Litter production in Pinusbanksiana dominated stands in northern Alberta

1986 ◽  
Vol 16 (4) ◽  
pp. 772-777 ◽  
Author(s):  
James W. Fyles ◽  
George H. La Roi ◽  
Robert A. Ellis
Keyword(s):  
Oil Sands ◽  
Physiological State ◽  
Basal Area ◽  
Early Summer ◽  
Litter Production ◽  
Litter Fall ◽  
Production Rates ◽  
Daily Production ◽  
Male Cone ◽  
Control Factors

Tree and shrub litter production was measured over 2 years in 12 jack pine (Pinusbanksiana Lamb.) and 2 white spruce (Piceaglauca (Moench) Voss) dominated stands located in the Hondo – Slave Lake and Athabasca Oil Sands areas of north central and northeastern Alberta. Annual and daily production rates were calculated for foliage (by species), male cones, and structural material (bark, twigs). Annual litter fall weights were typical of those measured in other boreal regions and were correlated with stand basal area. Seasonal patterns in daily production rates suggested that three classes of control factors were involved in determining litter fall rates within a stand. Random factors, such as weather, and chronic factors, such as insect or disease activity, contolled foliage and structural litter through most of the year. Predictable seasonal factors relating to plant physiological state controlled autumn foliage litter fall in deciduous and most coniferous species and production of male cone litter in early summer.

Seasonal Nutrient Dynamics of Litter in a Subtropical Eucalypt Forest, North Stradbroke Island

1977 ◽  
Vol 25 (1) ◽  
pp. 47
Author(s):  
RW Rogers ◽  
WE Westman
Keyword(s):  
Half Life ◽  
Forest Floor ◽  
Nutrient Dynamics ◽  
Early Summer ◽  
Litter Production ◽  
Litter Fall ◽  
Nutrient Inputs ◽  
Sodium Potassium ◽  
Nutrient Pools ◽  
Eucalypt Forest

The plant components and chemical composition of litter fall and the litter layer in a forest growing on deep, nutrient-poor sands were examined on North Stradbroke Island, south-eastern Queensland. The seasonal distribution of litter fall was examined over a 26-month period. While the total litter fall was greatest during summer months, the dominant tree species differed in their individual patterns of litter fall. Eucalyptus signata showed a single summer peak for leaf fall while E. umbra exhibited one peak in early summer and another in autumn. The possibility is discussed that these and other temporal differences are evolutionary expressions of niche differentiatibn to reduce competition between species in the ecosystem. The total litter fall averaged 640 g m-1 yr-1 and the accumulated forest floor mass totalled 2700 g m-2. Total nutrient pools and nutrient inputs in litter fall are presented. A litter half-life of 2.9 years is estimated, a figure close to the half-life of most of the nutrients in the litter. Manganese appears to be markedly concentrated in eucalypt leaves before they fall. Only sodium, potassium, copper and chloride appear to be leached easily from leaves slashed from trees and left on the forest floor. Patterns of litter production and decay in this subtropical forest fit within trends extrapolated from temperate Eucalyptus-dominated communities studied to date.

Comparative study on litter production and nutrient return to soil in Tarai and Hill Sal (Shorea robusta Gaertn.) forests of eastern Nepal

2018 ◽  
Vol 28 (1) ◽  
pp. 11-19 ◽  
Author(s):  
K. P. Bhattarai ◽  
T. N. Mandal
Keyword(s):  
Comparative Study ◽  
Tree Species ◽  
Winter Season ◽  
Forest Litter ◽  
Tropical Region ◽  
Litter Production ◽  
Species Variation ◽  
Litter Fall ◽  
Nutrient Return ◽  
Sal Forest

Litter production and nutrient return to soil through litter fall is important pathway for the regulation of nutrient cycling and primary production of the forest. Litter fall dynamics is generally influenced by phenology of tree species, seasons and altitude of the forest stand. As most of the information on litter production are from temperate and dry tropical region. A comparative study on litter production and nutrient return were conducted in Terai Sal forest (TSF) and Hill Sal forest (HSF) located in moist tropical region of eastern Nepal. Litter samples were collected from the litter traps (1m × 1m size) placed randomly in the forest. Collection was done at two months interval for one year. Annual litterfall in TSF (8.82 Mg ha-1y-1) was significantly (p < 0.001) higher than in HSF (7.18 Mg ha-1y-1).There was distinct seasonality in litter production. In TSF and HSF, litterfall was maximum in the summer (6.57 Mg ha-1 and 5.05 Mg ha-1, respectively) and minimum in winter season (0.86 Mg ha-1 and 0.72 Mg ha-1, respectively). Amount of nutrient return to forest soil through litter fall (kg ha-1 y-1) was higher in TSF (72.44 N, 6.80 P and 33.23 K) than HSF (54.31 N, 4.84 P and 22.23 K). The difference in litter production between these two forests was influenced by the phenology of dominant tree species, variation in altitude and seasons. Nutrient return through litter fall is a great input of nutrients in soil which is required for production process. Thus, litter constitutes a significant role in forest management.Banko JanakariA Journal of Forestry Information for NepalVol. 28, No. 1, 2018, page: 11-19

