Nutrient elements in large Chinese estuaries

1996 ◽  
Vol 16 (8) ◽  
pp. 1023-1045 ◽  
Author(s):  
Jing Zhang
Keyword(s):  
Nutrient Elements ◽  
Chinese Estuaries

scholarly journals Nutrient budgets for large Chinese estuaries and embayment

2009 ◽  
Vol 6 (1) ◽  
pp. 391-435 ◽  
Author(s):  
S. M. Liu ◽  
G.-H. Hong ◽  
X. W. Ye ◽  
J. Zhang ◽  
X. L. Jiang
Keyword(s):  
Jiaozhou Bay ◽  
Phytoplankton Growth ◽  
Nutrient Concentrations ◽  
Nutrient Elements ◽  
Exchange Flow ◽  
China Seas ◽  
The North ◽  
The China Seas ◽  
Chinese Estuaries ◽  
Nutrients Transport

Abstract. Nutrient concentrations among the Chinese rivers and bays vary 10–75 fold depending on nutrient elements. The silicic acid levels in South China rivers are higher than those from North China rivers and the yields of dissolved silicate increased from the north to the south of China, indicating the effect of climate on weathering. The nutrient levels in Chinese rivers are higher than those from the large and less-disturbed world rivers such as Amazon and Zaire, but comparable to the values for European and North American polluted and eutrophic rivers like the Loire and Po. This may be ascribed to both of extensive leaching and influences from agricultural and domestic activities over the drainage basins of Chinese rivers. DIN:PO3−4 ratios in most of Chinese rivers and bays are higher (up to 2800) than the other rivers in the world. The atomic ratios of DIN to PO43− in the major Chinese rivers and embayment decrease in exponential trend with increase in the atomic ratios of PO43− to Si(OH)4, indicating that primary production in coastal environments changes with the nutrients transport when the urbanization develops to a certain extent, and the potential limited nutrient elements can be changed from phosphorus to nitrogen limitation, which can modify aquatic food webs and then the ocean ecosystem. A simple steady-state mass-balance box model was employed. The output shows that the estuaries and embayment behave as a sink or source of nutrients. For the major Chinese estuaries, both residual and mixing flow transport nutrients off the estuaries, and nutrient transport fluxes in summer is 3–4 fold that in winter except comparable for NH4+. These fluxes are 1.0–1.7 fold that estimated by timing riverine nutrient concentrations and freshwater discharge. For the major Chinese embayment, nutrient elements are transported to China Seas except PO43− and Si(OH)4 in Sanggou Bay and Jiaozhou Bay. Seasonally, nutrients transport fluxes off the bays in the summer are 2.2–7.0 fold that in the winter. In the embayment, the exchange flow dominated the water budgets, resulting in average system salinity approaching the China seas salinity where river discharge is limited. The major Chinese estuaries and embayment transport 1.0–3.1% of nitrogen, 0.2–0.5% of phosphorus and 3% of silicon necessary for phytoplankton growth for the China Seas. This demonstrates regenerated nutrients in water column and sediments and nutrients transport fluxes between the China Seas and open ocean play an important role for phytoplankton growth. Atmospheric deposition may be another important source of nutrients for the China Seas.

scholarly journals Effect of different levels of humic acids on the nutrient content, plant growth, and soil properties under conditions of salinity

2011 ◽  
Vol 6 (No. 1) ◽  
pp. 21-29 ◽  
Author(s):  
H. Khaled ◽  
H.A. Fawy
Keyword(s):  
Plant Growth ◽  
Humic Substances ◽  
Humic Acids ◽  
Foliar Application ◽  
N Uptake ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Nutrient Content ◽  
Nutrient Elements ◽  
A Minor

In this study, the effects were investigated of salinity, foliar and soil applications of humic substances on the growth and mineral nutrients uptake of Corn (Hagein, Fardy10), and the comparison was carried out of the soil and foliar applications of humic acid treatments at different NaCl levels. Soil organic contents are one of the most important parts that they directly affect the soil fertility and textures with their complex and heterogenous structures although they occupy a minor percentage of the soil weight. Humic acids are an important soil component that can improve nutrient availability and impact on other important chemical, biological, and physical properties of soils. The effects of foliar and soil applications of humic substances on the plant growth and some nutrient elements uptake of Corn (Hagein, Fardy10) grown at various salt concentrations were examined. Sodium chloride was added to the soil to obtain 20 and 60mM saline conditions. Solid humus was applied to the soil one month before planting and liquid humic acids were sprayed on the leaves twice on 20<sup>th</sup> and 40<sup>th</sup> day after seedling emergence. The application doses of solid humus were 0, 2 and 4 g/kg and those of liquid humic acids were 0, 0.1 and 0.2%. Salinity negatively affected the growth of corn; it also decreased the dry weight and the uptake of nutrient elements except for Na and Mn. Soil application of humus increased the N uptake of corn while foliar application of humic acids increased the uptake of P, K, Mg,Na,Cu and Zn. Although the effect of interaction between salt and soil humus application was found statistically significant, the interaction effect between salt and foliar humic acids treatment was not found significant. Under salt stress, the first doses of both soil and foliar application of humic substances increased the uptake of nutrients.

NUTRIENT CONTENT OF THE PETIOLES OF SOME GRAPE CULTIVARS IN BRITISH COLUMBIA

1980 ◽  
Vol 60 (3) ◽  
pp. 873-877 ◽  
Author(s):  
D. C. PARSONS ◽  
G. W. EATON
Keyword(s):  
British Columbia ◽  
Nutrient Content ◽  
Nutrient Elements ◽  
Time Effects ◽  
Grape Cultivars

Prebloom and veraison petiole samples of the locally important grape cultivars Bath, Chelois, Dechaunac, Foch and Okanagan Riesling from 21 commercial vineyards in 1974, 1975 and 1976 were analyzed for N, P, K, Ca, Mg, Fe, Mn and Zn. Location differences were found for K, Mg and Mn and time of sampling effects for N, P, K, Ca, Mg and Mn. There were cultivar effects upon K, Ca, Mg and Zn and cultivar × time effects upon Mg and Mn. Diagnostic ranges of nutrient elements are suggested.

Manganese as a Micronutrient in Agriculture: Crop Requirement and Management

2021 ◽  
Vol 12 (1-2) ◽  
pp. 225-242
Author(s):  
MH Rashed ◽  
TS Hoque ◽  
MMR Jahangir ◽  
MA Hashem
Keyword(s):  
Growth And Development ◽  
Crop Production ◽  
Nutrient Elements ◽  
Biological Processes ◽  
Critical Levels ◽  
Plant Growth And Development ◽  
Safe Environment ◽  
Body Of Knowledge ◽  
Cell Compartments ◽  
Manganese Uptake

Manganese (Mn) as an essential plant micronutrient affects plant development, when at deficient or toxic levels. Manganese is used in several biological processes as an important contributor in plant growth and development. Manganese uptake depends on forms of Mn in soil solution, crop characteristics including growth rate, and ineteractions with other environmental factors. Its distribution in soils and requirement for crops vary from location to location, depending on soil type and reactions. Despite the metabolic roles of Mn in different plant cell compartments, the importance of Mn requirement in plants, distribution in soils and application to crops has been understated. As a micronutrient, judicious Mn management requires to critically evaluating its concentration in soils, biochemical functions, critical levels, soil availability and interactions with other nutrient elements is essential. This review has critically analysed the existing body of knowledge on Mn distribution in soils, dynamics, functions and management towards better crop production and safe environment. Environ. Sci. & Natural Resources, 12(1&2): 225-242, 2019

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