Effects of nutrients and water levels on species composition in prairie whitetop (Scolochloa festucacea) marshes

1990 ◽  
Vol 68 (5) ◽  
pp. 1015-1020 ◽  
Author(s):  
Christopher Neill
Keyword(s):  
Seed Germination ◽  
Species Composition ◽  
Water Levels ◽  
Depth Range ◽  
Moist Soil ◽  
Growth Responses ◽  
Nitrogen And Phosphorus ◽  
Understory Species ◽  
Standing Water ◽  
Nutrient Additions

Nitrogen and phosphorus fertilizers were added over two growing seasons to whitetop marshes growing at the shallow and deep extremes of whitetop's water depth range in a northern prairie marsh to assess the effects of nutrient additions and water levels on species composition and understory species biomass. Nitrogen and nitrogen plus phosphorus additions reduced understory species biomass and caused only small changes in marsh species composition after 1 year, but dramatically decreased whitetop biomass and increased the biomass of the understory moist soil annual Atriplex patula at both water depths after 2 years. Phosphorus alone had little effect on species composition. Water levels influenced both the biomass of understory species and their potential response to nutrient additions. Biomass of understory species during both years was lower in deeper water. Nutrients had no effect on understory species biomass when standing water was present because standing water prevented seed germination. A mulching effect caused by greater whitetop litter accumulation and weaker whitetop stems associated with nitrogen fertilization appeared to be more important influences on understory species composition than differential understory species growth responses to added nutrients. Predicting responses of whitetop marshes to multiyear fertilization requires an understanding of the interactions between the physical conditions caused by increased biomass of whitetop, the relative abilities of understory moist soil species to grow under those conditions, and water levels, which control understory species seed germination and plant survival.

scholarly journals Phytoremediation Potential of Typha orientalis and Scirpus littoralis in Removal of Nitrogen and Phosphorus from Intensive Whiteleg Shrimp Wastewater

2018 ◽  
Vol 68 ◽  
pp. 04003
Author(s):  
Ngo Thuy Diem Trang ◽  
Lam Thi Nhu Mo ◽  
Vo Chi Linh ◽  
Hans Brix
Keyword(s):  
Rapid Development ◽  
Mekong Delta ◽  
Water Levels ◽  
Shrimp Farming ◽  
Growth Responses ◽  
Nitrogen And Phosphorus ◽  
Shrimp Culture ◽  
Waterlogged Condition ◽  
Typha Orientalis ◽  
Whiteleg Shrimp

The rapid development of whiteleg shrimp farming in the Mekong delta of Vietnam has an adverse impact on the environment due to large amount of nitrogen and phosphorus content in wastewater and pond sludge/sediment. Phytoremediation is a promising technique to use plant for mitigating environmental impacts from intensively whiteleg shrimp culture. Growth responses, nitrogen and phosphorus removal of Typha orientalis and Scirpus littoralis were assessed at three water levels of +15 cm, +30 cm and +45 cm. They were arranged in a completely randomized design with three replications. The plants were supplied wastewater from intensive whiteleg shrimp tanks once every two weeks. Waterlogged assessment was conducted for 71 days. Water levels significantly affected plant growth rate and nutrient removal capacity. S. littoralis grew well with a lower mortality rate and had no statistical reduction of biomass compared to T. orientalis at the highest water level of +45 cm. T. orientalis had the best perfromance in growth and biomass responses to waterlogged at water levels of +15 cm and +30 cm. The results indicated that S. littoralis was the best of choice to grow in waterlogged condition of the shrimp pond for maintaining water quality.

scholarly journals The differential effect of synthetic growth substances and other compounds upon plant species II. Seed germination and early growth responses to some arylcarbamic esters and related compounds

1946 ◽  
Vol 133 (873) ◽  
pp. 480-485 ◽  
Keyword(s):  
Seed Germination ◽  
Differential Effect ◽  
Marked Effect ◽  
Early Growth ◽  
Growth Substances ◽  
Growth Responses ◽  
Low Concentrations ◽  
Dicotyledonous Plants ◽  
Related Compounds ◽  
Synthetic Growth

