Biostimulants can improve the percent of seeds germinating as well as seedling vigor
May 22, 2023 – We often take seeds for granted. We expect that we can plant them, they will grow, and produce a crop – or flower bed if that's your goal. But seeds don't always germinate. And if they do, the plant might not grow as expected. The May 22nd Sustainable, Secure Food Blog looks at work being done by Erik Augerson, Oregon State University, to improve hemp crops by studying ways to improve seed vigor and viability.
Viability is defined as the seed's ability to germinate and begin growth. This of course assumes they are given the proper environment. The environment in which the seed is planted plays a large role in its ability to germinate.
In some cases, a seed can be viable yet still not germinate when planted. This is often caused by the seed being stuck in a state of dormancy. In the case of dormant seed, certain environmental or physical conditions must be met to trigger germination. For example, many seeds must go through a chilling period prior to sowing to come out of dormancy.
Seed vigor refers to the ability of the seeds to quickly produce consistent, healthy plant growth under a wide range of environmental conditions.
Augerson is looking at using "seed enhancements" to improve the vigor and viability of hemp seeds. Typically, seed enhancements will not increase seedling viability, but they can improve the percent of seeds germinating as well as their vigor. In general, the goal of seed enhancement is to improve the crop producer's chances of having good establishment and a healthy crop.
Treating seed with products prior to planting can potentially save the producer time and money. The alternative is a grower applying the product across their entire field after planting. This would mean two passes through the field. So, treating seeds prior to planting makes sense.
Additionally, by treating the seed we ensure that the product added is in contact with the seed/seedling once it germinates. When spread across the field there are many variables that can prevent the treatment from contacting the seed – like rainfall, soil conditions and wind.
Multiple commercial examples of seed treatment exist; however, two common examples are seed priming and seed coating.
Seed priming typically involves soaking seed in a solution, water or a chemical, for a specific time. They are then taken out of the solution just prior to germination. The seeds can then be sown in the field. The goal of doing this generally is to increase the speed or uniformity of seed germination once the seed is planted in the field.
Seed coating, as the name suggests, involves coating a seed prior to its planting with a dry or liquid product. Many crops are sold with seed coatings that contain pesticides, or plant growth products.
Historically conventional plant growth products such as chemical fertilizers and synthetic pesticides have been marketed and used in both seed priming and in seed coatings. However, there is growing interest in producing solutions using certified organic products.
A new category of products being looked at as a potential seed treatment option are biostimulants, specifically humic substances. Biostimulants is a category of products that was defined in the USDA farm bill as "substances or microorganisms that, when applied to seeds, plants, or the root zone, stimulates natural processes to enhance or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, or crop quality and yield."
Humic substances are complex organic compounds found in soil and other natural sources. Humic substances, specifically humic acid and fulvic acids, have been shown to have biostimulant properties. These include improving seed germination, root, and shoot growth on multiple crops.
However, their effects on hemp (cannabis) seed are undocumented. My goal was to test if soaking seed prior to planting in biostimulants, specifically certified organic humic and fulvic acids solutions, would influence seed germination and seedling vigor on two varieties of CBD Hemp.
The reason that CBD hemp was chosen, in addition to being a new and interesting area of research, is that hemp grown for CBD is traditionally grown at lower plant densities than most other annual crops. Because of this it is important that good germination occurs.
The cost of hemp seed also can be extremely expensive, commonly found marketed above a dollar per seed. Because of this, seed enhancement could be well worth the cost if it successfully improves the % germination or vigor.
After the seed was soaked for a predetermined time in different humic acid solutions, they were dried and placed in a germination chamber where they remained for 7 days under optimal germination conditions. Daily germination counts were taken. After 7 days, samples were collected, and seedling vigor measurements were performed.
Our initial findings suggest that humic substances did not have a significant effect on seedling germination however humic acid did have a significant effect on root growth. As a graduate student, I am excited to continue this research and believe that it may have valuable applications for future crop producers.
