MEKDELA AMBA UNIVERSITY

College of Agriculture and Natural Resource

Department of Natural Resource Management
Review on:
The Role of Organic Fertilizer on Crop Production and Soil Management
in Ethiopia

Prepared by: ID No

1.GASHAW GELETAW 1400752

2.DEREJE GURMU 1400531
3.DERBE BEHAYLU 1400528
4.DIRIBA TEKLE 1300584
5.EMEBET CHANE 1400647

Advisor: Tadla G. (MSc)

A Senior Seminar Paper Submitted to the Department of Natural Resource

Management

March,2025 Tulu Awulia, Ethiopia

AKNOWLEDGEMENT
First and foremost,we would like to thank God Almighty and his Holy mother Virgin
Marry for giving for us the strength, knowledge, ability and opportunity to complete
this seminar paper on time. And,we went to express deepest thanks to ours advisor
(M.Sc.) Tadla G.for his valuable suggestions and guidance in the preparation of the
seminar paper. This Seminar paper would not have been possible without his
valuable suggestions and guidance.

I
II
LIST OF ABBREVIATIONS AND ACRONYMS

FAO Food And Agricultural Organization

FA Farming Association
AISCO Agricultural Input Supply Corporation
AISE Agricultural Input Supply Enterprises
OF Organic fertilizers

III
1. INTRODUCTION
1.1 Background

Ethiopia is one of the poorest countries in the world. The record of Ethiopia is even
far lower than the average Sub Saharan Africa (SSA) countries that are also termed
as poor by the world standard. For instance, between the period 1975-2000, GNP
per capita of Ethiopia is four times lower than the average SSA countries (World
Bank, 2002). Agriculture remains the key sector for the economic development for
most developing countries. It is critically important for ensuring food security,
alleviating poverty and conserving the vital natural resources that the world's
present and future generations will be entirely dependent upon for their survival and
well-being (FAO, 2004). Some three quarters of the world's absolute poor live in
rural areas, and their livelihoods are most often linked to agriculture. Like other
developing countries, the economy of Ethiopia draws its main strength from
agriculture because of the potentiality to produce multiplier effects on the growth of
other sectors of the economy. It is the principal source of livelihood for most of the
poor and has a key role in building their household food security (Ministry of
Agriculture, 2003).
However, the productivity of the land decreased from time to time due to adverse
effect of agro-chemicals on soil, water, food and atmospheric environment. Organic
farming system is therefore an important prerequisite for boosting up crop
production and sustaining higher yield over a period of time. Future strategies for
increasing agricultural production will have to focus on using available natural
resources more efficiently, effectively and sustainable than in the past. Organic
farming seems to be more appropriate, which considers the important aspects like
sustainability of natural resources and environment and economic development
(Gruh et al., 2000).
Organic farming is a production system which favors maximum use of organic
materials (crop residue, animal residue, legumes, on and off farm wastages, growth
regulators, and bio-

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pesticides) and discourages use of synthetically produced agro-inputs, for
maintaining soil productivity and fertility and pest management under conditions of
sustainable natural resources and healthy environment. It emphasis’s the use of
renewable natural resources and their recycling (Emsley, 2001).
This system helps farmers to make a decision regarding proper way of farm
management which enhances high crop yields and improves the soil fertility in the
long run (FAO, 1998).
Organic fertilizers include naturally occurring organic materials, (e.g. chicken litter,
manure, warm casting, compost, seaweed, guano ,bone meal) or naturally occurring
mineral deposits (e.g.saltbeter)poultry litter and cattle manure often create
environmental and disposal problems, making their use as fertilizer beneficial. Bones
can be processed into phosphate-rich bone meal; however, most are simply buried
in landfills. Even if all bones, human, animal and plant wastes were recovered to the
extent practical and used for fertilizer, mineral fertilizers and synthetic nitrogen
would still be required to make for losses to leaching, to the atmosphere, runoff and
the losses impractical to recover (Allan, 2003).

1.2. Objective

The general objective of this seminar paper is to review the role of organic fertilizers
on crop production and soil management.

