Assessment of bioavailable nitrogen and phosphorus content in the sediments of Indian mangroves

Author(s):  
Yudhistir Reddy ◽  
Dipnarayan Ganguly ◽  
Gurmeet Singh ◽  
Mamidala Harikrishna Prasad ◽  
Paneer Selvam Arumughan ◽  
...  
Author(s):  
Yudhistir Reddy ◽  
Dipnarayan Ganguly ◽  
Gurmeet Singh ◽  
Mamidala Harikrishna Prasad ◽  
Paneer Selvam Arumughan ◽  
...  

2019 ◽  
pp. 119-124
Author(s):  
Brigitta Simon ◽  
Tamás Kucserka ◽  
Angéla Anda

In lakes and wetlands, leaf litter input from the coastal vegetation represents a major nutrient load and plays a basic structural and functional role in several ecosystems. In Hungary, at the banks of lakes and wetlands, Salix and Populus trees are the most common species. In an experiment in Lake Balaton and Kis-Balaton Wetland between 16 November 2017 to and 3 June 2018, the decomposition rates and leaching dynamics of Salix, Populus and mixed leaves (50% Salix and 50% Populus) were investigated. Total nitrogen and phosphorus content of biomass samples were measured at the beginning and end of the experiment for the leaching dynamics experiment. We found that litter mass losses (Salix, Populus and mixed leaves) were not significantly different between the two mesh size litterbags and between Lake Balaton and Kis-Balaton Wetland. Different amounts of the total nitrogen and phosphorus leaching from Salix, Populus and mixed leaves were detected. The total nitrogen contents of the plant samples were around 8-18% at the end of the investigated period. Slightly higher values were measured compared to phosphorous (27-29%).


2021 ◽  
Vol 9 (3) ◽  
pp. 174-179
Author(s):  
K. R. Patel ◽  

A field experiment was conducted at College Agronomy Farm, N. M. College of Agriculture, Navsari Agricultural University, Navsari during summer, 2019 and 2020 comprising four intercropping treatments i.e. pearlmillet sole, pearlmillet+greengram, pearlmillet+cowpea, pearlmillet+clusterbean and three fertility levels viz., 75 % RDF, 100 % RDF and 125 % RDF. Among the different intercropping system examined, sole pearl millet (I1) accumulated significantly less content of N and P in pearl millet grain and straw as compared to intercropping with pulses treatments. Pearl millet + green gram (I2) recorded significantly higher N and P uptake by pearl millet straw than other intercropping systems. The sole pearl millet (I1) was at par with pearl millet intercropped with green gram (I2) had significantly higher K content and uptake in pearl millet grain and straw. In case of fertility levels, nitrogen and phosphorus content and uptake in pearl millet grain and straw were recorded significantly higher by application of 100 % RDF. Significantly higher N, P and K uptake by pearl millet grain and straw in pooled results were produced by treatment combination of pearl millet + green gram (I2) intercropping along with 75 % RDF (F1).


2019 ◽  
Vol 70 (11) ◽  
pp. 3778-3782
Author(s):  
Violeta Monica Radu ◽  
Petra Ionescu ◽  
Gyorgy Deak ◽  
Alexandru Anton Ivanov ◽  
Elena Diacu ◽  
...  

The aim of this paper is the evaluation of the trophic status of three lakes riparian to the Colentina River, namely Mogosoaia, Herastrau, Pantelimon, as Part III of an extended study on evaluation of the freshwater resources quality in Bucharest and surrounding areas [1, 2], supplementing the general quality assessment based on indices and indexes presented in Part I with a more in depth analysis of nutrient speciation and partitioning between water and upper sedimentary layers. Water and sediment samples were taken from the inlet and outlet areas of each lake in two sampling campaigns in July 2016 and September 2016. Some of the nutrient related water quality parameters presented in Part I of this series have been used here, together with the analysis of total nitrogen and total phosphorus content in sediments, to assess the general trophic state of the lakes and to highlight the relationships between the nitrogen and the phosphorus content from water and sediments.The studied lakes were found to be eutrophic, Mogosoaia and Pantelimon being in the most advanced state. A significant amount of nitrogen and phosphorus was detected in all sediments analysed, constituting a high accumulation of nutrients from anthropogenic activities. Actions to improve local sanitation infrastructure and to prevent anaerobic leakage of nutrients from sedimentary deposits are recommended.


2017 ◽  
Vol 4 (7) ◽  
pp. 170497 ◽  
Author(s):  
Caroline B. Turner ◽  
Brian D. Wade ◽  
Justin R. Meyer ◽  
Brooke A. Sommerfeld ◽  
Richard E. Lenski

Organismal stoichiometry refers to the relative proportion of chemical elements in the biomass of organisms, and it can have important effects on ecological interactions from population to ecosystem scales. Although stoichiometry has been studied extensively from an ecological perspective, much less is known about the rates and directions of evolutionary changes in elemental composition. We measured carbon, nitrogen and phosphorus content of 12 Escherichia coli populations that evolved under controlled carbon-limited, serial-transfer conditions for 50 000 generations. The bacteria evolved higher relative nitrogen and phosphorus content, consistent with selection for increased use of the more abundant elements. Total carbon assimilated also increased, indicating more efficient use of the limiting element. We also measured stoichiometry in one population repeatedly through time. Stoichiometry changed more rapidly in early generations than later on, similar to the trajectory seen for competitive fitness. Altogether, our study shows that stoichiometry evolved over long time periods, and that it did so in a predictable direction, given the carbon-limited environment.


1973 ◽  
Vol 24 (4) ◽  
pp. 497 ◽  
Author(s):  
KC Hodgkinson

Lucerne plants (Medicogo sativa cv. Hunter River) were either frequently or infrequently cut down and subsequent differences in shoot regrowth were compared in two experiments. The first experiment demonstrated that differences in final shoot weights arose from differences developed during the first 7 days of regrowth. High level cutting (15 cm) increased the shoot yield of frequently but not of infrequently cut plants. Net uptake of both nitrogen and phosphorus was related to the growth rate of shoots until commencement of flowering, when uptake ceased for c. 15 days even though both roots and shoots continued to gain weight. Towards the end of flowering uptake of nitrogen and phosphorus recommenced and accumulation of both nutrients occurred in the tap-root and lateral roots. The relative nitrogen and phosphorus content of leaves on crown shoots was highest on day 7 and the same for frequently and infrequently cut plants. Leaves on crown and stubble shoots 7 days after high level cutting had a significantly lower relative nitrogen and phosphorus content than leaves on plants cut low. Thereafter the relative nitrogen and phosphorus content of a11 leaves declined with the greatest decline occurring after the commencement of flowering. In the second experiment early morphogenesis of the shoot population was investigated. Establishment of shoots was completed between 3 and 5 days after cutting. Higher shoot weights on infrequently cut plants were accounted for by a larger number of small shoots at the time of cutting. Relative growth rates of shoots did not appear to be influenced by prior cutting frequency. The relative nitrogen content of buds and shoot apices was low at cutting but doubled within 2 or 3 days and then declined after day 7. These results are discussed in relation to the role of 'plant factors' in shoot regrowth of lucerne.


1968 ◽  
Vol 61 (6) ◽  
pp. 1746-1747
Author(s):  
Norris E. Daniels ◽  
Gillespie C. Wilson ◽  
Calvin S. Clarke

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