To maintain long-term productivity of forages, fertility has to be part of the plan. Legumes in a forage rotation add nitrogen, but they take away large amounts of potash and phosphate. High production of grasses grown for forage take away lots of all the nutrients including nitrogen required for plant grow. A plan needs to be put in place for anyone looking at maintaining long-term productivity of their forage stands. A big part of this plan must include nutrient management to ensure maximum potential plant growth happens in an economic fashion. If a producer is not doing this, mining of nutrients from the soil will be the result and finally, low yields of forage is all that can be expected. The first step in setting up a nutrient plan is to do some soil testing. The soil is the resource pool for all the nutrients that are required for plant growth. A soil test is a snapshot of what is in the soil at a specific time. Taking a soil test provides focus on which nutrients need to be dealt with to ensure proper plant growth. Once the soil test is done, a plan must be set up to deal with the nutrient issues that the soil test identifies. Identify the nutrients available. Manure from feeding areas will bring nutrients to the field. Feed that is brought in from other areas will increase nutrients in the soil. The problem with both these systems is that you have to bring the fertilizer nutrients in from other locations to see a net gain of fertility in the soil. Also, with this type of fertility program, there are only so many cows to be fed and so much manure to be spread. This means that in this country, all the acres of ground cannot be covered in a timely fashion with manure or feed to allow for the fertility to be maintained on all the acres in production. Once the soil fertility deficiencies have been identified, a producer has got to decide how to get the nutrients to the plants in the field. Hauled-in feed, manure and fertilizer can all be used to improve the fertility of a forage field. Fertilizing pasture is different than fertilizing hayland. With cattle, they leave 60 to 95 of the nutrients that they eat in manure and urine. Cattle must be distributed evenly throughout the pasture to ensure that fertilizer is being properly distributed. Feeding on pastures will bring fertilizer into a pasture or hay field. This will help improve fertility if enough cattle are being fed. Manure must be applied at adequate levels to ensure that the fertility is improved. When there are not enough cattle to feed or manure to cover all the land, it is time to start using fertilizer to make up the deficiencies. Planning nutrient management for your pastures or hay ground is essential for maintaining pasture yields. If you have any questions about how to do this, give me a call.
By Dave Cubbon, P Ag