By Trevor Lennox, Regional Forage Specialist
Saskatchewan Ministry of Agriculture
As grass starts to green again this spring, forage producers may find their thoughts shifting ahead to the upcoming growing season and what particular management practices need to be employed in order to maximize yield potential. Perhaps some particular fields have been suffering from low forage yields and will need some form of rejuvenation in order to improve yield potential.
As seeded forage stands age, a decline in yield is often noted. Soil fertility decreases as the forage crop utilizes available nutrients. Nutrients are continuously removed from the field but rarely replaced. For example, a grass stand cut for hay and yielding 3 tons per acre will result in the removal of 90 to 120 lbs of nitrogen (N) annually. The effect is compounded by other factors such as cutting too frequently, cutting too late in the fall, grazing too early in the spring, overgrazing, frost damage, and/or pocket gophers. As forage yields decline, producers may start to investigate different options for rejuvenation of tame pasture and hay stands.
Undesirable vegetation is dominating the forage stand
Evaluate the existing stand through a tame forage health assessment. Stand replacement is often recommended where more than half of the plants present are weedy or undesirable. Conventional break and seed practices as well as sod seeding are options to consider. Stand replacement can be the most expensive option and should be considered carefully. Obtain information on effective stand termination as well as weed control and choose forages best adapted to local environmental conditions.
Desirable vegetation is dominating the forage stand
Where more than half of the plants present are desirable forage plants, various rejuvenation options can be considered. It is possible that simple management changes may improve stand condition. Rest rotation or deferred grazing can allow pastures to rest and recover from previous grazing events. Resting a pasture can sometimes be the most economical option. Adding fertilizer is often the next option considered. Grass dominated stands are usually limited by N while alfalfa dominated stands are usually limited by phosphorus (P). An application of 50lbs of N should result in a yield increase of about 1,000lbs in a meadow brome grass stand under good moisture conditions. Good results have been observed where 30 to 50lbs of N were applied using a high clearance sprayer with dribble band tips. Alternative forms of fertilization can include liquid manure application or bale grazing. Where weed issues are affecting a stand, herbicide treatment may be a good investment. Consult the Guide to Crop Protection for product choice and restrictions. Combining weed control with fertilization can provide good results where weeds have suppressed desirable forage species. Where legumes are missing or making up a small portion of the stand, the addition of legumes through sod seeding or overseeding may be considered. Overseeding with legumes such as alfalfa or cicer milkvetch has been tested with variable results. Success depends on the capability to suppress the existing vegetation and moisture availability in the year of establishment. With any rejuvenation option it is important to identify the source of yield decline and to correct any management related causes which can lead to future production losses.
For more information on this or other topics please call Trevor at the Swift Current Ministry of Agriculture office (306) 778-8294, or contact the Agriculture Knowledge Centre at 1-866-457-2377 or visit our website http://www.agriculture.gov.sk.ca/ .