The preparation and biological examination of a number of arylcarbamic esters (arylurethanes) are described. The experiments demonstrate the marked effect of iso propyl phenylcarbamate and some related compounds in very low concentrations upon the germination and seedling growth of cereals. The absence of effect of the same compounds in similar concentrations upon some dicotyledonous plants is noted.

scholarly journals Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

2015 ◽  
Vol 12 (13) ◽  
pp. 10359-10387 ◽  
Author(s):  
W. Y. Dong ◽  
X. Y. Zhang ◽  
X. Y. Liu ◽  
X. L. Fu ◽  
F. S. Chen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Enzyme Activities ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Chinese Fir ◽  
Subtropical China ◽  
Nitrogen And Phosphorus ◽  
Soil Microbial ◽  
Nutrient Additions

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

scholarly journals Plankton Food Web Responses to Experimental Nutrient Additions in a Subtropical Lake

2006 ◽  
Vol 6 ◽  
pp. 827-833 ◽  
Author(s):  
Karl E. Havens ◽  
Therese L. East
Keyword(s):  
Food Web ◽  
Microbial Food Web ◽  
Cylindrospermopsis Raciborskii ◽  
Variable Response ◽  
Nitrogen And Phosphorus ◽  
Subtropical Lake ◽  
Nutrient Additions ◽  
Cyanobacteria Blooms ◽  
Enclosure Experiments

During two controlled enclosure experiments using water from a subtropical lake, the plankton food web displayed a highly variable response to combined addition of nitrogen and phosphorus. In July, the nutrients stimulated growth ofCylindrospermopsis raciborskii, and the biomass of macrozooplankton and microbial food web components did not increase. In October, the same addition of nutrients stimulated growth of small edibleLyngbyaspp., and there were coincident increases in biomass of macrozooplankton and components of the microbial web. Past generalizations that cyanobacteria blooms inhibit growth of other food web components may not always hold true.

scholarly journals Does Slash Management in a Eucalyptus globulus Labill. Plantation Influence the Potential Seed Germination and Early Growth of Understory Species?

2013 ◽  
Vol 59 (4) ◽  
pp. 494-503
Author(s):  
Marta Carneiro ◽  
Marta Ferreira ◽  
António Fabião ◽  
Luís Hilário ◽  
Mário Lousã ◽  
...  
Keyword(s):  
Seed Germination ◽  
Eucalyptus Globulus ◽  
Early Growth ◽  
Understory Species

scholarly journals Opportunities for Fertilization of Loblolly Pine in the Sandhills of the Southeastern United States

2009 ◽  
Vol 33 (3) ◽  
pp. 129-136 ◽  
Author(s):  
Timothy Albaugh ◽  
H. Lee Allen ◽  
Thomas R. Fox ◽  
Colleen A. Carlson ◽  
Rafael A. Rubilar
Keyword(s):  
Loblolly Pine ◽  
Volume Growth ◽  
Average Response ◽  
Growth Responses ◽  
Nitrogen And Phosphorus ◽  
Fertilizer Response ◽  
Foliar Nutrient ◽  
Wet Condition ◽  
Response Decisions ◽  
Research And Education

Abstract We examined growth responses to fertilization applied one or two times at three Sandhill sites versus annually at the Southeast Tree Research and Education Site (SETRES; and also in the Sandhills) and compared observed responses to the Southwide average response for midrotation fertilization (55 ft3 ac−1 year−1). At sites 1 and 2, average annual volume growth response (AVG) was significantly less (39 and 43%, respectively) than at SETRES, whereas site 3 AVG was similar to that of SETRES. At sites 2, 3, and SETRES, the AVGs of 82, 90, and 128 ft3 ac−1 year−1, respectively, significantly exceeded the Southwide average response of 55 ft3 ac−1 year−1. The diameter class with the most stems per acre at sites 2 and 3 increased 2 in. with fertilization. Resulting diameters were less than chip-n-saw size. Sandhill site fertilization may be appropriate where the superpulp premium is sufficient or wet-condition wood supply is limited. However, given the large Sandhill site fertilizer response, decisions regarding spacing, thinning, product goals, and fertilization become interdependent and require adequate planning to maximize economic return from fertilization. Foliar nutrient concentration assessments were recommended to identify nutrients other than nitrogen and phosphorus that may limit growth when fertilizing Sandhill sites.

