Resolution of the 15N balance enigma?

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1419 ◽  
Author(s):  
T. J. Clough ◽  
R. R. Sherlock ◽  
K. C. Cameron ◽  
R. J. Stevens ◽  
R. J. Laughlin ◽  
...  
Keyword(s):  
Soil Surface ◽  
Rice Paddy ◽  
Organic N ◽  
15N Recovery ◽  
Soil Core ◽  
15N Balance ◽  
N Losses ◽  
Balance Sheets ◽  
Gas Tight ◽  
Soil Gases

The enigma of soil nitrogen balance sheets has been discussed for over 40 years. Many reasons have been considered for the incomplete recovery of 15N applied to soils, including sampling uncertainty, gaseous N losses from plants, and entrapment of soil gases. The entrapment of soil gases has been well documented for rice paddy and marshy soils but little or no work appears to have been done to determine entrapment in drained pasture soils. In this study 15N-labelled nitrate was applied to a soil core in a gas-tight glovebox. Water was applied, inducing drainage, which was immediately collected. Dinitrogen and N2O were determined in the flux through the soil surface, and in the gases released into the glovebox as a result of irrigation or physical destruction of the core. Other components of the N balance were also measured, including soil inorganic-N and organic-N. Quantitative recovery of the applied 15N was achieved when the experiment was terminated 484 h after the 15N-labelled material was applied. Nearly 23% of the 15N was recovered in the glovebox atmosphere as N2 and N2O due to diffusion from the base of the soil core, convective flow after irrigation, and destructive soil sampling. This 15N would normally be unaccounted for using the sampling methodology typically employed in 15N recovery experiments.

scholarly journals New methods to quantify NH3 volatilization from fertilized surface soil with urea

2011 ◽  
Vol 35 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Ana Carolina Alves ◽  
Patrícia Perondi Anchão Oliveira ◽  
Valdo Rodrigues Herling ◽  
Paulo Cesar Ocheuze Trivelin ◽  
Pedro Henrique de Cerqueira Luz ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Surface Soil ◽  
Balance Control ◽  
Soil Surface ◽  
Phosphoric Acid Solution ◽  
15N Balance ◽  
Nh3 Volatilization ◽  
N Losses

Gaseous N losses from soil are considerable, resulting mostly from ammonia volatilization linked to agricultural activities such as pasture fertilization. The use of simple and accessible measurement methods of such losses is fundamental in the evaluation of the N cycle in agricultural systems. The purpose of this study was to evaluate quantification methods of NH3 volatilization from fertilized surface soil with urea, with minimal influence on the volatilization processes. The greenhouse experiment was arranged in a completely randomized design with 13 treatments and five replications, with the following treatments: (1) Polyurethane foam (density 20 kg m-3) with phosphoric acid solution absorber (foam absorber), installed 1, 5, 10 and 20 cm above the soil surface; (2) Paper filter with sulfuric acid solution absorber (paper absorber, 1, 5, 10 and 20 cm above the soil surface); (3) Sulfuric acid solution absorber (1, 5 and 10 cm above the soil surface); (4) Semi-open static collector; (5) 15N balance (control). The foam absorber placed 1 cm above the soil surface estimated the real daily rate of loss and accumulated loss of NH3N and proved efficient in capturing NH3 volatized from urea-treated soil. The estimates based on acid absorbers 1, 5 and 10 cm above the soil surface and paper absorbers 1 and 5 cm above the soil surface were only realistic for accumulated N-NH3 losses. Foam absorbers can be indicated to quantify accumulated and daily rates of NH3 volatilization losses similarly to an open static chamber, making calibration equations or correction factors unnecessary.

scholarly journals Coal Fly Ash and Polyacrylamide Influence Transport and Redistribution of Soil Nitrogen in a Sandy Sloping Land

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Kai Yang ◽  
Zejun Tang ◽  
Jianzhang Feng
Keyword(s):  
Fly Ash ◽  
Sandy Soil ◽  
Coal Fly Ash ◽  
Soil Layer ◽  
Nutrient Retention ◽  
Soil Surface ◽  
Rainfall Event ◽  
N Losses ◽  
N Concentration ◽  
Application Rates

