Urea and legume residues as 15N-N2O sources in a subtropical soil

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 287 ◽  
Author(s):  
J. Gomes ◽  
N. Brüggemann ◽  
D. P. Dick ◽  
G. M. Pedroso ◽  
M. Veloso ◽  
...  
Keyword(s):  
Cover Crops ◽  
Crop Residues ◽  
Isotope Ratio Mass Spectrometry ◽  
N2o Emissions ◽  
Soil Cores ◽  
N2o Formation ◽  
Mineral N ◽  
Undisturbed Soil ◽  
15N Labelling ◽  
Subtropical Soil

In this work, we used the 15N labelling technique to identify the sources of N2O emitted by a subtropical soil following application of mineral nitrogen (N) fertiliser (urea) and residues of a legume cover crop (cowpea). For this purpose, a 45-day incubation experiment was conducted by subjecting undisturbed soil cores from a subtropical Acrisol to five different treatments: (1) control (no crop residue or fertiliser-N application); (2) 15N-labelled cowpea residue (200 μg N g–1 soil); (3) 15N-labelled urea (200 μg N g–1 soil); (4) 15N-labelled cowpea residue (100 μg N g–1 soil) + unlabelled urea (100 μg N g–1 soil); and (5) unlabelled cowpea residue (100 μg N g–1 soil) + 15N-labelled urea (100 μg N g–1 soil). Cores were analysed for total N2O formation, δ15N-N2O and δ18O-N2O by continuous flow isotope ratio mass spectrometry, as well as for total NO3–-N and NH4+-N. Legume crop residues and mineral fertiliser increased N2O emissions from soil to 10.5 and 9.7 µg N2O-N cm–2 respectively, which was roughly six times the value for control (1.5 µg N2O-N cm–2). The amount of 15N2O emitted from labelled 15N-urea (0.40–0.45% of 15N applied) was greater than from 15N-cowpea residues (0.013–0.015% of 15N applied). Unlike N-poor crop residues, urea in combination with N-rich residues (cowpea) failed to reduce N2O emissions relative to urea alone. Legume cover crops thus provide an effective mitigation strategy for N2O emissions in relation to mineral N fertilisation in climate-smart agriculture. Judging by our inconclusive results, however, using urea in combination with N-rich residues provides no clear-cut environmental advantage.

Influence of dicyandiamide on nitrogen transformation and losses in cow-urine-amended soil cores from grazed pasture

2009 ◽  
Vol 49 (3) ◽  
pp. 253 ◽  
Author(s):  
Jagrati Singh ◽  
S. Saggar ◽  
N. S. Bolan
Keyword(s):  
Sandy Loam ◽  
Field Capacity ◽  
N Leaching ◽  
N2o Emissions ◽  
Gaseous Emissions ◽  
Soil Cores ◽  
N Losses ◽  
Mineral N ◽  
Undisturbed Soil ◽  
N Transformations

In New Zealand, urine deposited by grazing animals represents the largest source of nitrogen (N) losses, as gaseous emissions of ammonia (NH3) and nitrous oxide (N2O), and leaching of nitrate (NO3−).We determined the effect of dicyandiamide (DCD) on gaseous emissions from pasture with increasing rates of urine-N application, mineral N transformations and potential leaching of N using undisturbed soil cores of Manawatu sandy loam at field capacity. The treatments included four levels of urine-N applied at 0 (control), 14.4, 29.0 and 57.0 g N/m2 with and without DCD at 2.5 g/m2. Results showed a significant (P < 0.05) increase in NH3 and N2O-N emissions as urine application was increased. The addition of DCD to corresponding urine treatments reduced N2O emissions by 33, 56 and 80%, respectively. The addition of DCD with urine to the intact soil cores at field capacity moisture content resulted in a significant increase in the soil ammonium-N (NH4+-N) concentration but little change in NH3 emissions. Addition of DCD to urine reduced potential NO3−-N leaching by 60–65% but potential NH4+-N leaching increased by 2–3.5 times. There was no difference in pasture dry matter production with and without DCD treatments.

scholarly journals Early nitrogen supply as an alternative management for a cover crop-maize sequence under a no-till system

2021 ◽  
Author(s):  
Letusa Momesso ◽  
Carlos A. C. Crusciol ◽  
Rogério P. Soratto ◽  
Carlos A. C. Nascimento ◽  
Ciro A. Rosolem ◽  
...  
Keyword(s):  
Conventional Method ◽  
Cover Crops ◽  
Cover Crop ◽  
Crop Residues ◽  
N Fertilizer ◽  
Mineral N ◽  
N Application ◽  
N Release ◽  
Maize Grain ◽  
Biomass Decomposition

