53 The Business of Ontario Agriculture Better Farming | November 2024 crops: the lynch fileS wheat, you must have a plan to control volunteer wheat. You can use tillage right after harvest, allow volunteer wheat to emerge, spray it off, and plant wheat. Or, you can plant pure alfalfa, use a graminicide to control the volunteer wheat, and then plant a grass. There is no herbicide you can spray that will control volunteer wheat and be safe to grasses you seeded. I received numerous questions about how to control weeds in established alfalfa. The short answer is that there is no herbicide to control broadleaf weeds. The exception is HarvXtra alfalfa, which can be sprayed with glyphosate. The main way to control most of these weeds is by cutting and fertilizing. What may be of interest is some research that Mike Cowbrough, weed management specialist at the Ontario Ministry of Agriculture, Food and Agribusiness, has done on herbicides for forages. He found that bromoxynil, sold as Pardner and other generics, was safer on emerged alfalfa than was 2,4-DB. Insects I had very few calls about insects this year. There was some concern about alfalfa weevil, and a few acres were sprayed. The wet conditions may have helped to keep this insect under control. There were some fields with potato leafhopper. Luckily, only an average number of fields needed to be sprayed. There were some acres that looked like leafhopper damage, but they were actually boron deficiency. Boron deficiency causes alfalfa plants to be shortened and take on a yellow-to-red colour. Fertility I’ve spoken with many forage growers across numerous provinces who want a fertility recommendation but do not have a soil test. There are many reasons for this, but there are way too many farmers growing forages without a soil test. Soil testing for forages is more critical than for corn or soybeans. Forages have a unique need for magnesium, sulphur and boron, along with their need for phosphorous, potassium, and nitrogen. Every field growing forages in Ontario should have a minimum of 20 pounds per acre of actual sulphur. There are many ways to do this. A common way is to apply 100 pounds per acre of ammonium sulphate in the spring. A lot of fields need magnesium. Using 100 pounds per acre of Sul-PoMag gets you 20 pounds of sulphur and 11 pounds of magnesium. You probably need 20 pounds of magnesium on many soils that are growing forages. Only a soil test will let you know. Field trials by Harvey Wright, field crops specialist at OMAFRA in the 1980s, showed a substantial yield increase by applying one pound of boron per acre. His suggestion was to apply the boron in the fall. One potassium product, Aspire, contains 58 pounds of potassium oxide (K2O) and one-half pound of boron per 100 pounds of product. Muriate of potash contains 60 pounds of K2O per 100 pounds of product. I have spoken with many farmers growing forages who do not have a soil test. Of the farmers who do have a soil test, very few have manure analysis. So, this leaves me to guess at the value of their manure. I tend to estimate on the low side. It would sure help if they had a manure analysis. Here is an example. For dairy manure, the amount of available nitrogen is nine pounds per 1,000 gallons of manure, as reported by OMAFA in their manure summary, but the range is about seven to 20 pounds of available nitrogen per 1,000 gallons. At 5,000 gallons of manure per acre, this is 35 to 100 pounds per acre of nitrogen. At 10,000 gallons per acre, this is a 70 to 200 pounds of nitrogen per acre range. At today’s fertilizer prices, when you add in phosphorous and potassium, the range of the nutrient value of 5,000 gallons of dairy manure is $80 to $160. This type of difference makes it worthwhile to have your manure analyzed. A lot of fields had tall weeds early. Patrick Lynch photo
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