Chickpeas, also known as garbanzo beans, are a foundational pulse crop valued for their high protein and fiber content. They are grown extensively as a cash crop and hold significant importance in diets across the world. Successfully transitioning this legume from the field to a stable, storable product requires precise timing and careful mechanical processes. This journey involves distinct stages designed to preserve the quality and integrity of the seed.
Recognizing Harvest Readiness
Determining the precise moment to begin harvest is the most important decision a farmer makes, as it directly impacts final seed quality and yield. The plant provides physical indicators that signal maturity. The entire plant structure begins to dry down, changing from vibrant green to yellow or brown, typically coinciding with 80 to 90% of the leaves dropping off the stem.
Farmers look for the pods to change from green to a straw or tan color, indicating the seeds have reached physiological maturity. A simple test is to shake the pods; a distinct rattling sound confirms the seeds are dry and separated from the pod walls. Because the chickpea plant is indeterminate, a small amount of green material may still be present at the ideal harvest time.
The moisture content of the seed is the most reliable measure for optimal harvest timing. Combining typically begins when seed moisture reaches around 18%. If the crop is unevenly mature or contains too much green material, a desiccant may be applied when the seed moisture is 30% or less to promote uniform dry-down. Harvesting at this moisture range minimizes mechanical damage, but the crop must be dried immediately after harvest for safe storage.
The Mechanical Harvesting Process
Once the chickpeas are ready, removing them from the field is primarily accomplished through mechanized harvesting equipment. The most common method, used for over 90% of the crop, is direct combining, also known as straight cutting. This method utilizes a combine harvester equipped with a specialized flex header designed to cut the plants close to the ground. This is necessary because chickpea pods form several inches above the soil line.
The combine performs three concurrent functions: cutting, threshing, and cleaning. After the cutter bar severs the plant, the material is fed into the threshing system, separating the seeds from the pods and plant material. Due to the irregular shape of the chickpea seed, which makes it susceptible to chipping and cracking, the machinery must be operated with care. Farmers typically reduce the cylinder or rotor speed to 170 to 350 revolutions per minute and use wider concave settings to minimize physical damage.
The alternative method is swathing, which involves cutting the plants and laying them in continuous rows, called windrows, to dry further in the field. Swathing is less preferred because chickpeas do not cure well in the swath and can result in a higher percentage of undesirable green seeds. This technique is reserved for situations where the crop is highly unevenly matured or when straight-cut equipment is unavailable.
Post-Harvest Management
The successful harvest marks the beginning of the post-field process, which focuses on preserving seed quality. The first step involves initial cleaning of the bulk grain to remove foreign material such as dirt, stones, and plant debris. This is accomplished using mechanical sieve-type cleaners to ensure the final product meets market standards.
Handling the harvested chickpeas requires careful attention to prevent mechanical damage. Because the seeds are fragile, especially the larger Kabuli types, they are highly prone to cracking and chipping when moved. To mitigate this damage, conveyors are often utilized in place of traditional augers, which can be too aggressive.
Any chickpeas harvested above the safe storage moisture level of 14% must undergo a drying process. This is often achieved through forced-air aeration in storage bins, which gradually reduces the moisture content and cools the seed mass. If high-temperature drying is required, it is typically done in multiple stages to prevent rapid moisture loss, which can cause the seeds to become brittle and crack. Once ready for long-term storage, temperature and moisture must be continuously monitored to prevent the development of mold or insect infestations.