Ammonia Volatilization from some Forest Floor Materials Following Urea Fertilization

1975 ◽  
Vol 5 (2) ◽  
pp. 210-216 ◽  
Author(s):  
M. K. Mahendrappa
Keyword(s):  
Concentration Gradient ◽  
Forest Floor ◽  
Ammonia Volatilization ◽  
Experimental Period ◽  
Hardwood Forest ◽  
Forest Stands ◽  
Urea Nitrogen ◽  
Organic Layers ◽  
Ph Values ◽  
Urea Fertilization

Ammonia volatilization from urea-treated organic layers of four softwood and three hardwood forest stands was investigated under laboratory conditions. All samples were treated with urea at rates equivalent to 168, 336, and 500 kg N per hectare. In addition, samples from a jack pine (Pinusbanksiana) stand were treated with urea at rates equivalent to 1100 and 1680 kg N per hectare (1 ha = 104 m2). At the end of a 7-day volatilization period the pH values of L and F + H layers were determined.In both softwood and hardwood samples, the proportions of added N volatilized as ammonia were larger when higher dosages of urea were applied. It is suggested that the rate of ammonia volatilization is determined by the concentration gradient of urea in solution around the sites where the enzyme urease hydrolyses urea. Less ammonia was evolved from hardwood than from softwood organic layers. Ammonia volatilization from softwood and hardwood organic layers treated with 336 kg N per hectare in urea was 0.41 to 3.75 and 0.16 to 1.76% of the added N, respectively. At the end of the experimental period the pH values of the L layers were generally higher than those of the F + H layers. The organic layers from the hardwood stands showed a smaller shift in pH than those from the softwood stands treated with the same levels of urea nitrogen.

scholarly journals The role of pH on the survival of rumen protozoa in steers

2010 ◽  
Vol 39 (10) ◽  
pp. 2262-2267 ◽  
Author(s):  
Raul Franzolin ◽  
Burk A. Dehority
Keyword(s):  
Experimental Period ◽  
Adaptation Period ◽  
Individual Animal ◽  
Effect Of Ph ◽  
Ph Values ◽  
Rumen Protozoa ◽  
Rumen Ph ◽  
Sampling Times ◽  
Ciliate Protozoa

In order to study the effect of pH on defaunation in the rumen, four rumen fistulated steers were fed a basal roughage diet for a 4-week adaptation period followed by 17 weeks of feeding with three diets and two feeding levels of high concentrate diet. Rumen outflow fluid rate was evaluated in both ration levels. Rumen protozoa population was monitored weekly and when animals became defaunated, protozoa were reinoculated with rumen contents from one of the faunated steers. At every two weeks, during all the experimental period, rumen pH was measured in all animals at 0, 4, 8 and 12 h after feeding. It was observed an individual animal influence on the establishment and maintenance of the rumen ciliate protozoa population. In all sampling times, mean rumen pH values were higher in faunated steers than in the defaunated ones. No differences were observed in rumen outflow fluid rates between the two ration levels. Extended periods of low rumen pH are probably more detrimental to the survival of ciliate protozoa in the rumen than other factors.

Distillation in a boreal mossy forest floor

2003 ◽  
Vol 33 (4) ◽  
pp. 663-671 ◽  
Author(s):  
T J Carleton ◽  
K M.M Dunham
Keyword(s):  
Boreal Forests ◽  
Forest Floor ◽  
Growing Season ◽  
Mass Gain ◽  
Dew Point ◽  
Organic Layers ◽  
Dry Down ◽  
Microclimate Monitoring ◽  
Capillary Wicking

The feathermoss-dominated floor of coniferous boreal forests can experience midsummer drought. From ecophysiological studies, based on single shoots, it is unclear how the live moss carpet can survive such stress. External capillary wicking from the lowest, moist organic layers is one possibility. Another is evaporation from the same source followed by condensation on the upper, live moss shoots (distillation). A laboratory wicking experiment showed that, under ideal conditions, much of the organic forest floor profile can be supplied with moisture by capillarity from below. However, the uppermost live moss shoots could not be hydrated by this mechanism. In contrast, a gravimetric field experiment indicated nocturnal mass gain by turves of live moss shoots, placed in situ on the forest floor, during dry-down conditions. For turf treatments with an underlying vapour barrier, no such mass gain was evident. Turf treatments with a vapour barrier on top were little different from controls. It is concluded that nocturnal distillation occurs during all summer dry-downs and that this is likely to ensure moss shoot survival during diurnal periods of drought stress. Limited microclimate monitoring indicated that nocturnal cooling at the forest floor surface was sufficient to bring the moss shoot surfaces to the dew point and to reverse the daytime temperature gradient through the organic forest floor profile. This appears to be most noticeable late in the growing season when the lowermost organic layers have progressively warmed throughout the summer.

