Photosynthetic Characteristics and Cell Quota of Nitrogen and Phosphorus in Scenedesmus quadricauda under P Limitation

Abstract A two-year survey of the physicochemical parameters and nutrient speciation in a lower Oum Rabiaa basin, characterized by three dams in series (Imfout, Daourat and Sidi Maâchou), was performed from December 1998 to November 2000. The presence of the three dams in series is responsible for the nitrogen and phosphorus loads in the dams because of the reduction of fluvial contributions to the lower sector. Multivariate statistics were used to identify the principal factors influencing water chemistry in the individual dam systems. The three dams are influenced mainly by nutrient and organic sources. The eutrophication status of the studied systems was evaluated by N/P ratios. Mean N/P ratios at the three dams showed a high likelihood of P-limitation. Highest values were observed primarily during winter and early spring.

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Shoot-soil ecological stoichiometry of alfalfa under nitrogen and phosphorus fertilization in the Loess Plateau

Scientific Reports ◽

10.1038/s41598-021-94472-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jiaoyun Lu ◽

Hong Tian ◽

Heshan Zhang ◽

Junbo Xiong ◽

Huimin Yang ◽

...

Keyword(s):

Loess Plateau ◽

Ecological Stoichiometry ◽

Effective Means ◽

Phosphorus Fertilization ◽

The Loess Plateau ◽

Nitrogen And Phosphorus ◽

Soil C ◽

Soil P ◽

P Limitation ◽

C And N

AbstractPlants and soil interactions greatly affect ecosystems processes and properties. Ecological stoichiometry is an effective means to explore the C, N, P correlation between plants and soil and the relationship between plant growth and nutrient supply. Serious soil erosion on China’s Loess Plateau has further barrenness the soil. Fertilization solves the problem of ecosystem degradation by improving soil fertility and regulating the ecological stoichiometric between soil and plants. No fertilization (CK), nitrogen fertilization (N), phosphorus fertilization (P) and N and P combined fertilization (NP) treatments were set in an alfalfa grassland. Organic carbon (C), nitrogen (N) and phosphorus (P) nutrients and their stoichiometry were measured in shoot and soil. P and NP fertilization increased shoot C concentration (3.12%, 0.91%), and all fertilization decreased shoot N concentration (6.96%). The variation of shoot C and N concentrations resulted in a greater increase in shoot C:N under the fertilization treatment than that under CK (8.24%). Most fertilization treatments increased shoot P concentration (4.63%) at each cut, which induced a decrease of shoot C:P. Shoot N:P of most treatments were greater than 23, but it was lower under N and NP fertilization than that under CK. Fertilization only increased soil C in 2014, but had no effect on soil N. Soil P content was significantly higher under P fertilization in 2014 (34.53%), and all fertilization in the second cut of 2015 (124.32%). Shoot and soil C:P and N:P having the opposite changes to shoot and soil P, respectively. Our results suggest that the change of P after fertilization largely drove the changes of stoichiometric. The growth of alfalfa in the Loess Plateau was severely restricted by P. It is an effective method to increase the biomass of alfalfa by increasing the addition of N or NP fertilizer to alleviate P limitation.

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Exploring the distance between nitrogen and phosphorus limitation in mesotrophic surface waters using a sensitive bioassay

10.5194/bg-2016-313 ◽

2016 ◽

Author(s):

Enis Hrustic ◽

Risto Lignell ◽

Ulf Riebesell ◽

Tron Frede Thingstad

Keyword(s):

Baltic Sea ◽

Incubation Time ◽

N:P Ratio ◽

Early Summer ◽

Parameter Estimates ◽

Nitrogen And Phosphorus ◽

Field Station ◽

N Limitation ◽

P Limitation ◽

Two Samples

Abstract. The balance in microbial consumption of nitrogen and phosphorus was investigated in samples collected in two mesotrophic coastal environments: the Baltic Sea (Tvärminne field station) and the North Sea (Espegrend field station). For this, we have refined a bioassay based on the response in alkaline phosphatase activity (APA) over a matrix of combinations in nitrogen and phosphorus additions. This assay not only provides information on which element (N or P) is the primary limiting, but also gives a quantitative estimate for the excess of the secondary limiting element (P* or N*, respectively), as well as the ratio between N and P consumption over short time scales (days). As expected for a Baltic Sea late spring-early summer situation, the Tvärminne assays (n=5) indicated N-limitation with an average P*=0.30 &pm; 0.10 µM-P, when incubated for 4 days. For short incubations (1–2 days), the Espegrend assays indicated P-limitation, but the shape of the response surface changed with incubation time, resulting in a drift in parameter estimates toward N-limitation. Extrapolating back to zero incubation time gave P-limitation with N* &approx; 0.9 µM-N. The N:P ratio (molar) of nutrient consumption varied considerably between investigated locations; from 2.3 &pm; 0.4 in the Tvärminne samples to 13 &pm; 5 and 32 &pm; 3 in two samples from Espegrend. Our assays included samples from mesocosm acidification experiments, but statistically significant effects of ocean acidification were not found by this method.

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Contrasting responses of soil phosphatase activity to nitrogen and phosphorus loadings: Implications for phosphorus management

10.5194/egusphere-egu21-1655 ◽

2021 ◽

Author(s):

Ji Chen ◽

Yiqi Luo ◽

Junji Cao ◽

Uffe Jørgensen ◽

Daryl Moorhead ◽

...

