Field Pea Harvest Timing
EDMONTON - Aug 18/14 - SNS -- Timing field pea harvests can make a significant difference in the overall quality and yield of the harvested product, reminds Neil Whatley, crop specialist, Alberta Ag-Info Centre, Stettler.
"Field pea plants mature from the bottom up, which means seeds in the pods on lower plant branches will be more mature at harvest than those near the top. Harvesting too soon can result in immature seeds in the sample, while harvesting too late can result in excess shattering. Green pea is more susceptible to bleaching if harvested late, while harvesting too early can cause a grade reduction in yellow pea varieties."
Various systems can be used to harvest pea including swathing and combining when dry, allowing the field to mature while standing and straight combining, spraying with a desiccant and swathing directly ahead of the combine, or direct combining a desiccated crop. Whether swathing or desiccating, the timing of the operation is the same.
"Swathing or desiccating is carried out when the bottom one third of the pods are ripe, the middle one third of the pods and vines are yellow-colored and the upper one third are in the process of turning yellow," says Whatley.
"Ripeness of the lower pods is when the pods are dry and seeds are detached from the pods causing the pods to rattle when shaken. Seeds in the lower pods should not split when squeezed. Seeds in the middle pods will split when squeezed, while seeds in the top pods can be split with one's fingernail with no water emerging; if water emerges, wait to swath or desiccate.
"Seed color is especially important with achieving a high green pea grade. Green pea is susceptible to bleaching as it nears maturity, which causes downgrading if greater than two per cent. With green pea, the vein pattern in the upper pods should be easily recognizable and 75 to 90 per cent of the pods should have turned to a yellow CARS."
A crop desiccant facilitates greater harvest ease by drying immature green pea vegetation, especially at the top of pea plants, and also dries green weeds.
"Reglone, a contact herbicide, continues to be a popular pea desiccant," says Whatley. "While enhancing dry down of the vegetation, Reglone doesn't hasten crop maturity; however, it reduces the time from maturity to threshing readiness, as well as reducing shattering loss. Desiccation is especially recommended for green pea, reducing the time to harvest and resulting in a good green coloured seed. The effectiveness of Reglone may be enhanced when applied on cloudy days or just prior to nightfall."
If the pea field has many perennial weeds like Canada thistle, sow thistle, dandelion, toadflax or quackgrass, instead of desiccating with a product like Reglone, Whatley says glyphosate can be applied as a pre-harvest weed management tool.
"Glyphosate is applied at the same time as previously mentioned for Reglone and will provide some crop dry down, but this benefit is inconsistent and is unlikely to occur if cool, wet weather conditions are present. Overall crop dry down takes longer to achieve with glyphosate than with Reglone. One can generally thresh a pea crop seven to ten days after Reglone desiccation; however, it takes two to three weeks for the crop to dry down with glyphosate. Due to reduction in the seed's ability to germinate, re-planting the seed from a pea crop that was applied with glyphosate is not recommended."
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