scholarly journals Physiological tolerance to drought under high temperature in soybean cultivars

2019 ◽  
pp. 976-987 ◽  
Author(s):  
Jônatas Neves de Castro ◽  
Caroline Müller ◽  
Gabriel Martins Almeida ◽  
Alan Carlos Costa
Keyword(s):  
High Temperature ◽  
Water Deficit ◽  
Electron Flow ◽  
Soluble Sugar ◽  
Water Levels ◽  
Effective Quantum Yield ◽  
Growth Responses ◽  
Ps Ii ◽  
Total Electron ◽  
Soybean Cultivars

Soybean is one of the most economically important crops and has experienced adverse physiological and biochemical effects when subjected to drought stress and heat, resulting in lost productivity. Thus, the objective of this work was to evaluate the physiological, metabolic and growth responses of well-watered and drought-treated soybean cultivars under high temperature. The experimental design was set up in randomized blocks, in a factorial scheme with three soybean cultivars (7739 M, Anta 82 and Desafio) and two water levels (100% and 40% field capacity). The experiment was conducted in a controlled growth chamber with a gradual rise in temperature at 41°C for 5 hours daily. Morpho-physiological and metabolic analyses were performed 12 days after the treatments imposition. The parameters of water and osmotic potentials, relative water content, photosynthetic rate, stomatal conductance, transpiratory rate, electron flux for the carboxylation and oxygenation of RuBisCO were decreased for all cultivars under water deficit and high temperature. The results showed that the photorespiration and the rate of electrolyte leakage were increased as well. These results showed that these physiological behaviors are standard for soybean plants under water deficit, regardless of cultivars. The cultivars 7739 M and Desafio showed lower performance than the cultivar Anta 82 for the parameters of total electron flow and effective quantum yield of PS II. The 7739 M and Anta 82 were the only cultivars to show increased non-photochemical quenching dissipation and total soluble sugar content, respectively, under stress conditions. Desafio cultivar demonstrated greater physiological and growth traits stability, which could potentially indicate double tolerance to these stresses.

Effects of nutrients and water levels on emergent macrophyte biomass in a prairie marsh

1990 ◽  
Vol 68 (5) ◽  
pp. 1007-1014 ◽  
Author(s):  
Christopher Neill
Keyword(s):  
Water Level ◽  
Nutrient Limitation ◽  
Water Depth ◽  
Nitrogen Limitation ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Depth Range ◽  
Dry Conditions ◽  
Second Year ◽  
Water Depths

Nitrogen and phosphorus fertilizers were added over two growing seasons to marshes dominated by whitetop grass (Scolochloa festucacea) or cattail (Typha glauca) in a prairie lacustrine marsh to assess nutrient limitation and the interaction of nutrient limitation with water depth. For each species, stands were selected at the deep and shallow extremes of its water depth range. Water levels were high during the first year of fertilization and low during the second year, exposing the fertilized stands to a variety of water depths. Nitrogen limited growth in whitetop and cattail marshes. Water level, by controlling whether the soil was flooded or the water table was below the soil surface, affected growth and the degree of nitrogen limitation. In whitetop marshes, nitrogen increased biomass more when the soil was flooded or when standing water was deeper and in cattail marshes, it increased biomass more under intermediate water depths (approximately 0–20 cm) than under more deeply flooded (20–40 cm) or dry conditions. Nitrogen reduced biomass in whitetop marshes the second year, apparently because growth was inhibited by fallen litter from the previous year. Nitrogen did not limit cattail marsh biomass in the driest locations during a year of low water levels. Phosphorus caused a small increase in growth of both species after 2 years. Changes of nitrogen limitation with flooding suggest that annual water level fluctuations, by creating alternating flooded and dry conditions, may influence the primary production of emergent macrophytes through effects on nitrogen cycling.

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