scholarly journals Nitrogen Loss in Vegetable Field under the Simulated Rainfall Experiments in Hebei, China

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 552
Author(s):  
Baoguo Ma ◽  
Ronghao Guan ◽  
Liang Liu ◽  
Zhixi Huang ◽  
Shuanwang Qi ◽  
...  
Keyword(s):  
Nitrogen Fertilizer ◽  
Surface Runoff ◽  
Rainfall Intensity ◽  
Linear Trend ◽  
Nitrogen Loss ◽  
Rainfall Simulation ◽  
Utilization Rate ◽  
Pak Choi ◽  
Vegetable Field ◽  
The Impact

Agricultural non-point source pollution is one of the main factors contaminating the environment. However, the impact of rainfall on loss of non-point nitrogen is far from well understood. Based on the artificial rainfall simulation experiments to monitor the loss of dissolved nitrogen (DN) in surface runoff and interflow of vegetable field, this study analyzed the effects of rainfall intensity and fertilization scheme on nitrogen (N) loss. The results indicated that fertilizer usage is the main factor affecting the nitrogen loss in surface runoff, while runoff and rainfall intensity play important roles in interflow nitrogen loss. The proportion of DN lost through the surface runoff was more than 91%, and it decreased with increasing rainfall intensity. There was a clear linear trend (r2 > 0.96) between the amount of DN loss and runoff. Over 95% of DN was lost as nitrate nitrogen (NN), which was the major component of nitrogen loss. Compared with the conventional fertilization treatment (CF), the amount of nitrogen fertilizer applied in the optimized fertilization treatment (OF) decreased by 38.9%, and the loss of DN decreased by 28.4%, but root length, plant height and yield of pak choi increased by 6.3%, 2.7% and 5.6%, respectively. Our findings suggest that properly reducing the amount of nitrogen fertilizer can improve the utilization rate of nitrogen fertilizer but will not reduce the yield of pak choi. Controlling fertilizer usage and reducing runoff generation are important methods to reduce the DN loss in vegetable fields.

scholarly journals Effects of rainfall intensity on runoff and nutrient loss of gently sloping farmland in a karst area of SW China

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0246505
Author(s):  
Yiwen Yao ◽  
Quanhou Dai ◽  
Ruxue Gao ◽  
Yixian Gan ◽  
Xingsong Yi
Keyword(s):  
Surface Runoff ◽  
Rainfall Intensity ◽  
Simulation Method ◽  
Nutrient Loss ◽  
Rainfall Simulation ◽  
Karst Area ◽  
Nutrient Losses ◽  
Nutrient Runoff ◽  
Karst Areas ◽  
Sloping Farmland

Nutrient losses from sloping farmland in karst areas lead to the decline in land productivity and nonpoint source pollution. A specially tailored steel channel with an adjustable slope and underground hole fissures was used to simulate the microenvironment of the "dual structure" of the surface and underground of sloping farmland in a karst area. The artificial rainfall simulation method was used to explore the surface and underground runoff characteristics and nutrient losses from sloping farmland under different rainfall intensities. The effect of rainfall intensity on the nutrient loss of farmland on karst sloping land was clarified. The results showed that the surface was the main route of runoff and nutrient loss during the rainy season on sloping farmland in karst areas. The influence of rainfall intensity on the nutrients in surface runoff was more substantial than that on underground runoff nutrients. Nutrient loss was more likely to occur underground than on the surface. The losses of total nitrogen, total phosphorus, and total potassium in surface and underground runoff initially increased and then gradually stabilized with the extension of rainfall duration and increased with increasing rainfall intensity and the amount of nutrient runoff. The output of nutrients through surface runoff accounted for a high proportion of the total, and underground runoff was responsible for a low proportion. Although the amount of nutrients output by underground runoff was small, it could directly cause groundwater pollution. The research results provide a theoretical reference for controlling land source pollution from sloping farming in karst areas.

