Decomposition and nutrient release in Douglas-fir needle litter in relation to stand development

1979 ◽  
Vol 9 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Robert L. Edmonds
Keyword(s):  
Weight Loss ◽  
Nutrient Release ◽  
Nutrient Content ◽  
Douglas Fir ◽  
Strongly Correlated ◽  
Litter Bags ◽  
Net Productivity ◽  
Needle Litter ◽  
Weight Loss Data ◽  
Moisture Conditions

Decomposition rates and changes in the nutrient content of needle litter were examined in an age sequence of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Washington. The stands at the initiation of the study were 11, 24, 44, 75, and 97 years old. Nylon litter bags (1 mm mesh) containing needles from the 44-year-old stand were placed in the stands in February 1975. Bags were collected after 3, 6, 12, and 24 months, weighed, and analyzed for N, P, K, Ca, Mg, Mn, and lignin. Decomposition constants (k values) were determined. After 2 years, maximum decomposition rate occurred in the 24-year-old stand, where temperature and moisture conditions were most favorable. Low litter moisture tended to inhibit decomposition in summer. Values of k determined from 1-year weight loss data and percent needle lignin after 2 years were significantly different between stands. Values of k determined from weight loss were greater than those determined from litter fall weight: forest floor weight ratios. Loss of elements from litter bags after 2 years was in the following sequence in all stands, N < Mn < Ca < Mg < P < K. Annual stand net productivity was strongly correlated to N + K loss from litter bags (r = 0.96).

Litter decomposition and nutrient release in Douglas-fir, red alder, western hemlock, and Pacific silver fir ecosystems in western Washington

1980 ◽  
Vol 10 (3) ◽  
pp. 327-337 ◽  
Author(s):  
Robert L. Edmonds
Keyword(s):  
Weight Loss ◽  
Nutrient Release ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Silver Fir ◽  
Rapid Weight Loss ◽  
Red Alder ◽  
Cellulose Decomposition ◽  
The Pacific ◽  
Western Washington

Decomposition rates and changes in the nutrient content of needle and leaf litter were examined in Douglas-fir (Pseudotsugamenziesii Mirb. Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forbes), and red alder (Alnusrubra Bong.) ecosystems in western Washington, U.S.A. Nylon litterbags (1-mm mesh) were placed in the stands in November and December 1974. Bags were collected after 3, 6, 12, and 24 months and weighed, except in the Pacific silver fir stand when bags were collected after 6, 9, 14, and 24 months. Litter was analyzed for C, N, P, K, Ca, Mg, Mn, lignin, and cellulose. Decomposition constants (k values) were determined. Fastest decomposition after 2 years occurred in red alder leaves, followed by Douglas-fir, western hemlock, and Pacific silver fir needles. There were significant differences in weight loss among species after 1 year, but no significant differences were evident after 2 years. Red alder leaves showed rapid weight loss in the 1st year but decomposed little in the 2nd year. Decomposition constants were highly positively correlated with minimum air temperatures and negatively correlated with C:N ratios. Low litter moisture tended to reduce decomposition in summer, particularly in the Pacific silver fir stand. Decomposition proceeded under snow in this ecosystem. The pattern of loss of elements from litterbags after 2 years varied from ecosystem to ecosystem, particularly for N. The following element mobility series resulted for the four ecosystems: red alder (K > Mg > Ca > P > N > Mn), Douglas-fir (K > P > Ca > Mg > Mn > N), western hemlock (K > Ca > Mg > N > Mn > P), and Pacific silver fir (K > Mg > Ca > Mn > P > N).

Weight loss of litter and cellulose bags in a thinned white spruce forest in interior Alaska

1978 ◽  
Vol 8 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Harald Piene ◽  
Keith Van Cleve
Keyword(s):  
Weight Loss ◽  
Organic Matter ◽  
Forest Floor ◽  
Mineral Soil ◽  
White Spruce ◽  
Litter Bags ◽  
Soil Layers ◽  
Interior Alaska ◽  
Decomposition Processes ◽  
Moisture Conditions

Thinning in a white spruce, Piceaglanca (Moench) Voss, forest in interior Alaska stimulated organic matter decomposition in the forest floor as indicated by weight loss of litter and cellulose bags. The general higher weight loss in the most heavily thinned plot is attributed to observed higher average seasonal temperatures. Cellulose bags placed in the boundary between the fermentation–humus and the humus–mineral soil layers of the forest floor showed a significantly higher weight loss than those placed on top of the litter layer. This was attributed to more favorable moisture conditions and a more direct contact with the decomposing microbial populations in the fermentation–humus and humus–mineral soil layers.Regardless of thinning treatment, elements were grouped according to their rate of release from decomposing organic matter as follows: K > Mg > C ≈ P ≈ N ≈ Ca, where potassium is lease resistant. Since relatively small differences in weight loss of litter bags were observed between the treatments, similar studies should extend over a longer period in order to obtain a better understanding of the decomposition processes.

