The spring of 2015 has offered ranchers some stress relief in the form of what has been described by some as the ‘perfect’ calving season. However, one rancher was quick to follow his statement on the good calving weather by saying “if calving goes well, expect the pastures not to look so good”. There is a lot of truth to that statement as we know that April and May rains impact overall range and pasture production for the remainder of the growing season.
Drought & Weather Resources
Grassland managers can often be conflicted about the ‘best’ timing for certain actions, such as spring grazing turnout. On one hand we discuss the options related to early turnout for cool-season grass control, often recommending intensive short-duration grazing with rapid rotation to take advantage of early growth while preserving the ability of the native grasses to respond when conditions are more favorable in late spring and early summer. On the other hand, early turnout and rapid rotations may limit future use because grasslands might be slow to respond after the initial grazing period if rainfall is limited.
Before we discuss grazing options, it is important to re-acquaint readers with resources available for dealing with drought.
U.S. Drought Monitor
Drought is tracked throughout the U.S. via the U.S. Drought Monitor. The figure below shows the current drought conditions across South Dakota based on the latest US Drought Monitor data, indicating most of the state is abnormally dry (D0) to moderate drought (D1) .
|South Dakota drought conditions, April 21, 2015 | U.S. Drought Monitor|
Climate Prediction Center
A second resource for understanding future trend can be found at the National Weather Service’s Climate Prediction Center . This site allows the user to view predictive models for temperature and precipitation in 6-10 day, 8-14 day, one month, and three month timeframes. In this case, the Climate Prediction Center's 6-10 and 8-14 day (figure below) precipitation prediction map shows most of South Dakota in a band of below normal precipitation.
|8-14 Day Precipitation Outlook | Climate Prediction Center|
SD NRCS Drought Maps
Climatic trends often track well with growing conditions and there are additional tools available for assessing current and predicted grassland conditions. The South Dakota Natural Resources Conservation Service (NRCS) reports on grassland production expectations based on climatic and other information. NRCS recently distributed its updated drought maps for April and July, 2015 (figures below). Currently, most of eastern SD is experiencing conditions projected to produce about 75% or less than normal average annual forage. The July (peak production) model prediction is not as grim, indicating that average production for most of the east will range between 75% and 85% of normal. For the most part, western SD production models appear to predict close to normal grassland production levels except for those western counties in or near the Missouri River.
|S.D. Grasslands Drought Condition, Current Status - April 15, 2015 | NRCS||S.D. Grasslands Drought Condition, Projected Peak Production (July 1) - April 15, 2015 | NRCS|
SD NRCS South Dakota Drought Tool
The SD NRCS has also developed the South Dakota Drought Tool. This tool is a Microsoft Excel spreadsheet which may be downloaded for free from the SD NRCS website. The SD Drought Tool provides default information that is localized to nearby weather stations, but also can be customized by using rainfall information specific to each ranch. Current rainfall accumulation and temperatures are depicted graphically in comparison to historical averages. This tool does not base outputs on future weather inputs; rather on it is based on moisture received to date. So, based on current conditions forecasts of growing season vegetation production are provided as guidance for appropriate management responses. When used with other resources like the US Drought Monitor or the National Weather Service’s Climate Prediction Center, a grass manager can begin to identify management options based on various scenarios.
|Visit the SD NRCS website to download the South Dakota Drought Tool. *To use the tool, you must have a compatible version of Microsoft Excel.|
Here in SD, drought is a normal occurrence as evidenced by the graph below. Dr. Sandy Smart plotted rainfall at the SDSU Cottonwood Research Station over a 95 year period (1909 – 2004). In that timeframe, 28 years (1 out of 3) experienced drought conditions and had less than 75% of normal precipitation (Smart et al. 2005).
|Climate data plotted from the SDSU Cottonwood Research Station over a 95-year period indicates that drought is a normal condition in S.D.|
SDSU Extension Climate Field specialist Laura Edwards has reviewed climate data since 2000 (figure below), indicating that drought is a regular feature in our state’s climate. For that 15 year period, South Dakota has only been drought-free about one-third of that time, according to the U.S. Drought Monitor. In South Dakota, it is a wise decision to anticipate and plan for drought conditions.
|South Dakota climate data since 2000 shows that drought is a common feature of South Dakota's climate.|
While it is important to recognize the usefulness of the drought tools, their value is greatly diminished if they are only utilized when a crises develops. The real power comes when plans are in place before drought conditions occur. Drought planning requires prudence and caution, recognizing that grass, not livestock, is the base asset to be managed and protected.
If no drought plan exists for the farm or ranch, the first step is assessing potential effects of current and predicted drought before those conditions force decisions. While it is often said the worst time to plan for a drought is when you are in one and when emotions are running high, it is always wise to start the process - assuming conditions may get worse before they get better.
The drought planning process challenges one to take stock of the situation through objective and pre-determined indicators or ‘trigger points’ for decision making. Generally, trigger points begin with assessing whether the previous year was a drought or not. Once that baseline is established, decisions can be based on calendar dates that are associated with tangible and measurable indicators, such as rainfall conditions during the previous month. In addition to trigger dates, drought plans also include strategic actions such as increasing or decreasing stocking rates as well as guidance for more decisive actions such as culling or destocking. The National Drought Mitigation Center at the University of Nebraska-Lincoln is an excellent resource for starting or refining a drought plan for the ranch. Visit their impressive webpage dedicated to drought planning for the ranch for more useful information.
|The National Drought Mitigation Center at UNL-Lincoln is an excellent resource for starting or refining a drought plan for the ranch.|
2015 Pasture Turnout Considerations
As we approach the end of April, we are starting to see livestock going out to summer range. At this time, no one is quite certain what type of late spring and early summer growing conditions we will see, but trends indicate that we should prepare for a dry year with less than normal production throughout much of the state. As indicated above, conditions in the east are a bit worse than those in the west. Eastern SD pasture managers may be positioned well to: 1) either delay turnout by relying on left over feed stores, or 2) move ahead with grazing plans that target early cool season grasses but have the flexibility to return livestock to designated areas using harvested/stored feeds if pasture conditions do not improve within the first several weeks of the growing season. In a recent article, SDSU Extension Cow/Calf Field Specialist Warren Rusche discussed the pros and cons of dry lot feeding in today’s market and climate.
Drought is a common occurrence in South Dakota, and depending on the severity of conditions, the impacts can be mitigated through sound planning. SDSU Extension staff and our partners remain committed to helping producers plan for and mitigate drought impacts.