Ammonia Volatilization from Flooded Soil Systems: A Computer Model. I. Theoretical Aspects

Jayaweera, G. R.; Mikkelsen, D. S.

doi:10.2136/sssaj1990.03615995005400050039x

Cited by 69 publications

(47 citation statements)

References 33 publications

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“…The average relative errors between the measured and calculated ammonia volatilization fluxes were only 12.4 %, indicating that the model adequately predicted the ammonia volatilization flux of the rice season. Jayaweera and Mikkelsen (1990) also investigated that the ammonia volatilization process from paddy field was directly influenced by NH 4 ? -N concentration, pH, water temperature, floodwater depth and wind speed, and model of ammonia volatilization flux was determined by chemical kinetics using the five factors.…”

Section: Quantitative Prediction Of Ammonia Volatilization Fluxmentioning

confidence: 99%

Characteristics of ammonia volatilization on rice grown under different nitrogen application rates and its quantitative predictions in Erhai Lake Watershed, China

Chen

Lei

et al. 2014

Nutr Cycl Agroecosyst

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Ammonia (NH 3 ) volatilization was measured with the continuous airflow enclosure chamber method under different urea application amounts using pots in paddy fields in Erhai Lake Watershed, China. Several factors, such as the urea nitrogen application amount, days after fertilization, NH 4 ? -N concentration and pH of surface water, and climate, that could affect ammonia volatilization were also studied. The results indicated that ammonia volatilization loss increased linearly with increasing amounts of applied urea. The ratios of the ammonia volatilization loss to the applied nitrogen ranged from 16.59 to 18.43 % with different nitrogen application amounts. The ammonia volatilization loss peaked within the first 3 days after fertilization, which accounted for 65-82 % of the total ammonia loss in each period. We observed the following degree of the effects of various factors on ammonia volatilization: NH 4 ? -N concentration of surface water [ urea application amount [ pH of surface water [ days after fertilization [ water temperature of surface water. The wind velocity and rainfall were the key factors affecting ammonia volatilization. The model of ammonia volatilization flux was established by using the measured dates from 2013 and was represented as Y = 0.008(x 1 ? x 2 ? x 3 ) ? e 0.056x4-0.068x5 -0.623 (R 2 = 0.81, P \ 0.0001). The model was verified by using the measured dates from 2012. The calculated values fitted well with the field observations. However, the model parameters need to be amended using the model to predict the ammonia volatilization flux in the rice season from other regions.

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Section: Quantitative Prediction Of Ammonia Volatilization Fluxmentioning

confidence: 99%

Characteristics of ammonia volatilization on rice grown under different nitrogen application rates and its quantitative predictions in Erhai Lake Watershed, China

Chen

Lei

et al. 2014

Nutr Cycl Agroecosyst

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“…Esta teoria tem sido utilizada na modelagem de sistemas contendo solo (Jayaweera, 1990;Wang, 2010), e possui duas pressuposições importantes. A primeira é que a taxa de transferência entre filmes é regida pelas taxas de difusão através de cada uma das interfaces.…”

Section: A) Teoria Dos Dois Filmesunclassified

The nitrogen cycle and loss within a broiler chicken barn: a review

Mendes¹,

Tinôco²,

Souza³

et al. 2016

Pubvet

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Brazilian poultry production has reached unprecedented levels in recent years, especially regarding to the broiler chickens production activity. This increasing productivity is due to progressive implementation of technology in this sector of the animal production in Brazil, which is being mainly focused on improving the animal environment and also, the diets offered to the birds combined with genetic advances. One consequence of high productivity of broiler chickens is the exacerbated production of waste, especially used litter, which has high levels of nutrients, among which is the nitrogen (N), that makes the poultry litter a material with high biological potential to be used as fertilizer. One way of depleting the quality of the litter is through volatilization of N as gaseous ammonia (NH3). The cycling of N for a whole broiler barn has been poorly treated in the current Brazilian scientific literature, which is the reason why this literature review was developed. The aim was to depict all possible sources and sinks and the mechanisms transformation of N inside the barn. Special focus was given to the processes of formation and models of NH3 volatilization. As main conclusion, we observed that the increase in feed conversion ratio with age is one of the factors that contributed to non-utilization of N offered to broilers, implying in a higher concentration of this nutrient in the litter with increasing age and consequently potential of its loss through volatilized NH3.

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“…1) is adapted from Jayaweera and Mikkelsen (1990). Most farmers use urea as nitrogen (N) source in a flooded rice field.…”

Section: The Biochemical Model: Ammonia Volatilisationmentioning

confidence: 99%

Set-membership identification of an agro-ecosystem from a small data set: The case of ammonia volatilisation in a flooded rice field

2015

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Uncertainty analysis is an essential part of systems modelling. Preferably, the uncertainty analysis should start with a parameter estimation step. However, for agro-ecosystems, available data sets are typically small. Therefore, probabilistic parameter estimation techniques are not adequate. Alternatively, a set-membership or bounded-error approach can be used. In this paper, we demonstrate a set-membership approach to estimate the unknown parameters in a biochemical model from a small data set. As a case study, a biochemical model developed to estimate ammonia volatilisation in a flooded rice field was used. A total of 741 feasible parameter-vectors were found from 4000 simulated parametervectors. Eigenvalue decomposition of an ellipsoidal outer-bounding set indicated that the model was most sensitive to the growth rate of the rice plants,  . Visual inspection of the feasible parametervectors showed that the estimates of the nitrogen uptake rate wupt K are hyperbolically related to the estimates of  .

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Ammonia Volatilization from Flooded Soil Systems: A Computer Model. I. Theoretical Aspects

Cited by 69 publications

References 33 publications

Characteristics of ammonia volatilization on rice grown under different nitrogen application rates and its quantitative predictions in Erhai Lake Watershed, China

Characteristics of ammonia volatilization on rice grown under different nitrogen application rates and its quantitative predictions in Erhai Lake Watershed, China

The nitrogen cycle and loss within a broiler chicken barn: a review

Set-membership identification of an agro-ecosystem from a small data set: The case of ammonia volatilisation in a flooded rice field

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