Sandy soils are prone to nutrient losses, and consequently do not have as much as agricultural productivity as other soils. In this study, coal fly ash (CFA) and anionic polyacrylamide (PAM) granules were used as a sandy soil amendment. The two additives were incorporated to the sandy soil layer (depth of 0.2 m, slope gradient of 10°) at three CFA dosages and two PAM dosages. Urea was applied uniformly onto the low-nitrogen (N) soil surface prior to the simulated rainfall experiment (rainfall intensity of 1.5 mm/min). The results showed that compared with no addition of CFA and PAM, the addition of CFA and/or PAM caused some increases in the cumulative NO3−-N and NH4+-N losses with surface runoff; when the rainfall event ended, 15% CFA alone treatment and 0.01–0.02% PAM alone treatment resulted in small but significant increases in the cumulative runoff-associated NO3−-N concentration (p < 0.05), meanwhile 10% CFA + 0.01% PAM treatment and 15% CFA alone treatment resulted in nonsignificant small increases in the cumulative runoff-associated NH4+-N concentration (p > 0.05). After the rainfall event, both CFA and PAM alone treatments increased the concentrations of NO3−-N and NH4+-N retained in the sandy soil layer compared with the unamended soil. As the CFA and PAM co-application rates increased, the additive effect of CFA and PAM on improving the nutrient retention of sandy soil increased.

scholarly journals The effectiveness of the nitrification inhibitor dicyandiamide (DCD) for mitigating nitrogen leaching losses from a winter grazed forage crop on a free draining soil in northern Southland.

2012 ◽  
pp. 39-44 ◽  
Author(s):  
L.C.Smith T.Orchiston R.M. Monaghan
Keyword(s):  
Porous Ceramic ◽  
Nitrification Inhibitor ◽  
Drainage Water ◽  
Organic N ◽  
Livestock Farming ◽  
Forage Crops ◽  
N Losses ◽  
Forage Crop ◽  
Brassica Crop ◽  
Ceramic Cups

Evidence suggests that the wintering of stock on forage crops is a significant contributor to N losses from livestock farming. Losses are likely to be exacerbated if crops are grown on shallow free-draining soils types and grazed by dairy cattle. A three-year trial (December 2008 - November 2011) was conducted in northern Southland on a soil classified as having severe vulnerability for nutrient leaching to groundwater. Porous ceramic cups were installed under a brassica crop which was grazed by dairy cows in June each year and the leachate collected regularly for N analysis. The treatments evaluated were with and without a single application of DCD applied at the time of crop grazing. Concentrations of nitrate-N in drainage water ranged from 40 mg/L in May 2011. Concentrations of dissolved organic N (DON) also increased from a low initial value (

TRANSFORMATIONS AND DISPOSITION OF LATE-FALL APPLIED NITROGEN DURING WINTER IN SOUTHERN SASKATCHEWAN

1989 ◽  
Vol 69 (3) ◽  
pp. 551-565
Author(s):  
F. SELLES ◽  
A. J. LEYSHON ◽  
C. A. CAMPBELL
Keyword(s):  
Ammonium Nitrate ◽  
Bare Soil ◽  
Fertilizer Application ◽  
Organic N ◽  
N Recovery ◽  
Freezing And Thawing ◽  
N Losses ◽  
Mineral N ◽  
Late Fall ◽  
Soil Temperatures

Prairie farmers are interested in applying nitrogen (N) in the fall or winter to reduce fertilizer costs and allow a better distribution of labor and machinery use. Two studies were conducted in southwestern Saskatchewan to determine the consequences of applying N in late fall. In the laboratory, fertilizer N barely penetrated into the snow at constant subzero temperatures, but under freeze-thaw conditions, urea and ammonium nitrate descended 27 cm in 3 d. In the field, ammonium nitrate and urea were applied to snow-covered and bare microplots of grass sod and cereal stubble (1981–1982) and grass sod only (1985–1986). Nitrogen from ammonium nitrate penetrated deeper into the snow than N from urea. Nitrogen recovery in April 1982 was 55–59% from ammonium nitrate and 39–51% from urea, but was near 100% for both sources on bare soil treatments in April 1986. More N was recovered when fertilizer was applied to bare than to snow-covered soil, especially during 1985–1986 when all the applied fertilizer was blown off the snow-covered plots. Mineral N generally declined from fall to spring in all treatments, probably because of denitrification and immobilization. In 1985–1986, a period of extremely low temperatures in late fall resulted in no movement or transformation of N until after early December. By late January, periods of above-zero soil temperatures resulted in substantial mineralization of soil organic N, in the fertilized plots. This apparent priming effect was attributed to perturbations in the organic matter and microbial biomass due to fertilizer application and freezing and thawing. Following this period there was a general decrease in mineral N towards spring, as observed in 1981–1982. Producers must consider the benefits of using labor and equipment more efficiently and of lower fertilizer cost in the fall against the risk of large potential N losses over winter. Key words: Urea, ammonium nitrate, N recovery, frozen soils, fertilizing in winter

