- Photo by Jeffrey Banke / Dreamstime
Effective soil management is key to producing high quality alfalfa. That’s the message long-time journalist and researcher Harold Willis brings out in the booklet he authored, How to Grow Great Alfalfa. The 47-page, 6x9 booklet contains a number of black and white photos and outlines the steps involved in establishing a highly nutritious and productive alfalfa stand.
Research data that Willis included in the book comes from the work of several crop consultants he observed, including Gary Zimmer, president of Midwestern Bio-Ag in Blue Mound, Wisconsin. Zimmer, a farmer, author, agri-businessman and educator dedicated to biological agriculture, is recognized around the world for his commitment to improving farming through building healthy soils. He’s provided presentations to farmers and agribusiness professionals all across the U.S. and in Canada, Europe, Australia, New Zealand, and South Africa.
Zimmer has also authored two books; Advancing Biological Farming: Practicing Mineralized Balanced Agriculture to Improve Soils & Crops was written with his daughter Leilani Zimmer-Durand and published in 2010. The Biological Farmer, A Complete Guide to the Sustainable & Profitable Biological System of Farming was published in 2000.
Zimmer says refining a high quality alfalfa production system is challenging.
“I’ve been working with researchers and studying alfalfa for 10 years,” Zimmer says. “Alfalfa has been called the ‘queen of forages’ because of its ability to produce high yielding, nutritious forage. Successful production of alfalfa begins with a healthy stand. It’s critical for alfalfa plants to get off to a good start. Soil conditions play a major role in a healthy alfalfa stand.”
Is the tilth OK?
Well-drained and porous soil allows alfalfa to develop the unrestricted, deep-root system that will lead to vigor and quality.
“Soil organic matter will result in tilth (the physical state of the soil, how well it can grow a crop), water intake and water-holding capacity,” Zimmer says. “Mineral elements most essential for good stand establishment are calcium, phosphorus, and potassium. When farmers soil test for alfalfa, they sometimes miss the fact that calcium is lacking in the soil. Alfalfa is a calcium-loving plant. If your alfalfa stand isn’t full of leaves or you have a lot of foxtail or other weeds showing up, you probably have a calcium deficiency.”
Soil tests detecting soil pH don’t necessarily indicate that soil nutrients will support healthy alfalfa. After producing alfalfa for several years, soil health changes. Understanding how to balance the necessary nutrients is key to effectively continuing production.
Zimmer notes that the definition of quality alfalfa is one of the issues surrounding alfalfa production. He explains that high digestibility and highly nutritious alfalfa can’t be grown on nutrient-deficient soils.
“On my own farm, we cut our alfalfa five times,” Zimmer says. “We average 10 tons per acre every year. If the soil health is balanced, the alfalfa won’t grow so tall that you’re forced to cut it at bud stage. You might get one less cutting that way, but overall you’ll get more tonnage and far better quality.”
Due to prevailing beliefs about crop fertility, soil labs often recommend too much potassium and too little calcium for alfalfa fields. Producers can use a testing method that identifies readily available nutrients to determine what nutrients may need to be applied.
“To produce high quality alfalfa, soil should have a high level of available calcium and phosphorus,” Zimmer says. “Calcite lime and soft rock phosphate are good sources of these minerals. An application of organic matter, such as cattle or poultry manure or compost will take care of most alfalfa nutrient needs.”
A firm, moist seedbed will get alfalfa off to a good start with a variety of seeding methods. If companion crops are used, Zimmer recommends use of “less leafy” species.
Alfalfa quality is dependent on proper soil fertilization, hay stand management and cutting timing. Quality is more important than quantity because cows need smaller quantities of quality alfalfa to be productive and healthy. Numerous methods of quality measurement are available. Zimmer notes that the newest, latest digestibility test, RFQ (Relative Forage Quality), and wet chemistry on minerals gives the best clues as to quality.
“Poor quality alfalfa often contains excess nitrates, which can be interpreted to be high quality protein, but is actually a negative element of the alfalfa,” Zimmer says. “Good quality alfalfa will grow taller and be thicker than a less vigorous stand. Fewer cuttings are completed, but overall tonnage is the same or nearly the same, and requires lower input costs. Animals consume less, so in the long run the higher quality is more important than the quantity of cuttings.”
Healthy alfalfa won't flower as early, which means it can grow taller. It also has solid stems filled with healthy plant cells. It dries faster and can be baled when it's wetter without risk of spoilage because the moisture isn't water, it's plant cells.
Zimmer believes, and Willis’ booklet outlines, that there are several nutrient imbalances prevalent in today's alfalfa fields that help account for poor quality and premature flowering, etc.
“The main problem with growing alfalfa today is that traditional recommendations are for too much potassium in proportion to the other nutrients,” Zimmer says. “You can’t grow top quality alfalfa when the soil’s available potassium exceeds available phosphorus or calcium. High potassium alfalfa fields will produce beautiful plants, but the content will be too high in cellulose. Animals need high quality protein. That only comes from soil with plenty of calcium and phosphorus.”
Bugs and weeds
Research is confirming that bugs are less likely to attack high quality alfalfa; properly balanced soils reduce stress on plants, meaning they're more resistant to insect attacks.
In the booklet Willis notes that, if alfalfa is grown properly, it eliminates the need for genetically modified varieties because weeds can't thrive in a dense alfalfa field. Insect issues are also less likely to occur as healthy plants can ward off insect attacks.
“If your soil isn’t built up enough to produce high quality plants, you’ll need to use insecticide and herbicide,” Zimmer says.
Traditional methods of cutting alfalfa include cutting at bud stage, at 10% bloom, half bloom or full bloom. Scientific studies have documented that alfalfa’s content of minerals and digestible nutrients is highest during the plant’s succulent growth stage. At the flowering stage, mineral content and digestibility decline and fiber content were said to increase and food value decreased. In his book, Willis wrote that on-farm experience has shown that alfalfa quality is best when it’s cut between 25% and 50% of bloom.
“The best method to decide when alfalfa should be cut is use of a refractometer to measure the sugar content of the plant juice every day or two as plant blooms appear,” Willis says. “When the sugar readings reach a peak or begin to level off, that’s the time to cut. Emergence of new shoots at the crown is another sign, but that’s not as reliable as the refractometer.”
Alfalfa can reach heights of 40- to 50-inches before it’s ready to cut. The number of cuttings may be reduced with this method, but solid stems containing succulent plant cells will be obtained with this process.
Cutting should be done with a good clean cut to stems that are made above any new shoots sprouting from the plant crown. Regrowth can be stimulated with a nitrate-containing fertilizer topdressed at a low rate.
“Ammonium nitrogen fertilizers should be avoided,” Willis says. “They stimulate early flowering rather than vegetative growth.”
Producers should explore new alfalfa varieties, as researchers are continually developing new plants.
“If you cooperate with the biological laws of healthy growth and nutrition, you will produce high quality forage,” Zimmer says.
Willis’ booklet is available through Acres USA at www.acreusa.com or by calling 1-800-355-5313. Zimmer’s books are available through Midwestern Bio-Ag at www.midwesternbioag.com or by calling 1-800-327-6012.
