AGRICULTURAL SCIENCE

THEME – AGRICULTURAL ECOLOGY 

CLASS – SENIOR SECONDARY SCHOOLS (SS 1) 

TOPIC – AGRICULTURAL ECOLOGY 

LEARNING AREAS 

1. Meaning of Agricultural Ecology and Ecosystem

2. Components of Farm Ecosystem

3. Interactions of the Components in the Terrestrial and Aquatic Agro-ecosystem

INSTRUCTIONAL MATERIAL

1. Natural farm settings, ponds, forest setup, etc.

2. Guest speaker

LEARNING OBJECTIVES

By the end of the lesson, students should be able to:

1. define agricultural ecology and ecosystem.

2. state four (4) components of farm ecosystem.

3. discuss how farm crops/animals interact with other organisms and non living things under different farm settings.

CONTENTS OF THE LESSON

INTRODUCTION

MEANING OF AGRICULTURAL ECOLOGY AND ECOSYSTEM

Agricultural ecology encompasses the interactions between agricultural practices and the environment, including soil, water, plants, animals, and humans. It involves studying the relationships between agricultural systems and the surrounding ecosystems, considering factors such as biodiversity, nutrient cycling, and pest management.

Agricultural ecosystem refers to the complex network of interactions between the living organisms (plants, animals, and microorganisms) and non-living components (soil, water, air, and sunlight) in an agricultural system. This includes the relationships between crops, livestock, soil fertility, and the surrounding natural environment. The health and sustainability of the agricultural ecosystem are crucial for maintaining productive and resilient agricultural systems.

FARM ECOSYSTEM

A farm ecosystem refers to the interconnected system of living organisms and their environment that exist within a farm setting. It encompasses the relationships and interactions between various components such as plants, animals, soil, water, air, and microorganisms on the farm. These components work together in a complex and dynamic way to support agricultural production, biodiversity, and ecological sustainability.

In a farm ecosystem, plants serve as the primary producers by converting sunlight into energy through photosynthesis. Animals, including livestock and insects, act as consumers by feeding on plants or other animals for sustenance. Decomposers such as bacteria and fungi break down organic matter, returning nutrients to the soil for plant uptake. Soil provides a crucial foundation for plant growth, nutrient cycling, and water retention.

Water and air play vital roles in the farm ecosystem, providing essential resources for plant and animal life. Biodiversity, or the variety of species present on the farm, contributes to ecosystem resilience and stability. Farm management practices, human interventions, and interactions between different components also influence the overall health and functioning of the farm ecosystem.

By maintaining a balanced and sustainable farm ecosystem, farmers can optimize agricultural productivity, minimize environmental impacts, and promote the long-term health of the farm and surrounding natural habitats. Implementing conservation practices, crop rotation, integrated pest management, and soil health initiatives are some strategies used to enhance the resilience and sustainability of the farm ecosystem.

COMPONENTS OF FARM ECOSYSTEM

1. Biotic – Biotic factors refer to living components of an ecosystem, such as plants, animals, fungi, and microorganisms. These organisms interact with each other and with the abiotic (non-living) components of their environment to form an ecosystem. Biotic factors play crucial roles in ecosystem dynamics, as they contribute to energy flow, nutrient cycling, and overall biodiversity within an ecosystem.

2. Abiotic – Abiotic factors are non-living components of an ecosystem, including physical and chemical factors such as sunlight, temperature, water, soil, air, and nutrients. These abiotic factors can influence the distribution, abundance, and behavior of living organisms within an ecosystem. They play essential roles in shaping the physical environment and determining the types of biotic communities that can thrive in a particular habitat.

3. Autotrophism – Autotrophs, also known as primary producers, are organisms that can produce their own food using sunlight or inorganic compounds. Most autotrophs, such as plants, algae, and some bacteria, use photosynthesis to convert sunlight into energy for growth and survival. Others, like certain bacteria and archaea, use chemosynthesis to derive energy from inorganic chemicals in their environment. Autotrophs form the base of the food chain in ecosystems, providing energy for heterotrophs through consumption.

4. Heterotrophic – Heterotrophs are organisms that cannot produce their own food and must obtain nutrients and energy by consuming other organisms. Heterotrophs include animals, fungi, most bacteria, and some protists. They rely on autotrophs and other heterotrophs for their nutritional needs, either by consuming living organisms (predation) or by feeding on decaying organic matter (decomposition). Heterotrophs play vital roles in ecosystems by cycling nutrients, controlling populations, and participating in energy flow through food webs.

INTERACTIONS OF THE COMPONENTS IN THE TERRESTRIAL AND AQUATIC AGRO-ECOSYSTEM

1. MONO CROPPING SYSTEM

Mono or sole cropping is a type of agricultural system in which only one crop is grown on a piece of land at a time. This is in contrast to intercropping, where multiple crops are grown together in the same field. In a mono cropping system, the same crop is planted year after year in the same location.