Sugar cane straw left in the field during harvest: decomposition dynamics and composition changes

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 758 ◽  
Author(s):  
José G. de A. Sousa ◽  
Maurício R. Cherubin ◽  
Carlos E. P. Cerri ◽  
Carlos C. Cerri ◽  
Brigitte J. Feigl
Keyword(s):  
Sugar Cane ◽  
Management Practices ◽  
Soil Surface ◽  
Straw Decomposition ◽  
N Losses ◽  
No Removal ◽  
Bioenergy Production ◽  
Starting Point ◽  
Decomposition Dynamics ◽  
Straw Incorporation

The understanding of sugar cane straw decomposition dynamics is essential for defining a sustainable rate of straw removal for bioenergy production without jeopardising soil functioning and other ecosystem services. Thus, we conducted a field study in south-east Brazil over 360 days to evaluate sugar cane straw decomposition and changes in its composition as affected by increasing initial straw amounts and management practices. The sugar cane straw amounts tested were: (1) 3.5 Mg ha–1 (i.e. 75% removal); (2) 7.0 Mg ha–1 (i.e. 50% removal); (3) 14.0 Mg ha–1 (i.e. no removal); and (4) 21.0 Mg ha–1 (i.e. no removal plus 50% of the extra straw left on the field). In addition, two management practices were studied for the reference straw amount (14 Mg ha–1), namely straw incorporation into the soil and irrigation with vinasse. The findings showed that dry mass (DM) loss increased logarithmically as a function of the initial amount left on the soil surface. An exponential curve efficiently described straw DM and C losses, in which more readily decomposable compounds are preferably consumed, leaving compounds that are more recalcitrant in the late stages of decomposition. After 1 year of decomposition, net straw C and N losses reached approximately 70% and 23% respectively for the highest initial straw amounts. Straw incorporation in the soil significantly accelerated the decomposition process (i.e. 86% DM loss after 1 year) compared with maintenance of straw on the soil surface (65% DM loss after 1 year), whereas irrigation with vinasse had little effect on decomposition (60% DM loss after 1 year). We conclude that straw decomposition data are an essential starting point for a better understanding of the environmental effects caused by straw removal and other management practices in sugar cane fields. This information can be used in models and integrated assessments towards a more sustainable sugar cane straw management for bioenergy production.

Denitrification estimates in monoculture and rotation corn as influenced by tillage and nitrogen fertilizer

1997 ◽  
Vol 77 (3) ◽  
pp. 389-396 ◽  
Author(s):  
Ming X. Fan ◽  
Angus F. MacKenzie ◽  
Melissa Abbott ◽  
François Cadrin
Keyword(s):  
Agricultural Soils ◽  
Conventional Tillage ◽  
Nitrate Content ◽  
Soil Core ◽  
N Losses ◽  
Closed Chamber ◽  
Corn Production ◽  
Field Estimation ◽  
Glycine Max L ◽  
N Rates

Denitrification in agricultural soils results in loss of N for crop growth and production of N2O, a greenhouse gas. Agricultural management must be evaluated for denitrification losses in order to develop minimum N loss systems. Field estimation of denitrification losses is necessary to evaluate crop management effects. Two methods of field denitrification measurements, a soil core (SC) incubation and an in situ closed chamber (CC), were assessed in monoculture corn (Zea mays L.) and corn in rotation with soybean (Glycine max L. Merill) and alfalfa (Medicago sativa L.). Relative estimates of denitrification by the two methods depended on soil texture, with the CC method showing more treatment effects. Denitrification losses were higher with no-till than conventional tillage at one site, and were generally higher with corn than soybean. Nitrogen losses were linear with added N in monoculture corn plots, and ranged from 1.1 to 4.1% of added N. Losses were not related to added N in corn following alfalfa or soybean. Ratios of N2O/(N2O + N2) as measured with the SC method were lower at the Ste. Rosalie (1) site than at the Chicot site (0.95 to 2.84), but ratios of N2O/(N2O + N2) measured with the CC method were similar for the sites, from 0.46 to 1.20. Denitrification losses measured by either method were related to soil moisture and nitrate content in the soils. Corn production should be carried out with conventional tillage and minimum fertilizer N rates for minimum denitrification. Key words: Rotations, corn, soybean, denitrification, closed chamber, soil core