Problems in the use of microplots for assessing the fate of urea applied to flooded rice

1988 ◽  
Vol 39 (3) ◽  
pp. 351 ◽  
Author(s):  
ACF Trevitt ◽  
JR Freney ◽  
JR Simpson ◽  
WA Muirhead
Keyword(s):  
Solar Radiation ◽  
Preliminary Analysis ◽  
Ammonia Volatilization ◽  
Urea Hydrolysis ◽  
Incident Solar Radiation ◽  
Size And Shape ◽  
Flooded Rice ◽  
Ph Values ◽  
Plot Size ◽  
Heat Penetration

The effects of differences in size of microplot and type of enclosure on the floodwater parameters determining ammonia volatilization were studied. The results show that the use of enclosures can retard urea hydrolysis, suppress the maximum daytime pH values (an effect which is cumulative over a number of days), and significantly reduce the potential for ammonia volatilization. These effects are the consequence of lowered light (and heat) penetration in the enclosed area due to shading of the floodwater by the enclosure walls. The magnitude of these effects varies with plot size and shape, and the material used for construction of the plot wall. A preliminary analysis suggests that, if errors due to shading are acceptable when 90% or more of the incident solar radiation always penetrates to the enclosed floodwater, then square plots with opaque walls must be at least 1.2 m along a side and cylindrical plots must be at least 1.2 m in diameter when wall height is 0.1 m above the floodwater.

Ammonia volatilization potential: Prediction of urinary urea nitrogen output in lactating dairy cows

2005 ◽  
Vol 111 (1-4) ◽  
pp. 261-269 ◽  
Author(s):  
S.A. Burgos ◽  
P.H. Robinson ◽  
J.G. Fadel ◽  
E.J. DePeters
Keyword(s):  
Dairy Cows ◽  
Ammonia Volatilization ◽  
Urea Nitrogen ◽  
Lactating Dairy Cows

scholarly journals Amino acid transport by resealed ghosts from pigeon erythrocytes

1982 ◽  
Vol 202 (3) ◽  
pp. 613-621
Author(s):  
K P Wheeler
Keyword(s):  
Amino Acids ◽  
Concentration Gradient ◽  
Acid Transport ◽  
Ph Values ◽  
Intracellular Amino Acids ◽  
Net Flux ◽  
High Concentrations ◽  
Dependent Transport ◽  
Resealed Ghosts ◽  
Net Fluxes

Resealed ghosts from pigeon erythrocytes were shown to haemolyse during incubation in isotonic media with pH values greater than about 7 and high concentrations of Na+ inside the ghosts seemed to enhance this effect. At lower pH values the ghosts were stable but still highly permeable to Na+ and K+, and moderately permeable to sucrose. Under the latter conditions the ghosts transported amino acids in a way qualitatively but not quantitatively similar to intact erythrocytes. The Na+-dependent transport of serine and alanine by the ghosts consisted essentially of an exchange of extracellular for intracellular amino acids, with no significant net flux. In contrast, net fluxes of glycine in the direction of the Na+-concentration gradient across the ghost membrane were demonstrated. However, under one condition a small net influx of glycine occurred against the prevailing Na+-concentration gradient. Unlike Na+-dependent glycine uptake, the uptake of six other amino acids by intact pigeon erythrocytes was not influenced by the nature of the anion present. The significance of these findings in relation to previous work on the Na+-gradient hypothesis of membrane transport is discussed.

NITROGEN TRANSLOCATION IN AN ORTHIC FERRO-HUMIC PODZOL AFTER UREA FERTILIZATION

1989 ◽  
Vol 69 (2) ◽  
pp. 437-440 ◽  
Author(s):  
D. E. SWIFT ◽  
H. H. KRAUSE
Keyword(s):  
Nutrient Cycling ◽  
Forest Floor ◽  
C:N Ratio ◽  
High Rate ◽  
Fertilizer N ◽  
Forest Fertilization ◽  
Total N ◽  
Indigenous Forest ◽  
Urea Fertilization ◽  
N Status

