“You put animals on a field. The grass grows. They eat it. What’s there to manage?”
Well, quite a lot, actually. I’ve been interested in management intensive grazing ever since I read Gene Logsdon’s inspiring book All Flesh Is Grass. We only have about 3 acres on which we plan to raise sheep, and we’d like to maximize our pasture productivity for the health of our animals, to save money on purchased feed, and improve the long-term viability of our land. The ideas presented in that book showed me how much I didn’t know.
So, when I heard about a course being taught by Woody Lane Ph.D., a nationally known specialist in livestock nutrition and forage management, I signed us up. The class runs 10 weeks, every Wednesday night, and will feature some pre-class pasture tours and a weekend farm tour of 4 sites. It will cover plant identification, nutrition, growth habits, livestock grazing, storage (hay and silage), problems, and more. The information will be Western Oregon specific based on local research and trials, and that’s something we definitely can’t get from a book.
I’m taking extensive notes along with reading all the provided material and assigned chapters in the class reference, Greener Pasture on Your Side of the Fence
, which I fortunately already own. I thought I would write up a summary of each class on our blog, for the benefit of those interested. I’ll include links to additional information where appropriate. This will not be a transcript of the class. I recommend reading the books cited in this post and looking for a similar course taught in your area.
Disclaimer: These posts are based on my notes. Although I strive for accuracy, there may be mistakes. Please verify information before using it to make important decisions.
Here’s a complete list of our class-related posts. I’ll update it as more are added:
- Class 1 : Pasture plants (this post)
- Class 2 : pH and fertilizer
- Class 3 : Fertilizer and organic matter
- Class 4 : Forage nutrition
We aren’t the only blog that’s posted notes from a Woody Lane pasture management session. Over at Collie Farm Blog, workingcollies has posted notes from a lecture at the KHSI Expo. You might want to check out her notes for a different perspective. I’m providing the links here, as I had a hard time finding them in sequence:
- What I Learned About Grass at the KHSI Expo: Part I
- What I Learned About Grass at the KHSI Expo: Part II
- What I Learned About Grass at the KHSI Expo: Part III
- What I Learned About Grass at the KHSI Expo: Part IV
- Last KHSI Notes on Grass: RCG in the Northwest
Here’s the highlight from March 3rd.
The chemistry of plants
At their most basic form, plants use water, carbon dioxide, and sunlight to produce carbohydrates, specifically glucose. They combine glucose with nitrogen to produce amino acids. Amino acids are used to produce proteins, and proteins are used to grow the plan bigger to capture more water, carbon dioxide, sunlight, nitrogen, and so forth. Pastures are like vast solar panel factories. A well managed pasture is a solid mass of green, teeming with energy, but few of us have seen pastures like that. One problem is nutrition.
Plants need a variety of minerals to grow. The big three are potassium (k), phosphorus (P), and nitrogen (N), but sulfur (S), iron (Fe), copper (Cu), magnesium (Mg), manganese (Mn), and other elements are also needed. These must be present in the right proportions. Too much can be poisonous. Too little can affect the efficiency of growth. Most pasture plants have 6″ deep roots, so if the the minerals are deeper than that, they effectively don’t exist. Rain drives minerals such as nitrogen and sulfur deeper into the ground. Also, taking products off the land without paying back reduces the available nutrition. Consider this: every ton of hay removed from a field removes 40 lbs of potassium.
Types of pasture plants
There are three important groups of pasture plants: grasses, legumes, and forbs. Grasses are familiar to most people: perennial rye, timothy, orchard grass, johnson grass, bermuda, etc. Legumes are nitrogen fixing broadleaf plants such as: alfalfa, clovers, vetch, peas, beans, etc. Forbs are broad leaf plants that don’t fit in the other categories: brassicas, chicory, plantain. Yes, brassicas–radishes, turnips, rutabagas, and so forth–can be used as forages. Plantain apparently does very well in Oregon, with it’s deep tap roots and high levels of growth during the cloudy months of January and February.
Two types of grass
Grasses are divided into two types based on the first carbohydrate molecule they produce during photosynthesis. Most grasses produce a 3-carbon molecule, and are called C3 grasses (or cool season grasses). These have shallow roots and prefer cooler temperatures, with most growth occurring in the spring. They are easily stressed by lack of water, and generally go dormant in the summer. All the grain crops (wheat, barley, oats) are C3 grasses, as are most of the common lawn and pasture grasses.
The other group of grasses uses a modified chemical reaction to supercharge photosynthesis in hot weather, producing a 4-carbon molecule. These are called C4 grasses (or warm season grasses), and they are capable of producing explosive summer growth. These grasses are generally very water efficient, and can be properly timed in Oregon to fill in the dry summer months with useful forage production. Corn is the most famous of the C4 grasses, but also the least water efficient. Other species include sorghum-sudangrass, millet, and … wait for it … crab grass. Yes, crab grass can be a useful forage crop and has been tested in the Roseburg area of Oregon quite recently. Unlike most C4 grasses, it actively self-seeds (just ask anyone trying to keep a monoculture lawn), but has the potential to run-amuck without a well developed management technique. Warning: planting crab grass might get you tarred and feathered if you live in an area of grass seed production (much of Linn and Lane counties).
Some people will tell you that the grass only grows in Oregon for 4 months and then you have to feed hay the rest of the year, but this is entirely species and management dependent. The Oregon climate lends itself to forage production 365 days of the year.
As mentioned above, legumes have the unique ability to fix nitrogen. They do this forming a symbiotic relationship with soil dwelling rhizobia bacteria. The bacteria form in colonies called nodules, which are tiny white bumps on the plant’s roots. These colonies capture N2 from the air, break the powerful triple bonds, and convert it to soluble nitrogen forms that the plant can use. This gives legumes a distinct competive advantage over other plants, as they can sustain growth in low nitrogen soil by tapping into the 78% nitrogen content of the air.
There are many species of rhizobia bacteria, and a specific species can partner only with specific legumes. If the right bacteria is not present in the soil, legumes will still grow just fine but they will use existing soil nitrogen instead of fixing it from the air. This eliminates the greatest advantage of planting them. When seeding with legumes, be sure to buy pre-inoculated seed or coat with the appropriate inoculant before seeding. Also, you should occasionally pull up plants to ensure that the nodules are present on the roots. Note that nitrogen fixed by a legume is not immediately available to other plants growing in the pasture. When the upper potion of the legume is cut or grazed, the roots will die back proportionally, leaving high-nitrogen plant material underground where it can break down and be absorbed by grasses and forbs.
Well, that’s all for my summary of the first class. We discussed many other things (basic grass identification features, the commonly misidentified rushes and sedges, yearly growth patterns, vernalization, classic varieties vs. cultivars, use of scientific names, and mycorrhiza), but I want to keep these posts to a reasonable length. Robin says she didn’t know there was so much to learn about grass. In reality, these 30 hours of instruction will only scratch the surface.