Keyword(s):

Microbial Biomass ◽

Phosphatase Activity ◽

Soil Ph ◽

Meta Analysis ◽

Integrated Control ◽

Microbial Biomass C ◽

Nitrogen And Phosphorus ◽

Soil C ◽

P Limitation ◽

Soil Phosphatase

<p>Human activity has caused imbalances in nitrogen (+N) and phosphorus (+P) loadings of ecosystems around the world, causing widespread P limitation of many biological processes. Soil phosphatases catalyze the hydrolysis of P from a range of organic compounds, representing an important P acquisition pathway. Therefore, a better understanding of soil phosphatase activity as well as the underlying mechanisms to individual and combined N and P loadings could provide fresh insights for wise P management. Here we show, using a meta-analysis of 188 published studies and 1277 observations that +N significantly increased soil phosphatase activity by 14%, +P significantly repressed it by 30%, and +N+P led to non-significant responses of soil phosphatase activity. Responses of soil phosphatase activity to +N were positively correlated with soil C and N content, whereas the reverse relationships were observed for +P and +N+P. Similarly, effects of +N on soil phosphatase activity were positively related to microbial biomass C, microbial biomass C:P, and microbial biomass N:P, whereas reverse relationships were observed for +P. Although we found no clear relationship between soil pH and soil phosphatase activity, +N-induced reductions in soil pH were positively correlated with soil phosphatase activity. Our results underscore the integrated control of soil and microbial C, N and P stoichiometry on the responses of soil phosphatase activity to +N, +P, and +N+P, which can be used to optimize future P management.</p>

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Nitrogen and phosphorus resorption efficiency, and N : P ratios in natural populations of Typha domingensis Pers. in a coastal tropical lagoon

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x2013000200003 ◽

2013 ◽

Vol 25 (2) ◽

pp. 124-130

Author(s):

Bruno dos Santos Esteves ◽

Marina Satika Suzuki

Keyword(s):

Aquatic Macrophytes ◽

Natural Populations ◽

Typha Domingensis ◽

Resorption Efficiency ◽

Nitrogen And Phosphorus ◽

P Limitation ◽

Tropical Lagoon ◽

P Content ◽

Different Seasons ◽

One Year

AIM: We studied nitrogen (N) and phosphorus (P) resorption patterns in Typha domingensis Pers. in a tropical coastal lagoon during different seasons of throughout one year. METHODS: Resorption of N and P is uttered as resorption efficiency (NRE and PRE, respectively), which may be used as an indicator of a nutrient limitation. Higher resorption efficiency values might indicate limitation of a certain element for the growth of aquatic macrophytes. RESULTS: N was inferred to be less limiting than P for the growth of T. domingensis in Campelo Lagoon, since N content varied less than P content and resorption efficiency of N was lower than that of P and, concomitantly, low resorption efficiency of this element. However, T. domingensis of Campelo Lagoon frequently utilized P that was already present in its tissues, contributing to the longer residence time of this element in system. Green leaves of T. domingensis showed N : P ratio, ranging 49-96, corroborating the inference of P limitation. CONCLUSIONS: N : P ratio and resorption efficiency indicate P limitation by T. domingensis in Campelo Lagoon.

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Determining the Necessity of Applying N and P Fertilizer in a Mature Subtropical Torreya Grandis Orchard

10.21203/rs.3.rs-33724/v1 ◽

2020 ◽

Author(s):

Yini Han ◽

G.Geoff Wang ◽

Tonggui Wu ◽

Yongliang Ji ◽

Wenjing Chen ◽

...

Keyword(s):

Soil Nutrient ◽

Nutrient Content ◽

Carbon Accumulation ◽

Environmental Cost ◽

Fertilizer Treatment ◽

Nitrogen And Phosphorus ◽

High Productivity ◽

P Limitation ◽

P Fertilizer ◽

Torreya Grandis

Abstract Background In managed orchards, fertilizer treatments facilitate both high productivity and environmental pollution. Because economic profit takes priority over environmental cost, increasing amounts of chemical nitrogen and phosphorus fertilizer have been used in mature subtropical Torreya grandis orchards. However, given the magnitude of global nitrogen deposition, it’s worth considering whether heavy fertilizer treatment is necessary.Methods To elucidate the balance between T. grandis nutrient demands and the fertilizer supply, we determined the C, N, and P foliar and soil concentrations ([C], [N], [P]) at five orchards undergoing long-term varied intensity fertilizer treatments.Results After documenting the dynamic variation of available plant nutrients and the corresponding resorption efficiency, we found that increasing the fertilizer supply elevated foliar [P], yet foliar [C] and [N] remained stable. Because T. grandis was already equipped with a high nutrient content, the increased foliar [P] levels decreased C:P and N:P ratios. These results demonstrate that extra fertilizer in the N-saturated environment disturbs P-limitation. Furthermore, we also found that fertilizer supply failed to improve carbon accumulation, which in addition to soil nutrient content and leaf [P], highly impacted productivity.Conclusions Thus, based on the results of this study, there are ample reasons to propose rejecting N addition in the present orchards, and we recommend organic management as a more conducive method to realize sustainable development.

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