There is a very important aspect to my grazing management that many producers have a hard time accepting. “Wasted grass” is not wasted. Residual grass left in your pastures provides many benefits to your forage.
If you have ever taken my school or heard one of my presentations on grazing management, then you know I really emphasize the importance of the four grazing concepts: Graze Period, Rest Period, Stock Density and Animal Impact. These are concepts. They work in any environment because they need to be adjusted to fit your environment and they are the basics to understanding good grazing management.
I also promote four grazing principles that we follow in order to maintain a healthy and sustainable operation. These principles include management of the water cycle, nutrient cycles, sunlight harvesting and soil biological life. If you can grasp on to the concepts and use them to manage the principles, you are moving forward towards a profitable and sustainable ranch. So if leaving residue is so important, why is it not listed in my concepts or principles? That is simple. It is because residue overlaps in all areas of grazing management.
When we are managing the graze period and the rest period, the amount of residue left after grazing has a big factor on the rate of recovery. If you graze off all the green leaves from a plant, the new growth has to come entirely from the root reserves. This would slow the recovery time and you would need a longer rest period. If the animals were to only graze off the top part of the plant and there were plenty of leaves still left, the plant recovery would be much quicker as the plant can still capture solar energy to recover. This is also where the solar harvesting principle benefits from extra residue. Green leaves collect sunlight. Don’t waste your sunlight by allowing it to hit dirt! Leave more residue!
A high stock density will improve your residue because a lot of the forage is “stepped” into the ground. Some people see this as wasted forage but I beg to differ. This residue goes back into the soil as fertilizer. If half of my forage is stepped on, I’m happy. This is where nutrient recycling comes into play. Residue is slow to recycle if we can’t get some soil contact.
Animal impact is the physical stimulation of the soil by the animals’ hooves. If we can have the residual forage pushed down to touch the soil, our nutrient cycles will improve. From here the soil’s biological life takes over. All the bacteria, fungi, nematodes, dung beetles and larvae in my soil are my employees and they work for room and board. They break down the manure and litter, allowing the nutrients to be recycled. If you want your pasture to be profitable, you need to feed the soil. Room and board! You need to
provide food, water and shelter for your employees. If you do, they will build your soil by converting residue into organic matter. So leave more residue!
Speaking of water, residue is very important for the water cycle. The more you can leave on the surface, the higher your effective rainfall will be. Effective rainfall is the amount of rain that your plants get to use. This is compared to actual rainfall, which is the amount that falls from the sky. The difference is mostly due to runoff and evaporation. The more residue left, the more water your soil can hold on to. The more soil moisture, the more growth you get. It is incredible how much growth potential we lose every year to run-off and evaporation. As the manager you have the ability to reduce that loss. You cannot control the amount of rain that falls, but you can manage your effective rainfall. Leave more residue!
OK, how much residue should we leave? Many times I have heard the old “take half, leave half” rule of thumb. In some cases this works well, but I know I have some pastures that if I take half, there is not nearly enough residue left over to cover the ground. I might need to leave all of it, and sometimes I do. On good years, I will skip over one of the poorest-producing paddocks in my pasture and allow all the growth to stay as residue. I also have some pastures that have so much growth, that if I leave a quarter of the forage, I will still have plenty of residue cover.
You also need to leave residue every time you graze, not just in the fall. By leaving some residue during your first graze period, some plants might get to go to seed which of course adds to your seed bank. To be sustainable, we need the next generation. Residue left over the winter insulates the soil from the frost and collects more snowfall. The more residue you carry over in winter, the better your growth will be in the spring. Leave more residue!
How much is enough? I am a producer, and I know that I always have to arm wrestle myself. It comes down to long-term sustainability versus short-term cash flow. There has been many times when I know I needed to leave more residue than I did. I know the long-term benefits from leaving it, but some years my needs for cash flow makes me take more than I should. And we all have to deal with other variables, as well, such as drought and high hay prices.
Every year is different. You are the manager and it is your call, but my recommendation is to leave as much residue as you can cash flow. The more you leave, the better next year will be. And if next year brings more grass, chances are your cash flow should be better.
I would also suggest you try not to fluctuate your stocking rate year to year because of rainfall. Keep your stocking rate relatively constant and just leave more residue in the good years. If you do, the drought years will not be so hard when they come. When Mother Nature gives to you, give back.
Have I made my point? Leave more residue! It’s fertilizer, it improves the water cycle and it protects the soil and the soil organisms. Don’t be afraid to “waste” a little grass.
Steve Kenyon runs Greener Pastures Ranching Ltd. in Busby, Alta.,www.greenerpasturesranching.com, (780) 307-6500, email