Agriculture Form 2 – Crop production IV (Field Practices I)

Introduction

Field practices are activities carried out on the field to facilitate proper growth and maximize the yield of various crops grown. These practices are essential for ensuring healthy crops and sustainable farming.

They include the following:

• Crop Rotation
• Mulching
• Routine Field Practices
• Crop Protection
• Harvesting

Crop Rotation

Crop rotation is the practice of growing different types of crops on the same piece of land in different seasons, following an orderly sequence. This method helps maintain soil health and reduces pest and disease buildup.

Importance of Crop Rotation

• Maximizes the use of nutrients and moisture in the soil.
• Breaks the life cycle of pests and disease agents, reducing their impact.
• Maintains good soil structure, preventing degradation.
• Reduces soil erosion by ensuring adequate soil cover throughout the year.
• Controls weeds specific to certain crops, such as striga on cereals.
• Improves soil fertility when legumes are included in the rotation, as they fix nitrogen.

Factors Influencing Rotational Programme

• Growth habits and nutrient requirements of the crops involved.
• Liability of the soil to erosion, which affects crop choice and sequence.
• Crops attacked by the same pests and diseases should not follow one another to prevent pest buildup.
• Availability of capital and market demand, for example, legumes like beans or peas.

Mulching

Mulching involves placing materials such as banana leaves or polythene sheets on the ground next to growing crops. These materials help conserve moisture and protect the soil but should not touch the base of the crop to avoid encouraging pest attacks.

Importance of Mulching

• Reduces the rate of evaporation, conserving soil moisture.
• Smothers weeds, reducing competition for nutrients and water.
• Moderates soil temperature, protecting roots from extreme heat or cold.
• Reduces the speed of runoff, minimizing soil erosion.

Types of Mulching Materials

• Organic mulching materials such as sawdust, wood shavings, coffee pulps, rice husks, dry grass, banana leaves, dry maize stalks, and napier grass.
• Inorganic or synthetic materials commonly used include black or transparent polythene sheets.

Advantages of Mulching

• Prevents water evaporation, maintaining moisture in the soil for crop use.
• Acts as an insulator, modifying soil temperature to benefit plant growth.
• Helps control soil erosion by protecting the soil surface.
• Suppresses weeds by blocking sunlight.
• After decomposition, organic mulch adds nutrients to the soil, improving fertility.
• Humus produced from decomposed organic mulch improves soil structure and water-holding capacity.

Disadvantages of Mulching

• Poses a fire risk, especially with dry organic materials.
• Can provide breeding grounds and hiding places for pests that may attack crops.
• Traps light rainfall, reducing the amount of water reaching the soil.
• Can be expensive to acquire, transport, and apply, especially synthetic mulches.

Routine Field Practices

Thinning

• Removal of excess, weak, damaged, or diseased seedlings to reduce competition.
• Allows remaining seedlings to access sufficient nutrients and moisture.
• Aims to achieve optimum plant population for better yield.

Gapping

• Filling gaps in the field to maintain proper plant population.
• Gaps occur due to failure of seeds to germinate or death of seedlings.
• Should be done early to allow new seedlings to catch up with others.

Rogueing

• Removal and destruction of diseased parts of a plant or the entire plant.
• Destruction is usually done by burning the uprooted plants to prevent disease spread.

Pruning

• Removal of extra or unwanted parts of the plant to improve growth and yield.

Reasons for pruning include:

• Removing old, unproductive, diseased, or damaged parts of the plant.
• Training plants to take a desirable shape, such as formative pruning in tea.
• Controlling crop leaf ratio to avoid overbearing and improve fruit quality.
• Controlling diseases and pests, for example, antestia bugs in coffee.
• Facilitating other operations such as spraying, picking, and seeding.
• Reducing wastage of chemicals applied on the crop.
• Removing branches that interfere with traffic, telephone lines, or views.
• Opening up the plant to allow free air circulation and exposure of leaves to sunlight.

Note: Tools used include secateurs, pruning saws, and pruning knives.

Earthing-up

• Placement of soil in the form of a heap around the base of the plant.
• Commonly done in tuber crops such as Irish and sweet potatoes to improve tuber formation.
• Also carried out in groundnuts and maize.
• In groundnuts, it promotes pod production, while in maize it provides support to prevent lodging.

Crop Protection

Weed Control

• Weeds are plants growing where they are not wanted, often competing with crops for resources.
• Common weeds include blackjack, couch grass, thorn apple, and McDonald’s eye.
• Weeds should be eradicated or controlled using recommended methods to protect crop growth.

Pest Control

• Crop pests are living organisms harmful to crops.
• They include insects, nematodes, rodents, thrips, and mites.
• Pests cause significant damage to crops both in the field and in stored produce.

Control of Crop Diseases

• A disease is any alteration in the state or function of a plant or its parts.
• Disease-causing organisms are known as pathogens.
• Pathogens include fungi, viruses, and bacteria.
• Diseases caused by fungi are called fungal diseases, while those caused by viruses and bacteria are called viral and bacterial diseases, respectively.

Harvesting

• Harvesting is the gathering of farm produce after it has matured.

Time of harvesting depends on:

• The stage of maturity of the crops.
• The intended use of the crop.
• Tastes and preferences of consumers.
• Weather conditions, which affect the liability to spoilage.
• Moisture content of the produce.

Methods of harvesting are determined by:

• The scale of farming; for example, large-scale farms use machines.
• The type of crop; for example, pyrethrum is harvested by hand.
• Uniformity in ripening; for example, wheat is harvested using a combine harvester, while coffee is harvested by hand.
• Uniformity in height of the crop and size of seeds, fruits, or flowers.
• The financial status of the farmer.
• The part of the plant to be harvested.

Post-Harvest Practices

• These are preparations carried out on crop produce before it reaches the consumer. They include:
• Threshing or shelling.
• Drying to reduce moisture content and prevent spoilage.
• Cleaning to remove dirt and impurities.
• Sorting and grading to classify produce by quality and size.
• Dusting to protect against pests.
• Processing to add value or prepare for consumption.
• Packaging for protection and ease of transport.

Storage

The purpose of storage is to:

• Prevent spoilage of produce.
• Make the produce available for future use.
• Allow farmers to wait for favorable market prices.

Requirements for a proper store include:

• Cleanliness to prevent contamination.
• Good ventilation to reduce moisture and heat buildup.
• Raised floors to prevent damp conditions.
• Dry conditions to avoid spoilage.
• Strong structure to hold the produce safely.
• Ease of cleaning to maintain hygiene.
• Vermin-proof to prevent damage by rodents and insects.
• Security from theft.
• Treatment against pests such as weevils.

Types of Storage

• Traditional storage structures, often made from local materials.
• Modern storage structures, which may include silos and warehouses with controlled environments.

Preparation of the Store

• Cleaning the store thoroughly before use.
• Maintenance to repair any damages and ensure suitability.
• Dusting the store with appropriate chemicals to control pests.
• Clearing vegetation around the store to keep off vermin and pests.