scholarly journals Application of biochar-coated urea controlled loss of fertilizer nitrogen and increased nitrogen use efficiency

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yiman Jia ◽  
Zhengyi Hu ◽  
Yuxin Ba ◽  
Wenfang Qi
Keyword(s):  
Oilseed Rape ◽  
Nitrogen Uptake ◽  
Nitrogen Use Efficiency ◽  
Nitrogen Fertilizer ◽  
Ammonia Volatilization ◽  
Nitrogen Loss ◽  
Nitrogen Use ◽  
Coated Urea ◽  
Use Efficiency ◽  
The Impact

Abstract Background The use of biochar-based N fertilizers have been considered among the most effective strategy for reducing nitrogen loss and improving nitrogen use efficiency (NUE). However, effect and mechanism of biochar-coated urea (BCU) controlling the loss of nitrogen from soil and NUE are rarely reported. Methodology In this study, a 65-d culture pot experiment of oilseed rape was used to investigate the impact of BCU on nitrogen leaching, ammonia volatilization, soil nitrogen concentrations, soil pH, nitrogen uptake, NUE and oilseed rape biomass as compared with urea and urea combined with biochar at same nitrogen level. Results Results showed that the application of BCU could minimize nitrogen loss mainly by reducing nitrate leaching loss; which could be attributed to the slow-release performance of BCU, followed by biochar induced adsorption/fixation of nitrogen due to the porous nature and surface functional groups of biochar. However, the application of BCU enhanced ammonia volatilization due to the increase of soil NH4+–N concentration and pH value of microenvironment around urea by BCU. The application of BCU increased NUE by about 20% when compared with urea, since BCU reduced losses of nitrogen fertilizer and increased concentration of nitrogen in the soil as well as nitrogen uptake in oilseed rape. Furthermore, the reduction of nitrogen application by 20% when BCU served as a nitrogen source not only reduced nitrogen loss but significantly improved NUE, with no negative effect on the biomass of oilseed rape. Conclusion BCU can serve as a promising control release nitrogen fertilizer for reducing loss of nitrogen and increasing NUE. However further investigations are required to validate the dosage-effect relationship of BCU on crop yield at the field scale.

DAMPAK VOLATILITAS HARGA MINYAK DI INDONESIA TERHADAP PENYESUAIAN KESEIMBANGAN FISKAL

2015 ◽  
Vol 15 (2) ◽  
pp. 37-52
Author(s):  
Mahpud Sujai
Keyword(s):  
Linear Trend ◽  
The State ◽  
Oil Price ◽  
Output Gap ◽  
State Budget ◽  
Price Changes ◽  
Potential Output ◽  
Budget Cycle ◽  
Actual Output ◽  
The Impact

This paper is intended to analyze the effect of oil price changes on potential output and actual output in the state budget cycle and identifies the output gap which is the difference between potential output and actual output. The research methodology uses a quantitative approach to analyze problems that occur related to the impact of oil price changes to the state budget cycle. Data analysis was carried out through the approach cyclically adjusted fiscal balance with a simplified approach. This research identified that the potential output is likely to continue increasing in line with Indonesia's oil price trends which is continue to rise following the world oil price movements. In calculating the output gap using a linear trend and HP filter, the result is fuctuating depend on the percentage changes in both potential output and actual output. This paper concludes that Indonesian oil price (ICP) has a significant impact on changes in the state budget cycle. If oil prices rise, the output gap between potential output and actual output is greater, and vice versa. This will make the budget vulnerable to shock that occurs as an external infuence.

