching losses from a cultivated soil (silt loam on sandy loam; Udic Ustochrept) was measured using undisturbed monolith lysimeters (500 mm diameter, 700 mm long) during consecutive winters in Canterbury, New Zealand. The addition of 15N-labelled fertilizer at 50 kg N ha-1 did not significantly increase nitrate leaching losses. Soil-derived-N contributed 78 and 88% (1996 and 1997, respectively) of the nitrate leached beneath fertilized lysimeters. Warmer weather and wetter soil conditions at cultivation and fertilizer application during 1997, compared with 1996, resulted in an increased release of soil-derived-N in 1997. Nitrate leaching and average nitrate concentrations were therefore 41% and 56% higher, respectively, during the winter of 1997 than the winter of 1996. However, fertilizer leaching losses were relatively consistent between years (7.8 and 8.6%). Although not statistically significant, total N leaching losses and average nitrate concentration were 24 to 30% higher below fertilized lysimeters as compared with unfertilized lysimeters, indicating a priming effect of fertilizer on soil N release. During both late winter periods, leachate nitrate concentrations from fertilized and unfertilized lysimeters exceeded World Health Organisation (WHO) limits for drinking water. Higher release of soil-derived-N in 1997 also meant WHO limits were exceeded for 6 weeks longer than in 1996. In conclusion, the application of 15N fertilizer in autumn directly contributed only a small proportion of the total amount of N leached in this cultivated soil. However, the apparent priming effect of autumn applied-N fertilizer has importance on the overall environmental impact of this production system, as the amount of N leached, and extent to which health limits were exceeded, was largely determined by the factors which controlled the release of soil-derived-N.

Short rotation forestry for land treatment of effluent: a lysimeter study

Land treatment of wastewater using short rotation forestry (SRF) has potential as a sustainable method for disposal of dairy-farm euent. We compared 3 SRF species, 2 evergreen species of eucalypts (Eucalyptus nitens, E. saligna) and a deciduous willow (Salix kinuyanagi), in the land treatment of dairy-farm euent. The trees were grown in lysimeters (1 . 8 m diameter, 1 . 0 m depth), and a bare soil treatment was used as a control. The application of dairy-farm oxidation-pond euent totalled 218 g N/lysimeter (equivalent to 870 kg N/ha) over 2 irrigation seasons (December 1995–June 1996 and September 1996–April 1997). Euent was applied weekly in summer at a rate of 18 . 9 mm/week. No euent was applied during the winter period. The evapotranspiration (ET) rates of the trees, and the volumes and nitrogen contents of the leachates are compared for a winter period (4 weeks) and a summer period (5 weeks). The biomass accumulation and the uptake of nitrogen by the 3 tree species were also investigated. The SRF trees improved the renovation levels of dairy-farm euent and produced biomass suitable for energy conversion. Of the 3 tree species, only the S. kinuyanagi treatments maintained leachate nitrate concentrations below the New Zealand drinking water standard of 11 . 3 mg NO– 3 -N/L throughout both the winter and summer periods. The E. nitens treatment produced significantly more oven-dry biomass (19 . 1 kg/tree) than the E. saligna trees (9 . 7 kg/tree) (P = 0 . 05). The S. kinuyanagi treatment had intermediate production (13 . 3 kg/tree) and was not significantly different from the other 2 tree species (P = 0 . 05). The nutrient accumulation was not significantly different among the species (P = 0 . 05). S. kinuyanagi was considered the best overall performer for the land treatment of dairy-farm euent, based on the concentrations of leachate moving beyond the root-zone.

A comparative study of nitrate leaching from intensively managed monoculture grass and grass–clover pastures

Nitrate leaching losses from intensively managed monoculture grass and grass–clover pastures were measured during 1994–96 at a long-term experimental farm in south-west Scotland. Field-size lysimeter plots were established in 1993 on the existing pastures on a silty clay loam non-calcareous gley. No fertilizer-N was applied to the grass–clover, while the monoculture grass was fertilized with c. 240 kg N ha−1 year−1, but both swards received 2–3 cattle slurry applications annually (120–390 kg total N ha−1 year−1). The pastures supported 2–3 cuts for silage conservation, and were grazed by dairy cattle and stocked with sheep during the winter months.Initially, leachate nitrate concentrations from the fertilized grass were considerably larger than those from the clover-based pasture, but became similar with time. The annual nitrate leaching losses from the grass–clover (24–38 kg NO3-N ha−1) were less than that from the monoculture grass (30–45 kg NO3-N ha−1), but the differences were not large considering the additional fertilizer-N applied to the latter treatment. Results also suggested that greater leaching losses occur during a warmer, drier year, compared to a cooler, wetter year, regardless of the source of N-input.