Nitrogen fixation in summer-grown soybean crops and fate of fixed-N over a winter fallow in subtropical sugarcane systems

Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 845
Author(s):  
Lee J. Kearney ◽  
Emma Dutilloy ◽  
Terry J. Rose
Keyword(s):  
Cover Crops ◽  
N2 Fixation ◽  
Cropping Systems ◽  
Soil Surface ◽  
Climatic Conditions ◽  
Peat Soils ◽  
N Losses ◽  
Soybean Residue ◽  
Glycine Max L ◽  
Winter Fallow

Legumes including soybeans (Glycine max L.) can provide substantial nitrogen (N) inputs into cropping systems when grown as a part of a rotation. However, in the wet subtropics where land is fallowed for 4–6 months after soybean crops before planting of sugarcane (Saccharum L. spp. hybrids), climatic conditions over winter can be conducive to rapid mineralisation of N from residues with consequent N losses through nitrate leaching or denitrification processes. Using 15N natural abundance methodology, we estimated N2 fixation in 12 summer-grown soybean crops in the Australian wet subtropics, and tracked the fate of soybean residue-N from brown manure crops (residue from plants at late pod-filling left on the soil surface) using 15N-labelled residue in three of these fields over the winter fallow period. Disregarding two poor crops, N2 fixation ranged from 100–290 kg N ha–1 in shoots at mid pod-filling, equating to 170–468 kg N ha–1 including estimated root N contributions. Following the winter fallow, 61 and 68% of soybean residue-N was recovered in clay and peat soils respectively, to 0.9 m depth at one location (Coraki) but only 55% of residue-N could be accounted for to 0.9 m depth in a sandy soil at another location (Ballina). In addition, around 20% of the recovered 15N at this site was located at 0.3–0.6 m depth in the soil profile. Our results indicate that substantial loss of soybean residue-N can occur during winter fallows in the wet subtropics, suggesting that winter cover crops may be necessary to retain N in fields and minimise losses to the environment.

scholarly journals Management Intensity Controls Nitrogen-Use-Efficiency and Flows in Grasslands—A 15N Tracing Experiment

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 606
Author(s):  
Marcus Zistl-Schlingmann ◽  
Steve Kwatcho Kengdo ◽  
Ralf Kiese ◽  
Michael Dannenmann
Keyword(s):  
Land Use ◽  
N Balance ◽  
15N Tracer ◽  
15N Recovery ◽  
Soil N ◽  
N Losses ◽  
Soil System ◽  
Land Use Intensification ◽  
Plant Soil ◽  
Montane Grasslands

The consequences of land use intensification and climate warming on productivity, fates of fertilizer nitrogen (N) and the overall soil N balance of montane grasslands remain poorly understood. Here, we report findings of a 15N slurry-tracing experiment on large grassland plant–soil lysimeters exposed to different management intensities (extensive vs. intensive) and climates (control; translocation: +2 °C, reduced precipitation). Surface-applied cattle slurry was enriched with both 15NH4+ and 15N-urea in order to trace its fate in the plant–soil system. Recovery of 15N tracer in plants was low (7–17%), while it was considerably higher in the soil N pool (32–42%), indicating N stabilization in soil organic nitrogen (SON). Total 15N recovery was only 49% ± 7% indicating substantial fertilizer N losses to the environment. With harvest N exports exceeding N fertilization rates, the N balance was negative for all climate and management treatments. Intensive management had an increased deficit relative to extensive management. In contrast, simulated climate change had no significant effects on the grassland N balance. These results suggest a risk of soil N mining in montane grasslands under land use intensification based on broadcast liquid slurry application.

