Dr. Joel Gruver is one of the leading agriculturists in the cover crop field. He goes to many seminars and guest appearances all over the Midwest talking about cover crops. He is the leading ag professional in the cover crop field actively advocating cover crops. I have taken some of his classes and I decided to reach out to him with some interview questions about cover crops. I did this in hope that I would learn more about cover crops and talk to one of the leading professionals tackling cover crops head on.
1. What are the advantages of Cover Crops?
Cover crops can have many beneficial effects including erosion control, improved infiltration, nutrient scavenging and recycling, organic matter building, compaction alleviation, and provision of forage.
When compared with other strategies for improving water quality, CC have the advantage over edge of field practices like buffers in that they improve soil properties in the field as well as improving water quality.
2. By the numbers how much do Cover Crops reduce certain pressures such as weeds runoff etc.
The impact of CCs on weeds, run-off, nutrient leaching etc. varies with respect to lots of factors such as CC species, CC planting date and weather conditions. > 50% reduction in run-off and nutrient leaching are commonly reported in the research literature.
At the Allison Farm, we normally achieve >9o% weed suppression in our organic no-till soybean plots. In these plots we plant into standing 6’ tall cereal rye. The rye that gets knocked flat by either a double pass with the drill or 1 pass followed by a roller.
3. What is the effective method of planting Cover Crops? Good planting dates in general.
I assume that you inquiring about the most effective method of establishing cover crops.
The most effective methods of CC establishment precisely place CC seeds in moist soil. This can be done very effectively with a drill or precision planter (i.e., corn planter) but the cost is higher than less precise methods such as blending CC with fertilizer and then spreading the mix with a fertilizer buggy. The seed does not need to be incorporated if timely rains occur. Without timely rains, light incorporation with a vertical tillage tool or other types of tillage tools can improve stand establishment.
4. For corn what would you suggest be planted as a Cover Crop?
Ahead of corn it is generally best to focus on legumes (e.g., hairy vetch or clovers) and/or brassicas (e.g., radishes) that release N quickly. Some farmer make grass CC species (e.g., oats and annual ryegrass) work ahead of corn by killing the grass when it is young and applying some N with the planter
5. For beans what would you suggest planted as a Cover Crop?
Cereal rye and other grass species work well ahead of soybeans.
6. What are the main advancements coming for Cover Crops?
One of the most interesting recent developments is early interseeding. This is when cover crops are planted (mostly in corn) before the crop canopy closes. Only very shade tolerant CC species like annual ryegrass will work and herbicide programs need to designed carefully but the result is significantly more CC growth than late over-seeding (when canopy is opening) and much more growth than planting CC after harvest. Here is a link to some info:http://www.interseedertech.com/
7. Do you see Cover Crops picking up speed in the agriculture community and why do you think that?
CCs require management and reward management… so I don’t see them being a good fit on farms where the management skills are already spread thin. The most obvious places to add CCs are highly erodible fields and fields where crop residues are currently grazed without CCs. Other favorable scenarios included fields prone to nutrient leaching and fields with herbicide resistant weeds. I think CC acres will continue to expand in areas where these scenarios are common and where good technical support and some cost share is available. Lower commodity prices have definitely reduced farmer interest in CCs and all other sources of added cost.
8. Are there a lot of jobs in the Cover Crop industry?
The job market in the CC industry has tightened with lower commodity prices. One of the biggest CC seed companies currently owes CC seed producers millions of dollars. I think there are still good opportunities for CC seed sales and custom CC seeding especially if the company can position itself well to improve farmer success with cover crops and tap into conservation program payments.
i would like to give sincere thanks to Dr. Gruver for taking time out of his busy schedule to answer some questions for me about cover crops.