Nitrate Losses from a Corn‐Alfalfa Rotation: Lysimeter Measurement of Nitrate Leaching

AbstractAn array of 18 zero‐tension pan lysimeters installed 1.2 m below the soil surface in 1988 was used to examine NO3 leaching in 1991 to 1995. The experiment was designed to study NO3 losses from continuous, fertilized corn, alfalfa, and the first year of corn rotated from alfalfa as a function of crop type, applied N fertilizer rate and longer‐term weather variability. The flow‐weighted mean leachate NO3‐N concentration from the 3‐yr alfalfa stand was 4 mg L−1. Annual leachate NO3‐N concentrations from continuous, fertilized corn and corn following alfalfa at the estimated Economically Optimum N (EON) rate averaged 15 mg L−1. Annual flow‐weighted average NO3‐N concentrations in leachate from post‐alfalfa corn receiving 50 and 100 kg N ha−1, which were above the EON rate, were 18 and 24 mg L−1, respectively. The masses of NO3‐N leached from the root zone of continuous corn at the estimated EON rate were 81 and 55 kg ha−1 in 1991 to 1992 and 1994 to 1995, respectively. Nitrate‐N losses from alfalfa in 1991 to 1992 were 9 kg ha−1. Nitrate concentrations in leachate from an alfalfa stand were one‐quarter to one‐fifth as high as from corn receiving the EON rate. This research provides evidence that including alfalfa in a rotation would result in a considerable reduction in the amount of NO3 leaving a farm in leachate.

Effects of climate change on nitrogen dynamics in upland soils. 1. A transplant approach

AbstractThe impact of climate change on N leaching from hill land plant/soil systems was investigated using a transplant technique involving the movement of intact lysimeter cores of three contrasting soil types down an altitudinal gradient at Great Dun Fell, Cumbria. Air and soil temperatures and precipitation were monitored at four elevations down an altitudinal transect using automatic weather stations for a period of two years. The altitudinal sequence of air temperature followed the anticipated pattern, providing mean annual temperatures at the four locations of 3.4, 5.0, 6.3 and 8.1 °C. Lapse rates of both mean air and soil temperatures over the altitudinal range 171–845 m were 6.6 (1993) and 7.0 °C km–1 (1994). Soil monthly temperature gradients for a particular soil type for each of the two years showed a seasonal range of 6.0 and 7.4 °C km–1, respectively, and for air temperature of 4.3 and 3.1 °C km–1. Precipitation gradients showed the expected general increase with altitude, but were less predictable. Inorganic nitrogen leaching was studied in lysimeter leachates with climatic amelioration resulting in dramatic reductions in leachate nitrate concentrations and associated total concentrations of inorganic nitrogen. Decreases in leachate nitrate concentrations were observed for all three soil types studied. Soils receiving supplemented rainfall also showed decreased N concentrations, suggesting that temperature was the main controlling factor responsible for the observed reductions. Increased N uptake by the vegetation, in response to the increases in temperature, is considered to be critical in controlling soil solution chemistry at these sites.

