Influence
of Albit on Soil Microbial Community: Increased Fertility and Healthier
Soils
In contrast to most of analogues, Albit has direct effect not
only on plants and also can indirectly stimulate plant growth, influencing
on soil microbial communities, living in plant rots and soil.
In comparison with other habitats, soil has more diversity and abundance
of microorganisms. More than one billion of live microorganisms are
in gram of healthy fertile soil. It is a huge strength, which has the significant
effect on growth and productivity of agricultural plants. It is only required
to «direct» the development of soil microorganisms into «favorable direction»
for agrosenosis. Microscopic fungi, some microalgae and a huge diversity of
bacteria, such as of genera Bacillus, Pseudomonas, Klebsiella, Azotobacter,
Beijerinckia, Clostridium, Arthrobacter, Flavobacterium, Aquaspirillum, Cellulomonas,
Cytophaga, Mycobacterium, Derxia, Nocardia, Agromyces, Rhizobium, Agrobacterium and
others refer to soil microorganisms. The majority of soil microorganisms positively
affect plants (Lysak et al., 2003).
The richest biodiversity and largest number of microorganisms are typical
for rhizosphere (the narrow area adjacent to plant roots). The most important
factor determining the distinctions of rhizosphere and others parts of soil
is the close interaction between microorganisms and plant. Plant activity determines
to a great extent gaseous and water metabolism, as well as feed conditions
inside of rhizosphere. In turn, soil microorganisms significantly positively
affect plants: provide physiologically active compounds, vitamins, fixed nitrogen
(nitrogen fixation), release phosphorous, potassium and microelements from
soil minerals (Bab’eva, Zenova, 1989).
The majority of known soil bacteria are not free-living, but live in various
types of interaction (association, symbiosis, and parasitism) with plants,
animals, and fungi. Interaction between bacteria plays the most important part
in phyllosphere, rhizoplane, and rhizosphere. In soil community, bacterial
species closely interact with each other and with variable environment.
Enrichment of soil by organic fertilizer can selectively guide the
development of microbial consortiums towards the formation of new
associations characterized by other functions (Fukui, 2003). This approach
creates the background of microbiological control of plant pathogens. In
the absence of external stress, natural bacterial consortium is a stabilizing
factor preventing plant pathogens development within the soil. It is well-known
that soil microorganisms can enhance or diminish fungicide effect. Suppressive
soils are the soils which resist plant diseases (Singleton, Sainsbury, 1993).
Positive impact of Albit upon plants could be in part explained by indirect
effect on soil community. Albit gets into soil mainly from the treated seeds
and involve changes in operation of soil microflora including microorganisms
in rhizosphere.
External influence of sufficient intensity causes microbial succession. Ecological
succession is the systematic and well-organized process of change in the biodiversity
and species structure
of an microbiological community over time. From a practical point of view,
it is important to guide microbial succession in the right direction — toward
the maximal stimulation of plant growth and suppression of pathogens.
Investigations showed that Albit acts within the specified paradigm. Effect
of Albit on soil microorganisms was studied at the Pedology Faculty of Moscow
State University (the Department of Soil Biology and Agricultural Chemistry).
Soil samples from the vegetation experiment pledged at the Department of Agricultural
Chemistry in 1999 were studied.
It was found that treatment by Albit causes changes in the microbial community
of plants’ rhizosphere, resulting in the reduction of pathogenic microscopic
fungi number (e.g. Fusarium genus), and increasing
of bacterial amount. Also the growth of micromycetes abundance (Gliocladium,
Sladosporium and Trichoderma), antagonists of plant
pathogens, was shown. After Albit treatment the number of Trichoderma and
other soil fungi-antagonists increases. Thus, Albit application is an
important factor of biostimulant activity together with plant immunization
(Table 1, Fig.1).
The influence of Albit on biodiversity of different
philogenetic groups of microscopic fungi in the rhizosphere of spring barley
(Pot experiment was conducted at the Department of Pedology, Moscow State University, 1999)
The table shows the decline in the biodiversity of fungi or increase
relative to control (%) after the standard Albit application (seed treatment + sprayings).
"0" - no changes compared with the control
Group of Microscopic fungi
Rhizosphere
Bulk soil
Penicillium (P. chrysogenum, P. ñommune,
P. expansum, P. waksmani, P. ñåêöèè Biverticillata,
Penicillium spp.)
