scholarly journals Estimation of the Root System of Rice Plant by Decrease Pattern of Ammonium Nitrogen Concentration in the Soil Solution.

Root Research ◽  
1999 ◽  
Vol 8 (1) ◽  
pp. 17-19 ◽  
Author(s):  
Osamu KUSUDA
2006 ◽  
Vol 42 (3) ◽  
pp. 351-366 ◽  
Author(s):  
J. J. COMIN ◽  
J. BARLOY ◽  
V. HALLAIRE ◽  
F. ZANETTE ◽  
P. R. M. MILLER

The aim of this work was to study the effects of soluble aluminium on the morphology and growth of the adventitious root system, aerial biomass and grain yield of maize (Zea mays). The analysis focuses on two hybrid cultivars (Al-sensitive HS7777 and Al-tolerant C525M). Experiments were carried out in the field and in a rhizotron in Curitiba, Paraná, Brazil. In the field, four levels of lime application were used: T0 = 0 t ha−1, T1 = 3.5 t ha−1, T2 = 7.0 t ha−1, and T3 = 10.5 t ha−1. Two levels were used in a rhizotron: T0 and T3. In the surface horizon (0–15 cm), the Al concentrations of the soil solution were: T0 = 15, T1 = 5.1, T2 = 4.4, and T3 = 3.1 μM. In the field, neither Al concentration in the soil solution nor cultivar affected the number of primary adventitious roots per internode or the total number of primary adventitious roots. However, root diameter, plant population and grain yield of the two cultivars confirmed the differences in Al tolerance between them. Al was observed to have an adverse effect on the grain yield from C525M, while low yields from HS7777, at all levels of Al, precluded any response to liming. In the rhizotron studies, Al concentration and cultivar affected the root branching and total root length. Cultivar C525M had more branches and total root length than HS7777, mainly at low concentrations of soil Al solution, leading to greater spatial colonization of the soil down to 0.9 m depth.


1994 ◽  
Vol 10 (3) ◽  
pp. 399-416 ◽  
Author(s):  
Barrios E. ◽  
Herrera R.

ABSTRACTSeasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.The predominance of mineralization versus nitrification (56 and 5 μgsoil month−1respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.


2021 ◽  
Author(s):  
Petru Spataru

Abstract The braking effect of the ammonium derivatives on the natural aquatic environment varies dramatically with the number and nature of organic radical substitutions at nitrogen atom, particularly with their structure, composition and genesis. The most common discrepancy in their toxic effect are showing the natural and synthetic amines. For instance, the values of the maximum allowable concentration (MAC) of the derivatives of the natural origin for drinking water exceed the MAC of the synthetic ones by two orders. On the other hand, it has been found out that 1- naphtylamine (1-NA) inhibitory effect is associated to its toxicity. The Diethylamine (DEA) braking impact on the nitrification process is effectively lower than that of the toxicity. Our experiments show that the carbon-radicals of organic amines act as reducing agents. It is found that DEA decomposition leads to a high NH4+ ions (approx. 3.8 mg/L ammonium nitrogen) concentration in river water samples. By laboratory simulations two types of fixations by microbial organisms have been established: 1) absorption-desorption, the hydromicrobiotic reaction to ammonium (HMBRA) at the instantaneous increase of the concentration of ammonium ion in the river water (so-called shock/stress effect); 2) nitrogen fixation stimulated by a certain concentration (0.05mg/L) of a 1-NA and other amines.


Chemosphere ◽  
2019 ◽  
Vol 236 ◽  
pp. 124322 ◽  
Author(s):  
Shulan Jin ◽  
Zhongjun Hu ◽  
Yizong Huang ◽  
Ying Hu ◽  
Huahua Pan

2013 ◽  
Vol 69 (6) ◽  
pp. 1227-1233 ◽  
Author(s):  
Vojtech Kouba ◽  
Michael Catrysse ◽  
Hana Stryjova ◽  
Ivana Jonatova ◽  
Eveline I. P. Volcke ◽  
...  

The application of nitrification–denitrification over nitrite (nitritation–denitritation) with municipal (i.e. diluted and cold (or low-temperature)) wastewater can substantially improve the energy balance of municipal wastewater treatment plants. For the accumulation of nitrite, it is crucial to inhibit nitrite-oxidizing bacteria (NOB) with simultaneous proliferation of ammonium-oxidizing bacteria (AOB). The present study describes the effect of the influent total ammonium nitrogen (TAN) concentration on AOB and NOB activity in two moving bed biofilm reactors operated as sequencing batch reactors (SBR) at 15 °C (SBR I) and 21 °C (SBR II). The reactors were fed with diluted reject water containing 600, 300, 150 and 75 mg TAN L−1. The only factor limiting NOB activity in these reactors was the high concentrations of free ammonia and/or free nitrous acid (FNA) during the SBR cycles. Nitrite accumulation was observed with influents containing 600, 300 and 150 mg TAN L−1 in SBR I and 600 and 300 in SBR II. Once nitrate production established in the reactors, the increase of influent TAN concentration up to the original 600 mg TAN L−1 did not limit NOB activity. This was due to the massive development of NOB clusters throughout the biofilm that were able to cope with faster formation of FNA. The results of the fluorescence in situ hybridization analysis preliminarily showed the stratification of bacteria in the biofilm.


2011 ◽  
Vol 233-235 ◽  
pp. 528-531
Author(s):  
Li Na He ◽  
Hua Ye ◽  
Can Cao ◽  
Ying Fen Li

Large quantities of ammonia-nitrogen (-N) in wastewater is one of the main causes of eutrophication that endanger both natural water bodies and fresh water seriously. Thus, it is necessary to find an economic and feasible method to remove the ammonium-nitrogen in wastewater before they are returned to the environment. Magnesium ammonium phosphate precipitation method is one of the effective technology of wastewater treatment. In this paper, the influence of initial ammonia-nitrogen concentration, pH, temperature and mole ratio of :NH+4 :Mg2+were studied, What is more, the optimum condition of this process was determined. The results indicated that ammonia-nitrogen concentration is decreased from 1434 mg/L to 95.65 mg/L, and the removal rate reached 93.33% at the optimum conditions, which laying a foundation for the following biochemical treatment.


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