Harvesting of Field Crops – SS1 Horticulture and Crop Production Lesson Note (Third Term)

What is Harvesting?

Harvesting is the “happy hour” for every farmer. It is the process of gathering mature crops from the field. After months of clearing the land, planting seeds, weeding, and protecting the crops from pests, it is finally time to reap the rewards.

However, harvesting field crops like Maize, Rice, Cassava, and Yam is a bit different from harvesting backyard vegetables. Field crops are usually grown on large areas of land, and we often wait for them to be fully mature and dry before we move them.

Why Harvesting is Important:

• It is the end of the production cycle.
• If done correctly, it ensures we have high-quality food to eat or sell.
• If done poorly or at the wrong time, all the hard work of the season can be wasted in just one day.

Timing – When is it Ready?

Knowing exactly when to harvest is a skill. If you harvest too early, the seeds will be watery and will rot. If you harvest too late, birds might eat the grain, or the sun might make the pods “shatter” (burst open) and spill the seeds on the ground.

Signs of Maturity in Field Crops:

1. Change in Color: Maize husks turn from green to brown/white. Rice stems and grains turn golden yellow.
2. Moisture Content: The seeds or grains become hard. If you can dent a grain of corn with your fingernail, it is usually not dry enough yet.
3. Drying of Leaves: For crops like Yam and Cassava, the green leaves start to turn yellow and wither away. This tells the farmer that the plant has finished storing food in the tubers.
4. The “Snap” Test: For beans and cowpeas, the pods should feel dry and “snap” or crackle when you touch them.

Tools for Harvesting Field Crops

In Nigeria, most small-scale farmers harvest by hand using simple tools. Large-scale farmers use big machines.

Common Hand Tools:

• Sickle: A curved blade used for cutting cereal crops like Rice and Wheat at the base of the stem.
• Cutlass (Machete): The most common tool in Nigeria. Used for cutting maize stalks or clearing the way to reach tubers.
• Harvesting Knife: A small, very sharp knife used to cut cocoa pods or oil palm bunches.
• Garden Fork / Digging Mattock: Used for lifting root crops like Yam, Cassava, and Sweet Potatoes out of the ground without breaking them.

Mechanical Tools:

• Combine Harvester: A giant machine that cuts, threshes (removes the seeds), and cleans the grain all at once.

Methods of Harvesting

The method we choose depends on the type of crop and how much money the farmer has.

1. Manual Harvesting (Hand Method)

This is what most of us do in our school gardens.

• Pulling/Digging: We use a fork or hoe to lift root crops (Yam, Cassava) out of the soil.
• Plucking: We use our hands to pull the cobs off the maize plant.
• Cutting: We use a sickle to cut the stalks of rice or millet.

2. Mechanical Harvesting

This is done on very large farms. It is much faster but requires expensive machines.

Important Rule:

Regardless of the method, we must be gentle. If you bruise a yam with your hoe, that wound will become a “doorway” for rot, and the yam will not last in the barn.

Post-Harvest Care (The Final Step)

The work doesn’t stop the moment the crop is cut! To keep the harvest safe, we follow these steps:

1. Threshing: For grains like Rice and Cowpea, we beat the dry stalks or pods to release the seeds.
2. Winnowing: We use the wind to blow away the light “chaff” (dust and dry husks) from the heavy seeds.
3. Drying: Most field crops need to be spread out in the sun on a clean mat to dry completely before they are put in bags.
4. Bagging: We put the dry grains into jute bags and store them in a cool, dry place away from rats and weevils.

Summary Table for Students