Harvest aids are tools to help us harvest rice faster and more efficiently. Any tool can be misused. My favorite example is a hammer: it’s great when it hits the nail, not so great when it hits your thumb. Same with harvest aids.
Sodium chlorate does an excellent job of desiccating rice foliage for ease of harvest and lowering grain moisture content. However, applied at the wrong time or in the wrong manner and it causes more problems than it solves.
As of last weekend we still had ~30% of rice left in the field. That number is probably down to only 20% now, but much of it is lodged due to the high wind and rain event that hit the Delta last Sunday. So the question has been, can I apply sodium chlorate (salt) on my rice.
Sodium chlorate isn’t mobile in the plant. It’s only going to affect the parts of the plant that it touches. So in downed rice, only the plants on top are going to be affected. But the entire plant will receive coverage and dry down much more extremely than in standing rice. And the rice underneath? It will stay green and moist. That means you’ll be harvesting rice that is a mixture of the two extremes – this always creates issues.
In this situation, the rice treated will be much drier than the untreated rice below it. The drier rice will be more prone to rewetting and drying in the field which can increase breakage and lower head rice yields. If harvested and dried with grain of mixed moisture levels, the grains that become overly dry will break up and lower milling yields. Plants that become too dry also increase the chance of shattering as the panicles dry and do not hold the grain, leading to direct yield loss.
This is not to say that sodium chlorate can’t be used if there’s any lodging in a field. The point is in fields with a high percentage of severe lodging it should be avoided.
When using sodium chlorate properly in standing rice, use a rate of 3-6 lb ai/acre. Apply it when rice grain moisture is below 25% (DO NOT apply below 18%). If you use the proper rate and timing, and harvest in no more than 4-7 days, research has shown no adverse effects on grain or milling yields.
The coming week looks like a decent one for harvest. Good luck and let’s get this crop out of the field and say goodbye to 2016.