Crop Production IV (Field Practices) - Agriculture Form 2 Notes

• Introduction
• Crop Rotation
  • Importance of Crop Rotation
  • Factors Influencing Rotational Programme
• Mulching
  
  • Importance of Mulching
  • Types of Mulching Materials
  • Advantages of Mulching
  • Disadvantages of Mulching
• Routine Field Practices
  • Thinning
  • Gapping
  • Rogueing
  • Pruning
  • Earthing-up
  • Crop Protection
• Harvesting
  • Factors Determing the Time of Harvesting
  • Factors that Determine the Methods of Harvesting
• Post-Harvest Practices
• Storage
  • Purpose of Storage
  • Requirements for a Proper Store
  • Types of Storage
  • Preparation of the Store

Introduction

• Field practices are activities carried out on the field to facilitate proper growth and maximum yield of the various crops grown.
• They include the following:
  • Crop Rotation
  • Mulching
  • Routing field practices
  • Crop protection
  • Harvesting      

Crop Rotation

• This is the growing of different types on the same piece of land in different seasons, in an orderly sequence.

Importance of Crop Rotation

• Maximizes use of nutrients and moisture.
• Breaks the life cycle of pests and disease agents.
• Maintains good soil structure.
• Reduces soil erosion due to adequate soil cover.
• Controls weeds that are specific to certain crops e.g. striga on cereals
• Improves soil fertility when legumes are included in crop rotation.

Factors Influencing Rotational Programme

• Growth habits and nutrient req uirements.
• Liability to soil erosion.
• Crops attacked by the same pests and diseases should not follow one another in the programme.
• Availability of capital and market for example beans or peas in legumes.

Mulching

• This is the placement of materials such as banana leaves or polythene sheets on the ground next to the growing crop.
• These materials should not come into contact with the base of the crop as they may encourage pest attack.

Importance of Mulching

• Reduction of evaporation rate.
• Smothers weeds.
• Moderation of soil temperature.
• Reduction of speed of run offs.

Types of Mulching Materials

• Organic mulching materials such as;
  • Sawdust, wood shavings, coffee pulps, rice husks,
  • Dry grass, banana leaves, dry maize stalk, napier grass.
• Inorganic or synthetic materials commonly used are either black or transparent polythene sheets.

Advantages of Mulching

• Prevents water evaporation thus maintaining moisture in the soil for crop use.
• Acts as an insulator thus modifying the soil temperature.
• It helps to control soil erosion.
• It controls weeds by suppressing them.
• After decomposition organic mulch add nutrients to the soil thus improving its fertility.
• Humus produced after the decomposition of organic mulch improves soil structure and the water holding capacity of the soil.

Disadvantages of Mulching

• It is a fire risk.
• Provides a breeding ground as well as a hiding place for pests that finally may attack the crops.
• Traps the light showers of rainfall thus lowering the chances of rain drops reaching the soil.
• It is expensive to acquire, transport and apply.

Routine Field Practices

Thinning

• Removal of excess, weak, damaged or diseased seedlings.
• Allows the remaining seedlings to get enough nutrients and moisture.
• It is aimed at obtaining optimum plant population.

Gapping

• Filling the gaps so as to maintain proper plant population.
• Gaps occur as a result of failure of seeds to germinate or dying of seedlings.
• It should be done early enough for the seedlings to catch up with the other plants

Rogueing

• This is the removal and destruction of a diseased part of a plant or the whole plant.
• The destruction can be achieved through burning of the uprooted plant.

Pruning

• Removal of extra unwanted parts of the plant.

Reasons for pruning are:

• To remove old, unproductive or diseased, damaged parts of the plant.
• To train plants to take a desirable shape for example formative pruning in tea.
• To control crop leave ratio hence avoiding overbearing.
• To control diseases and pests for example antestia bugs in coffee.
• To facilitate other operations such as spraying, picking and seeding.
• To reduce wastage of chemicals applied on the crop.
• To remove branches that interfere with traffic, telephone lines and view.
• Open up the plant to allow free air circulation and exposure of leaves to sunlight.

Note: Tools used are secateur, pruning saw and pruning knife.

Earthing-up

• This is the placement of soil in form of a heap around the base of the plant.
• It is mostly carried out in tuber crops such as Irish and sweet potatoes to improve tuber formation.
• It is also carried out in groundnuts and maize.
• In groundnuts it promotes production of pods while in maize it provides support to prevent lodging.

Crop Protection

Weed Control

• Weeds are plants growing where they are not wanted, that is a plant out of place.
• Such plants include blackjack, couch grass, thorn apple and Mcdonald's eye.
• Such plants should be eradicated or controlled using recommended methods.

Pest Control

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

Control of Crop Diseases

• A disease is any alteration in the state of an organism and functions of a plant or its parts.
• Disease causing organisms are known as pathogens.
• They include fungi, viruses and bacteria.
• Diseases caused by fungi are referred to as fungal diseases while those caused by viruses and bacteria are referred to as viral and bacterial respectively.

Harvesting

• It is the gathering or of the farm produce after maturity.

Factors Determing the Time of Harvesting:

• Stage of maturity of the crops.
• Use of the crop.
• Tastes and preferences of consumers.
• Weather conditions, hence liability to spoilage.
• Moisture.

Factors that Determine the Methods of Harvesting:

• Scale of farming for example large scale farming machines are used.
• Type of crop for example pyrethrum is harvested by hand.
• Uniformity in ripening of the crop for example wheat is harvested by use of combined harvester while coffee is harvested by hand.
• Uniformity in height of the crop and size of seed, fruits and flowers.
• Financial status of the farmer.
• Part of the plant to be harvested.

Post-Harvest Practices

• These are the preparations carried out on crop produce before it gets to the consumer.
• They include;
  • Threshing/shelling.
  • Drying.
  • Cleaning.
  • Sorting and grading.
  • Dusting.
  • Processing.
  • Packaging.

Storage

Purpose of Storage

• Prevent spoilage
• Make the produce available for future use
• To await good market prices.

Requirements for a Proper Store

• It should be clean.
• It should be well ventilated.
• It should be raised from the ground to prevent damp conditions.
• It should be dry.
• It should be strong to hold crop produce.
• It should be easy to clean.
• It should be vermin-proof.
• It should be secure from theft.
• It should be treated against pests such as weevils.

Types of Storage

• Traditional storage structures.
• Modern storage structures.

Preparation of the Store

• Cleaning the store.
• Maintenance
• Dusting the store with appropriate chemicals.
• Clearing the vegetation around the store to keep off vermin.