Tuesday, November 27, 2012

Monday, September 24, 2012

Importance of Soil Testing

Beef cattle producers advised to get soil test, save on input costs
A Texas A&M AgriLife Extension Service soil fertility expert advised beef producers to get a soil test as residual nutrients from previous fertilizer applications may still be in reserve.
“We are still facing drought conditions as we did last year, and if producers applied fertilizer last year or this year, they didn’t grow much of a forage crop,” said Dr. Mark McFarland, AgriLife Extension state soil fertility specialist in College Station, at the recent Beef and Forage Expo in Bryan. “As a result, there can be a substantial amount of that fertilizer remaining in the soil for next year.”

At a recent agricultural expo in Bryan, Dr. Mark McFarland, Texas A&M AgriLife Extension Service state soil fertility specialist, advised beef producers to have soil tests performed on hay and pastureland. The test can help determine if there is any available carryover of nutrients from previous fertilizer applications, saving producers money over the long term. (Texas A&M AgriLife Extension Service photo by Blair Fannin)
McFarland said to be certain, producers are advised to soil test each field they plan to fertilize.
“Fertilizer prices remain very high,” he said. “We are looking at 50 cents to 70 cents per pound of nutrient for nitrogen, phosphorus and potassium. It is a significant part of the overall input cost for forage production.”
A soil test is a “tried and tested method” for determining the correct fertilizer product  and rate of application, he said. Applying unnecessary nutrients is expensive and does not improve forage yield or quality.
“A soil test allows us to credit any carryover fertilizer due to the drought and can save producers a significant amount of money,” McFarland said.
In areas where soil acidity is a concern, soil testing should be done in late fall so that limestone, if needed, can be applied and allowed to react and increase pH by next year. In other areas, soil testing for warm-season forage production should be done in winter or early spring.
Meanwhile, McFarland also discussed alternative fertilizers for producers to consider. There are several viable options, including livestock manures, poultry litter, composts and municipal biosolids. Producers should request a nutrient analysis for any product they are considering and compare the cost to standard fertilizer on a pound-of-nutrient basis, McFarland said.
“Good quality poultry litter may be worth $62 or more per ton,” he said. “But you also will need a good soil test to determine if an alternative fertilizer has a nutrient content that is an economical fit for a particular hayfield or pasture.”
McFarland also said to consider delivery and spreading of products as well.
“Hauling and spreading costs  are extremely high, so you also need to consider those in any product comparison.”
McFarland said soil sample forms and other information related to forage fertility are available online at http://soilcrop.tamu.edu.
“There you will find detailed information that will assist your forage production program,” he said. “Another good source is the AgriLife Extension agent in your county. They are a great resource if you have questions on how to respond to the drought.”

Monday, July 23, 2012

What is really killing Texas trees?

Drought is only part of the story


Hypoxylon is a fungus that is usually considered a weak pathogen — not aggressive enough to take over healthy, unstressed trees, according to a Texas AgriLife Extension Service forestry specialist. Once the signs of the fungus infection are obvious, as here, the tree is already dead.