AbstractOptimizing agronomic efficiency (AE) of nitrogen (N) fertilizer use by crops and enhancing crop yields are challenges for tropical no-tillage systems since maintaining crop residues on the soil surface alters the nutrient supply to the system. Cover crops receiving N fertilizer can provide superior biomass, N cycling to the soil and plant residue mineralization. The aims of this study were to (i) investigate N application on forage cover crops or cover crop residues as a substitute for N sidedressing (conventional method) for maize and (ii) investigate the supply of mineral N in the soil and the rates of biomass decomposition and N release. The treatments comprised two species, i.e., palisade grass [Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster] and ruzigrass [Urochloa ruziziensis (R. Germ. and C.M. Evrard) Crins], and four N applications: (i) control (no N application), (ii) on live cover crops 35 days before maize seeding (35 DBS), (iii) on cover crop residues 1 DBS, and (iv) conventional method (N sidedressing of maize). The maximum rates of biomass decomposition and N release were in palisade grass. The biomass of palisade grass and ruzigrass were 81 and 47% higher in N application at 35 DBS compared with control in ruzigrass (7 Mg ha−1), and N release followed the pattern observed of biomass in palisade and ruzigrass receiving N 35 DBS (249 and 189 kg N ha−1). Mineral N in the soil increased with N application regardless of cover crop species. Maize grain yields and AE were not affected when N was applied on palisade grass 35 DBS or 1 DBS (average 13 Mg ha−1 and 54 kg N kg−1 maize grain yield) compared to conventional method. However, N applied on ruzigrass 35 DBS decreased maize grain yields. Overall, N fertilizer can be applied on palisade grass 35 DBS or its residues 1 DBS as a substitute for conventional sidedressing application for maize.

scholarly journals Dynamics of mineral nitrogen in topsoil, during regrowth of pasture in two contrasting grassland systems

1991 ◽  
pp. 203-208
Author(s):  
B.E. Ruz-Jerez ◽  
P.Roger Ball ◽  
R.E. White
Keyword(s):  
Mineral Nitrogen ◽  
Organic N ◽  
Soil Cores ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Undisturbed Soil ◽  
Net Mineralisation ◽  
Organic Combination ◽  
Undisturbed Soil Cores ◽  
Intensive System

Changes in soil mineral nitrogen(N) were monitored during regrowth of pasture between consecutive grazings in two contrasting grassland systems; Grass-clover (the norm in NZ) and a more intensive system, Grass+N400 (pure grass + 400 kg fertiliser N/ha/year). The experiment was carried out during autumn at DSIR Grasslands.Palmerston North. Net mineralisation of N under field conditions was estimate_d- i~n- an ancillary experiment, using soil samples from undisturbed soil cores contained in PVC tubes. The dynamics of mineral N in soil were dominated by a 'pulse' of ammonium, observable soon after grazing. Nitrification proceeded rapidly thereafter. Mineral N in soil then progressively declined, much of it going into organic combination presumably through uptake by plants. Since nitrate formation in the soil is minimised by maximising the residence time of N in plant (organic) form, differentmanagementoptions(varyinginfrequency and intensity of defoliation) may have important influences, not only on pasture utilisation and production, but also on the management of mineral N in the soil-plant-animal complex. Tubes embedded in soil and incubated in the field have provided some additional, useful perspectives. There was only limitedevidence for significant net mineralisation of organic N throughout the period of regrowth. Analyses of individual soil cores demonstrated a sharp contrast between the pasture at large and the 10 - 15% of total area influenced by urine from the previous grazing, in terms of mineral N content. 'Averaging' these by bulking numerous cores into a composite sample can provide an accurate quantitative estimate of mineral N, which can be related to herbage uptake of N over the whole area. But if losses of N (by leaching or volatilisation) are disproportionate to the concentration of mineral N in affected and unaffected volumes of soil, then bulking samples and averaging will not be the most appropriate way to estimate these losses. The results of this study point to the importance of the urine of grazing ruminants as a N substrate for pasture regrowth in the absence of fertiliser N. At the same time, urine patches provide the main avenue for Nescape to the wider environment from developed pastures. Keywords mineral N, N in pastures, N cycling by animals

scholarly journals Reviews and syntheses: Review of causes and sources of N<sub>2</sub>O emissions and NO<sub>3</sub> leaching from organic arable crop rotations

2019 ◽  
Vol 16 (14) ◽  
pp. 2795-2819 ◽  
Author(s):  
Sissel Hansen ◽  
Randi Berland Frøseth ◽  
Maria Stenberg ◽  
Jarosław Stalenga ◽  
Jørgen E. Olesen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
Crop Residues ◽  
Cropping Systems ◽  
Crop Rotations ◽  
N2o Emissions ◽  
Arable Crop ◽  
Organic Fertilisers ◽  
N2o Fluxes

