By Luke Jorgensen, AAg. Range Management Extension Specialist, Humboldt
The primary objective of a pasture system is often to maximize forage yield to feed your livestock. There are many ways to improve pasture productivity such as applying fertilizer or introducing legumes, but a healthy level of plant litter is a critical component of a productive pasture.
Litter is the plant material that is left over from previous growing seasons. It includes residue on the soil surface as well as dead tissue that is still standing. Litter decomposes over time and contributes to soil organic matter, so it is important to add to the litter bank every year. Litter is what's left after the growing season, so the only way to build it is to make sure that there is plant material remaining in your pastures when the snow falls. This can be achieved by letting a pasture rest and recover after a grazing event, or by taking your livestock off the pasture before they have utilized all of the available forage. Some years it might not be feasible to leave forage in the field, but litter accumulation is a long-term process and managing for litter is a long-term objective.
It's easy to assess the litter on your pastures. An accurate way to measure litter is to rake it up with your hand from a small patch of soil, then dry and weigh it. A 50cm x 50cm (0.25m2) quadrat is often used to define an area to collect litter from. You can build a frame with these dimensions, or just use a measuring tape every time you collect litter. Make sure to only collect dead plant tissue. Dry the litter in an oven and weigh it, then multiply the dry weight in grams by 35.6 to convert it to pounds per acre. You can keep the dried litter in plastic bags to use as a visual reference when assessing litter in the field. Raking litter from a 0.25m2 area and visually comparing it to your reference bags is another good option for measuring litter. You should aim for at least 250lbs/acre of litter on tame fields, and consult page 41 of the Native grassland and forest Rangeland Health Assessment field workbook for recommended litter levels in your native pastures.
Managing your pastures to improve litter cover means leaving some forage left ungrazed, but there are many advantages. Adequate litter can improve forage yield by up to 50 per cent through several processes. The benefits of litter are most pronounced in times of drought because litter acts as a sponge that absorbs rainfall and slowly releases it into the soil. This means more water stays in the field instead of running off, and it reduces the chance of soil erosion. The blanket of litter on the soil surface also helps keep the soil cool which reduces moisture loss by evaporation. Litter is also a food source for soil microorganisms, which use it to produce nutrients for your forage crop. Managing litter is a key component of keeping your pastures healthy and productive, and it's a long-term investment that pays off.