scholarly journals Exposure to exogenous estrogens in food: possible impact on human development and health

1999 ◽  
Vol 140 (6) ◽  
pp. 477-485 ◽  
Author(s):  
AM Andersson ◽  
NE Skakkebaek
Keyword(s):  
Human Development ◽  
Steroid Hormones ◽  
Scientific Data ◽  
Animal Tissues ◽  
Production Rates ◽  
Daily Production ◽  
Prepubertal Children ◽  
The Us ◽  
Residue Levels ◽  
Low Levels

There has been increasing concern about the impact of environmental compounds with hormone-like action on human development and reproductive health over the past decades. An alternative but neglected source of hormone action that may be considered in this connection is hormone residues in meat from husbandry animals treated with sex steroid hormones for growth promotion. Treatment of cattle with naturally occurring or synthetic sex hormones may enhance lean muscle growth and improve feed efficiency and is therefore a very cost effective procedure for cattle producers who have used it for decades in some Western countries, including the USA and Canada. The Joint Food and Agricultural Organisation/World Health Organisation (FAO/WHO) expert committee on food additives (JECFA) and the US Food and Drug Administration (FDA) considered, in 1988, that the residues found in meat from treated animals were safe for the consumers. We have re-evaluated the JECFA conclusions regarding the safety of estradiol residues in meat in the light of recent scientific data, with special emphasis on estradiol levels in prepubertal children. These levels are needed for estimates of the normal daily production rates of estradiol in children, who may be particularly sensitive to low levels of estradiol. In our opinion, the conclusions by JECFA concerning the safety of hormone residues in meat seem to be based on uncertain assumptions and inadequate scientific data. Our concerns can be summarized as follows. 1) The data on residue levels in meat were based on studies performed in the 1970's and 1980's using radioimmunoassay (RIA) methods available at the time. The sensitivity of the methods was generally inadequate to measure precisely the low levels found in animal tissues, and considerable variation between different RIA methods for measuring steroids exists. Therefore the reported residue levels may be subject to considerable uncertainty. 2) Only limited information on the levels of the various metabolites of the steroids was given despite the fact that metabolites also may have biological activity. 3) Reliable data on daily production rates of steroid hormones were and are still lacking in healthy prepubertal children. This lack is crucial as previous guidelines regarding acceptable levels of steroid residues in edible animal tissues have been based on very questionable estimates of production rates in children. Thus, even today the US FDA bases its guidelines on the presumably highly overestimated production rates in prepubertal children given in the JECFA 1988 report. 4) The possible biological significance of very low levels of estradiol is neglected. In conclusion, based on our current knowledge possible adverse effects on human health by consumption of meat from hormone-treated animals cannot be excluded.

Early responses of elevated nutrient input on above-ground net primary production of a lower-montane tropical forest in Uganda

2020 ◽  
Author(s):  
Raphael Manu ◽  
Marife D. Corre ◽  
Edzo Veldkamp ◽  
Oliver van Straaten
Keyword(s):  
Primary Production ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Net Primary Production ◽  
Forest Growth ◽  
Nutrient Addition ◽  
Litter Production ◽  
N Addition ◽  
Litter Fall ◽  
Montane Tropical Forest

