Controls on N Retention and Exports in a Forested Watershed

1999 ◽  
pp. 187-210 ◽  
Author(s):  
K. Nadelhoffer ◽  
M. Downs ◽  
B. Fry ◽  
A. Magill ◽  
J. Aber
Keyword(s):  
Forested Watershed ◽  
N Retention

scholarly journals Role of stormflow in reducing N retention in a suburban forested watershed, western Japan

2010 ◽  
Vol 115 (G2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Masaaki Chiwa ◽  
Ryoko Maruno ◽  
Jun'ichiro Ide ◽  
Takeaki Miyano ◽  
Naoko Higashi ◽  
...  
Keyword(s):  
Forested Watershed ◽  
N Retention ◽  
Western Japan

Laboratory Prediction of Phosphorus Release from Deciduous Leaves to Urban Runoff

1995 ◽  
Vol 30 (2) ◽  
pp. 243-246 ◽  
Author(s):  
Heather Culbert ◽  
Robert France
Keyword(s):  
Total Phosphorus ◽  
Empirical Equation ◽  
Urban Runoff ◽  
Phosphorus Release ◽  
Total Export ◽  
Forested Watershed ◽  
Distilled Water ◽  
Trembling Aspen ◽  
Urban Catchments

Abstract In urban centres, leaves are customarily gathered and temporarily stored in large roadside piles prior to their transport to disposal sites. To simulate the release of total phosphorus to urban runoff, birch and trembling aspen leaves were leached with distilled water in laboratory flasks. There was no difference in rate of total phosphorus release between oven-dried and non-dried leaves. An empirical equation developed from these data and knowledge of the litterfall rates for southern Canada indicated that leaves yielded from 11 to 45 mg TP m−2 of forested watershed. This amount represents up to 5% of the total export of total phosphorus from urban catchments and has the potential to exacerbate eutrophication of municipal waters if leaf pickup is not promptly enforced.

scholarly journals SWAT Model Adaptability to a Small Mountainous Forested Watershed in Central Romania

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 860
Author(s):  
Nicu Constantin Tudose ◽  
Mirabela Marin ◽  
Sorin Cheval ◽  
Cezar Ungurean ◽  
Serban Octavian Davidescu ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Hydrological Model ◽  
Assessment Tool ◽  
Swat Model ◽  
Decision Makers ◽  
Forested Watershed ◽  
Sensitive Parameters ◽  
Lower Uncertainty ◽  
Validation Stage ◽  
Water Assessment

This study aims to build and test the adaptability and reliability of the Soil and Water Assessment Tool hydrological model in a small mountain forested watershed. This ungauged watershed covers 184 km2 and supplies 90% of blue water for the Brașov metropolitan area, the second largest metropolitan area of Romania. After building a custom database at the forest management compartment level, the SWAT model was run. Further, using the SWAT-CUP software under the SUFI2 algorithm, we identified the most sensitive parameters required in the calibration and validation stage. Moreover, the sensitivity analysis revealed that the surface runoff is mainly influenced by soil, groundwater and vegetation condition parameters. The calibration was carried out for 2001‒2010, while the 1996‒1999 period was used for model validation. Both procedures have indicated satisfactory performance and a lower uncertainty of model results in replicating river discharge compared with observed discharge. This research demonstrates that the SWAT model can be applied in small ungauged watersheds after an appropriate parameterisation of its databases. Furthermore, this tool is appropriate to support decision-makers in conceiving sustainable watershed management. It also guides prioritising the most suitable measures to increase the river basin resilience and ensure the water demand under climate change.

scholarly journals 14 Challenges and opportunities for formulating low-protein diets for maintaining growth and N-retention of weanling and growing-finishing pigs

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 16-17
Author(s):  
John K Htoo
Keyword(s):  
Energy Content ◽  
Optimal Growth ◽  
Energy Utilization ◽  
Backfat Thickness ◽  
Finishing Pigs ◽  
N Retention ◽  
Insufficient Amount ◽  
Challenges And Opportunities ◽  
Pig Performance ◽  
Crystalline Amino Acids