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2.1 Role of Organic Fertilizer

OF are derived from natural sources such as plant residues, animal manure, and
compost. They play a significant role in improving soil structure, enhancing nutrient
content, and promoting microbial activity. Unlike chemical fertilizers, organic
fertilizers release nutrients slowly and steadily, which improves soil fertility and crop
productivity in the long term (Pimentel et al., 2005).
OF contribute significantly to the physical, chemical, and biological properties of the
soil. They enhance the soil’s organic matter content, leading to better aggregation,
increased porosity, improved water-holding capacity, and reduced erosion.
(According to Palm et al. ,2001), the consistent use of organic materials enhances
cation exchange capacity (CEC) and nutrient-holding potential, which are essential
for nutrient cycling.
Furthermore, (Adekiya et al. ,2019) found that the application of poultry manure
improved soil pH, organic carbon, and nitrogen content, which in turn positively
influenced maize and okra yield. The presence of macro and micronutrients in
organic materials provides a balanced nutrient supply for crops
Research indicates that organic fertilizers increase the organic matter content of the
soil, which enhances water retention, aeration, and root development. )Edwards and
Arancon 2004) emphasized that continued use of organic inputs boosts soil microbial
populations and enzyme activities, which are essential for sustainable crop
production.
(Adediran et al.2003) conducted a field experiment using poultry manure and found
a significant improvement in maize yield, indicating that organic fertilizers can be as
effective as chemical fertilizers under certain conditions. Similarly,( Zheljazkov and
Warm an 2004) reported improved nutrient uptake and plant growth in vegetables
treated with composted organic matter.
Additionally, organic fertilizers contribute to environmental sustainability by
minimizing chemical runoff, reducing soil and water pollution, and decreasing
greenhouse gas emissions. According to the Food and Agriculture Organization (FAO,
2018), organic inputs are vital in supporting climate-smart agricultural practices and
enhancing biodiversity.

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The future of agriculture lies in integrated nutrient management (INM), which
combines organic and inorganic fertilizers to optimize productivity and sustainability.
(Sagging and Boomer 2009) emphasized the need for integrated systems in sub-
Saharan Africa to address soil degradation while boosting food security.

2.2. Organic Fertilizer Sources

OF are derived from natural biological sources and are essential for maintaining soil
health and fertility in sustainable agriculture systems. These sources can be broadly
categorized into plant-based, animal-based, and mineral-based materials. Each
category contributes specific nutrients and organic matter to the soil, improving its
physical, chemical, and biological properties.

Animal: Animal-sourced and human urea are suitable for application organic
agriculture, while pure synthetic forms of urea are not. The common thread that can
be seen through these examples is that organic agriculture attempts to define itself
through minimal processing (in contrast to the man-made Haber process), as well as
being naturally occurring or via natural biological processes such as composting.
Besides immediate application of urea to the soil, urine can also be improved by
converting it to strutted already done with human urine by a Dutch firm. The
conversion is performed by adding magnesium to the urine. An added economical
advantage of using urine as fertilizer is that it contains a large amount of phosphorus
(Barbara et al., 2003).

Plant: Leguminous cover crops are also grown to enrich soil as green manures
through nitrogen fixation from the atmosphere as well as phosphorus (through
nutrient mobilization) content of soils (Stefan, 2008).

2.2.1 Crop Residues

Crop residues refer to the plant parts left in the field after harvesting, including
stems, leaves, roots, and husks.Incorporating crop residues into the soil increases
organic matter and provides nutrients like nitrogen, phosphorus, and potassium
during decomposition. They also improve soil structure, water retention, and reduce

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erosion. When properly managed, residues help maintain soil fertility and reduce
dependence on chemical fertilizers.(According to Palm et al. ,2001), crop residues
are critical in nutrient recycling and contribute significantly to sustainable soil
fertility.Crop residues are carbon-rich materials that contain much nitrogen,
phosphorus, potassium and microelements. Crop residue input is a sustainable way
of improving soil quality without disturbing its biological balance. The decomposition
of crop residues can increase the contents of organic carbon and available
phosphorus, potassium in soils, which can provide nutrients for microorganisms and
crops. In addition, soil moisture, aggregate stability, and porosity also can be
improved. The negative effects of allelochemicals on crop growth can be adjusted by
crop residue returning management. However, the results of crop residue effects on
pH and heavy metals are inconsistent. Crop residues have inhibitory effects on some
heavy metals under some conditions. Furthermore, crop residues have positive
effects in reducing bioavailability of some soil organic pollutants, alleviating several
soil-borne pathogens, and improving saline-alkali soils.

