INTRODUCTION
Soil is losing its fertility quality due to human practices and
because people do not know the importance of microorganisms in conservation of
soil and its fertility in Pakistan.
THE
OBJECTIVE
The aim of the project is to conserve soil and increase fertility
in lieu with Sustainable Development Goals (SDG) -15. The objectives are;
·
determine soil health of agricultural land,
·
determine role of microorganism in soil
·
provide solutions to improve soil fertility.
The improvement in soil health and fertility will help the country
and increase business such as, support the farmers, more grazing land for
cattle thus, increase in dairy products, good quality and quantity of
vegetables and fruits will be available, increase in export of agriculture
products, grow ornamental plants for nurseries, herbs for medicinal purposes
and increase in agriculture and botany research.
From available data it is now known that 33% of earth’s soil is
degraded and 24 billion ton of fertile soil is lost per year through
agricultural practices. Decrease in soil fertility leads to food security.
There are various
goals needed to be achieved to maintain a sustainable developed environment.
One of the important is the SDG 15, Life on Land. SDG 15 believes in
protecting, restoring, sustainably managing of the forestation, and preventing
soil desertification in order to stop biodiversity loss.
Worldwide, 2.6
billion people thrive on agricultural practices. Therefore, land management
that also promotes soil health is essential. Soil degradation is one of the
major problems.
SOIL
FUNCTIONS
SOIL
DEGRADATION ISSUE IN PAKISTAN
Soil is the most important part of earth. It provides many benefits
and services to the ecosystem. Reduce in soil health will cause many
sustainable issues, such as; there will be increase in green house gasses,
flood risk, and decrease in soil fertility.
It is reported
that Pakistan has not made much progress in achieving the SDGs. Soil erosion is
one of the major issues in Pakistan which affects the productivity of soil and
also the agriculture. Pakistan is known for its fastest urbanization in south
Asia as the population sets to keep increasing. Thus, urbanization, meaning
losing the land management is a greatest threat to biodiversity and soil
quality
Pakistan’s
agriculture is dropping low due to it losing its land to degradation. There is
prominently low-yield production of crops and livestock. Large area of the
country is conflicted with decreasing soil fertility and water logging.
DEGRADATION IN URBAN LANDSCAPE
The urban
landscape for example in Islamabad is increasing highly day by day disturbing the
ecology and environmental aspects. Pakistan is losing its forest cover, and
thus also the fertile soil that was home to many organisms and plantation. As
the population increases, so does the development and thus consumed up the
agricultural land in the process and tree cover.
Loss of soil fertility leads to loss of nutrients and minerals
which causes decrease in crop production. There are many degraded soils
worldwide and there number is increasing yearly. This is giving rise to food
security issues. For example, the wind in New Mexico is causing soil erosion
and the rate of erosion has increased to 23 tons/acre as recorded in 2015.
Table 1 Degraded Land
|
Productivity Decreased |
Soil Degraded |
|
20% |
Cropland |
|
16% |
Forests |
|
19% |
Grassland |
|
27% |
Rangeland |
SIGNIFICANCE
OF SOIL MICROORGANISMS
Microorganisms are known to be soil indicators as they indicate
about the health of the soil. They adapt and respond to change in environment.
Thus, causing change in the physical and chemical properties of soil and
indicating for improvement or warming of degradation of soil.
Topsoil:
Most of the biological activities occur in topsoil. The topsoil is
measure approximately 30cm where the natural microbiota is found. The reason of
large biological activities is the presence of microorganism.
Functions
of Microorganisms:
Microorganisms are involved in mineral cycles. Other functions
performed by the microbes in soil are;
·
decomposition,
·
scavenging
·
immobilization
of minerals
·
maintenance
of soil structure
NON-SYMBIOTIC BACTERIA
The free-living
nitrogen fixing bacteria known as non-symbiotic bacteria do not require any
host and therefore mostly live in the soil or aquatic conditions.
i.
Nostoc
Example
includes Nostoc, found in freshwater.
These mostly grow as filaments that are chains of cells.
ii.
