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How to harvest pulse crops

If you’re new to pulses or want a refresher, here are four harvest factors


With pulse crops, a successful harvest starts not long after seed goes into the ground, says Dale Risula, provincial crop specialist with the Saskatchewan Ministry of Agriculture. Knowing when to use land rollers, choosing a desiccant and knowing the best ways to harvest and store the crops are all key to succeeding with pulses.

1. Using land rollers

Pulses, particularly lentils, are fairly short crops, says Risula, and the machinery that’s used to cut them is often very close to the ground. Rollers are used to flatten out any grooves that the seeder may have caused and also to push stones back into the soil so that they’re no longer an obstruction to the combine operation.

Rollers should be used after seeding, following emergence and between the five- to seven-node stage in lentils and the five-node stage in peas, says Risula. Beyond that, land rolling can damage plants, reduce yields and spread foliar diseases, so it is not recommended.

In chickpeas, land rollers are less beneficial since they don’t usually lodge and they have higher stubble. Post-emergent land rolling is not recommended, especially since it can spread disease, like ascochyta blight, which is always a potentially devastating problem in chickpeas.

When rolling, the best results are obtained when soils are not wet, says Neil Whatley, crop specialist with Alberta Ag-Info Centre. Under wet conditions, the roller could build up mud, damage seedlings and not pack correctly.

Rolling when crops are damp is also not recommended since it can spread disease. Avoid rolling if the seedlings have been under stress — extreme heat, frost or herbicide application. Whatley recommends leaving three days between herbicide application or frost and rolling.

Finally, it’s best not to roll first thing in the morning when plants have more turgor pressure, he says. Stems are stiffer and more apt to break. For best results, wait until 10 am or noon to begin rolling.

2. Using a desiccant

As harvest approaches, pulse crops are nearing the end of their maturity. Pulse crops have an indeterminate growing nature, so their time to mature can vary, says Risula. To help break that vegetative growth and initiate the maturity process, some sort of stress is needed.

As that maturity date approaches, it’s really important that the weather cooperates. Until the crop is ripe, frost needs to be avoided.

“Also, just as the time approaches when you want to either desiccate or apply some pre-harvest herbicide to the crop or swath it before harvesting — that the weather be dry and not rainy,” he says. “Warm, dry days are in order when it comes to harvesting pulse crops.”

If the crop is treated with glyphosate, notes Risula, it shouldn’t be used for seed.

Weather can also damage and downgrade pulse crops, he says. Peas, in particular, are quite vulnerable to damage, green peas, especially.

“Colour is an important factor in determining the quality of the pea,” says Risula. “If there’s any degree of bleaching, then it’s downgraded. Bleaching occurs when the swathed crop is exposed to combinations of bright sunlight and rain showers. It seems to worsen the affect of bleaching on green peas.”

3. When to combine

Pulse crops will reach the maturity stage at around 30 per cent moisture content. At that point in time, they’re ready for either swathing or pre-harvest applications of herbicide. They then need to dry so they can be threshed or combined. The best time to combine is at around 18 per cent moisture content. Some growers, says Risula, prefer to wait until the crop is at 15 per cent moisture content.

“I guess it depends on how experienced they are and what kind of machinery they have,” he says. “Pulse crops, if they’re too dry, tend to chip and downgrade in value. If they’re very dry, the seed coat will chip and crack. That’s why a lot of producers will begin harvesting around 18 per cent moisture content.”

Seed coats are also prone to damage if they’re handled at high speeds, too. “Basically, the machinery that’s being utilized for threshing the pulse crops need to be operated at slower speeds.” Great care should be taken when transferring grain through augers and into bins so that it is not subjected to high speeds or lengthy falls.

4. Storing pulse crops

Often, conditioning is required very soon after freshly harvested pulses are binned, Risula says. If the crop was harvested on a hot day, it will need to be cooled to an acceptable level in an aeration bin. Risula says that 15°C or cooler is ideal because crops will sweat after they’re harvested.

“Some of that moisture is emitted as a gas and accumulates within the bin around the seed,” he says. “Then it’s subject to all sorts of movement and gathering points within the bin where hot spots and deterioration of the grain could occur.”

Similarly, if the crop is harvested when the moisture content is too high, it needs to be dried as well. “Generally, somewhere around 14 per cent, or in the case of red lentils, a lot of processors require that it be stored at around 13 per cent.”

It’s not a good idea to store new crop on old crop, says Risula. It tends to reduce the quality of the crop, especially lentils, which can turn brown and lose value quickly. “New crop should be stored by itself,” he concludes.

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