The Rotational Benefits of Forages: Crop Yield and Quality Yields are often higher after forages particularly after nitrogen-fixing forages Grain quality also improves .

1992 Forage Survey - 67% of farmers said they had a yield benefit in grains after forages .

Wheat after legumes yields more than wheat after canola.

20 bu/acre yield benefit in year 1 58 bu/ac benefit over 5 years…. This graph represents the grain yield benefit to wheat when alfalfa was in the rotation compared to when only annual crops were in rotation.

Continuous wheat for 6 years, no N fertilizer . Continuous wheat for 6 years, no N fertilizer

Third wheat crop with no N fertilizer after 6 years of alfalfa . Third wheat crop with no N fertilizer after 6 years of alfalfa

Fourth wheat crop with no N fertilizer after 5 years of alfalfa . Fourth wheat crop with no N fertilizer after 5 years of alfalfa

. Long-term wheat yield following alfalfa similar to that of fertilized wheat in a fallow system.

Wheat quality also benefits from alfalfa in rotation.

To determine the Fertilizer Replacement Value of legumes, a non-legume test crop (e.g. oats) is planted on land that had legumes (e.g. alfalfa) on it the year before. The yield of these oats are compared to the yield of oats grown with different rates of fertilizer (e.g. 0, 40, 80 and 120 kg/ha). See http://www.fewerchemicals.com/research/frv.html for more details.

Overall, the fertilizer replacement value (FRV) was higher at Winnipeg than at Carman. This can be attributed to drier conditions and much lower legume dry matter yields at Carman. Under ideal moisture conditions, alfalfa fixed the largest amount of nitrogen per 1000 lb dry matter produced. When conditions were dry, alfalfa produced very little nitrogen and red clover used more than it produced. The annual legumes, chickling vetch and black lentil were better nitrogen producers under dry conditions. In fact, chickling vetch produced nearly 50% more nitrogen under dry conditions.