Percentage Of Total Biomass Research Articles

Pemetaan Potensi Biomassa Permukaan Rawan Terbakar Berbasis Citra Landsat 8 Oli Di Kecamatan Kahayan Hilir Kabupaten Pulang Pisau

Peatland fires in 2015 in Central Kalimantan were biomass fires on peatlands that burned with an area of ​​196,987 hectares and one of them was in Kahayan Hilir District. this research aims to determine the potential distribution of surface biomass and identify the types of vegetation. this research uses Landsat 8 OLI imagery in 2020 as well as land cover classification and calculation of the Vegetation Index (NDVI) which is then combined with an overlay to create a map of the distribution of land cover types based on their density which is then used for field checks and surface biomass calculations using the allometric formula on each type of land cover. Based on the research conducted, there are 8 types of land cover that can be identified and the percentage of total biomass, namely high density forest (1,419,013,40 tons or 62.58%), high density shrubs and shrubs (770,449.68 tons or 33.98%). ), High density settlements (44.169.32 tons or 1.95 %), high density oil palm plantations (21,518.77 tons or 0.95 %), High density open land (8,025.37 tons or 0.35%), plantations medium density palm oil (2,690.09 tons or 0.12%), medium density open land (1,545.81 tons or 0.07%) and low density open land (79.65 tons or 0.004%). The types of tree-level vegetation found in high-density forests are laban (Vitex pinnata), mahang damar (Macaranga triloba), and bungur (Lagerstroemia speciosa), while on understorey grass species rija-rija (Scleria sumatrensis) are found

Integrated Weed Management Strategies in Cover Crop–based, Organic Rotational No-Till Corn and Soybean in the Mid-Atlantic Region

Cover crop–based, organic rotational no-till (CCORNT) corn and soybean systems have been developed in the mid-Atlantic region to build soil health, increase management flexibility, and reduce labor. In this system, a roller-crimped cover crop mulch provides within-season weed suppression in no-till corn and soybean. A cropping system experiment was conducted in Pennsylvania, Maryland, and Delaware to test the cumulative effects of a multitactic weed management approach in a 3-yr hairy vetch/triticale–corn–cereal rye–soybean–winter wheat CCORNT rotation. Treatments included delayed planting dates (early, intermediate, late) and supplemental weed control using high-residue (HR) cultivation in no-till corn and soybean phases. In the no-till corn phase, HR cultivation decreased weed biomass relative to the uncultivated control by 58%, 23%, and 62% in Delaware, Maryland, and Pennsylvania, respectively. In the no-till soybean phase, HR cultivation decreased weed biomass relative to the uncultivated treatment planted in narrow rows (19 to 38 cm) by 20%, 41%, and 78% in Delaware, Maryland, and Pennsylvania, respectively. Common ragweed was more dominant in soybean (39% of total biomass) compared with corn (10% of total biomass), whereas giant foxtail and smooth pigweed were more dominant in corn, comprising 46% and 22% of total biomass, respectively. Common ragweed became less abundant as corn and soybean planting dates were delayed, whereas giant foxtail and smooth pigweed increased as a percentage of total biomass as planting dates were delayed. At the Pennsylvania location, inconsistent termination of cover crops with the roller-crimper resulted in volunteer cover crops in other phases of the rotation. Our results indicate that HR cultivation is necessary to achieve adequate weed control in CCORNT systems. Integration of winter grain or perennial forages into CCORNT systems will also be an important management tactic for truncating weed seedbank population increases.