&lt;p&gt;Nutrient availability in tropical forest ecosystems plays a critical role in sustaining forest growth and productivity. Observational evidence for nutrient limitations on net primary productivity (NPP) in the tropics is rare yet crucial for predicting the impacts of human-induced changes on tropical forests, particularly for underrepresented tropical regions in Africa. In an ecosystem-scale nutrient manipulation experiment, we assessed the response of different components of above-ground net primary production (ANPP) to nutrient addition of nitrogen (N), phosphorus (P), potassium (K) and all possible combinations (NP, NK, PK, and NPK) at rates of 125 kg N ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;, 50 kg P ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt; and 50 kg K ha&lt;sup&gt;-1&lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;We established 32 (8 treatments &amp;#215; 4 replicates) experimental plots of 40 &amp;#215; 40 m&lt;sup&gt;2&lt;/sup&gt; each and measured stem growth of over 15,000 trees with diameter at breast height (dbh) &amp;#8805; 1 cm as well as litter production and above-ground woody biomass production (AWBP), of a lower-montane tropical forest (1100 m a.s.l.) in northwestern Uganda.&lt;/p&gt;&lt;p&gt;After 18 months of nutrient addition, we found that different aspects of ANPP, including litter production and AWBP are controlled by multiple soil nutrients. Specifically, we measured higher total fine-litter production in the N (13.6 &amp;#177; 1.4 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) and K (13.3 &amp;#177; 1.8 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) addition plots than the control (11.1 &amp;#177; 0.6 Mg ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;) plots. Both reproductive litter (flowers and fruits; 10% of total fine-litter fall) and leaf litter (62% of total fine-litter fall) significantly increased with K addition. In general, fine-litter production in our plots is higher than what has been reported so far for lower-montane tropical forests. Increased AWBP is associated with N addition plots. The response of trees to nutrient addition however, varied with tree sizes. Trees with dbh between 10 &amp;#8211; 30 cm increased significantly in AWBP under PK addition. There was no effect of nutrient addition associated with either smaller (1 &amp;#8211; 10 cm dbh) or larger trees (dbh &gt; 30 cm). The medium-sized trees which may have experienced resource competition but have now transitioned into the canopy layer (exposed to sunlight) are able to use additional nutrient for active growth. In contrast, bigger trees may allocate extra nutrient for reproduction and leaf-vitality, while smaller trees remain shaded, co-limited by sunlight and therefore unable to utilize increased available nutrients for stem diameter growth. ANPP increased by 39% with N addition and marginally by 23% with K additions relative to the control. In conclusion, our experiment provides evidence of N and potentially K limitation of ANPP in this lower-montane tropical forest, and highlights that, in a highly diverse ecosystem different components of ANPP may be regulated by multiple nutrients.&amp;#160;&lt;/p&gt;

Effect of sod-seeding oats or barley, renovation, herbicide and broadcast nitrogen fertilizer on forage production of dryland lucerne

1976 ◽  
Vol 16 (79) ◽  
pp. 240
Author(s):  
RA Spurway ◽  
AC Gleeson
Keyword(s):  
Avena Sativa ◽  
New South ◽  
Basal Area ◽  
Early Summer ◽  
N Fertilizer ◽  
Total Production ◽  
Forage Production ◽  
South Wales ◽  
Cereal Species ◽  
Forage Yields

In four experiments at Tamworth, New South Wales in 1973 and 1974, forage production from dryland lucerne pastures (Medicago sativa cv. Hunter River) was evaluated following sod-seeding with oats (Avena sativa cv. Cooba and Coolabah) or barley (Hordeum vulgare cv. Beecher) in autumn, treatment with diquat and topdressing with 50 or 100 kg nitrogen (N) ha-1. Comparisons were also made with production from lucerne alone and with crops of oats and barley sown on conventional seedbeds. Total forage production from lucerne was approximately doubled (P < 0.05) in winter by sod-seeding with oats or barley. Differences between the cereal species were small and both responded significantly to N fertilizer. Herbicide did not significantly affect forage production. The sod-sown cereal reduced (P < 0.05) lucerne growth in winter, but in early summer when cereal growth had ceased neither the growth of lucerne nor its basal area differed significantly from that of unseeded lucerne pastures. In most experiments renovation or broadcasting N fertilizer gave small, but significant increases in lucerne production. Forage yields from conventionally sown oats and barley were 2 to 3 times larger (P < 0.05) than the total production of sod-sown plots. Per cent N in sod-sown oats or barley was almost always less (P < 0.05) than in conventional sowings. Per cent N in both cereals declined significantly between winter and spring

scholarly journals Measurement of broiler litter production rates and nutrient content using recycled litter

2006 ◽  
Vol 85 (3) ◽  
pp. 398-403 ◽  
Author(s):  
C.D. Coufal ◽  
C. Chavez ◽  
P.R. Niemeyer ◽  
J.B. Carey
Keyword(s):  
Nutrient Content ◽  
Litter Production ◽  
Production Rates ◽  
Broiler Litter

scholarly journals Physiological state of plants and quality of plum fruits grafted on the rootstocks of various strength of growth depending on the plant nutrition mode

