N-loss photodissociation dynamics of N2O+(B2Π) near the NO+(Σ+1) + N(2P) dissociation limit

2019 ◽  
Vol 150 (22) ◽  
pp. 226101 ◽  
Author(s):  
Zhengfang Zhou ◽  
Hao Liang ◽  
Zefeng Hua ◽  
Shaowen Feng ◽  
Dongfeng Zhao ◽  
...  
Keyword(s):  
Dissociation Limit ◽  
N Loss

Agricultural practices and diffuse nitrogen pollution in Denmark: empirical leaching and catchment models

1999 ◽  
Vol 39 (12) ◽  
pp. 257-264 ◽  
Author(s):  
Hans E. Andersen ◽  
Brian Kronvang ◽  
Søren E. Larsen
Keyword(s):  
Agricultural Land ◽  
Root Zone ◽  
Agricultural Practices ◽  
Animal Manure ◽  
Annual Runoff ◽  
N Leaching ◽  
N Loss ◽  
Total N ◽  
Model Calculations ◽  
N Removal

An empirical leaching model was applied to data on agricultural practices at the field level within 6 small Danish agricultural catchments in order to document any changes in nitrogen (N) leaching from the root zone during the period 1989-96. The model calculations performed at normal climate revealed an average reduction in N-leaching that amounted to 30% in the loamy catchments and 9% in the sandy catchments. The reductions in N leaching could be ascribed to several improvements in agricultural practices during the study period: (i) regulations on livestock density; (ii) regulations on the utilisation of animal manure; (iii) regulations concerning application practices for manure. The average annual total N-loss from agricultural areas to surface water constituted only 54% of the annual average N leached from the root zone in the three loamy catchments and 17% in the three sandy catchments. Thus, subsurface N-removal processes are capable of removing large amounts of N leached from agricultural land. An empirical model for the annual diffuse N-loss to streams from small catchments is presented. The model predicts annual N-loss as a function of the average annual use of mineral fertiliser and manure in the catchment and the total annual runoff from the unsaturated zone.

scholarly journals Improving the Sustainability of Dairy Slurry by A Commercial Additive Treatment

2019 ◽  
Vol 11 (18) ◽  
pp. 4998 ◽  
Author(s):  
Federica Borgonovo ◽  
Cecilia Conti ◽  
Daniela Lovarelli ◽  
Valentina Ferrante ◽  
Marcella Guarino
Keyword(s):  
Climate Change ◽  
Environmental Impact ◽  
Environmental Sustainability ◽  
Ghg Emissions ◽  
Mineral Fertilizer ◽  
Cattle Slurry ◽  
N Loss ◽  
Beneficial Effects ◽  
Environmental Impact Categories ◽  
Carbon Dioxide Co2

Ammonia (NH3), methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) emissions from livestock farms contribute to negative environmental impacts such as acidification and climate change. A significant part of these emissions is produced from the decomposition of slurry in livestock facilities, during storage and treatment phases. This research aimed at evaluating the effectiveness of the additive “SOP LAGOON” (made of agricultural gypsum processed with proprietary technology) on (i) NH3 and Greenhouse Gas (GHG) emissions, (ii) slurry properties and N loss. Moreover, the Life Cycle Assessment (LCA) method was applied to assess the potential environmental impact associated with stored slurry treated with the additive. Six barrels were filled with 65 L of cattle slurry, of which three were used as a control while the additive was used in the other three. The results indicated that the use of the additive led to a reduction of total nitrogen, nitrates, and GHG emissions. LCA confirmed the higher environmental sustainability of the scenario with the additive for some environmental impact categories among which climate change. In conclusion, the additive has beneficial effects on both emissions and the environment, and the nitrogen present in the treated slurry could partially displace a mineral fertilizer, which can be considered an environmental credit.

scholarly journals Effect of Ridge Height, Row Grade, and Field Slope on Nutrient Losses in Runoff in Contour Ridge Systems under Seepage with Rainfall Condition

2021 ◽  
Vol 18 (4) ◽  
pp. 2022
Author(s):  
Juan An ◽  
Jibiao Geng ◽  
Huiling Yang ◽  
Hongli Song ◽  
Bin Wang
Keyword(s):  
Polynomial Regression ◽  
Influential Factors ◽  
Nutrient Loss ◽  
Rainfall Simulation ◽  
N Loss ◽  
Rainfall Condition ◽  
Erosion Processes ◽  
P Loss ◽  
Ridge Height ◽  
Negative Effect

