Adjusting Turnout Dates To Meet Range And Weather Conditions30 April 2013
Precipitation rates in Dakota have caused concern for cattle producers over soil condition of the State's rangelands. Pete Bauman, South Dakota State University looks at how to arrive a suitable turn-out date for the 2013 livestock grazing season.
As livestock producers continue to make plans and adjustments for the upcoming grazing season it is important to consider all parameters affecting 2013 pasture conditions. Although turnout dates can vary with individual management schemes and location, many producers consider May 15 an initial target date. This year turnout date planning is more complex than usual due to limited feed resources, mud/wet conditions in home lots due to recent moisture, and relative lack of residual forage on rangelands across the state.
Those who turn out early risk late winter/early spring severe weather, such as the recent snow storm that hit most of South Dakota. Although storm reporting is not a perfect science and is generally recorded based on location, SDSU Extension Climate Field Specialist Laura Edwards indicates that at least four to five major storms have hit widespread portions of South Dakota in April since the mid 1990’s, some of them as late as the last week in April and some dumping 10-20 inches of snow. In this period of drought, it is hard to argue with moisture of any kind, but now is a good time to assess when, where, and why you turn your livestock out to pasture. It also may be time to make adjustments to your normal turnout dates based on range health and condition.
Some things to consider when determining your 2013 turnout date(s) and pasture condition, depending on where you are located in the state:
Current Pasture and Soil Moisture Status
2012 was a difficult year for many producers, and the current condition of grazing lands reflects the intensity of the drought in many locations. Most of the state’s rangeland soils went into the late summer and fall with moderate to severe moisture deficits. In addition, most rangeland plants were grazed intensively, leaving plants with limited nutrient reserves to begin their 2013 life cycle. Climatologists are clear that although average precipitation may sustain regrowth, it will take above average precipitation to restore our soil moisture profile and “normal” forage production. This is an important factor to consider when planning turnout and stocking rates, as early-season green up and growth might be short-lived. Season-long plant growth may be suppressed without above average moisture due to an overall time lag in plant response to available soil moisture. South Dakota NRCS’s current model predicts that the vast majority of the states rangelands will produce less-than-normal forage through July even with normal precipitation (Figure 1).
Roots and Shoots
With the pressures of drought it becomes easy to ignore what we cannot see in our pastures. Leaves and roots work in tandem for a healthy plant, and below-ground vegetation (roots) cannot sustain itself long without healthy above-ground structure (leaves) and vice versa. It is important to consider the vital role that leaf area plays in plant growth…without leaf area (the solar panel), plant growth will be limited. Many producers consider a three to four leaf (boot stage) as their target for beginning grazing, but continuous clipping of the plant can prevent recovery, thus limiting root and shoot growth. Adjusting stocking rates and/or rotations to allow adequate rest between grazing periods is key to maintaining plant health and vigor. Chapter 5 of NRCS’s National Range and Pasture Handbook is a great resource for understanding this dynamic relationship (Table 1).
Table 1: Relationship of Leaf Removal to Root Growth Stoppage in Plants.
Pasture plant composition is important to understand and consider when assessing turnout dates. Recent moisture across most areas of the state will likely ensure at least some growth of cool season grasses such as exotic species like Kentucky bluegrass and smooth brome. Early native cool season grasses will also benefit. The timing, duration, and volume of production may be negatively affected by persistent drought conditions in some locals, so careful monitoring will be necessary to avoid over-harvesting. If your goal is to utilize livestock to control cool season exotic grasses such as smooth brome, turnout dates that coincide with early growth of the plant can be advantageous. Livestock may need to be moved to an alternative pasture as warm season grasses begin growth to avoid unnecessary damage to the plants during early growth - giving them time to recover from drought and to build roots and leaves for the season. Remember, if over 50% of the above ground vegetation is removed, root growth is limited. A good rule of thumb in many areas is to avoid grazing vegetation under 4 inches at any time during the year. Be prepared to carefully monitor plant growth patterns. One way to determine true plant growth patterns and production in your pasture is to incorporate a few simple grazing exclosures like the one shown in Figure 2 for easy vegetation growth monitoring.
Ground Conditions and Non-local Supplemental Feed
Invasive and noxious weeds are a threat to our rangelands. Consider your overall soil conditions when planning turnout dates and locations. Moist or saturated soils are more easily disturbed and/or exposed by hoof action and vehicle tires. If there is a history or threat of invasive species in the immediate area, caution should be practiced to protect your soil surface from unnecessary disturbance. A prime example is feeding ‘wild’ hay in your higher quality native pastures during early turnout to supplement limited natural vegetation. If you are uncertain of the source of the hay you are feeding, it is best to contain spring feeding operations to low-quality areas that are easily accessible for future weed control should weed germination become an issue later in the growing season.