2.2.2 Crop Rotation

Crop rotation is the practice of growing different types of crops sequentially on the
same land to enhance soil health and nutrient balance.Rotating crops, especially
with legumes or deep-rooted plants, improves nutrient cycling, reduces soil-borne
diseases, and minimizes pest infestations. It enhances soil fertility by breaking pest
cycles and improving microbial activity.( Sanginga and Woomer 2009) emphasized
that strategic crop rotation increases nitrogen availability, especially when legumes
are included in the sequence.Crop rotation is a smart farming technique involving
growing different crops in a specific sequence on the same land. This practice has
been around for centuries, and it’s not just a traditional Crop rotation is the practice
of growing a series of different types of crops in the same area across a sequence of
growing seasons.
Growing the same crop in the same place for many years in a row, known as
monocropping, gradually depletes the soil of certain nutrients and selects for both a
highly competitive pest and weed community. Without balancing nutrient use and

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diversifying pest and weed communities, the productivity of monocultures is highly
dependent on external inputs that may be harmful to the soil's fertility. Conversely, a
well-designed crop rotation can reduce the need for synthetic fertilizers and
herbicides by better using ecosystem services from a diverse set of crops.
Additionally, crop rotations can improve soil structure and organic matter, which
reduces erosion and increases farm system resilience.thod; it’s a powerful strategy
to enhance soil health and increase crop yields.(WorldAtlas 2017)

2.2.3 Legumes

Legumes are a family of plants (e.g., beans, peas, lentils) that form a symbiotic
relationship with nitrogen-fixing bacteria (Rhizobium spp). Legumes enrich soil by
converting atmospheric nitrogen into usable forms through biological nitrogen
fixation. This natural fertilization reduces the need for synthetic nitrogen inputs and
boosts subsequent crop yields. (FAO 2018) reported that leguminous crops can add
up to 100 kg/ha of nitrogen to the soil annually. When growing legumes, the best
fertilizer for beans and peas varies according to the nutrients in the soil but is usually
a low-nitrogen formulation. Because legumes have a symbiotic relationship with
nitrogen-fixing bacteria, they don't need extra nitrogen to thrive in the garden. In
fact, legumes fix nitrogen in the soil, so by rotating their location every year, the
entire garden benefits from your bean and pea plants.

2.2.4 Green Manures

Green manures are fast-growing crops, often legumes or cover crops, that are grown
specifically to be plowed into the soil to improve its fertility. These plants add
organic matter, fix nitrogen, suppress weeds, and enhance soil structure. Green
manures, such as sunhemp or clover, are especially effective in restoring depleted
soils. (Lal 2005) confirmed that green manures significantly enhance microbial
activity and soil carbon content.

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2.2.5 Compost

Compost is the product of aerobic decomposition of organic waste like crop residues,
food scraps, and manure, turned into stable humus-like material. Compost improves
soil structure, water retention, and provides slow-release nutrients. It also increases
microbial biomass and enzymatic activity in the soil. (Edwards and Arancon 2004)
showed that compost enhances plant growth and disease resistance, making it a key
input in organic farming systems.

2.2.6 Vermicompost

Vermicompost is the nutrient-rich organic fertilizer produced through the

breakdown of organic material by earthworms, particularly species like Eisenia
fetida. Vermicompost contains essential plant nutrients, plant growth regulators,
and beneficial microbes. It enhances seed germination, flowering, and fruiting.
(Domínguez and Edwards 2004) reported that vermicompost is more effective than
conventional compost due to its high microbial activity and bioavailable nutrients.
Vermicompost is a type of organic fertilizer made through the process of
vermicomposting, where earthworms are used to break down organic waste
materials like food scraps, crop residues, and manure into a nutrient-rich, soil-like
substance.

2.3 Importance of Organic Fertilizer

OF are materials derived from natural sources such as plants, animals, or minerals
that provide essential nutrients to plants. Unlike synthetic fertilizers, organic
fertilizers release nutrients gradually, improving soil health and promoting long-term
agricultural sustainability.

2.3.1 Soil Health Improvement

OF enhance the structure and texture of the soil by increasing its organic matter
content. This improves soil aeration, water retention, and microbial activity. Soil
Structure Improvement: Organic fertilizers enhance the soil structure, increasing its

7
ability to retain moisture and nutrients, which leads to better aeration and root
development.
Microbial Activity: They promote the growth of beneficial microorganisms in the soil,
which are essential for nutrient cycling and organic matter decomposition.(According
to Brady and Weil 2016), the increased organic matter helps create stable soil
aggregates, which prevents soil erosion and compaction.