Azobacter
Another example of
free living bacteria is Azobacter
genera. It is able to grow in substrates that have aromatic compounds. In a
research, strains of these bacteria were found in soil that was heavy in olive mill
wastewater (OMWW). Therefore, to enhance the soil OMWW is added in order to
facilitate the growth and nourishment of Azobacter
bacteria.
Moreover, they are located onto
submersed aquatic angiosperms and submersed portions of emergent macrophytes [13]. In an experiment performed, Azobacter was enabled to grow by culturing without nitrogen but H2
supply. The results were positive [14].
Figure 2 - Bioremediation of OMWW and how Azobacter is added for its known importance
iii.
Beijerinckia
Next we have the genus known as Beijerinckia. It is
abundantly found in the tropical forests soil. Study shows presence of 48% soil
full of Beijerinckia. They can also be grown on media, hence
on agar media that contains absence of nitrogen but glucose mineral present,
and it will produce elastic slime like colony. Whereas, on liquid media tends
to produce viscous colonies.
An interesting study shows that strains of Beijerinckia were found to be growing and
functioning in the waterlogged rice soils. It is possible for this strain to
grow in extremely low pH levels. Mainly the distribution of Beijerinckia is in
the tropical.
iv.
Azospirillum sp
Another example
of free-living bacteria is Azospirillum sp. It is however found in roots and rhizospheres of
different plants (figure 2). Examples of such plants are sugar-cane, maize and
sorghum. These species are known to be growth-promoting rhizobacteria (PGPR).
These can adapt to soil acidity very quickly. They can be cultured in mediums
with good supply of sucrose.
of plant from the soil
SIGNIFICANCE OF NON-SYMBIOTIC NITROGEN FIXING BACTERIA
Excessive quantities of costly fertilisers are
used in intensive agricultural methods to produce full crop yields. Biological
nitrogen fixation by symbiotic and non-symbiotic bacteria, on the other hand,
can help increase soil fertility and crop production while reducing the use of
chemical fertilizers.
Non-symbiotic
nitrogen fixation (by free-living bacteria in soils or with the
rhizosphere) has the capacity to solve some of this demand, particularly in
low-input cropping systems around the world. Although the ultimate aim may be
to insert nitrogenase genes into major non-leguminous crop plants, it may be
more practical in the short term to improve plant-microbe interactions to
increase N2 fixation when the plant's N needs are highest.
Inoculation with highly
efficient N2-fixing bacteria, particularly if they also have the ability to
promote plant growth, may yield a lot of benefits. The ability to survive in
soil and colonise plant roots is the greatest measure for perhaps the most beneficial
inoculant. Inoculation with bacteria capable of forming an endophytic
relationship with the plant (either in below-ground or above-ground parts) can
improve the chances of success. The true diversity of diazotrophic bacteria in
agricultural and natural habitats, as well as their ability to be used as
inoculants in agricultural environments, can be shown by new studies using
molecular techniques.
Furthermore, co-occurrence network analysis
using nifH sequence data shows that free-living diazotrophs have more diverse
co-occurrence patterns than symbiotic diazotrophs. Such new insights into
diazotroph ecology can contribute to the production of inoculant mixtures that
facilitate overall N2 fixation. The reintroduction of traits that facilitate
the colonisation of highly productive diazotrophic populations into modern
varieties can help agricultural systems contribute more biologically fixed
nitrogen, particularly in non-leguminous crops.
CONCLUSION
Finally, to conclude, we can say that Non-symbiotic nitrogen fixation offers an
appealing choice as an environmentally friendly alternative fertiliser source
for long-term food production, especially in low organic matter and low
fertility soils around the world.
References
[1] J. S. Head, M. E. Crockatt, Z. Didarali,
M.-J. Woodward, and B. A. Emmett, “The Role of Citizen Science in Meeting SDG
Targets around Soil Health,” Sustainability, vol. 12, no. 24, 2020.
[2] N.
Ravindra, “SUSTAINABLE LAND MANAGEMENT INDICATORS UNDER THE FRAME OF UN SDG 15:
LIFE ON LAND (A CASE STUDY ON INDIA).”
[3] S. Ahmed,
“Social development and the Sustainable Development Goals in South Asia: edited
by Nitya Mohan Khemka and Suraj Kumar, London and New York, Routledge, 2020,
xxix+ 219 pp.(hardback), ISBN 978-1-138-49047-5.” Taylor & Francis, 2021.