10.5219/1469 ◽  
2020 ◽  
Vol 14 ◽  
pp. 1075-1087
Author(s):  
Valentina Popova ◽  
Natalya Sergeyeva ◽  
Olesya Yaroshenko ◽  
Anna Kuznetsova
Keyword(s):  
Amino Acids ◽  
Abiotic Factors ◽  
Physiological State ◽  
Mineral Fertilizer ◽  
Calcium Content ◽  
Fruit Weight ◽  
Early Summer ◽  
Nitrogen And Phosphorus ◽  
Fertilizer System

The influence of the nutrition mode on the physiological state, productivity, and quality of the plum harvest of the Stanley variety on the rootstocks of various strengths of growth was investigated. The fertilizer system included the intra-soil application of the complex organic-mineral fertilizer based on peat and non-root dressings combined with the “Novosil” phytoregulator. The nutrition mode of plum plants was studied by the method of gross content diagnostics of elements in leaves and fruits. The significant increase of nitrogen and phosphorus content, number of functional pigments, free amino acids, and protein synthesis, especially in plants on the rootstock Best, was established during the period of the intensive shoot and ovary growth. In the early summer, the increase of calcium content and decrease of secondary metabolite one was found against the background of a decline of growth activity in plum leaves on the dwarf and medium rootstocks. The statistically reliable positive correlation between nitrogen, potassium, calcium and their content in plum fruits on the rootstock VVA 1 (r = 0.68, r = 0.74, r = 0.52) and rootstock Best (r = 0.75, r = 0.84, r = 0.61) was identified against the background of the application of fertilizers during the period of stress influence of abiotic factors in July. The green pigment content was also increased. The decline of protein content in leaves in the trees on the rootstock Best and rootstock PK SK 1 was minimal. At that time maximum losses of shared water were in plants on the rootstock cherry plum seedlings and minimum ones were on the rootstock PK SK 1. In early August the gross content of nitrogen, potassium, and calcium in the leaves of shoots increased with the application of fertilizers. In early September the excess of the sum of amino acids in plum leaves was 26,6-30,8% while the one in plum fruits was 12.5 and 23.5%; 24.2 and 11.5%; 17.3 and 19.6% on the rootstock VVA 1, rootstock Best, rootstock PK SK 1 respectively. The nutrition mode optimization promoted increasing of plant productivity on the rootstock Best and fruit weight on the rootstock VVA 1, rootstock Best, and rootstock PK SK 1.

The hidden, nonexchangeable pool of 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine in man: does it exist?

1989 ◽  
Vol 120 (5) ◽  
pp. 667-671 ◽  
Author(s):  
Jens Faber ◽  
Carsten Kirkegaard ◽  
Bo Jørgensen ◽  
Jørgen Kludt
Keyword(s):  
Production Rate ◽  
Metabolic Pathways ◽  
Bolus Injection ◽  
Fecal Excretion ◽  
Local Production ◽  
Noncompartmental Analysis ◽  
Production Rates ◽  
Oxidative Deamination ◽  
Daily Production ◽  
Derived Data

Abstract. The validity of estimation of the production rates of T3 and rT3 in man based on noncompartmental analysis of blood-derived data has been questioned owing to incomplete exchangeability of T3 and rT3 between plasma and extrathyroidal tissues in which a local production of these iodothyronines takes place. The possible existence of a nonexchangeable or hidden pool of T3 and rT3 would result in an underestimation of the daily production. By contrast, the production rate of T4 can be estimated reliably using noncompartmental analysis. We have studied 16 women with pretreatment severe hypothyroidism on constant levothyroxine therapy. Simultaneous measurements of T4, T3 and rT3 production rates were performed using bolus injection of radiolabelled iodothyronines. The tracers were isolated from plasma using gel separation/antibody extraction, and production rates were calculated by noncompartmental analysis. Mean (± sd) production rate of T4, T3 and rT3 were: 119 ± 43, 40.0 ± 22.0 and 54.9 ± 20.0 nmol · day−1 · (70 kg)−1, respectively. Thus 79.5 ± 7.0% of T4 was deiodinated into T3 and rT3. This leaves 20.5% to other metabolic pathways of T4 and to a possible underestimation of T3 and rT3 production rate. Based on conservative estimates from the literature, the other metabolic pathways of T4 amount: oxidative deamination 1.1%; ether link cleavage 0%; urinary excretion 2.5%; and fecal excretion 14%. Thus, the various metabolic pathways seem to explain 97% of daily produced and degradated T4 in man. Therefore the understimation of T3 and rT3 production rates in man using noncompartmental analysis seems of little if any importance, and existence of a hidden pool of these iodothyronines may be questioned.