3,4/1,7
–3/–2,4*
Mucor
–30,8/14,3
16,7/–12,5
Fusarium
–71,4/–75
–25/0
Acremonium
0/0
0/–16,7
Trichoderma
0/0
25/20
Gliocladium fimbriatum
**/150
0/**
Aspergillus (A. niger, A. fumigatus)
–100/200
0/0
Verticillium
0/0
0/0
Cladosporium cladosporiodides
200/600
0/100
Paecylomyces
–60/–100
0/–33,3
Scopulariopsis brevicaulis
0
–50/–50
Chrysosporium
200/0
–100/–50
Talaromyces luteus
0/–100
0/0
Humicolagrisea
—
0/–100
Äðóãèå ãðèáû ñåì. Dematiaceae
—
33,3/–100
Mycelia sterilia
0/100
–25/0
* numerator is the fungi amount, determined by plating on Czapek’s medium,
denominator – on Getchinson media;
** – Microscopic fungi of this philogenetic group were not determined.
Fig. 1. Influence of Albit on the quantity of microscopic
fungi of basic taxonomic groups in rhizosphere of spring barley. Calculated
on nutrient media (Pot experiment of the Department of Pedology, Moscow state
University, 1999)
The pot experiments were confirmed afield. According to the Ryazan and Saratov
regional plant protection stations, systematical application of Albit improves
the phytosanitary conditions of the soil. The experiments conducted in All-Russian
Institute of Floriculture and Subtropical Crops demonstrated that Albit application
the number of conidia of pathogen Phytophtora cactorum in garden soil
was reduced by 52-56% (Fig. 2).
Fig. 2. Influence of applying of different doses of Albit
into soil (3 treatments during vegetation season) on infectious background of
Phytophtora cactorum in plantation of sweet actinidia
(VNIITsiSK, 2013, assessment in the end of trial - october).
It was found out that Albit enhances total amount of microorganisms in soil
and radical area, increase copiotrophs and nitrogen-fixing bacteria content
in rhizosphere. Albit increased total amount of bacteria (from 3 to 3.5 õ 106
per g of soil, and from 8 to 14.7 õ 106 on roots of plants). However the amount
of rhizospheric bacteria was reduced (Table 2). By the end of vegetation the
differences in the number of distinct groups of bacteria were smoothed out.
It was noted for both kopiotrophic and oligotrophic bacteria. At the same time
the reduction of total bacterial amount was shown for both the control, and,
especially, the variant with Albit. It is connected with the fact that Albit
application leads to significant stimulation of growth and launch of the soil
microbial succession. As a result the number of bacteria initially increases,
and then, at the final stages of succession, decreases as compared with the
control.
Table 2. Microbiological characteristics of the soil following the
treatment of barley with Albit (based on the pot experiment at Moscow State University, 1999) Dosage of Albit - 30 ml / m + 30 ml / ha.
The number of microorganisms (million of colonies / g of soil), inoculation on glucose-peptone agar media , registered at the tillering stage.
Variant
Total
Actinomycetes
Sporeforming bacteria
Epiphytic bacteria
Corynebacteria
Soil
control
3,0
2,0
0,6
0,0
1,0
treated with Albit
3,5
0,1
0,8
0,0
3,0
Rhisosphere
control
4,0
0,5
0,1
0,0
3,5
treated with Albit
2,0
0,1
0,1
0,0
1,8
Barley roots
control
8,0
0,0
0,1
1,0
6,9
treated with Albit
14,7
0,0
0,9
2,5
11,3
At the same time, the number of growth-stimulating and nitrogen-fixing bacteria
in soil increased under the influence of Albit (e.g., Azotobacter),
growth-stimulating capacity of the soil increased by 50-100%, its overall toxicity
significantly reduced: from 25-55 to 0-30 units (Table 3). Under the influence
of Albit the increase in activity of beneficial microorganisms that encourage
plant growth, and reduced activity of pathogenic microorganisms was established
(Kostina, Zlotnikov, 2000).
Table 3. The influence of barley treatment with Albit (30 ml/t)
on toxicity of rhizosphere soil (Soil Biology Department of Moscow State University, 1999)
Plants growth stage
Diameter of toxicity zone, mm
control
treatment with Albit
The beginning of vegetation
40-55
0-30
The middle of vegetation
25-30
0-30
The end of vegetation
25-30
0
Thus, reorganization of soil microbial community is an important mechanism
that reduces the harmfulness of pathogens without inoculation of living biofungicides.
Albit just stimulates the growth of fungicidal microorganisms, which are already
present in the rhizosphere.
Albit does not contain living nitrogen-fixing bacteria. However, Albit enhances
the potential activity of nitrogen fixation in rhizosphere at the beginning
of the growing season by 12-66% due to the regulatory effect on the native
microflora. It should be noted that this effect did not continue during all
growing season, starting from the stage of stem elongation the level of nitrogen
fixation decreased, but denitrification - increased (Fig. 3).
Fig. 3. The effect of Albit treatment on the
activity of the nitrogen cycle processes in the rhizosphere of barley in
a pot experiment (Department of Pedology, Moscow State University, 1999). NFa - actual nitrogen fixation,
NFp - potential nitrogen fixation, DNa - actual denitrification
DNp - potential denitrification
Influence of Albit on soil N2-fixers was evaluated on the most active ones, Rhizobia.