[4] M. Shuaib
et al., “Impact of rapid urbanization on the floral diversity and agriculture
land of district Dir, Pakistan,” Acta Ecol. Sin., vol. 38, no. 6, pp. 394–400,
2018.
[5] H. Gilani,
S. Ahmad, W. A. Qazi, S. M. Abubakar, and M. Khalid, “Monitoring of Urban
Landscape Ecology Dynamics of Islamabad Capital Territory (ICT), Pakistan, Over
Four Decades (1976–2016),” Land, vol. 9, no. 4, p. 123, 2020.
[6] R. F. Hüttl
and M. Frielinghaus, “Soil fertility problems — an agriculture and forestry
perspective,” Sci. Total Environ., vol. 143, no. 1, pp. 63–74, 1994.
[7] J. Idowu,
R. Ghimire, R. Flynn, and A. Ganguli, “Soil Health;Importance, Assessment and
Management,” Aces.Nmsu.Edu/Pubs, pp. 1–16, 2019.
[8] M. N.
Nielsen, A. Winding, and S. Binnerup, “Microorganisms as indicators of soil
health,” 2002.
[9] T. H.
DeLuca, L. E. Drinkwater, B. A. Wiefling, and D. M. DeNicola, “Free-living
nitrogen-fixing bacteria in temperate cropping systems: Influence of nitrogen
source,” Biol. Fertil. Soils, vol. 23, no. 2, pp. 140–144, 1996.
[10] W. H.
Gerwick, “Plant sources of drugs and chemicals,” 2017.
[11] K. Killham
and J. I. Prosser, “Chapter 3-The Bacteria and Archaea en Paul EA (Eds) Soil
Microbiology, Ecology and Biochemistry.” Academic Press, Boston, 2015.
[12] M.
Niaounakis and C. P. Halvadakis, “Olive processing waste management: literature
review and patent survey,” 2006.
[13] R. Athavale
et al., “In situ ammonium profiling using solid-contact ion-selective
electrodes in eutrophic lakes,” Anal. Chem., vol. 87, no. 24, pp. 11990–11997,
2015.
[14] T. Y. Wong
and R. J. Maier, “H2-dependent mixotrophic growth of N2-fixing Azotobacter
vinelandii.,” J. Bacteriol., vol. 163, no. 2, pp. 528–533, 1985.
[15] D. S.
Thuler, E. I. S. Floh, W. Handro, and H. R. Barbosa, “Beijerinckia derxii
releases plant growth regulators and amino acids in synthetic media independent
of nitrogenase activity,” J. Appl. Microbiol., vol. 95, no. 4, pp. 799–806,
2003.
[16] J.-H.
Becking, “Genus Beijerinckia Derx 1950, 145^,” Bergey’s Man. Syst. Bacteriol.,
pp. 311–321, 1984.
[17] J. H.
Becking, “Beijerinckia in irrigated rice soils,” Ecol. Bull., pp. 116–129,
1978.
[18] O.
Steenhoudt and J. Vanderleyden, “Azospirillum, a free-living nitrogen-fixing
bacterium closely associated with grasses: genetic, biochemical and ecological
aspects,” FEMS Microbiol. Rev., vol. 24, no. 4, pp. 487–506, 2000.
[19] R. Cecagno,
T. E. Fritsch, and I. S. Schrank, “The plant growth-promoting bacteria
Azospirillum amazonense: genomic versatility and phytohormone pathway,” Biomed
Res. Int., vol. 2015, 2015.
[20] M. Turan et
al., “Nonsymbiotic and Symbiotic Bacteria Efficiency for Legume Growth Under
Different Stress Conditions,” in Microbes for Legume Improvement, A. Zaidi, M.
S. Khan, and J. Musarrat, Eds. Cham: Springer International Publishing, 2017,
pp. 387–404.
[21] M. M. Roper
and V. Gupta, “Enhancing non-symbiotic N2 fixation in agriculture,” Open Agric.
J., vol. 10, no. 1, 2016.
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This article has been shared by the following authors to
PAKAGRIFARMING.
Authors: Fatima Haider, Jaweria Malik, Samra Hayat Khan