Estimating peak nitrate concentrations from annual nitrate loads

The feasibility of adopting an empirical approach to predicting peak nitrate concentrations in water draining agricultural land is examined in the light of the relationships derived from leaching experiments on a range of soils, and from river data for England and Wales for the period 1974–1986. Well-fitted linear regressions were obtained of peak nitrate concentration in leachate on the annual load of leachable nitrate in the soil. The slopes to the regressions ranged in value from greater than 1.3 for measurements in shallow soils over limestone in a low rainfall area, to 0.25 for a well-structured clay soil with mole drainage in a high rainfall area. (A slope of 1.0 means that a load of 100 kg N ha −1 gives rise to a peak concentration of 100 mg N 1 −1). This range mainly reflected the ranges in soil water capacity and degree of preferential flow occurring during drainage. The slopes to the regressions for river waters were consistently smaller than those for clay soils in the same areas. The slopes for rivers draining mainly low-lying clay or chalk catchments in drier areas (Thames, Anglian and Southern Water Authority areas) were generally greater than those for rivers draining mainly wetter and more upland areas (South West and Welsh Water Authority areas). The differences between the slopes to the regressions for rivers could be partly accounted for by differences in average rainfall, suggesting possible effects from systematic differences in land use, soil structure and date of rewetting of soils in different climatic areas. The regressions indicated that peak concentrations in excess of the European Community limit (11.3 mg 1 −1 nitrate-N) might be associated with total nitrate loads in rivers draining clay catchments of 30 kg N hat in central and eastern England, or greater than 70 kg N ha −1 in Wales. The results indicate that the regressions for soils might form the basis of a catchment-scale model of nitrate leaching, provided that it is linked with a hydrogeological sub-model that accounts for the contribution to river discharge from upland and groundwater sources, and for the effects of different land uses on the timing of the peak nitrate concentrations.

Changes in soil chemical properties following a 12-year fallow: A 2-year comparison of conventional tillage and no-tillage agroecosystems

Soil chemical parameters including total N, exchangeable ammonium, soluble nitrate, and extractable phosphate, potassium, calcium and magnesium, were compared between conventional and no-tillage treatments on land which had been left fallow in old-field vegetation for 12 years. Tillage treatments were also compared to an adjacent old-field which was not cropped. The study was carried out on the Georgia Piedmont for 2 years following the fallow period. Soil nutrient availability was related to chemical concentrations in the soil solution, plant nutrient uptake and litter decomposition. During 1978–1979, soil nitrate concentrations were highest in plowed systems and lowest in the old field. Extractable cation concentrations were generally higher in conventional tillage than in no-tillage soil during the 1st year after fallow (1978). However, during the 2nd year, higher cation concentrations in no-tillage soil prevailed. Nitrate concentrations in the soil solution at 60 cm depth were generally highest in conventional tillage, followed by no-tillage and lowest in old-field systems. During 1978–1979, total nutrient uptake by crops (grain sorghum and rye) and weeds was higher in conventional than in no-tillage systems. From 1978–1979 to 1979–1980, uptake decreased in both cropping systems, but proportionately more in conventional tillage systems so that uptake in 1979–1980 was similar in the two cropping treatments. Higher nitrate concentrations in leachate of conventional than in no-tillage and old-field systems suggested that plowing stimulated nitrification processes.

Nitrogen Source Effect on Nitrate and Ammonium Leaching and Runoff Losses from Greens1

AbstractThe use of sandy rooting media with rapid infiltration rates in the construction of golf greens provides the potential for N pollution of nearby water supplies. This study was designed to measure the effects of different N sources on NO−3 and NH+4 concentrations in leachate and runoff from golf greens constructed with various rooting media.Individual golf greens with USGA‐type profiles were constructed in the field with upper 30 cm layers consisting of sand‐peat, sandsoil‐peat and sandy loam soil mixtures. All profiles were equipped with subsurface tile drains over a plastic sheet and were treated sequentially with the following N fertilizers: NH4NO4, ureaformaldehyde, 12‐12‐12, Milorganite, and IBDU. Leachate and runoff were collected and analyzed for NO−3 and NH+4. Nitrate concentrations in leachate from sand, mixed, and soil greens fertilized with quick release materials ranged from 45 to 326, 8 to 314 and 8 to 170 mg liter−1, respectively and remained in this range for a 3‐week period. Runoff concentrations from the greens constructed of sandy loam soil exceeded 30 mg liter−1. No runoff was collected from sand or mixed greens.Nitrate N losses from various sources were in the order of NH4NO3 > 12‐12‐12 > Milorganite > Isobutylenediurea (IBDU) > Ureaformaldehyde. lsobutylenediurea provided a very uniform release rate. Milorganite had a 25 to 30 day delay before NO−3 appeared in the leachate. Soluble sources, NH4NO3, and 12‐12‐12 exhibited leaching within 5 days after application. It appears that regular moderate applications of slow release N sources would provide minimum NO−3 loss while supplying a continuous N supply.Ammonium losses ranked from greatest to smallest were NH4NO3 > Ureaformaldehyde > Milorganite > 12‐12‐12 > IBDU. Ammonium losses contributed very little to the total N losses from golf greens. Highest total N loss was 23% of the applied N.