scholarly journals How nutrient rich are decaying cocoa pod husks? The kinetics of nutrient leaching

2021 ◽  
Author(s):  
D.-G. J. M. Hougni ◽  
A. G. T. Schut ◽  
L. S. Woittiez ◽  
B. Vanlauwe ◽  
K. E. Giller
Keyword(s):  
Nutrient Release ◽  
Nutrient Content ◽  
Nutrient Leaching ◽  
Intense Rainfall ◽  
Decomposition Rates ◽  
Rainfall Events ◽  
Rainfall Frequency ◽  
Water Saturated ◽  
Kinetics Of ◽  
Cocoa Pod Husks

Abstract Aim Recycling of cocoa pod husks has potential to contribute to mineral nutrition of cocoa. Yet little is known of the nutrient content and nutrient release patterns from the husks. The potassium (K) rich husks are usually left in heaps in cocoa plantations in Africa. We aimed to understand and quantify release patterns of K and other nutrients from husks under varying rainfall regimes and assessed the effects of partial decomposition and inundation on nutrient leaching rates. Methods We incubated chunks of cocoa pod husks to assess decomposition rates and we measured nutrient leaching rates from two sets of husk chunks: one set was placed in tubes that were submitted to simulated scheduled rainfall events while the second set was continuously inundated in beakers. Results Decomposition of husks followed a second-order exponential curve (k: 0.09 day−1; ageing constant: 0.43). Nutrient losses recorded within 25 days were larger and more variable for K (33%) than for other macronutrients released in this order: Mg > Ca ≈ P > N (less than 15%). Potassium leaching was mainly driven by rainfall frequency (P < 0.05) and reinforced by intense rainfall, especially at lower frequency. Under water-saturated conditions, 11% of K was leached out within 48 h from fresh husks compared with 92% from partially decayed husks. Conclusion Some initial decomposition of cocoa pod husks is required to expose K to intense leaching. As decomposition progresses, abundant K losses are to be expected under frequent and/or intense rainfall events.

scholarly journals Brushite cement containing gelatin: evaluation of mechanical strength and in vitro degradation

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 261-266 ◽  
Author(s):  
L. P. Silva ◽  
M. D. P. Ribeiro ◽  
E. S. Trichês ◽  
M. Motisuke
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Compressive Strength ◽  
Solid Phase ◽  
Setting Time ◽  
Biological Properties ◽  
Solubility In Water ◽  
Ringer’S Solution ◽  
Weight Loss Data

Abstract Calcium phosphate cements (CPCs) are potential materials for repairing bone defects, mainly due to their excellent biocompatibility and osteoconductivity. Nevertheless, their low mechanical properties limit their usage in clinical applications. The gelatin addition may improve the mechanical and biological properties of CPCs, but their solubility in water may increase the porosity of the cement during degradation. Thus, the aim of this work was to investigate the influence of gelatin on the setting time, compressive strength and degradation rate of a brushite cement. CPCs were prepared with the addition of 0, 5, 10 and 20 wt% of gelatin powder in the solid phase of the cement. The results indicated that the setting time increased with gelatin. Furthermore, cement with 20 wt% of gelatin had an initial compressive strength of 14.1±1.8 MPa while cement without gelatin had 4.5±1.2 MPa. The weight loss, morphology and compressive strength were evaluated after degradation in Ringer’s solution. According to the weight loss data, gelatin was eliminated of samples during degradation. It was concluded that the presence of gelatin improved CPCs mechanical properties; however, as degradation in Ringer’s solution evolved, cement compressive strength decreased due to gelatin dissolution and, consequently, an increase in sample porosity.

Biomass and nutrient content of Douglas-fir logs and other detrital pools in an old-growth forest, Oregon, U.S.A.

