Interactions of Humic Substances with Trace Metals and Their Stimulatory Effects on Plant Growth

2005 ◽  
pp. 83-113 ◽  
Author(s):  
A. Kaschl ◽  
Y. Chen
Keyword(s):  
Trace Metals ◽  
Plant Growth ◽  
Humic Substances

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.

Chemical and Biochemical Properties of Humic Substances Isolated from Forest Soils and Plant Growth

2000 ◽  
Vol 64 (2) ◽  
pp. 639-645 ◽  
Author(s):  
S. Nardi ◽  
D. Pizzeghello ◽  
F. Reniero ◽  
N. Rascio
Keyword(s):  
Plant Growth ◽  
Humic Substances ◽  
Forest Soils ◽  
Biochemical Properties

Soil Augmentation by Humus: Replenishing lost soils and supplementing new ones

2021 ◽  
Author(s):  
Hemlata Bagla ◽  
Asma Khan
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Plant Growth ◽  
Humic Substances ◽  
Soil Degradation ◽  
Lunar Regolith ◽  
Radioactive Waste Disposal ◽  
Saline Stress ◽  
Plant Metabolites ◽  
Growth Phenomenon

&lt;p&gt;Earth&amp;#8217;s regolith consists of a vital component that is lacking on other planets &amp;#173;&amp;#173;&amp;#8211; the pedosphere or soil body &amp;#8211; that is rich in organic matter, soil fauna, minerals, water, gases, that together support life and is thus essential for plant growth. In stark contrast to our blue planet, Martian regolith is devoid of organic matter and contains crushed volcanic rocks, with high mineral content and toxic chemicals like perchlorates. Nevertheless, Martian and Lunar regolith simulants formulated by NASA, have been experimented for crop growth by addition of organic matter suitable to bind xenobiotics and provide ample nutrients, as an essential step towards expanding our horizon in the extensive field of soil sciences.&lt;/p&gt;&lt;p&gt;Soil is an ecosystem as a whole and acts as a modifier of planet Earth&amp;#8217;s atmosphere. The organic matter present in it originates mainly from plant metabolites with the onset of senescence and humification. Humic substances thus formed in the pedosphere exhibit exceptional characteristics for soil conditioning. Besides providing nutrients and aeration to the soil, they interact and bind with toxic heavy metals, radionuclides, pesticides, industrial dyes, and other xenobiotics that may be present as pollutants in the ecosystem, thus acting as natural sieves. As top soils have maximum organic matter, essential for plant growth, phenomenon like soil erosion leave the soils devoid of humic substances. Another major reason for soil degradation is excessive salinity, leading to osmotic and ionic stress in plants, eventually reducing their growth. Addition of humic acid in soils provides protection against high saline stress and minimizes yield losses. In India, one of the leading agrarian countries, it is a common practice to enrich soils with manure, which is an inexpensive form of humus-boost for the crops. Such practices aid the cyclic flow of organic matter in the environment, against the background of widespread soil degradation.&lt;/p&gt;&lt;p&gt;Another global form of soil degradation is radioactive contamination of soils which occurs mainly due to nuclear accidents and improper practices of radioactive waste disposal. In order to explore such interactions with humic acid following Green technique, batch biosorption studies were performed over a range of parameters, with radionuclides Cs and Sr that are found in low level radioactive wastes. Biosorption percentages of 91&amp;#177;2% and 84&amp;#177;1% were obtained for Cs and Sr respectively. The technique is chemical-free and emphasizes the &amp;#8216;nature for nature&amp;#8217; outlook of solving environmental problems. Humic acid and its various forms thus act as traps for radionuclides and work as excellent restorative soil stimulants that supplement depleted soils, boost plant growth, and play a vital role in sustaining life on Earth.&lt;/p&gt;

Stimulation of Plant Growth by Humic Substances

1976 ◽  
Vol 40 (6) ◽  
pp. 876-879 ◽  
Author(s):  
Yong Seok Lee ◽  
Richmond J. Bartlett
Keyword(s):  
Plant Growth ◽  
Humic Substances ◽  
Stimulation Of

scholarly journals A Meta-Analysis and Review of Plant-Growth Response to Humic Substances

2014 ◽  
pp. 37-89 ◽  
Author(s):  
Michael T. Rose ◽  
Antonio F. Patti ◽  
Karen R. Little ◽  
Alicia L. Brown ◽  
W. Roy Jackson ◽  
...  
Keyword(s):  
Plant Growth ◽  
Humic Substances ◽  
Growth Response ◽  
Meta Analysis ◽  
Plant Growth Response

EFFECTS OF HUMIC SUBSTANCES ON PLANT GROWTH

1988 ◽  
pp. 412-412 ◽  
Author(s):  
Y. Chen ◽  
T. Solovitch
Keyword(s):  
Plant Growth ◽  
Humic Substances

Mechanisms of micronutrient uptake in plants

2001 ◽  
Vol 28 (7) ◽  
pp. 661 ◽  
Author(s):  
Robert J. Reid
Keyword(s):  
Plasma Membrane ◽  
Trace Metals ◽  
Plant Growth ◽  
Expression Systems ◽  
Cation Uptake ◽  
Micronutrient Uptake ◽  
Heterologous Expression Systems ◽  
Metal Micronutrients ◽  
Uptake Studies ◽  
Kinetics Of

In plants, the elements Fe, Zn, Mn, Cu, Ni, B, Mo and Cl are considered to be micronutrients essential for plant growth. Micronutrient uptake systems are intrinsically more difficult to investigate than their macronutrient counterparts because of the low fluxes involved. Currently, the mechanism of transport for these micronutrients has not been clearly identified, except for Cl. In the case of the trace metal micronutrients, uptake studies point to the presence of high and low affinity transporters with broad substrate specificity. The kinetics of these transporters is clouded by the failure of many investigators to consider the effects of the electrostatic nature of the plasma membrane on cation uptake. Recent work has helped to clarify the nature of B movement across membranes and there is now evidence of a facilitated transport system for B, in addition to its passive permeation directly through the membrane. The uptake of Mo is known to be induced by NO3 and inhibited by W, but little further information is available on how Mo enters cells. In recent years, the emphasis has shifted from physiological studies of micronutrient uptake to molecular investigations of transporters cloned in plants and characterized in heterologous expression systems. There is now a substantial catalogue of transporter genes, mostly for trace metals, whose functions in plants have yet to be clearly defined.

Humic substances and trace metals associated with Fe and Al oxides deposited in an acidic mountain stream

1992 ◽  
Vol 117-118 ◽  
pp. 485-498 ◽  
Author(s):  
Diane M. McKnight ◽  
Robert L. Wershaw ◽  
Kenneth E. Bencala ◽  
Gary W. Zellweger ◽  
Gerald L. Feder
Keyword(s):  
Trace Metals ◽  
Humic Substances ◽  
Mountain Stream
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