Conserving Pasture Production During Dry Conditions

How you manage your pasture from the start of the grazing season will influence how it responds to drought conditions. The root system is usually proportional to the top growth. Maintaining a residual height of 3-4 inches (7-10 cm) and adequate rest and re-growth time will provide for a strong deep root system. These roots can gather moisture during dry periods and continue to grow to soil moisture when the surface soil is very dry. All the principles of good pasture management will be rewarded during a drought, so the effects are less severe than they could be. Grazing management must be adjusted quickly to drought conditions but species and plant health will also have a major impact on production.

Plants that are healthy because of good soil fertility programs and good rest periods that preserve root reserves will be ready to respond quickly once the rains return. Nitrogen, especially, will need to be applied in conjunction with moisture to be of benefit. Natural fertility or applications of phosphorus and potash will help to keep root systems healthy

Healthy plants provide a more complete canopy which will reduce soil evaporation and keep the soil from drying out as quickly.

Subdividing fields will help you to manage pastures better. Grazing management is really "harvest management" of the forage you have produced. In a continuous graze system 70% of the forage produced is wasted, in a rotational system this is reduced to 45%.In a strip grazing system only 30% or less of the material is wasted. If pastrues are not managed cattle tramp, lie and foul on too much material. If you can keep their heads all pointed in one direction and moving systematically across the field then you can greatly reduce these losses. We don't tramp fields with haybines so why do we allow livestock to do even worse? Setting up smaller fields addresses all the principles listed at the first of this article. With smaller fields you can restrict livestock from a section allowing it time to rest and to re-grow. You can prevent livestock from re-grazing and thus overgrazing forages. In this manner you will allow the plant to refill the root reserve system. Plants that have a larger leaf area left after grazing can rebound more quickly. It provides more area for photosynthesis and helps to maintain a larger root system. Seven days of overgrazing can delay re-growth by two weeks. You can never afford that delay but especially during a drought it is too expensive!

You have likely already faced the question of whether to leave fields for pasture or take them for hay. If you are grazing taller pastures tramping can be reduced by keeping the fields small. Livestock can effectively graze these if their movements are confined. The next decision will be when to return to a pasture. It is generally recommended that pastures with less than 6 inches (15 cm) of growth and less than 30 days re-growth not be grazed as they have the potential for more growth with rain. If the re-growth period has been over 30 days they should be grazed to remove the growth and to restart the buds so that re-growth may occur."

Supplementing pastures may be necessary to keep animals from overgrazing. This will mean moving them onto a "sacrifice" pasture and feeding. Livestock will usually prefer pasture so will keep re-grazing and weakening pastures rather than accepting the supplemental feed if they have access. Producers find that they require less supplemental feed and have better gains if they supplement early before livestock condition is affected and before pastures are weakened. Neither has to be adversely affected, but you will have to take control of the situation. Balanced rations are the most efficient method of feeding.

Pastures can be extended by bringing other crops into the rotation. Second cut hay is often used to lengthen the rest period for pastures. Other crops such as cereals, sorghums, kale, annual ryegrass or others can also be grazed during summer to give an extended break to the main pastures. Half of the forage is produced in the first 60 days of the season with the other half produced throughout the rest of the season. Knowing this plan your grazing needs and plant an annual crop to be available for grazing in mid to late summer. Decide what you are going to do. Don't be backed into decisions by trying to respond when it is too late.

Careful attention to grazing management will allow you to realize the maximum production from your pastures without sacrificing next year's production to salvage forage for this year. Rest the root systems, do not overgraze and leave enough ground cover that recovery can be quick once the rains return. Good grazing management allows you to grow and harvest the production of the field more effectively.

 


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: Jack Kyle - Grazier Specialist/OMAFRA
Creation Date: 23 July 2007
Last Reviewed: 13 July 2012