Soybean harvest has begun, and many growers have asked if they could sample for soybean cyst nematode this fall. For many growers, managing soybean cyst nematode (SCN) means planting SCN resistance varieties BUT effective SCN management does not end when you have selected your soybean varieties! It is imperative to not only know your SCN population levels in each of your fields but what is happening to those levels over time and it begins with SCN soil testing!
If your SCN is decreasing, this could indicate your management program is working. If your is SCN rising, this is a big red flag that the problem is getting worse and could get out of hand, costing you significantly in lost yields, dollars and sleep! If you do not know what is happening to your SCN population levels in your fields over time, your efforts may be wasted. One of the most important decisions a producer can make concerning this devastating pest is to take a SCN soil test.
The fall is a perfect time to sample harvested soybean fields or those which will be planted to soybeans in 2021. Sampling for SCN after or at harvest provides a perfect opportunity to “take the test” since it is typically a time when soil samples are taken to determine next year’s fertilizer program. It is as simple as taking a few more soil cores from the field, mix them together, split the sample and send in half for your fertilizer recommendations and the other half for a SCN analysis. Fall sampling also helps identify poor yielding fields or areas within the field that need sampling while they are fresh in your mind. A fall sample takes into account any significant SCN population changes that have occurred during the growing season.
Remember, the results of the test are only as good as the soil sampling technique. Therefore, it is necessary to obtain a soil sample that is representative of the field. Ideally the numbers of acres in any one sample should not exceed 20 to 25 acres. The fewer acres a sample represents the more accurate the results will be. Having said that, one large field sample (50-100 acres) is better than no sample at all. Make sure to clearly mark that the samples are for a SCN test and they can be sent to any of the SCN testing labs in the province (OMAFRA Agronomy Guide Publication 811 – Appendix E, page 413).
To read the full Ontario Field Crop Report for Sept. 17, visit fieldcropnews.com.