Writer: Robert Burns, rd-burns@tamu.edu
OVERTON – Although drought is often the cause, trees can die for other reasons besides lack of soil moisture, said Dr. Eric Taylor, Texas AgriLife Extension Service forestry specialist, Overton.
“Drought is the primary contributor to tree kill, but it may not be exactly the way you might be thinking,” Taylor said. “You may find this hard to believe, but relatively few trees likely died directly from dehydration in 2011. Instead, the 2011 drought severely weakened mature trees, making them susceptible to opportunistic pathogens like hypoxylon canker and insects like pine bark engraver beetles.”
 He said that in most instances, the trees that died in 2011 were already stressed from a number of pre-existing environmental factors such as overcrowding, growing on the wrong site, age, soil compaction, trenching or inappropriate use of herbicides. If not for these factors, a large proportion of the trees that died might have recovered from the drought.
“This is an important concept to remember because our best defense against drought is to promote a tree’s health and vigor through proper care and management,” Taylor said.
This is not to play down the importance of water to tree health, he said. Water, particularly soil moisture, is critical for all a tree’s physiological processes. Trees require water to make and transport food, take in and release carbon dioxide, conduct biochemical reactions, build tissue and more.
“You name it, the tree needs water to do it,” Taylor said.
Though moisture stress may be the trigger,many trees likely died from insect damage, invasion of fungi and other diseases, and even heat stroke, according to Taylor.
“Much of the recent tree deaths and general decline might also be attributed to the extreme and prolonged heat of 2011,” he said. “Extreme temperatures, not only during the day but also in the early evenings and night, have negative impacts to tree physiological processes.”
Taylor said although it is the lack of water that’s at the root of tree death by heat stroke, there’s more to it than the tree being thirsty. As do humans, trees sweat to cool themselves off. Only with trees, the process is called “transpiration,” and it’s water evaporating primarily from leaves that dissipates heat.
Inadequate soil moisture coupled with hot air temperatures means a tree’s ability to transpire is limited.
“As a result, the cells in leaves and small branches can ‘cook’ to death,” Taylor said.
This “cooking” results in cell and protein breakdown, the generation and/or buildup of toxins, lesions and eventually death of the tree, he said.
As for tree deaths from macro fungi on hardwoods such as hypoxylon canker, it’s stress brought on by drought and heat that creates opportunity for the disease, not the direct effects of moisture shortage, Taylor said. Hypoxylon is a white-rot fungus that is usually considered a weak pathogen — not aggressive enough to take over healthy trees.
“It is only of consequence when the trees are under severe stress and wood moisture drops significantly,” he said. “Often, the first symptom that may be observed is the dying back or thinning of the crown.”
As the fungus develops underneath the bark, it causes the bark to pop loose and slough off, exposing a mat of grey, tan, olive green or reddish-brown powdery spores,” he said.
“By the time the spores become visible, the tree is dead,” Taylor said.
For more information about the identification and prevention of hypoxylon canker, go to http://txforestservice.tamu.edu , he said.
Another odd sign occurring this year is the dropping of seemingly healthy, green leaves, according to Taylor. One explanation for green leaf dropping is that the tree lost part of its root system during the 2011 drought.
“When spring came, there was enough food reserves for the trees to leaf out, but the root system was no longer sufficient to provide enough water to all of the leaves that developed,” Taylor said. “Now the trees are compensating by dropping some of the leaves in order to provide adequate moisture to the residual leaves.”
But don’t start your chainsaw yet, he said. If this is the first year that a tree’s dropped leaves, it may eventually recover, according to Taylor.
If the drought continues or intensifies, homeowners can reduce tree stress by paying attention to over-crowding, proper pruning, minimizing damage to the stem and roots, and proper watering.
For existing landscapes, proper watering during a drought is the best way to reduce water stress.
“A rule of thumb is to begin supplemental watering if significant rainfall has not occurred in the past seven to 10 days,” he said. “Begin sooner if it’s extremely hot and humidity is low.”
Taylor recommended using a soaker hose or by trickle or drip irrigation, and water just outside the drip line of the tree’s crown. (The drip line is the area on the ground directly under the farthest-reaching branches.)
“It is not necessary to encircle the entire tree, especially if a very large tree” he said. “A good watering on half or one quarter of the root system can be very beneficial. Do not concentrate the water at the base of the tree. Doing so can lead to root diseases.”
The water should soak into the soil without run off. If the water runs off or puddles, reduce the flow rate. Water until the moisture has soaked in to the soil to a depth of at least 8 to 10 inches.
The best time to water is during the early evening and at night, Taylor said. This is the time when trees normally catch up and replenish the water they loose during daytime activities like photosynthesis.
During the drought, plan on watering trees once a week. Be forewarned though. Large trees drink from a big bucket, Taylor said.
There’s more than just water involved in maintaining healthy trees. In August, Taylor is conducting a four-part course on woodland management with urban landowners in mind. See http://today.agrilife.org/2012/07/10/private-woodlands for more information.

Monday, June 25, 2012

Hello From the New Agent


Good Morning, I thought I might introduce myself: my name is Julie Zimmerman and I am the new Agriculture and Natural Resources Agent with Texas AgriLife Extension Service in Travis County. With this blog I plan to keep you apprised of news and events relating to agriculture and natural resources in your area.

I grew up in Burnet County on a small family ranch and was a 10 year 4-H member .  I obtained a bachelor’s and master’s degree of science in agriculture from Tarleton State University.  I first came to Travis County in 2006 and worked with the 4-H CAPITAL Program (a youth program under the umbrella of Texas AgriLife Extension – Travis County) as the Animal Science Coordinator.

In my new role I will serve the residents of Travis County in both urban and rural settings, helping educate in subject areas of: conservation of natural resources, sustainable agriculture, livestock, land management and crops.

I’m looking forward to continuing to serve the people of Travis County in my new position as county Extension Agent for Agriculture and Natural Resources.  AgriLife Extension is all about serving the residents of Texas and improving their lives through educational outreach. I hope to continue in that mission and tradition.