中国南方3种主要人工林生物量和生产力的动态变化

Forests form the main body of terrestrial ecosystems and play an important role in mitigating global climate change through carbon dioxide sequestration in forest biomass. Biomass and productivity are essential characteristics of forestecosystem structure and function,and knowledge of both are essential for the study of carbon sink function and carbon sequestration. Cunninghamia lanceolata,Pinus massoniana,and Eucalyptus urophylla × Eucalyptus grandis are the primary plantation trees used in southern China,accounting for 90% of the plantation area in ten southern provinces. However,few studies have analyzed the dynamics of forest biomass and productivity of these forest types. Forty-five 20 m × 50 m research plots were established and analyzed using three dominant plantation species( C lanceolata,P. massoniana,E. urophylla ×E. grandis) in southern China with the goal of improving our understanding the vertical structure of each community,the distribution of biomass to the various organs,and gaining a better understanding of forest biomass and productivity of differently aged stands. Each plantation type was studied using five age classes: young,middle-aged,near-mature,mature,and over-mature forest,with three replicates of each. Regression models relating tree biomass to diameter at breast height( DBH 1.3 m) were developed to estimate tree biomass. Other biomass components were sampled in quadrats within the same forty-five research plots: shrubs( three 4 m2quadrats),herbs( three 1 m2quadrats),and litterfall( three 1 m2quadrats). This method was used for estimating biomass,productivity,and biomass allocation rates to various organs in the three main plantations types; we also analyzed the relationships between stand age and biomass productivity to determine the biomass allocation rates to various organs. Results showed that a significant relationship exists between stand biomass and stand productivity of the three main plantation types as they relate to stand age,with a high degree of fitting in growth models. The total biomass of C. lanceolata,P. massoniana,and E. urophylla × E.grandis plantations increased with stand age and the biomass of mature forest was 192.30,191.53,105.77 Mg /ha,respectively. Living biomass made up 95.76%—98.39%,75.01%—99.14%,85.60%—97.61% of these three plantation types,respectively. Most of the biomass of the three main plantation types was concentrated in the tree layer and biomass increased with stand age for all three types. The biomass of other layers accounted for only a small percentage of total biomass,and generally litterfall herb shrub biomass. The trunk biomass occupied the greatest proportion of the tree layer; for C. lanceolata,P. massoniana,and E.urophylla × E. grandis truck biomass made up 54. 89%—75. 97%,49. 93%—83. 10%,and 51. 07%—98. 48% of total biomass,respectively,and trunk biomass increased with stand age. Root biomass made up the second largest percent of tree biomass and the percentages of both branch and leaf biomass were lower than root biomass and decreased with stand age.Shrub branches made up the majority of shrub biomass; both the above-and belowground biomass allocation of herbs did not exhibit an obvious trend or pattern of change. Compared with other forest types,the total biomass of C. lanceolata plantations and P. massoniana plantations were both greater than most and the total biomass of E. urophylla × E. grandis was lower than most,but the level of productivity of all three plantation types was high,or 12.37,8.98,21.10 Mg hm-2a-1,respectively. All three are fast growing forest tree species with higher photosynthetic efficiency and potential carbon sequestration than other forest plantation species in South China.

Inorganic soil nitrogen under grassland plant communities of different species composition and diversity

We measured aboveground plant biomass and soil inorganic nitrogen pools in a biodiversity experiment in northern Sweden, with plant species richness ranging from 1 to 12 species. In general, biomass increased and nitrate pools decreased with increasing species richness. Transgressive overyielding of mixed plant communities compared to the most productive of the corresponding monocultures occurred in communities with and without legumes. N2‐fixing legumes had a fertilizing function, while non‐legumes had a N retaining function. Plant communities with only legumes had a positive correlation between biomass and soil nitrate content, whereas in plant communities without legumes they were negatively correlated. Both nitrate and ammonium soil pools in mixed non‐legume communities were approximately equal to the lowest observed in the corresponding monocultures. In mixed legume/non‐legume communities, no correlation was found for soil nitrate with either biomass or legume biomass as percentage of total biomass. The idea of complementarity among species in nitrogen acquisition was supported in both pure non‐legume and mixed non‐legume/legume communities. In the latter, however, facilitation through increased nitrogen availability and retention, was probably dominating. Our results suggest that diversity effects on biomass and soil N pools through resource use complementarity depend on the functional traits of species, especially N2fixation or high productivity.