2. MIXED CROPPING SYSTEM

Mixed cropping system, also known as intercropping, is a farming method where two or more crops are grown together in the same field. This method has several benefits, including maximizing land use, increasing biodiversity, reducing soil erosion and improving soil fertility.

In a mixed cropping system, the crops can be chosen based on their compatibility and ability to complement each other in terms of nutrient requirements, growth patterns, and pest control. For example, one crop may provide shade for another, while another crop may fix nitrogen in the soil to benefit the other crops.

Mixed cropping systems are a sustainable and efficient way to increase crop yields and reduce the reliance on synthetic inputs. By diversifying the crops grown in a field, farmers can also reduce the risk of crop failure due to weather events or pest outbreaks.

3. MIXED FARMING SYSTEM

Mixed farming system is a type of agricultural practice where farmers grow crops and raise livestock on the same piece of land. This system integrates crop production and animal husbandry in a complementary and synergistic way.

In a mixed farming system, crops and livestock can benefit from each other in various ways. For example, crop residues can be used as feed for livestock, while animal manure can be used as fertilizer for crops. This integrated approach helps in nutrient recycling, increases overall farm productivity, and reduces the need for external inputs.

Mixed farming systems also provide farmers with multiple sources of income and reduce the risks associated with relying solely on one type of farming. Diversifying the farm activities can help in spreading the financial risk and ensuring a more stable income throughout the year.

Mixed farming systems are considered to be more sustainable and resilient compared to monoculture systems. They promote biodiversity, improve soil health, and contribute to the overall sustainability of the farming operation.

4. FISH PONDS

Fish ponds are man-made bodies of water specifically designed for raising and breeding fish. They can vary in size and shape, and are typically used for aquaculture purposes to cultivate various types of fish for food consumption or for recreational fishing. Fish ponds may also be used for ornamental purposes, such as in garden or landscaping designs. Proper management and maintenance of fish ponds are essential to ensure the health and growth of the fish population. This may include monitoring water quality, feeding the fish, and controlling predators and pests.

5. FOREST (RAIN FOREST OR SAVANNA)

A forest is a large area dominated by trees and other vegetation, typically covering a large expanse of land. Forests are important ecosystems that provide a wide range of environmental, economic, and social benefits. They help to mitigate climate change by absorbing carbon dioxide, provide habitats for diverse plant and animal species, support biodiversity, regulate water cycles, and offer recreational opportunities for people.

Forests can be classified into different types based on factors such as climate, location, and tree species composition. These include tropical rainforests, temperate forests, boreal forests, and mangrove forests, among others.

Forests around the world are facing numerous threats, including deforestation, illegal logging, habitat fragmentation, climate change, and wildfires. Conservation efforts are essential to protect and sustainably manage forests to ensure they continue to provide their valuable ecosystem services for future generations.

LESSON PRESENTATION

TEACHER’S ACTIVITIES

The teacher,

1. takes students out to a natural farm setting.

2. explains the key concepts.

3. guides discussions on the relationships between organisms of interest (plant/animals and other organisms or non-organisms)

4. groups students for out of class study of different farm settings.

STUDENT’S ACTIVITIES

The students,

1. listen and interact with the environment.

2. undertake group work and produce reports.

LESSON EVALUATION

Teacher asks students to,

1. State the meaning of agricultural ecology and ecosystem.

2. What are the components of a farm ecosystem.

3. Identify at least three farm settings and discuss how farm crops/animals interact with other components of the ecosystem.

MONO OR SOLE CROPPING SYSTEM

Mono or sole cropping is a type of agricultural system in which only one crop is grown on a piece of land at a time. This is in contrast to intercropping, where multiple crops are grown together in the same field. In a mono cropping system, the same crop is planted year after year in the same location.

There are several advantages and disadvantages associated with mono cropping:

ADVANTAGES OF MONO CROPPING 

1. Simplified Management – Growing only one crop simplifies management practices such as planting, fertilizing, and harvesting.

2. Specialization – Farmers can specialize in the cultivation of a single crop, allowing them to develop expertise in its specific requirements.

3. Increased Efficiency – Machinery and equipment can be optimized for the specific crop, leading to increased efficiency in farming operations.

4. Disease and Pest Control – Mono cropping can make it easier to control diseases and pests that are specific to a particular crop, as there are no other crops present that could serve as alternate hosts.

DISADVANTAGES OF MONO CROPPING 

1. Soil Depletion – Growing the same crop continuously can deplete the soil of specific nutrients, leading to reduced productivity over time.

2. Increased Pest Pressure – Monocultures are more susceptible to pest outbreaks, as pests that specialize in a particular crop can build up in the absence of other crops.

3. Weeds – Without the presence of other crops to compete with weeds, weed populations can become a major problem in mono cropping systems.

4. Environmental Impacts – Mono cropping can lead to increased chemical inputs such as fertilizers and pesticides, which can have negative impacts on the Environment.

Overall, while mono cropping can offer certain advantages in terms of management and specialization, it also comes with potential drawbacks related to soil health, pest management, and environmental sustainability. Farmers often need to carefully consider these factors when deciding whether to implement a mono cropping system on their land.