CROP PRODUCTION I ( LAND PREPARATION)

Introduction

• A piece of land which is prepared is known as seedbed.
• A seedbed is a piece of land that is prepared ready to receive planting materials.

Seedbed Preparation

Reasons for Seedbed Preparation;

• To enable water to infiltrate.
• To kill weeds
• To improve soil aeration.
• To destroy pests and diseases.
• To incorporate organic matter in the soil.
• For easy planting.
• To facilitate root penetration.

Operations in Land Preparation

Land Clearing

• Clearing of land is necessary when:
• Opening up a virgin land.
• A stalk growing crop was previously plan
• There is long interval between primary and secondary cultivation.
• Land was left fallow for a long time.

Procedure

• Tree felling and removal of stumps and roots.
• Burning
• Slashing
• Use of chemicals.

     Note: Burning should be avoided where possible since it;

• Leads to loss of organic matter,
• Kills soil organisms
• Destroys soil structure and plant nutrients.

Primary Cultivation

• This is the initial breaking of land.
• It is done early before the onset of the rains to:
• Give time for soil organisms to act on organic matter.
• Allow gaseous exchange to take place, thus carbon dioxide diffuses out of the soil while oxygen enters into the soil.
• Allow other operations to take place in time.

Reasons for primary cultivation:

• Remove weeds.
• Burry organic matter.
• Open up soil for infiltration of water and air.
• Expose pests and disease causing organisms.
• Soften the soil for easy planting.

Operations in primary cultivation

Hand digging ;

     Use of hand tools ;

• Jembes,
• Mattocks,
• Fork-jembes.

Mechanical cultivation ;

   Use of mouldboard ploughs;

• Disc ploughs,
• Chisel ploughs,
• Subsoilers
• Rippers.

Use of Ox–Ploughs ;

    Which can be drawn by;

• Oxen,
• Donkeys,
• Camels

Depth of Cultivation

  Depends on:

• The type of crop to be planted/size of seed.
• The implements available.
• The type of soil.

Choice of Implement

   Determined by:

• The condition of land.
• The type of tilth required/type of crop.
• Depth of cultivation.

Secondary Tillage

• These are refinement practices on the seedbed that follow primary cultivation.
• It is also known as harrowing.

Reasons for secondary Tillage:

• To remove the germinating weeds.
• To break soil clods to produce required tilth.
• To level the seedbed for uniform planting.
• To incorporate organic matter/manure into the soil. 

Factors determining number of secondary cultivation:

• Soil moisture content.
• Size of the planting materials.
• Condition of the soil after primary cultivation.
• Slope of the land.

Tertiary Operations:

• Ridging ;
• The process of digging soil on a continuous line and heaping on one side to produce a furrow and a bund (ridge).
• It is important for root crops, to allow root expansion and for soil and water conservation.
• Rolling:
• It is the compaction of the soil to produce a firm surface which increases seed-soil contact and prevents wind erosion.

• Levelling;
• Production of an even, uniform surface which promotes uniform planting.

Subsoiling:

• This is deep cultivation into the subsoil layer to break up any hardpan which might have developed.

It is done for the following reasons:–

• To facilitate drainage.
• Bring up leached nutrients to the surface.
• Increase aeration of the soil.
• To improve root penetration.
• The implements used include chisel plough and subsoilers.

 

Minimum Tillage:

• This is the application of a combination of farming practices with the aim of reducing the disturbance of the soil.

Examples of which include:

• Use of herbicides.
• Mulching and cover-cropping.
• Timely operations to prevent weed infestation.
• Strip cultivation.
• Uprooting and slashing of weeds.

Reasons for Minimum Tillage

• To reduce cost of cultivation.
• To control soil erosion.
• To preserve soil moisture.
• To prevent root exposure and damage.
• To reconstruct destroyed soil structure.