2.3.2 Slow-Release Nutrients

OF provide a steady supply of nutrients as they decompose, reducing the risk of

nutrient leaching and minimizing environmental impact. (FAO 2017) emphasizes that
organic fertilizers help balance soil nutrient content over time, preventing nutrient
imbalances and supporting plant growth.

2.3.3 Reduced Dependency on Synthetic Chemicals

OF are free from synthetic chemicals, reducing the environmental hazards associated
with chemical fertilizers, such as water contamination, soil degradation, and harm to
beneficial organisms. (Magdoff and Van Es 2009) highlight that organic fertilizers
contribute to the sustainability of agricultural ecosystems by reducing the need for
chemical inputs.

2.3.4. Enhancing Soil Microbial Activity

OF encourage the growth of beneficial soil microorganisms, such as bacteria, fungi, and
earthworms, which are essential for nutrient cycling and soil health. (Lal 2006) notes that
the microbial life stimulated by organic fertilizers helps in the decomposition of organic
material, making nutrients available to plants.The enhancement of soil microbial activity
through organic fertilizers is of paramount importance for fostering a healthy, productive,
and sustainable agricultural system. By supporting microbial life, organic fertilizers facilitate
nutrient cycling, improve soil structure, increase plant health, and promote resilience against
environmental challenges. This holistic approach not only benefits individual plants but also
contributes to the overall sustainability of agricultural practices and ecological balance.

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2.3.5. Improved Crop Yield and Quality

OF contribute to better crop yields and improved crop quality by promoting robust
plant growth, healthy root systems, and resistance to pests and diseases.( According
to Altieri and Nicholls 2003), organic fertilizers enhance plant resistance to abiotic
stresses like drought and extreme temperatures.OF are fundamental to achieving
improved crop yield and quality. By enhancing soil health, providing essential
nutrients, promoting beneficial microbial activity, and improving plant resilience,
organic fertilizers contribute to sustainable agricultural practices that yield both
quantity and quality in crops. This holistic approach not only benefits farmers and
consumers but also promotes environmental stewardship and resilience within
agricultural systems.

2.3.6 Entrancement of sustainable Ecological Agriculture

(According to IFOAM 2005) the major importance of organic farming activities is a

sustainable production of quality food with little or no effect on the environment.
The growing concern about environmental degradation, dwindling natural resources
and urgency to meet the food needs of the increasing population are compelling
farm scientist and policy makers to seriously examine alternative to chemical
agriculture.
(According to Ananata 2002), an organic farm spend rupees 10,590 to produce 5625
kg paddy and 8 tonnes of straw/ha. The net returns from the ecological farming
system at the current cost of rupees 3.34/kg paddy is rupees 8,197.50. In chemical
farming, the net profit is rupees 7500. If one gets a premium price for the poison
force, organically grown rice, the economic returns from the ecological farming
system will highly encouraging.

2.3. 7 The economic value

The decline in the soil fertilities wide spread in Ethiopia and is threatening food
security in the country. The use of inorganic fertilizers to improve soil fertility has
immediate results the escalating price makes it impossible for the majority of
smallholders’ farmers to use them. There is therefore, need for alternative low cost

9
soil fertility enhancing technologies. An OF therefore seems to be available option to
be promoted. The economic value of an organic waste or residues to the farmer is
the increase in crop yield and/or crop quality that is derived from its use (Colacicco,
2002).
The actual profitability of using organic materials will vary with the quality of the
organic materials and the actual profitability of using organic materials is more
importance than inorganic fertilizers estimated that the cumulative economic value
of some organic materials applied to agricultural soils could be as much as five times
greater in succeeding years than the value realized during the application year
(Barbarika et al., 2003).

2.4 Disadvantages of Organic Fertilizers

While organic fertilizers offer numerous benefits for soil health and sustainable
agriculture, they also come with certain drawbacks that need to be considered in
agricultural practices. These disadvantages may affect their efficiency, application,
and overall impact on crop production.