Some Morphological and Biochemical Changes in Coho Salmon, Oncorhynchus kisutch, During Parr–Smolt Transformation

1968 ◽  
Vol 25 (11) ◽  
pp. 2403-2418 ◽  
Author(s):  
W. E. Vanstone ◽  
J. R. Markert
Keyword(s):  
Exponential Growth ◽  
Coho Salmon ◽  
Chemical Constituents ◽  
Physiological State ◽  
Early Summer ◽  
Least Square ◽  
Unit Weight ◽  
Late Winter ◽  
Lighting Conditions ◽  
Least Square Fit

Growth rates and changes in some chemical constituents were investigated in laboratory-reared and wild coho salmon in the pre-smolt, smolting, and early post-smolt stages of their life cycles.Laboratory-reared pre-smolts of coho salmon continued to grow during fall and early winter but at an ever diminishing rate. During late winter, spring, and early summer, growth in both length and weight of these fish was exponential with time. In wild coho pre-smolts there was no apparent winter growth but, with the onset of warmer waters and longer day lengths in the spring, growth in both length and weight became exponential with time. Exponential growth continued in wild post-smolts held in seawater pens but at a slower rate than during smolting.It is postulated that the power b in the weight–length formula W = aLb is approximately 3.2 and that during smolting, when the fish are becoming more streamlined, the parameter a decreases from approximately 7.5 to about 6.2.Guanine levels in belly skin, which appeared to be related to lighting conditions and physiological state of the fish rather than to length or weight, increased during smolting to about 6 μg/mm2 skin and remained at these levels.In pre-smolt laboratory-reared fish total lipid increased with increasing growth. With further weight increases during exponential growth, the weight of lipid remained relatively constant and the amount of lipid per unit weight decreased. A decrease in percent lipid did not occur in wild fish.Total moisture, dry material, and nitrogen were linearly related to weight in the size-range investigated, but a sharp inflection in each least-square fit line occurred for moisture and dry material at a fish weight of 15 g and for total nitrogen at 7.5 g. These shifts in composition were related to fish size rather than to age, environment, or physiological state. During exponential growth, moisture, dry material, and nitrogen increased with increasing weight but whereas moisture increased at a slower rate than weight, solids and nitrogen increased more rapidly.

Weight and nutrient content of litter during secondary succession on well-drained uplands of the East Gulf Coastal Plain in Mississippi

1991 ◽  
Vol 21 (6) ◽  
pp. 848-857 ◽  
Author(s):  
L. E. Hlnesley ◽  
L. E. Nelson ◽  
G. L. Switzer
Keyword(s):  
Coastal Plain ◽  
Secondary Succession ◽  
Basal Area ◽  
Nutrient Content ◽  
Forest Litter ◽  
Nutrient Concentrations ◽  
Litter Production ◽  
Gulf Coastal Plain ◽  
Pine Stands ◽  
Mature Stands

Production of forest litter was examined over 2 years in a chronosequence of stands representing four stages of secondary succession on well-drained uplands of the East Gulf Coastal Plain in Mississippi. Average age for these stands was from 22 to 207 years. Early succession was dominated by dense pine stands, whereas mature forests were about 75% hardwood. Litter mass was greatest early in succession, when productivity was highest, and decreased as stands matured. Foliage was approximately 70% of the litter throughout succession. The remaining 30% was mostly large woody material in young pine stands, but a heavy reproductive component in mature stands. Stands dominated by pines produced litter throughout the year, whereas hardwood stands were more cyclic. In young pine stands, the N and P content of litter was already 80–90% of the maximum value realized later in succession, whereas Ca and Mg accumulated in proportion to hardwood basal area. Nutrient concentrations in litter varied by season, component, and stage of succession. Foliar litter that fell in the spring and summer had higher N and P concentrations than that that fell in the fall. Seasonal patterns of litter production, as well as variations in nutrient concentration, made the monthly variation of nutrients returned to the forest floor less extreme than that of foliar litter fall weights.

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