Sampling of soil 9 yr after a high-rate urea application showed a significant increase in total N content and a decrease of the C:N ratio in the Bhf horizon. This change corresponded to a gain of 368 kg of N ha−1 in the 3-cm thick, sampled portion of this horizon. The changes in N status were accompanied by a general darkening of the soil. It is assumed that both fertilizer N and indigenous forest floor N were translocated to the B Horizon after the treatment. Key words: Forest fertilization, nitrogen, nutrient cycling, urea

scholarly journals Short-Term Temperature Response in Forest Floor and Soil to Ice Storm Disturbance in a Northern Hardwood Forest

2004 ◽  
Vol 21 (4) ◽  
pp. 209-219 ◽  
Author(s):  
Gene E. Likens ◽  
Brian K. Dresser ◽  
Donald C. Buso
Keyword(s):  
Forest Floor ◽  
Reference Site ◽  
Hardwood Forest ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Northern Hardwood Forest ◽  
Ice Storm ◽  
Reference Sites ◽  
Northern Hardwood ◽  
Open Site

Abstract Significant changes in the temperature of forest floor and soil of the Hubbard Brook Experimental Forest occurred as a result of canopy damage caused by a major ice storm in Jan. 1998. The summertime patterns among open, brush-pile, and reference sites were clear and repeatable: (1) air temperatures at all sites peaked at about the same time each day although the average open-site values were 1 to 4°C higher; (2) the pattern at 2- and 15-cm [0.8- and 5.9-in.] depths was similar to air; (3) the open value was 5 to 9 and 6 to 10°C higher than that in the reference site and brush-pile sites, respectively; (4) there was a lag of ∼0.3 hours for daily peak temperatures between the air and 2-cm depth, and ∼3.3 hours between the daily maximum temperature at 2- and 15-cm depth for the open sites; (5) the open site temperature at both 2- and 15-cm depth was ∼2°C higher than reference and brush-pile temperatures (average daily temperature for the brush-pile site rose to be roughly equal to that in the open site in Aug. 1999 and Aug. 2000, while the reference site remained about 2°C lower); (6) small, but not statistically significant, changes were observed at the 50-cm [19.7-in.] depth where the open site was ∼1°C higher than the brush-pile or reference sites; and (7) regrowth of vegetation in the canopy gaps during the first 3 years reduced forest floor temperatures to or below the temperature at the 2-cm depth in the reference site. These results have potential ecological importance to the northern hardwood forest ecosystem. North. J. Appl. For. 21(4):209 –219.

NUTRIENT DISTRIBUTION IN FOREST SOIL LEACHATES AFTER THINNING AND FERTILIZING DOUGLAS-FIR FOREST

1982 ◽  
Vol 62 (1) ◽  
pp. 197-208 ◽  
Author(s):  
P. C. PANG ◽  
K. McCULLOUGH
Keyword(s):  
Nitrogen Fertilization ◽  
Forest Floor ◽  
Unit Area ◽  
Nitrate Concentration ◽  
Nutrient Distribution ◽  
Plate Method ◽  
Area Basis ◽  
Forest Floor Leachates ◽  
Urea Fertilization ◽  
Nitrate Fertilization

The nutrients NH4+, NO3−, Ca2+, Mg2+ and K+ in leachates from immediately below the forest floor and from the mineral horizons at 10- and 30-cm depths were monitored with tension lysimeter plates held at 10 ± 1.0 kPa. Experimental plot treatments were thinning, fertilizing with nitrogenous fertilizers (448 kg N∙ha−1), and both. Concentrations (mg∙L−1) of these nutrients in the forest floor leachates increased immediately following nitrogen fertilization, but returned to near those of untreated levels about 5–10 mo later. Concentrations fluctuated at 10- and 30-cm depths in the mineral horizons. With urea fertilization, the increases in concentrations of nutrients were primarily associated with the forest floor. Nitrate concentration of 200 mg N∙L−1 in the forest floor leachate 5 mo after urea fertilization compared to 0.1–0.5 mg N∙L−1 of the untreated, indicated that nitrification had taken place. With ammonium nitrate fertilization, substantially higher concentrations of NO3−, Ca2+, Mg2+, and K+ were detected at 10- and 30-cm depths compared with urea fertilization. Thinning, when combined with urea fertilization, enhanced the movement of nutrients to greater depth in the soil profile. On a unit area basis (kg∙ha−1) the leaching of nutrients from soil horizons could be overestimated by the tension lysimeter plate method, as these plates do not only draw soil water from directly above.

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