Abstract. The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) from agricultural cropping systems have considerable negative impacts on climate and the environment. Although these environmental burdens are less per unit area in organic than in non-organic production on average, they are roughly similar per unit of product. If organic farming is to maintain its goal of being environmentally friendly, these loadings must be addressed. We discuss the impact of possible drivers of N2O emissions and NO3 leaching within organic arable farming practice under European climatic conditions, and potential strategies to reduce these. Organic arable crop rotations are generally diverse with the frequent use of legumes, intercropping and organic fertilisers. The soil organic matter content and the share of active organic matter, soil structure, microbial and faunal activity are higher in such diverse rotations, and the yields are lower, than in non-organic arable cropping systems based on less diverse systems and inorganic fertilisers. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential for SMN accumulation and losses after crop termination, harvest or senescence. The risk of high N2O fluxes increases when large amounts of herbage or organic fertilisers with readily available nitrogen (N) and degradable carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mechanical mixing of crop residues into the soil further enhance the risk of high N2O fluxes. N derived from soil organic matter (background emissions) does, however, seem to be the most important driver for N2O emission from organic arable crop rotations, and the correlation between yearly total N-input and N2O emissions is weak. Incorporation of N-rich plant residues or mechanical weeding followed by bare fallow conditions increases the risk of NO3 leaching. In contrast, strategic use of deep-rooted crops with long growing seasons or effective cover crops in the rotation reduces NO3 leaching risk. Enhanced recycling of herbage from green manures, crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissions and NO3 leaching. Mixtures of legumes (e.g. clover or vetch) and non-legumes (e.g. grasses or Brassica species) are as efficient cover crops for reducing NO3 leaching as monocultures of non-legume species. Continued regular use of cover crops has the potential to reduce NO3 leaching and enhance soil organic matter but may enhance N2O emissions. There is a need to optimise the use of crops and cover crops to enhance the synchrony of mineralisation with crop N uptake to enhance crop productivity, and this will concurrently reduce the long-term risks of NO3 leaching and N2O emissions.

scholarly journals Effect of Crop Residue Decomposition on Soil Aggregate Stability

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 527
Author(s):  
Gheorghe Stegarescu ◽  
Jordi Escuer-Gatius ◽  
Kaido Soosaar ◽  
Karin Kauer ◽  
Tõnu Tõnutare ◽  
...  
Keyword(s):  
Wheat Straw ◽  
Functional Groups ◽  
Oilseed Rape ◽  
Cover Crops ◽  
Crop Residues ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
N2o Emissions ◽  
Decomposition Rates ◽  
Soil Aggregate Stability

The decomposition of fresh crop residues added to soil for agricultural purposes is complex. This is due to different factors that influence the decomposition process. In field conditions, the incorporation of crop residues into soil does not always have a positive effect on aggregate stability. The aim of this study was to investigate the decomposition effects of residues from two different cover crops (Brassica napus var. oleifera and Secale cereale) and one main crop (wheat straw) on soil aggregate stability. A 105-day incubation experiment was conducted in which crop residues were mixed with sandy loam soil at a rate of 6 g C kg−1 of soil. During the incubation, there were five water additions. The decomposition effects of organic matter on soil conditions during incubation were evaluated by determining the soil functional groups; carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions; soil microbial biomass carbon (MBC); and water-stable aggregates (WSA). The functional groups of the plant residues and the soil were analyzed using Fourier transform infrared spectroscopy (FTIR) and a double exponential model was used to estimate the decomposition rates. The results show that the decomposition rate of fresh organic materials was correlated with the soil functional groups and the C/N ratio. Oilseed rape and rye, with lower C/N ratios than wheat straw residues, had faster decomposition rates and higher CO2 and N2O emissions than wheat straw. The CO2 and N2O flush at the start of the experiment corresponded to a decrease of soil aggregate stability (from Day 3 to Day 10 for CO2 and from Day 19 to Day 28 for N2O emissions), which was linked to higher decomposition rates of the labile fraction. The lower decomposition rates contributed to higher remaining C (carbon) and higher soil aggregate stability. The results also show that changes in the soil functional groups due to crop residue incorporation did not significantly influence aggregate stability. Soil moisture (SM) negatively influenced the aggregate stability and greenhouse gas emissions (GHG) in all treatments (oilseed rape, rye, wheat straw, and control). Irrespective of the water addition procedure, rye and wheat straw residues had a positive effect on water-stable aggregates more frequently than oilseed rape during the incubation period. The results presented here may contribute to a better understanding of decomposition processes after the incorporation of fresh crop residues from cover crops. A future field study investigating the influence of incorporation rates of different crop residues on soil aggregate stability would be of great interest.

scholarly journals Post-Harvest N2O Emissions Can Be Mitigated With Organic Amendments