1992 ◽  
Vol 22 (10) ◽  
pp. 1536-1546 ◽  
Author(s):  
Joseph E. Means ◽  
Paul C. MacMillan ◽  
Kermit Cromack Jr.
Keyword(s):  
Forest Floor ◽  
Soluble Fraction ◽  
Close Association ◽  
C:N Ratio ◽  
Mineral Soil ◽  
Nutrient Content ◽  
Douglas Fir ◽  
Area Index ◽  
Old Growth Forest ◽  
N Release

Logs, forest floor, and mineral soil were sampled and measured, and snags were measured, in a 450-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand on the H.J. Andrews Experimental Forest, Oregon. Logs, some still identifiable after 300 years on the forest floor, contained large amounts of organic matter (222 Mg/ha), C (100 Mg/ha), water (559–10 700 L/log), N (183 kg/ha), and Ca (141 kg/ha), and smaller amounts of P (5.5 kg/ha), K (22 kg/ha), Mg (14 kg/ha), and Na (3.7 kg/ha). Logs and snags covered about 17% of the forest floor and had an all-sided area index of 0.69 m2/m2. Through mineralization, C, N, and K were lost through time; Ca and Mg increased; and P and Na increased then decreased, showing no net change. Also through mineralization, cellulose and hot acid detergent soluble fraction decreased more rapidly than lignin. Lignin was apparently not lost until the later stages of decay, when N was also lost in significant amounts. This parallels the shift from initial dominance by white rots that degraded cellulose and lignin to later dominance by brown rots that preferentially degraded cellulose. Lignin and cellulose were eventually lost at more similar rates in later decay stages. This may have been due in part to a close association between the remaining cellulose and lignin in later decay stages. Lignin was a better predictor of the onset of N release than was the C:N ratio.

Comments on diffusion coefficients from weight loss data

1975 ◽  
Vol 9 (6) ◽  
pp. 709-711 ◽  
Author(s):  
P. J. Shires ◽  
A. L. Hines ◽  
T. Okabe
Keyword(s):  
Weight Loss ◽  
Diffusion Coefficients ◽  
Weight Loss Data ◽  
Loss Data

The Effect of Various Lead Species on the Leaching Behavior of Borosilicate Waste Glass

1984 ◽  
Vol 44 ◽  
Author(s):  
Richard L. lehman ◽  
Frank A. Kuchinski
Keyword(s):  
Weight Loss ◽  
Glass Surface ◽  
Lead Concentration ◽  
Pure Water ◽  
Waste Glass ◽  
Leaching Behavior ◽  
Weight Loss Data ◽  
Nuclear Waste Glass ◽  
Lead Metal ◽  
Lead Species

AbstractA borosilicate nuclear waste glass was static leached in pure water, silicate water, and brine solution. Three different forms of lead were included in specified corrosion cells to assess the extent to which various lead species alter the leaching behavior of the glass. Weight loss data indicated that Pbm and Pb0 greatly reduce the weight loss of glass when leached in pure water, and similar effects were noted in silicate and brine. Si concentrations, which were substantial in the glass-alone leachate, were reduced to below detection limits in all pure water cells containing a lead form. Lead concentration levels in the leachate were controlled by lead form solubility and appeared to be a significant factor in influencing apparent leaching behavior. Surface analysis revealed surface crystals, which probably formed when soluble lead in the leachate reacted with dissolved or activated silica at the glass surface. The net effect was to reduce the release of some glass constituents to the leachate, although it was not clear whether the actual corrosion of the glass surface was reduced. Significantly different corrosion inhibiting effects were noted among lead metal and two forms of lead oxide.

A rapid method for detecting cold injury in conifer seedling root systems

1990 ◽  
Vol 20 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Gary A. Ritchie
Keyword(s):  
Weight Loss ◽  
Root Systems ◽  
Douglas Fir ◽  
Cold Injury ◽  
Percent Weight Loss ◽  
Seedling Root ◽  
Seedling Roots ◽  
Temperature Exposure ◽  
Low Temperature Exposure ◽  
Conifer Seedling

A method is described for rapidly determining the extent of cold injury to Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedling root systems. It is based upon pressure:volume theory but short-cuts the tedious pressure:volume method. Injured root systems were brought to full hydration, then weighed and placed into a pressure chamber. A pressure of 1.5 MPa was applied for a 5-min period, then the root system was removed from the chamber and reweighed. The percent weight loss was then calculated. Percent weight loss was closely related to degree of low temperature exposure in Douglas-fir seedling roots. Percent weight loss values were near 5 in uninjured controls, whereas freeze-injured seedlings had percent weight loss values of 7 or greater. Percent weight loss values measured on seedlings just before planting were closely correlated with seedling vigor and mortality 3 months following planting in both a field test and a greenhouse pot trial.

Sign in / Sign up

Export Citation Format

Share Document