Seepage plays a key role in nutrient loss and easily occurs in widely-used contour ridge systems due to the ponding process. However, the characteristics of nutrient loss and its influential factors under seepage with rainfall condition in contour ridge systems are still unclear. In this study, 23 seepage and rainfall simulation experiments are arranged in an orthogonal rotatable central composite design to investigate the role of ridge height, row grade, and field slope on Nitrate (NO3−–N) and Orthophosphate (PO4+3–P) losses resulting from seepage in contour ridge systems. In total, three types of NO3−–N and PO4+3–P loss were observed according to erosion processes of inter-rill–headward, inter-rill–headward–contour failure, and inter-rill–headward–contour failure–rill. Our results demonstrated that second-order polynomial regression models were obtained to predict NO3−–N and PO4+3–P loss with the independent variables of ridge height, row grade, and field slope. Ridge height was the most important factor for nutrient loss, with a significantly positive effect and the greatest contribution (52.35–53.47%). The secondary factor of row grade exerted a significant and negative effect, and was with a contribution of 19.86–24.11% to nutrient loss. The interaction between ridge height and row grade revealed a significantly negative effect on NO3−–N loss, whereas interactions among the three factors did not significantly affect PO4+3–P loss. Field slope only significantly affected NO3−–N loss. The optimal design of a contour ridge system to control nutrient loss was obtained at ridge height of 8 cm, row grade of 2°, and field slope of 6.5°. This study provides a method to assess and model nutrient loss, and improves guidance to implement contour ridge systems in terms of nutrient loss control.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

Characteristics of Non-Point Source N Export via Surface Runoff from Sloping Croplands in Northeast China

2011 ◽  
Vol 347-353 ◽  
pp. 2302-2307 ◽  
Author(s):  
Hong Xiang Wang ◽  
Yi Shi ◽  
Jian Ma ◽  
Cai Yan Lu ◽  
Xin Chen
Keyword(s):  
Point Source ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Inorganic Nitrogen ◽  
Rainfall Amount ◽  
Organic N ◽  
Dissolved Inorganic Nitrogen ◽  
Slope Gradient ◽  
N Loss ◽  
Total N

A field experiment was conducted to study the characteristics of non-point source nitrogen (N) in the surface runoff from sloping croplands and the influences of rainfall and cropland slope gradient. The results showed that dissolved total N (DTN) was the major form of N in the runoff, and the proportion occupied by dissolved inorganic nitrogen (DIN) ranged from 45% to 85%. The level of NH4+-N was generally higher than the level of NO3--N, and averaged at 2.50 mg·L-1and 1.07 mg·L-1respectively. DIN was positively correlated with DTN (R2=0.962). Dissolved organic N (DON) presented a moderate seasonal change and averaged at 1.40 mg·L-1. Rainfall amount and rainfall intensity significantly affected the components of DTN in the runoff. With the increase of rainfall amount and rainfall intensity, the concentrations of DTN, NH4+-N and NO3--N presented a decreased trend, while the concentration of DON showed an increased trend. N loss went up with an increase in the gradient of sloping cropland, and was less when the duration was longer from the time of N fertilization.fertilization.

Tracing the nitrogen, sulfur, and carbon released from plant residues in a soil/plant system

Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 699 ◽  
Author(s):  
Yothin Konboon ◽  
Graeme Blair ◽  
Rod Lefroy ◽  
Anthony Whitbread
Keyword(s):  
Triticum Aestivum ◽  
Nutrient Cycling ◽  
Wheat Straw ◽  
Medicago Truncatula ◽  
Plant Residue ◽  
Plant Residues ◽  
Plant Nutrient ◽  
N Loss ◽  
Leaching Losses ◽  
Nutrient Demand

Matching plant residue mineralisation rate to plant nutrient demand is one way of increasing the efficiency of nutrient cycling. A glasshouse experiment was conducted in a Soloth soil with a C4d13 C signature using drained pots to examine the effect on the yield of Japanese millet (Echinochloa frumentocea) and the fate of 15 N, 35 S, and C (using d 13 C shift) from the C 3 plants Flemingia macrophylla, Medicago truncatula hay, and wheat (Triticum aestivum) straw applied at 3 t/ha in the presence of N and NPKS fertiliser. The yield of Japanese millet at 91 days was highest where medic hay had been added (13.7 g/pot) and lowest where wheat straw was used (11.5 g/pot). Recovery of 35 S by the millet was highest in the wheat straw and medic hay treatments (mean 11.5%), whilst recovery of 15 N was highest from medic hay (15.8%). Leaching losses of 35 S were highest in the Flemingia and medic treatments (mean 8.1%), and 15 N loss in leachate was highest in the medic hay treatment (6.6%). A maximum of 1.5% of the C added in residues was recovered in the leachate of the medic hay treatment.

Line shapes and decay dynamics of dissociative resonances above the second dissociation limit of molecular hydrogen

1998 ◽  
Vol 57 (2) ◽  
pp. 949-957 ◽  
Author(s):  
C. H. Cheng ◽  
J. T. Kim ◽  
E. E. Eyler ◽  
N. Melikechi
Keyword(s):  
Molecular Hydrogen ◽  
Dissociation Limit ◽  
Line Shapes
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