scholarly journals Nitrogen Fixation in Subtropical Seagrass Sediments: Seasonal Patterns in Activity in Santa Rosa Sound, Florida, USA

2021 ◽  
Vol 9 (7) ◽  
pp. 766
Author(s):  
Rachel Presley ◽  
Jane M. Caffrey
Keyword(s):  
Organic Matter ◽  
Nitrogen Fixation ◽  
Organic Matter Content ◽  
High Growth ◽  
Matter Content ◽  
Seasonal Patterns ◽  
Seagrass Beds ◽  
Halodule Wrightii ◽  
Substrate Types ◽  
Nitrogen Demand

Seagrass beds are important coastal habitats that are diminishing globally. Nitrogen, a key nutrient, often limits seagrass growth. Nitrogen fixation provides new, bioavailable nitrogen to the plants. This study explores its importance and factors controlling rates in sediments colonized by two dominant taxa in Northwest Florida, Thalassia testudinum and Halodule wrightii, compared to unvegetated sediments. We hypothesized that nitrogen fixation rates would be greater in seagrass colonized sediments, particularly during high growth periods. We expected to observe a positive relationship between rates and porewater sulfide concentrations because sulfate reducers were the dominant diazotrophs in similar studies. Rates were higher in vegetated areas. In H. wrightii beds, nitrogen fixation was driven by the decreased availability of porewater ammonium relative to phosphorus. In T. testudinum beds, rates were highest during winter. Organic matter may be a controlling factor in all substrate types albeit the exact mechanism driving nitrogen fixation differs slightly. During the summer and fall, nitrogen fixation provided between 1–15% of T. testudinum nitrogen demand. Annually, nitrogen fixation provided 4% and 1% of T. testudinum and H. wrightii nitrogen demand, respectively. Nitrogen fixation was an important source of nitrogen during periods of senescence and dormancy when organic matter content was high.

scholarly journals Identification of Native Microorganisms of the Amazon Rhizosphere to Speed up the Decomposition Process of Agro-Industrial Organic Waste

2021 ◽  
Vol 10 (9) ◽  
pp. 473-483
Author(s):  
Ocampo-Guevara Jhon-Alexander ◽  
Vega Espinoz Johana Jazmín ◽  
Rivera González Johanna Rivera ◽  
Carlos Jacome
Keyword(s):  
Organic Matter ◽  
Nitrogen Fixation ◽  
Metabolic Activity ◽  
Organic Waste ◽  
Organic Matter Content ◽  
Degradation Process ◽  
Matter Content ◽  
Uniform Structure ◽  
Plant Tissues ◽  
Speed Up

Agribusiness is one of the areas with the greatest impact, which, due to the processes involved within this area, generates waste that, given its composition, is used in optimal materials to be used for degradation methods in the production of composting, different microorganisms such as Pseudomonas, Bacillus, Aspergillus help in the decomposition of waste from agribusiness, the metabolic activity of these microorganisms allows the degradation of animal and plant tissues such as cellulose, starch, pectin, proteins, agar that intervene in nitrification and nitrogen fixation processes, for the degradation process it is necessary to carry out in composting beds of organic waste isolated with strains of the rhizosphere from the natural forest of CIPCA the strains use the dimensions of 4 x 1 x 1 giving a city layer of 4𝑚3 or about 640 kg of organic rough which are covered with geo mucosa, surrounded by gutters to collect leachate two produced by the effect of degradation, this process of degradation of organic matter allows to obtain a product with characteristics such as earthy odor, texture and uniform structure, where a pH close to neutral was registered in the control beds, gradually increasing from that moment with slightly alkaline values where it does not present characteristics of the initial organic matter, reducing the volume by 35%, for this the objective is to maintain Controller of certain parameters of temperature, humidity, pH, compost ratio and organic matter content.

scholarly journals ESTRUCTURA DE LAS PRADERAS DE THALASSIA TESTUDINUM EN UN GRADIENTE DE PROFUNDIDAD EN LA GUAJIRA, CARIBE COLOMBIANO

2016 ◽  
Vol 39 (2) ◽  
Author(s):  
Margarita R. Albis Salas ◽  
Diana I. Gómez López ◽  
Guillermo Duque
Keyword(s):  
Organic Matter ◽  
Leaf Area ◽  
Organic Matter Content ◽  
Shoot Density ◽  
Thalassia Testudinum ◽  
Matter Content ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Seagrass Beds ◽  
Substrate Type