Atmospheric CO2 enrichment alters energy assimilation, investment and allocation in Xanthium strumarium

Energy-use efficiency and energy assimilation, investment and allocation patterns are likely to influence plant growth responses to increasing atmospheric CO2 concentration ([CO2]). Here, we describe the influence of elevated [CO2] on energetic properties as a mechanism of growth responses in Xanthium strumarium. Individuals of X. strumarium were grown at ambient or elevated [CO2] and harvested. Total biomass and energetic construction costs (CC) of leaves, stems, roots and fruits and percentage of total biomass and energy allocated to these components were determined. Photosynthetic energy-use efficiency (PEUE) was calculated as the ratio of total energy gained via photosynthetic activity (Atotal) to leaf CC. Elevated [CO2] increased leaf Atotal, but decreased CC per unit mass of leaves and roots. Consequently, X. strumarium individuals produced more leaf and root biomass at elevated [CO2] without increasing total energy investment in these structures (CCtotal). Whole-plant biomass was associated positively with PEUE. Whole-plant construction required 16.1% less energy than modeled whole-plant energy investment had CC not responded to increased [CO2]. As a physiological mechanism affecting growth, altered energetic properties could positively influence productivity of X. strumarium, and potentially other species, at elevated [CO2].

Nutritional parameters for assessing pasture condition in the semiarid rangelands of Argentina

Range condition is usually estimated from the palatability and ecological attributes of rangeland species. The aim of this research was to assess whether the inclusion of nutritional parameters improves the estimation of range condition in the semiarid Prosopis caldenia Burk rangeland of La Pampa, Argentina. Plots (24 ha) containing rangeland in different condition (fair and good) were grazed at low stocking rates during fall, winter and spring of two successive years. The aerial biomass (kg DM ha-1), in vitro dry matter digestibility (IVDMD) and crude protein content (% CP) of monthly samples of each species were determined. The percentage of total biomass (% TB) and % CP were estimated for each of six IVDMD ranks. In both years, and across nearly all IVDMD ranks, the % TB was different (p < 0.05) for the two range conditions, though % CP was similar (p > 0.05). The carrying capacity of good rangeland was 2.5 times greater than that of fair one when total aerial biomass and expected animal performance were similar. Taking nutritional parameters into account improves estimates of range condition in P. caldenia rangeland.

Temporal changes in phytoplankton structure and composition at the Turkwel Gorge Reservoir, Kenya

Temporal changes in phytoplankton chlorophyll a, composition, diversity, biomass (density and fresh weight) and primary production were investigated at the Turkwel Gorge Reservoir (Kenya) over a two year period (1994 and 1995). The phytoplankton properties investigated revealed a seasonal pattern that was very distinct in 1994 and muted in 1995. The wet season was characterized by higher levels of chlorophyll a, biomass and primary production and a lower diversity. A prominent seasonality in 1994 was found to be the result of a higher river inflow volume as compared to 1995. Chlorophyll a changes showed some positive correlation to changes in total nitrogen and total phosphorus. Diversity changes were inversely correlated to changes in total counts (R = −0.84 and −0.96 for 1994 and 1995 respectively). Individual species density changes varied from a distinct seasonal pattern to a nearly uniform density. While the diatom Achnanthes dominated the wet season in 1994, coccoid blue green algae were dominant during most of 1995. Throughout the study period, most biomass was due to the diatoms but with a lower percentage of total biomass in 1995 (40%) as compared to 1994 (88%). The wet season biomass in each year was dominated by the diatoms. Dominance of the intervening period changed irregularly between diatoms, dinoflagellates, green algae and blue green algae. The range of variation in chlorophyll a, total biomass and primary production were; 4.9 to 36.8 µg l-1, 440.14 to 11172.70 mg m-3 and 1.85 to 9.67 g O2 m-2 d-1 in 1994 and 4.9 to 11.5 µg l-1, 486.46 to 1351.39 mg l-1 and 3.08 to 5.41 g O2 m-2 d-1 in 1995 in the same order.

Biomass Allocation in Fireweed Epilobium angustifolium L. (Onagraceae) in Response to Simulated Defoliation

Potted fireweed plants, Epilobium angustifolium L., were grown both from seed and root segments and subjected to early, late, and continuous defoliation and to apical excision during a single growing season. Seed-grown plants and root regenerates compensated completely for the early defoliation treatment and did not differ significantly from controls with respect to the dry weight of any yield component. Late defoliation significantly reduced the weight of flowers and fruit in seed-grown plants and root regenerates, and the annual increment of root weight in root regenerates. Continuous defoliation (early + late) significantly reduced the weight of flowers in seed-grown plants and the weight of both flowers and fruit in root regenerates. Apical excision significantly increased the total weight, shoot weight, and root weight of seed-grown plants but did not significantly affect any yield component in root regenerates. Reproductive allocation, defined as the percentage of total biomass in flowers and fruit, was significantly reduced in both seed-grown plants and root regenerates by the late and continuous defoliation treatments.

