Why Wet Grass is Best: The Power of Dry Season Grazing

In the Maasai Steppe of northern Tanzania, dry season grazing areas actually show the best grass regrowth. This is a big deal because these semi-arid rangelands have to deal with really unpredictable rainfall. Traditionally, pastoralists have kept these lands healthy by moving their herds around with the seasons. But with climate change, this might not work as well as it used to. To figure out how to keep these rangelands strong, scientists did an experiment. They set up three types of rangeland management: rainy season grazing, dry season grazing, and areas closed off to grazing (called exclosures). They then clipped the grass in these areas either once a month or once during the whole growing period. Some plots were left open to grazing, while others were fenced off. Here’s what they found: Rainy season grazing areas had the lowest grass regrowth and most bare ground. When it didn’t rain much, the exclosures had the least bare ground. Plots that were clipped once a season and not grazed grew the most grass and had the least bare ground. Excluding animals from grazing didn’t do much for the overall plant cover, but it did help grass regrow faster when it rained a lot. Clipping once a season also helped stop bare ground from forming and usually led to more grass and regrowth than monthly clipping. So, the idea of moving herds seasonally is still a good one for keeping rangelands productive and tough. Just make sure not to overgraze during the rainy season and give the land a break after heavy grazing. Dry season grazing, with a rest period during the rainy season, seems to be the best way to keep the grass growing and control erosion.