The spatial distribution of seagrass beds depends on environmental factors such as light, temperature, salinity, substrate type, and nutrient availability. There is an extensive area of seagrass beds dominated by Thalassia testudinum along the shallow continental shelf of La Guajira, representing more than 80 % of the seagrass beds in Colombia. In order to describe seagrass distribution and its relation to organic matter, substrate type and depth structural variables of T. testudinum were measured at l5 locations placed at one of the following depth ranges: shallow (0-2 m), intermediate (2-4 m), and deep (>4 m). Shoot density was measured with 20 x 20 cm quadrants while shoot samples were collected from 20 x 10 cm sub-quadrants in order to measure leaf biomass, epiphyte weight, grazing and leaf area. Total biomass and sediment core were measured from sediments core samples. High values of shoot density (437.5 m-2), leaf biomass (84.8 g m-2), total biomass (5.9 kg m-2) and leaf area (24.8 cm2), were related with depths less than 3.5 m while at higher depths plants presented lower shoot density (137.5 m2), biomass (7.5 g m-2) and leaf area (4.6 cm2). The epiphyte weight registered high values in deeper seagrass beds (52.5 %) where grazing had lesser impact (53.3 %). Additionally, better devolped seagrass beds were found in areas of organic matter content, fine sediments and protected areas.

HEAVY METAL SPECIATION IN BOTTOM SEDIMENTS OF THE VYSHNEVOLOTSKY RESERVOIR

2018 ◽  
pp. 46-54
Author(s):  
O. A. Lipatnikova
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Bottom Sediments ◽  
Metal Speciation ◽  
Organic Matter Content ◽  
Water Reservoir ◽  
Matter Content ◽  
Heavy Metal Speciation ◽  
Mobile Forms ◽  
Manganese Hydroxides

The study of heavy metal speciation in bottom sediments of the Vyshnevolotsky water reservoir is presented in this paper. Sequential selective procedure was used to determine the heavy metal speciation in bottom sediments and thermodynamic calculation — to determine ones in interstitial water. It has been shown that Mn are mainly presented in exchangeable and carbonate forms; for Fe, Zn, Pb и Co the forms are related to iron and manganese hydroxides is played an important role; and Cu and Ni are mainly associated with organic matter. In interstitial waters the main forms of heavy metal speciation are free ions for Zn, Ni, Co and Cd, carbonate complexes for Pb, fulvate complexes for Cu. Effects of particle size and organic matter content in sediments on distribution of mobile and potentially mobile forms of toxic elements have been revealed.

Physico-Chemical Properties of Soil Collected from Chandrabhaga River in Kalmeshwar, Nagpur, Maharashtra

2020 ◽  
Vol 07 (02) ◽  
pp. 1-3
Author(s):  
Amita M Watkar ◽  
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Agricultural Land ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Matter Content ◽  
Soil Attributes ◽  
Essential Components ◽  
Agricultural Land Management ◽  
Physical And Chemical

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.

scholarly journals Soil nitrogen supply of peat grasslands estimated by degree days and soil organic matter content

2020 ◽  
Vol 117 (3) ◽  
pp. 351-365
Author(s):  
J. Pijlman ◽  
G. Holshof ◽  
W. van den Berg ◽  
G. H. Ros ◽  
J. W. Erisman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Nitrogen ◽  
Organic Matter Content ◽  
Matter Content ◽  
Nitrogen Supply ◽  
Degree Days ◽  
Soil Organic Matter Content ◽  
Soil Nitrogen Supply

scholarly journals Effect of Clay, Soil Organic Matter, and Soil pH on Initial and Residual Weed Control with Flumioxazin

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Weed Control ◽  
Soil Ph ◽  
Organic Matter Content ◽  
Amaranthus Retroflexus ◽  
Matter Content ◽  
Weed Species ◽  
Soil Organic Matter Content ◽  
Field Soils

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.

scholarly journals Assessment of Potato Farmland Soil Nutrient Based on MDS-SQI Model in the Loess Plateau

2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Fertility ◽  
Soil Quality ◽  
Soil Nutrients ◽  
Organic Matter Content ◽  
Soil Nutrient ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Farmland Soil

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.

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