2021 ◽  
Vol 9 ◽  
Author(s):  
S. Rothardt ◽  
R. Fuß ◽  
I. Pahlmann ◽  
H. Kage
Keyword(s):  
Oilseed Rape ◽  
Faba Bean ◽  
Crop Residues ◽  
N Uptake ◽  
Organic Amendments ◽  
N2o Emissions ◽  
Soil Mineral Nitrogen ◽  
Mineral N ◽  
Microbial Decomposition ◽  
The Impact

After the harvest of winter oilseed rape and faba bean crops, considerable high soil nitrate values may be built up before winter in central to north European regions. High precipitation and a low N uptake by the subsequent crop in fall cause a high risk of N2O emissions and nitrate leaching. Microbial decomposition of crop residues or high carbon amendments may immobilize mineral N temporarily and may prevent losses by direct N2O emissions. Five treatments, including crop residue removal and application of different organic amendments after harvest, were tested in a field trial in Northern Germany to elucidate the potential of this mechanism as a mitigation option. N2O emissions and the soil mineral nitrogen status were monitored from August to March for three consecutive years. Observed emissions ranged from 0.1 to 3.4 kg N ha−1 in 180 days. An empirical model approach was applied to separate the impact of spatially and temporally heterogeneous environmental conditions between the plots of the field experiment from treatment effects in the subsequent statistical analysis of N2O emissions. Results show that the exchange of the initial crop residues with organic amendments with high C:N ratios (i.e., winter wheat straw and sawdust) after the harvest of faba bean or oilseed rape can reduce N2O emission during fall and winter by up to 45%.

scholarly journals Characterization and Classification of Soils of Zamra Irrigation Scheme, Northeastern Ethiopia

2021 ◽  
Vol 14 ◽  
pp. 117862212110265
Author(s):  
Workat Sebnie ◽  
Enyew Adgo ◽  
Hailu Kendie
Keyword(s):  
Cover Crops ◽  
Crop Residues ◽  
Sandy Loam ◽  
Laboratory Analysis ◽  
Available Phosphorus ◽  
Irrigation Scheme ◽  
Undisturbed Soil ◽  
Genetic Horizon ◽  
Reference Base

Understanding soil types of a given area is an important prerequisite to design optimum management strategies such as irrigation water management. The study was thus conducted on characterization and classification of Zamra irrigation scheme in Abergelle district of Amhara Region, which has an area of 196.16 ha. For this study, 53 auger observations, four profile pits, extensive visual observations, reconnaissance survey, and descriptions of soil profiles and laboratory analysis were used to study the morphological and physicochemical properties of the soils of the scheme. Twelve disturbed and undisturbed soil samples were collected from all profiles of each genetic horizon for laboratory analysis. The soils of the study area were identified based on Food and Agricultural Organization of the United Nations/World Reference Base for Soil Resources (FAO/WRB) 2015. The results revealed that the textural classes of all profiles of the study site ranged from sandy clay loam to sandy loam. The chemical properties of the soil in terms of total nitrogen, organic matter, and available phosphorus were in the very low and low categories as per the criteria developed by Tekalign and Olsen, respectively, whereas exchangeable bases (Ca, Mg, K, and Na), cation exchange capacity, and extractable micronutrients (Fe, Mn, Zn, and Cu) were medium to high. Based on morphological, physical, and chemical analyses, the soils were classified as Leptic Regosols (Eutric, Loamic; 21.99% of the area), Vertic Cambisols (Hypereutric; 17.87%), Haplic Regosols (Eutric; 36.69%), and Rhodic Nitisols (Eutric; 23.44%). Therefore, management techniques that enhance soil fertility (including crop rotations, manuring, fallow periods, proper management of crop residues, and leguminous cover crops) and water-saving technologies suitable to the terrain of the area are the best options to enhance land productivity in the area.

Isoproturon movement and dissipation in undisturbed soil cores from a grassed buffer strip

Agronomie ◽  
2000 ◽  
Vol 20 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Pierre Benoit ◽  
Enrique Barriuso ◽  
Philippe Vidon ◽  
Benoit Réal
Keyword(s):  
Soil Cores ◽  
Undisturbed Soil ◽  
Buffer Strip ◽  
Undisturbed Soil Cores

Chloride and Tritiated Water Flow in Disturbed and Undisturbed Soil Cores

1974 ◽  
Vol 38 (5) ◽  
pp. 727-732 ◽  
Author(s):  
M. A. McMahon ◽  
G. W. Thomas
Keyword(s):  
Water Flow ◽  
Tritiated Water ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Undisturbed Soil Cores

Measurement of effective air diffusion coefficients for trichloroethene in undisturbed soil cores

2002 ◽  
Vol 56 (3-4) ◽  
pp. 193-208 ◽  
Author(s):  
Shannon L Bartelt-Hunt ◽  
James A Smith
Keyword(s):  
Diffusion Coefficients ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Air Diffusion ◽  
Undisturbed Soil Cores
Sign in / Sign up

Export Citation Format

Share Document