More Numbers, Grass and Pasture Factoids

(post by Jason) Melissa ran some very interesting numbers in her last blog post. Since I’m a science geek, a weather nerd AND a farmer I had to extrapolate on some of her numbers. I should probably say I’m sorry to all of you reading this who AREN’T all of the above because you’ll probably find this post a bit dry. However I could happily talk about this stuff for days……on and on and on…..you get the picture! At any rate, on with the show! Perhaps the only number we have never calculated was an estimate of how many pounds/kilograms of grass these horses eat over the course of a year. As you know we rely on our pastures to provide much of our forage intake. Even I didn’t realize quite how much we rely on pasture! I calculated that over the course of a year the horses would graze roughly 506,000 pounds of pasture dry matter. Because green grass is mostly water (I’ve used 75 % water….this would vary through the season) the actual weight of grass the horses consume is roughly 1,512,000 pounds or 686,025 kilograms of grass! Whew ! This is in addition to consuming 375,000 pounds of hay and 114,000 pounds of grain! Our latitude is roughly 35 degrees North which means we live far enough south that some grazing is possible in every month of the year. Our winter climate is mild with short spells of severe cold occurring a few times a season. The ground never freezes to any depth or for any length of time. We don’t even consider frost lines when burying water or sewer lines…we bury water lines deep enough so when we drive over them they won’t break. We have both C3 cool season grasses and C4 warm season grasses. Cool season grasses predominate from November through mid April. Warm season grasses predominate from late May through the end of September. I can’t quantify it beyond an educated guess but I would say that in a normal year warm season grasses out produce cool season grasses at least 3:1 if not more. Thus a minimum of 75% of our pasture forage dry matter gets produced and consumed during the warmest six months of the year. Our lulls in pasture growth happen from mid April to mid May and again from early October through early November when the pasture species change from temperate to tropical and back again. Winter growth is significantly slower than summer growth and even in the best years we rely on hay for the majority of dry matter intake from mid-November through the end of February. Growing and managing all that pasture grass is labour and time intensive. We maintain over $100,000 worth of machinery solely to look after the pastures. As compared to most grazing animals horses are incredibly hard on pastures. I calculated that every acre of pasture would have a tractor driven across it a minimum of eight times per year; once to apply manure, twice more to apply commercial fertilizer, four times to clip seed heads to promote more vigourous pasture growth and once for weed control. We put roughly 500 hours on our tractors each year just looking after pastures.