Chickpeas are considered ready to harvest when the majority of the plants are yellow and most pods are mature. At this stage, the top of the plant may still be green.
Chickpeas can be swathed as early as 30 per cent seed moisture, but is usually left until the majority of pods are straw yellow. Swathing too early, while the pods are still green, can lead to an increase in green seed and loss of grade. Chickpeas may be swathed ahead of the combine if straight cutting equipment is not available. Swathing the crop when plants are slightly damp may aid in the formation of an intact swath, less susceptible to wind movement. The dampness may also reduce pod loss while swathing. Swathing is an option to put an end to late season growth if moisture is still readily available to the plant.
Chemicals for Harvest Management and Desiccation
Glyphosate can be applied for pre-harvest weed control when seed grain moisture is less than 30 per cent. At this stage, chickpea stems are green to brown in colour, pods are mature (yellow to brown in colour) and 80 to 90 per cent leaf drop (original leaves) has occurred. The main advantage of using pre-harvest glyphosate is for perennial weed control. It can also be used to stop late season chickpea re-growth, but drydown time will still be governed by the weather. Do not apply glyphosate products to any crops that will be harvested for seed.
Reglone® desiccant is registered for crop drydown in chickpeas. It will not speed maturity of green crops. Additional products that can be used as a harvest aid or desiccant before crop harvest in chickpeas include Aim®, CleanStart®, glyphosate, and Heat® (LQ or WG). It should be applied when plants have yellowed, the pods have matured, and seeds have changed colour and detached themselves from the pods (pod rattle stage). This is a very mature stage of the crop, so the reduction in days to threshing following a Reglone® application compared to lentils or peas is less. As well, with the later maturity of chickpeas, cooler conditions and shorter days later in the growing season will reduce the speed of drydown, compared to applications made earlier in the growing season. However, Reglone® can still be expected to dry down green plant material and result in threshing of the crop sooner than if no desiccant is used.
Research has shown that direct cutting without desiccation (natural-maturity) results in the highest yields and largest seed size. Desiccation with Reglone® or application of pre-harvest glyphosate applied prior to pod rattle stage, when 80 per cent of pods were tan coloured, preserved yield. However, these treatments did not speed the time to maturity and seed size was reduced. Although desiccation is not as common on chickpeas compared to peas and lentils, it can still be a valuable tool in some situations.
Most chickpea acres are straight cut without the aid of a desiccant. Chickpeas have stiff stems and a relatively upright growth habit, with pods developing several inches above the ground. Pods are quite shatter resistant (although under the drought conditions in 2001, some chickpea growers reported shattering of maturing pods). Pods and seeds often mature before the stems and leaves. These characteristics result in chickpea plants being well-suited to straight cutting. However, if the plants are left standing too long following maturity there is a risk of pod drop and reduced quality with adverse weather.
Threshing can start when seed reaches about 18 per cent moisture. Avoid combining chickpeas that are wet or immature. When straight cutting, air or pick-up reels should reduce harvest loss compared to bat reels. Initial combine settings should be similar to those used for peas, however, a wider concave setting for larger seeds and an increased cylinder or rotor speed may be required to remove the seed from the pod. Care must be taken not to damage the seed, especially with the large Kabuli-types. The use of stripper headers was found to reduce weed seed dockage and shriveled chickpea seeds as opposed to samples from straight cut or pick up headers. Stripper headers in chickpeas are able to strip off ripened pods and leave green leaves on the plants. Very little green material goes into the combine.
Chickpea seed colour is an important grading factor. The stage of the crop should be closely monitored, as harvesting too early increases the chance of green seed in the crop, which lowers the grade and value of the grain. Deductions are implemented if immature green seeds comprise more than 0.5 per cent in Kabuli, and one per cent in Desi chickpeas. Early frost, as little as 2°C or 3°C, during pod filling and ripening can result in immature green seed in the harvested crop, significantly reducing the grade and value. Other factors that negatively affect seed quality are Botrytis or Sclerotinia in the seed, admixtures, small seed size, and a lack of seed uniformity.