1033 REDUCING NITROGEN FERTILIZER APPLICATIONS BY BALANCING THE NITROGEN SULFUR RATIO

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 576d-576
Author(s):  
Ellen T. Paparozzi
Keyword(s):  
Groundwater Contamination ◽  
Nitrogen Fertilizer ◽  
Nutrient Balance ◽  
Ornamental Plants ◽  
Consumer Perceptions ◽  
Consumer Acceptance ◽  
Statistical Techniques ◽  
Physiological Processes ◽  
The Impact ◽  
Future Plans

Fertilizer particularly nitrogen is part of the concern about groundwater contamination. Many floricultural and ornamental plants do not need the high rates of nitrogen that are typically recommended. However, whenever one alters the quantity of a given nutrient the overall nutrient balance, as well as other physiological processes, changes. A brief overview of our research on poinsettias, roses, and chrysanthemums will be presented. Suggested ratios, critical S levels and nutrient problems associated with incorrect balances will be shared. Limitations due to statistical methods and the impact nutrient balance has on certain plant processes such as flowering and coloring and thus, consumer acceptance will be summarized. Future plans in this area may focus on the need for new statistical techniques, nutrient acquisition by roots and consumer perceptions of plant quality.

The Impact of a Chemostat Discharge Containing Oil Degrading Bacteria on the Biological Kinetics of a Refinery Activated Sludge Process

1988 ◽  
Vol 20 (11-12) ◽  
pp. 131-136 ◽  
Author(s):  
A. D. Wong ◽  
C. D. Goldsmith
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Waste Treatment ◽  
Treatment Plant ◽  
Utilization Rate ◽  
Activated Sludge Process ◽  
Kinetic Evaluation ◽  
Degrading Bacteria ◽  
Waste Treatment Plant ◽  
The Impact

The effect of discharging specific oil degrading bacteria from a chemostat to a refinery activated sludge process was determined biokinetically. Plant data for the kinetic evaluation of the waste treatment plant was collected before and during treatment. During treatment, the 500 gallon chemostatic growth chamber was operated on an eight hour hydraulic retention time, at a neutral pH, and was fed a mixture of refinery wastewater and simple sugars. The biokinetic constants k (days−1), Ks (mg/L), and K (L/mg-day) were determined before and after treatment by Monod and Lineweaver-Burk plots. Solids discharged and effluent organic concentrations were also evaluated against the mean cell retention time (MCRT). The maximum utilization rate, k, was found to increase from 0.47 to 0.95 days−1 during the operation of the chemostat. Subsequently, Ks increased from 141 to 556 mg/L. Effluent solids were shown to increase slightly with treatment. However, this was acceptable due to the polishing pond and the benefit of increased ability to accept shock loads of oily wastewater. The reason for the increased suspended solids in the effluent was most likely due to the continual addition of bacteria in exponential growth that were capable of responding to excess substrate. The effect of the chemostatic addition of specific microbial inocula to the refinery waste treatment plant has been to improve the overall organic removal capacity along with subsequent gains in plant stability.

scholarly journals Non-Parametric Generalized Additive Models as a Tool for Evaluating Policy Interventions

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 299
Author(s):  
Jaime Pinilla ◽  
Miguel Negrín
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Linear Trend ◽  
Generalized Additive Models ◽  
Additive Models ◽  
Linear Regression Models ◽  
Non Linear ◽  
Nonlinear Trends ◽  
The Impact ◽  
Non Parametric

The interrupted time series analysis is a quasi-experimental design used to evaluate the effectiveness of an intervention. Segmented linear regression models have been the most used models to carry out this analysis. However, they assume a linear trend that may not be appropriate in many situations. In this paper, we show how generalized additive models (GAMs), a non-parametric regression-based method, can be useful to accommodate nonlinear trends. An analysis with simulated data is carried out to assess the performance of both models. Data were simulated from linear and non-linear (quadratic and cubic) functions. The results of this analysis show how GAMs improve on segmented linear regression models when the trend is non-linear, but they also show a good performance when the trend is linear. A real-life application where the impact of the 2012 Spanish cost-sharing reforms on pharmaceutical prescription is also analyzed. Seasonality and an indicator variable for the stockpiling effect are included as explanatory variables. The segmented linear regression model shows good fit of the data. However, the GAM concludes that the hypothesis of linear trend is rejected. The estimated level shift is similar for both models but the cumulative absolute effect on the number of prescriptions is lower in GAM.