Abstract For more than two decades, numerous studies have been conducted evaluating the effects of lowering CP level in pig diets. It is now accepted that lowering dietary CP level and adding crystalline amino acids (CAA) improves N utilization and consequently reduces N excretion. Increased availability of CAA such as Lys, Thr, Met, Trp, Val (Ile, Arg and His) allows nutritionists to further reduce dietary CP level while meeting pigs’ AA requirements more closely. However, pig performance was sometimes compromised when the dietary CP level was reduced more than 4 percentage units and adding high inclusion levels of CAA. An increase in backfat thickness was also sometimes reported when feeding finishing pigs with low CP diets. The potential reasons for such inconsistent results are due to the deficiency of the next limiting AA (typically Val and Ile), inaccurate feed mixing and insufficient amount of non-essential AA (NEAA) in the low CP diets. Formulating low CP diets on similar energy content as for the high CP diets on ME basis sometimes led to a greater backfat thickness in finishing pigs which was mainly due to increased energy utilization of pigs fed low CP diets coupled with the excess energy being stored as carcass fat. Based on the results of these experiments, optimal growth performance, carcass quality and N retention of pigs can be maintained when low CP diets are balanced for adequate levels of both essential AA and NEAA on the standardized ileal digestible basis combined with formulating on NE basis. Research suggests that keeping a maximum total Lys:CP ratio of 7.4% could overcome deficiency of NEAA in the low CP diets. Based on published N-balance studies, 1 percent unit dietary CP reduction results on average 9% reduction in N excretion in pigs which is an effective approach to become more sustainable pork production.

Nutritive value of Albizia lebbek supplements for growing sheep

1992 ◽  
Vol 32 (3) ◽  
pp. 273 ◽  
Author(s):  
i Dwatmadj ◽  
E Teleni ◽  
AR Bird ◽  
JB Lowry
Keyword(s):  
Plasma Glucose ◽  
Nutritive Value ◽  
Environmental Temperature ◽  
Daily Maximum ◽  
Albizia Lebbeck ◽  
N Retention ◽  
Grass Hay ◽  
Ad Libitum ◽  
Dietary Treatments ◽  
Albizia Lebbek

This study was undertaken to evaluate the effect of supplements of siris (Albizia lebbeck) flowers and leaves on Merino wethers fed Mitchell grass hay (Astrebla spp.). Three groups, each of 6 sheep, were fed the following diets: hammermilled Mitchell grass hay ad libitum (M); M + 181 g DM/day of siris flowers (MF), and M + 216 g DM/day of siris leaves (ML). The experiment, conducted over 17 days, measured feed intake and digestibility, nitrogen (N) retention, and plasma glucose and urea concentrations. The total DM intakes by MF and ML sheep were significantly (P<0.01) higher than those in M sheep. As a result of the supplement of siris flowers, the digestibility of the MF diet was highest (P<0.01). Sheep fed the M diet showed negative N retention, while MF and ML sheep showed positive N retention. The increased (P<0.01) N retention in the MF and ML sheep was associated with increased (P<0.01) urinary N excretion. The improved nutritional state of MF and ML sheep was associated with increases in plasma glucose and urea concentrations. Environmental temperature, which reached a mean daily maximum of 31.3�C, did not interact with the dietary treatments.

171 Effects of Dietary Valine, Isoleucine, and Tryptophan Supplementations to Diets Containing Excess Leucine on Nitrogen Balance of Growing Pigs

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 61-61
Author(s):  
Woongbi Bi Kwon ◽  
Jose A Soto ◽  
Hans H Stein
Keyword(s):  
Body Weight ◽  
Crude Protein ◽  
Random Effect ◽  
Basal Diet ◽  
Growing Pigs ◽  
Negative Effects ◽  
Initial Body Weight ◽  
N Retention ◽  
Biological Value ◽  
Main Effects

Abstract An experiment was conducted to test the hypothesis that increasing concentrations of dietary Val, Ile, or Trp alone or in combination will alleviate negative effects of excess dietary Leu on N balance of growing pigs. Seventy-two barrows (initial body weight: 33.9 ± 2.6 kg) were housed in metabolism crates and randomly assigned to 1 of 8 diets and 3 blocks with 3 pigs per diet in each block in a 12-d experiment. Treatments were arranged in a 2 × 2 × 2 factorial with the main effects of L-Val (0 or 0.1%), L-Ile (0 or 0.1%), and L-Trp (0 or 0.05%) that were added to a basal diet containing corn and a high-protein corn product (48% crude protein; 5.9% Leu). The basal diet contained 1.00 % standardized ileal digestible (SID) Lys and 171% SID Leu:Lys. Data were analyzed using the PROC MIXED of SAS with concentrations of Val, Ile, and Trp, and all interactions as main effects and replicate as a random effect. No 3-way interactions were observed (Table 1). Results indicated that fecal N output increased if Ile was added to diets without added Val, but that was not the case if Val was added (interaction, P &lt; 0.05). Addition of Ile to diets reduced N retention, but N retention increased with Trp addition to diets without Val addition, but not if Trp was added to diets with added Val (interaction, P &lt; 0.05). The biological value of protein increased if Trp was added to diets without addition of Ile, but if Ile was added, Trp addition did not increase the biological value of protein (interaction, P &lt; 0.05). In conclusion, adding Ile to a diet with excess Leu reduced N retention, but if Trp was added alone or in combination with Ile or Val, N retention increased.

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