Foliar litter position and decomposition in a fire-maintained longleaf pine – wiregrass ecosystem

2002 ◽  
Vol 32 (6) ◽  
pp. 928-941 ◽  
Author(s):  
Joseph J Hendricks ◽  
Carlos A Wilson ◽  
Lindsay R Boring
Keyword(s):  
Mass Loss ◽  
Longleaf Pine ◽  
Pinus Palustris ◽  
Soil Surface ◽  
Fire Regimes ◽  
Pine Forests ◽  
N Losses ◽  
Surface Mass ◽  
Decay Constants ◽  
P Immobilization

Foliar litter position and decomposition were assessed in longleaf pine (Pinus palustris Mill.) - wiregrass (Aristida beyrichiana Trin. & Rupr.) woodlands during a 3-year burn interval. Position assessments revealed 57.7 and 67.4% of foliar litter was elevated in wiregrass crowns 1 and 2 years, respectively, following burning. Decomposition assessments revealed soil-surface mass loss decay constants (range 0.097–0.282) similar to those measured in comparable pine forests. However, elevated longleaf pine and wiregrass litter exhibited decay constants (0.052 and 0.074, respectively) 50% lower than corresponding soil-surface rates and among the lowest values in the literature. With the exception of wiregrass, which did not exhibit an immobilization of the nutrients (N, P, Ca, K, and Mg) assessed, foliar litter exhibited either extensive P immobilization with minimal N immobilization or minimal, short-lived immobilization of N, P, or both N and P. The percentage of original N and P remaining after 3 years varied widely among the soil surface (N range 6.3–56.3%; P range 3.4–204.7%) and elevated (N range 76.8–94.9%; P range 52.0–99.2%) litter. These results suggest that fire regimes typically employed in longleaf pine – wiregrass woodlands may balance N losses via volatilization with P limitations via litter immobilization.

The effect of dicyandiamide addition to cattle slurry on soil gross nitrogen transformations at a grassland site in Northern Ireland

2013 ◽  
Vol 152 (S1) ◽  
pp. 125-136 ◽  
Author(s):  
K. L. McGEOUGH ◽  
C. MÜLLER ◽  
R. J. LAUGHLIN ◽  
C. J. WATSON ◽  
M. ERNFORS ◽  
...  
Keyword(s):  
Northern Ireland ◽  
Nitrification Inhibitor ◽  
Organic N ◽  
Ammonium Oxidation ◽  
Nitrogen Transformations ◽  
Cattle Slurry ◽  
N Losses ◽  
N Transformations ◽  
Dominant Process ◽  
Grassland Site

SUMMARYMany studies have shown the efficacy of the nitrification inhibitor dicyandiamide (DCD) in reducing nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. However, there is no information on the effect of DCD on gross soil N transformations under field conditions, which is key information if it is to be used as a mitigation strategy to reduce N losses. The current field study was conducted to determine the effect of DCD on ten gross nitrogen (N) transformations in soil following cattle slurry (CS) application to grassland in Northern Ireland on three occasions (June 2010, October 2010 and March 2011).Ammonium (NH4+) oxidation (ONH4) was the dominant process in total NO3− production (ONH4+ONrec (oxidation of recalcitrant organic N to NO3−)) following CS application, accounting for 0·894–0·949. Dicyandiamide inhibited total NO3− production from CS by 0·781, 0·696 and 0·807 in June 2010, October 2010 and March 2011, respectively. The lower inhibition level in October 2010 was thought to be due to the higher rainfall and soil moisture content in that month compared to the other application times. As DCD strongly inhibited NH4+ oxidation following CS application, it also decreased the rate of total NO3− consumption, since less NO3− was formed. The rates of mineralization from recalcitrant organic-N (MNrec) were higher than from labile organic-N (MNlab) on all occasions. The DCD significantly increased total mineralization (MNrec+MNlab) following CS application in June 2010 and March 2011, but had no significant effect in October 2010. In contrast, the rate of immobilization of labile organic-N (INH4_Nlab) was higher than from recalcitrant organic-N (INH4_Nrec) on all occasions, accounting for 0·878–0·976 of total NH4+ immobilization from CS. The DCD significantly increased total immobilization (INH4_Nrec+INH4_Nlab) when CS was applied in June 2010, but had no significant effect at other times of the year.Dicyandiamide was shown to be a highly effective inhibitor of ammonium oxidation at this grassland site. Although there was evidence that it increased both NH4+ mineralization and immobilization following CS application, its effect on these processes was inconsistent. Further work is required to understand the reason for these inconsistent effects: future improvements in 15N tracer models may help.

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