scholarly journals Thirty-Nine-Year Wave Hindcast, Storm Activity, and Probability Analysis of Storm Waves in the Kara Sea, Russia

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 648
Author(s):  
Stanislav Myslenkov ◽  
Vladimir Platonov ◽  
Alexander Kislov ◽  
Ksenia Silvestrova ◽  
Igor Medvedev
Keyword(s):  
Climate Change ◽  
Pareto Distribution ◽  
Linear Trend ◽  
Wind Waves ◽  
Kara Sea ◽  
The Arctic ◽  
Storm Events ◽  
Storm Activity ◽  
Significant Linear Trend ◽  
The Impact

The recurrence of extreme wind waves in the Kara Sea strongly influences the Arctic climate change. The period 2000–2010 is characterized by significant climate warming, a reduction of the sea ice in the Arctic. The main motivation of this research to assess the impact of climate change on storm activity over the past 39 years in the Kara Sea. The paper presents the analysis of wave climate and storm activity in the Kara Sea based on the results of numerical modeling. A wave model WAVEWATCH III is used to reconstruct wind wave fields for the period from 1979 to 2017. The maximum significant wave height (SWH) for the whole period amounts to 9.9 m. The average long-term SWH for the ice-free period does not exceed 1.3 m. A significant linear trend shows an increase in the storm wave frequency for the period from 1979 to 2017. It is shown that trends in the storm activity of the Kara Sea are primarily regulated by the ice. Analysis of the extreme storm events showed that the Pareto distribution is in the best agreement with the data. However, the extreme events with an SWH more than 6‒7 m deviate from the Pareto distribution.

scholarly journals Prediction of factors affecting activation of soil erosion by mathematical modeling at pedon scale under laboratory conditions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Saeed Shojaei ◽  
Zahra Kalantari ◽  
Jesús Rodrigo-Comino
Keyword(s):  
Soil Loss ◽  
Rainfall Intensity ◽  
Quadratic Function ◽  
Interactive Effects ◽  
Soil Protection ◽  
Single Factor ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
The Impact ◽  
Runoff Production

AbstractSoil degradation due to erosion is a significant worldwide problem at different spatial (from pedon to watershed) and temporal scales. All stages and factors in the erosion process must be detected and evaluated to reduce this environmental issue and protect existing fertile soils and natural ecosystems. Laboratory studies using rainfall simulators allow single factors and interactive effects to be investigated under controlled conditions during extreme rainfall events. In this study, three main factors (rainfall intensity, inclination, and rainfall duration) were assessed to obtain empirical data for modeling water erosion during single rainfall events. Each factor was divided into three levels (− 1, 0, + 1), which were applied in different combinations using a rainfall simulator on beds (6 × 1 m) filled with soil from a study plot located in the arid Sistan region, Iran. The rainfall duration levels tested were 3, 5, and 7 min, the rainfall intensity levels were 30, 60, and 90 mm/h, and the inclination levels were 5, 15, and 25%. The results showed that the highest rainfall intensity tested (90 mm/h) for the longest duration (7 min) caused the highest runoff (62 mm3/s) and soil loss (1580 g/m2/h). Based on the empirical results, a quadratic function was the best mathematical model (R2 = 0.90) for predicting runoff (Q) and soil loss. Single-factor analysis revealed that rainfall intensity was more influential for runoff production than changes in time and inclination, while rainfall duration was the most influential single factor for soil loss. Modeling and three-dimensional depictions of the data revealed that sediment production was high and runoff production lower at the beginning of the experiment, but this trend was reversed over time as the soil became saturated. These results indicate that avoiding the initial stage of erosion is critical, so all soil protection measures should be taken to reduce the impact at this stage. The final stages of erosion appeared too complicated to be modeled, because different factors showed differing effects on erosion.

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.

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