2.4.1. Slow Release of Nutrients

OF release nutrients more slowly than synthetic fertilizers, meaning crops may not
receive nutrients immediately when they need them. This can lead to delayed plant
growth or nutrient deficiencies during critical growing stages. (According to Brady
and Weil 2016), while organic fertilizers improve long-term soil fertility, their slow
nutrient release rate might not be suitable for high-demand crops or fast-growing
plants.While organic fertilizers have many benefits for promoting sustainability and
soil health, their slow release of nutrients and other associated disadvantages can
present challenges for farmers and agricultural producers. It’s essential for growers
to understand these drawbacks and consider integrated nutrient management
practices that combine both organic and inorganic fertilizers to meet the specific
needs of their crops and soils. By balancing these approaches, farmers can effectively
enhance productivity while minimizing potential negative outcomes.

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2.4.2. Inconsistent Nutrient Content

OF are often heterogeneous in nutrient composition. For example, manure and

compost can vary in nutrient levels based on the source material and decomposition
process. (FAO 2017) highlights that this variability makes it difficult to apply organic
fertilizers with precision and could lead to under- or over-fertilization.

2.4.3. Bulkiness and Transportation Issues

OF, particularly compost and manure, tend to be bulky and heavy, which increases
transportation costs and handling time. (Magdoff and Van Es 2009) point out that
large quantities are often required to meet the nutritional needs of crops, making
the use of organic fertilizers less practical for large-scale farming without adequate
infrastructure.While organic fertilizers offer many benefits, such as improved soil
health and sustainability, their inconsistency in nutrient content presents challenges
that can affect crop management and productivity. Farmers must carefully consider
these disadvantages and may need to integrate organic and synthetic fertilizers or
adopt a comprehensive nutrient management approach to optimize crop yield and
maintain soil health. Understanding the nutrient profiles and consistent testing of
organic fertilizers can help mitigate some of these issues.

2.5. Importance and Value of Organic Fertilizers

What makes organic fertilizers different from chemical fertilizers is that the materials
are a by-product of vegetables, animals or minerals. The decomposing matter from
these sources, break down naturally and will provide nutrients and minerals to the
soil. When considering lawn maintenance it is necessary to make sure that the lawn
or garden gets the all of the nutrients that it needs for healthy growth. Although
nutrients are available in regular soil, fertilizers can provide and ensure that plants
have a balanced and sustainable access to the nutrients. Proper lawn care includes
providing for the health of the lawn and garden (Abram, 2005).

One of the benefits of organic fertilizer is that the nutrients are released more slowly
than in chemical fertilizers. This slower process allows the plants to process the
fertilizer in a more natural way and will not result in over fertilizing which could

11
damage the plants. Another benefit of organic fertilizer in your landscaping and lawn
care is that it will actually help to improve the soil itself. It will help the soil to retain
moisture (Barbarika et al., 2003).
The organic substances can break up clay in the soil. The soil drainage and air
circulation of the soil can also be improved. When considering what sort of organic
fertilizer to use, there are a variety of choices. You can ask your lawn care provider if
they use organic fertilizers. Having a compost pile is also a great way to get rid of
food waste and still contribute to your lawn care and the environment. Natural
organic fertilizer is the best choice for the healthy lawn and garden. It is an
important valuable option that will help the soil and the environment be healthy and
produce the best plants (Emsley, 2001).

CONCLUSION

Agriculture remains the key sector for the economic development for most
developing countries. It is critically important for ensuring food security, alleviating
poverty. The economy of Ethiopia draws its main strength from agriculture because

12
of the potentiality to produce multiplier effects on the growth of other sectors of the
economy. Organic farming is a production system which favors maximum use of
organic materials (crop residue, animal residue, legumes, on and off farm wastages,
growth regulators, and bio-pesticides) and discourages use of synthetically produced
agro-inputs, for maintaining soil productivity and fertility. More recently, organic
fertilizer is on the rise as people are resorting to environmental friendly green
products. Although organic fertilizers usually contain a lower concentration of
nutrients, this lower concentration avoids complication of nitrogen burn harming the
plants. Most of the time the sours of organic fertilizers are animal and plant. Organic
fertilizer encourages the use of rotations and measures to maintain soil fertility.
Carefully managed soil with a high production of humus offer essential advantages
with respect to water retention ion exchange, soil erosion and animal life in the soil.
Good manure management means improved fertilizers value of manure and slurry
and less nutrient losses. Organic fertilizers from composts and other sources can be
quite variable from one batch to the next. The economic value of an organic waste or
residues to the farmer is the increase in crop yield and/or crop quality that is derived
from its use and nutrients are available in regular soil, fertilizers can provide and
ensure that plants have a balanced and sustainable access to the nutrien

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