Shoot mortality and dynamics of live and dead biomass in a stand of Salix viminalis

Cumulative shoot mortality in a dense, productive stand of coppiced Salix viminalis amounted to nearly 90% of the initial shoot number after three years following a single cut. The decline in shoot number per area and the increase of stem dry weight per area indicated that mortality was due to self-thinning. Death occurred mainly among the smallest shoots. Although the proportion of living stems decreased drastically, the living biomass constantly accounted for almost 90% of the total standing biomass. Shoots of Salix viminalis lost about 25% of their biomass per year during the first two years after death. Weight loss was by loss of distal parts, which turned into litter, and through decrease of wood density. Cumulative weight loss as a percentage of cumulative biomass increased from 3.1% after the first season to 10.4% after the third season. For a rotation period of four years it is predicted that the proportion of standing dead and live biomass (0.1 and 0.9, respectively) would remain approximately constant, while the cumulative weight loss as a percentage of total biomass is expected to stay below 14%.

Influence of Herbaceous Interference on Growth and Biomass Partitioning in Planted Loblolly Pine (Pinus taeda)

Three herbaceous regimes were established, using herbicides, to examine the effects of interference on growth and biomass partitioning in loblolly pine (Pinus taedaL.). Trees were sampled near Auburn and Tallassee, AL. Trees at the Auburn site grown with low weed interference (LWI) had 4, 10, 10, 8, and 4 times greater total aboveground biomass than did trees with high weed interference (HWI) for ages one through five, respectively. Medium weed interference (MWI, Auburn site only) resulted in three times greater biomass the first 4 yr and two times greater total biomass by the fifth year compared to trees grown with HWI. Trees growing with LWI were 5, 8, 10, and 6 times larger than those with HWI for ages one through four, respectively, at the Tallassee site. At all levels of interference, the percentage of total biomass in foliage decreased, and stem and branch components increased, with increasing tree size at both sites. Trees growing with HWI had a lower percentage of total biomass in foliage and a greater percentage of total biomass in stem than those growing with LWI when compared over a common size. Growth efficiency per tree, expressed as annual increase in stem biomass per unit leaf area (g m−2), was slightly greater for trees growing with LWI compared to HWI when leaf area index (LAI3, total surface) was less than 0.2. For LAI values greater than 0.2 the relationship was reversed. The latter contradicts the idea that growth efficiency can be used as a measure of vigor for young loblolly pine. Changes in carbon partitioning to the development of leaf area are suggested to be driving the accelerated growth responses associated with a reduction of weed interference.

NATURAL DIET OF CALLINECTES ORNATUS (BRACHYURA: PORTUNIDAE) IN BERMUDA

ABSTRACT Foregut contents of 56 specimens of Callinectes ornatus collected from Mullet Bay, Bermuda, in 1981 and 1988 were examined. Foreguts which were ≥ half full contained more prey items per gut (x = 4.67) than did guts < half full ( x = 2.73). Dietary analysis was based on 2 methods: (1) the index of relative importance (IRI), which combined frequency of occurrence (FO), percentage of total biomass, and percentage of total numbers consumed, and (2) weighted points, which combined FO and estimated relative volumes of each prey item. No significant differences were revealed in relative proportions of foregut contents between males and females, or between adult and juvenile crabs. Modulus modulus, a cerithiacean gastropod mollusk, dominated the diet, accounting for 21.1 % of the total IRI. Two other cerithiaceans collectively ranked second (19.9% of total IRI). Carbonate substrate was the most frequently occurring category (51.79%) and ranked third in IRI (17.2% of total). Plant material, crustaceans, nereid polychaetes, fish, and bivalve mollusks ranked fourth through eighth in IRI. The validity of including carbonate substrate as a dietary component is discussed, as is the relative merit of the indices used in dietary analysis.

