Oklahoma farmers and ranchers are no strangers to drought conditions, and for most, planning for dry conditions starts now.
Leland McDaniel, an Oklahoma State University South Central Extension forage specialist, provided insight on how to jump start warm season forages with limited rainfall in a lunchtime webinar last week.
“If we look at rainfall patterns in Oklahoma, we can see it tends to be cyclical,” McDaniel said. “Generally speaking, it tends to go in seven to ten year swings.”
From the ‘80s to the early 2000s, Oklahoma saw a 30-year wet cycle which had a great impact on the plant growth and production practices in the state.
“The significance of this is that under this heavy and consistent rainfall over this long of a duration, it changed the landscape in terms of flora and general biomass,” McDaniel said. “So when we grow more biomass we require more water, and when we don’t get these rains, the impact is more severe than it would be under a more moderate rainfall scenario.”
The increased rainfall also allowed ranchers to increase stocking rates and mature cow size, in turn increasing demand for forage resources. McDaniel said while most of the state looks to have low risk of drought conditions, some areas of the panhandle and western Oklahoma could be facing issues.
“The old saying goes ‘we’re never more than two weeks from a drought,’” McDaniel said. “I think that tends to be very true.”
Contrary to what many believe, McDaniel said fertilizing is one of the best ways to prepare pastures for drought conditions.
“As risky as that may seem, contrary to conventional wisdom, I think we should look at fertility as drought insurance,” McDaniel said.
According to McDaniel, this is not a new concept. In fact, a study done in 1958 found it takes 20 inches of rain to produce 1 ton of unfertilized bermudagrass, while under high fertility, 4 inches of rain is needed to produce the same amount.
“That’s telling us fertilizer makes forage about four to five times more efficient at utilizing whatever limited rainfall we get,” McDaniel said.
However, McDaniel also cautions ranchers to refrain from just throwing nitrogen on their fields.
“Sometimes we overlook some of the simplistic things,” McDaniel said. “Plants, just like people and cattle, have complex nutrient requirements. It’s not just about nitrogen. Producers too often get in the habit of worrying too much about how much nitrogen they put out without giving adequate concern for phosphorus, potassium and soil pH.”
He likens it to taking care of your car. If nitrogen is like the fuel in the fuel tank, phosphorus is the oil and potassium is like the coolant in the radiators. While nitrogen needs replenished more often than the other nutrient requirements, they all have to be in harmony to achieve good yields.
“The analogy is that nitrogen, like gas, determines how much we grow or how far we go,” McDaniel said. “But if we don’t have enough phosphorus or coolant in the radiator, that system is going to lock up and freeze before we can burn that entire tank of fuel.”
A balanced pH is another important factor to consider when monitoring your fields and preparing for drought conditions.
“If pH is too acidic or too alkaline, nutrients get bound up in other compounds and are unavailable to the plant,” McDaniel said. “So in addition to ensuring that we supply adequate amounts of nitrogen, phosphorus and potassium, to utilize them we have to ensure we have adequate pH.
“I equate that to tire pressure. We can address nitrogen, potassium and phosphorus, but if pH is off we're not going to do a good job of utilizing that nitrogen we put in.”
McDaniel encourages ranchers to have soil samples done and to consult with local extension agents to better understand which fertilizers they should be using and how much they should be applying.
A 2005 study showed while there’s no significant difference in forage growth when using different types of nitrogen, the timing of fertilizer application can have an impact.
“An August application just prior to fall rains can produce some additional forage prior to a killing frost,” McDaniel said. “The key is we must have the fertility down before it rains and not after. Even in a drought, we’ll see windows of opportunity when we get some rainfall.”
While McDaniel acknowledges that some grass species, like Crabgrass and Teff, are more drought resistant, he reminds ranchers that management practices are the most important concern when it comes to making the most of the drought season.
“Mother nature, over thousands of years, selected species that were capable of tolerating and thriving in our Oklahoma conditions.” McDaniel said. “They’re deep rooted and can extract moisture from greater depths. We just have to learn how to manage them.”