Indigenous soil population of Rhizobia is usually insufficient for formation
of required amount of root nodules of legumes. Generally, additional treatment
of seeds with Rhizobia inoculants is used to overcome this problem. Albit allows
to use the alternative approach directly in the field: stimulation of activity
and virulence of natural soil Rhizobial population. In field trial, performed
by National Institute of Biological Plant Protection (Rus. Acad. Agric. Sci.)
(Krasnodar, 2010) on soybean, it was shown, that Albit improves formation of
root nodules on non-inoculated plants. In the field trial, application of Albit
(seed treatment and spraying in combination with herbicides 30-50 mL/t) increased
amount of nitrogen fixing nodules per one plant up to 13.5-53.2% over herbicide-only
control.
Seed treatment with Albit increased the amount of nodules up to 39.7% over
control, sprayings with Albit in combination with herbicide – up to 50.8%,
combined application (seed treatment + spraying) – 53.2% (Fig. 4). Increased
amount of nodules proportionally resulted in increased crop yield (up to 17
% over control).
Fig. 4. Influence of application rate of Albit and different
ways of treatment, on the amount of nitrogen fixing nodules on soybean roots
(field trial by National Institute of Biological Plant Protection, Krasnodar,
2010)
At the basis of the action of Albit on the soil microbial community, in our
opinion, lies the properties of poly-beta-hydroxybutyric acid (see
details).
This compound, like many polymers of biological origin (starch, cellulose,
chitin) promotes initiation of microbial succession, formation of specific
hydrolytic, and related organisms community, which has an indirect positive
effect on plants. As a result, the Albit application provides an additional
input of nitrogen and other nutrients in plants (see àor more
details).
Chemicalization in agriculture using intensive technology destroys the natural
microbiocenosis capable of protecting plants from phytopathogens. Pesticides
inhibit microbial activity of the soil by 30-50% [Karpun,
Janushevskaya, 2014]. In perennial field trials performed at National
Scientific Research Institute of Floriculture and Subtropical Crops RAAS (Sochi)
it was shown that Albit is able to reduce the negative impact of pesticides
(based on dithianon,
α-cypermethrin, λ-cyhalothrin, δ-methrin) on soil microbial
consortium (Janushewskaya,
Kaprun, 2011). Albit increases the resistance of soil microflora to the
toxins, and normalizes its biological activity which is suppressed by the usage
of pesticides (Fig. 5). Field trials were carried out on plantations of peach
and apple trees (the farm gardens of All-Russian Scientific Research Institute
of Floriculture and Subtropical Crops RAAS (Sochi)). Albit was used within
standard protection protocol of gardens in conjunction with chemical pesticides
(insecticides and fungicides). The first treatment of peach trees with Albit
and dithianon was performed before flowering stage. Albit was used together
with pyrethroids after flowering during the second and third treatments. Gardens
without usage of pesticides, as well as virgin forest were taken as a control.
During the field trials the dynamics of the overall biological activity of
the soil all over the growing season was determined.
Fig. 5. The dynamics of potential activity of soil of apple
garden after treatment with insecticide (a.i. is δ-methrin) in conjunction
with Albit
The treatment of plot trials of apple garden with chemical pesticides decreased
the basal respiratory activity of soil microflora (Fig. 4). Complete normalization
of the respiratory activity of the soil was not observed even a month after
application of pesticides. Albit used together with pesticides significantly
reduced their negative side-effects: addition of Albit to standard
chemical treatment almost regained the level of microbial activity on the level
of undisturbed soil. These patterns were observed annually during
the all studied period of 2008-2010 both with insecticides, and fungicides).
The adaptogenic activity of Albit was especially expressed in drought conditions
of 2009.
It was found that the intensity of the adaptogenic properties of Albit essentially
depends on the soil conditions, which stimulate metabolic processes. The main
non-specific mechanism of adaptogenic action of Albit is the activation of
substrate-induced aerobic respiration, which laid in the base of increasing
intracellular bioenergy resources and provide adaptation of microbial consortium
to stress factors of different origins.
Albit is able to significantly reduce oil pollution of soil by stimulation
the natural soil microflora and plant growth. The rate of oil decomposition
in the soil increases in average by 1.67-3.15 times under the influence of
Albit. Industrial tests showed that Albit together with sowing of oil-tolerant
grasses reduces oil contamination of soils by 1.5-10.0 times during one growing
season.
Thus, Albit exerts beneficial influence upon plants, increases their mineral
nutrition, reduces the possibility of pathogens injury, reduces the toxicity
of soils, acting indirectly through the soil microbial community. Albit acts
as an integrated, balanced, and protective bio-stimulant, embracing nearly
all spheres of plants vital activity.
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