Reflectance of blue, green, red and near infrared radiation from wetland vegetation used in a model discriminating live and dead above ground biomass.

Field measurements of canopy reflectance of wetland vegetation in the blue (450 ran), green (548 nm), red (655 nm) and NIR (805 nm) wavebands were correlated with plant biomass variables. Negative relationships, asymptotic in nature, were observed between visible wavebands, canopy reflectance and total live biomass as well as green biomass, with correlation coefficients r between -0·52 and -0·93. Curvilinear relations were observed between NIR canopy reflectance and total live biomass as well as green biomass, with r between 0·39 and 0·88. Different normalization indices (NIR blue-1 , NIR red-1 , VI, PI and NIRlbio ) were tested and positive relations between these indices and total live biomass and green biomass were observed, with r between 0·69 and 0·96. Inverse relations of an asymptotic nature were observed between dead biomass as a percentage of total biomass and of green biomass, with r between 0·90 and 0·91. A model discriminating live and dead above-ground biomass was developed to improve correlations between canopy reflectance and biomass variables. The model nearly doubled the correlation coefficient between reflectance and green biomass for a canopy containing large amounts of interfering dead biomass, but did not change this correlation for a canopy containing small amounts of dead biomass.

Feeding habits of the dungeness crab Cancer magister as determined by the index of relative importance

Specimens of the Dungeness crab Cancer magister, were collected subtidally and intertidally from an estuary in Washington State, USA in June and September 1980, and January, April, May and July, 1981. Gut contens of freshly collected crabs were analyzed by the Index of Relative Importance; for each prey taxon, this method measured frequency of occurrence, percentage of total biomass, and percentage of total numbers consumed. The most important higher taxon eaten was fish; however, the most important prey genus was the shrimp Crangon spp. There was greater predation on Crangon spp. at night at the intertidal site, and during winter and spring when the shrimp were most abundant there. Feeding activity, as indicated by a weight-specific gut-fullness index, showed no consistent diel pattern. There were significant ontogenetic changes in feeding patterns: first-year crabs preyed primarily on very small bivalves or small crustaceans including their conspecifics; second-year crabs preferred Crangon spp. and fish, and third-year crabs preyed less on Crangon spp. and more on fish. Such changes in feeding habits with ege could be purely due to mechanics of food handling, but might also reduce competition among age groups of crabs, possibly partitioning resources within the estuary. Findings are discussed in terms of optimal foraging and compared to other similar studies.

Standing crops of dominant &lt;i&gt;combretum&lt;/i&gt; species at three browsing levels in the Kruger National Park

In red bushwillow veld near the Sand River in the Kruger National Park, Republic of South Africa, a determination was made of the standing crops of Combretum apiculatum and C. zeyheri at browsing levels delineated by the maximum feeding heights of impala (1,5 m), kudu (2,5 m) and giraffe (5,5 m). Using harvested sample trees, logarithmic or linear regression equations were generated which related basal diameter or stem height to biomass or percentage of total biomass at the different levels. Biomass was divided into two components: current shoots and wood plus bark. Regression forms and variables which produced the highest correlation coefficients changed with changes in species or browsing level, however, most equations were logarithmic with basal diameter as the independent variable.

SEED AND VEGETATIVE REPRODUCTION IN RELATION TO DENSITY IN FRAGARIA VIRGINIANA (ROSACEAE)

Transplants of Fragaria virginiana Duchesne, the wild strawberry, from field and woods sites, were studied under controlled laboratory conditions to determine their seed and vegetative reproduction responses under different density conditions. The following results were obtained: (1) Increased competition among high density grown plants resulted in lower total biomass when compared to low density grown plants; (2) Increased shading in high density plots resulted in a greater percentage of biomass in leaves; (3) The percentage of total biomass in reproductive organs (seed and vegetative) was higher in low density grown plants; (4) Vegetative “reproductive effort” was higher in low density plots than in high density plots while seed “reproductive effort” remained constant between the two density treatments; (5) No significant difference between plants from habitats of different successional maturity was observed under the experimental treatments. These results are discussed in relation to reproductive density response models.