GRAZING DAYS Pasture Management July 23, 2009

Why a Soil Test We can’t mange what we can’t measure. With an accurate soil test, a strategy can be made to solve even the most difficult of problems Encourages plant growth by providing the best lime / fertilizer recommendations Promotes environmental quality Saves money

What is a Soil Test A soil test is a process by which elements (phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper and zinc) are chemically removed from the soil and measured for their "plant available" content within the sample. The quantity of available nutrients in the sample determines the amount of fertilizer that is recommended. A soil test also measures soil pH. These analyses indicate whether lime is needed and, if so, how much to apply.

A routine soil test consists of: pH and lime requirement Calcium Magnesium Phosphorus Potassium  Can add organic matter if desired.

The soil testing puzzle is made up of three parts.

Taking the sample

UF-ESTL Available Tests Test A ($3.00) pH Lime requirement Test B ($7.00) Test A + P, K, Mg Photo Credit: Amy Shober, UF-IFAS

Lab procedures Dry Screen Scoop Extract Measure

Soil Test Interpretation

Soil Test Results Soil Test Phosphorus (Lbs/Acre) Relative Yield (%) Amy Shober, UF-IFAS

18 essential plant nutrients: From air/water Carbon = C Hydrogen = H Oxygen = O From soil and fertilizer Macro-Nutrients Nitrogen = N Phosphorus = P Potassium =K Calcium =Ca Magnesium = Mg Sulfur = S Micro-Nutrients Manganese =Mn Zinc = Zn Copper = Cu Iron = Fe Boron = B Molybdenum = Mo Chlorine = Cl Nickel = Ni Cobalt = Co

Nitrogen Relative quantities of soil-supplied nutrients in dry plant tissue. Potassium Phosphorus Calcium Magnesium Sulfur All micronutrients combined

Quickness of nutrient availability Soil minerals Organic matter Fertilizer Very slow Very fast Availability to plants

Soil nutrient deficiency: Add fertilizer, get a response

FERTILIZER UPDATE

The future of N fertilizers N fertilizer comes from air, hydrogen (from natural gas), heat, and pressure. It is more economical to produce N off-shore where natural gas is cheap. The USA is now a net importer of N. Our future N supply may be dominated by urea produced overseas.

The future of P fertilizers Single superphosphate and triple superphosphate are no longer produced in Tampa. Production is now limited to mono- ammonium phosphate (MAP) and di- ammonium phosphate (DAP). Florida still has mineable P ore, but the mines are moving to the south.

The future of K fertilizers Saskatchewan province in Canada has several hundred years worth of mineable K salts. Price will be driven by worldwide demand, particularly from China and India.

Economics of Hay Production Elena Toro, Suwannee Co. and Dan Fenneman, Madison Co. Extension Agents FertilizersCost per TonCost per Unit/Ton Cost to apply 80 lbs N/ Acre Amm Nitrate34-0-0$350$0.51$ Amm Sulfate Coated Urea Liquid Potash

Economics of Hay Production Elena Toro, Suwannee Co. and Dan Fenneman, Madison Co. Extension Agents Commercial Blends Cost per TonUnit per Ton80 lbs N & K / Acre $463.47$1.16$ N K

WEED CONTROL UPDATE

Fall Late Summer Winter Spring

Weed Control What are the options? –Spray –Fertilize –Spray and fertilize –Mow –Do nothing

30 Bermudagrass, Ragweed and Nitrogen Lbs/bermuda/ac N = 34 lbs/ac John Boyd, U of Arkansas

31 34 lb N will cost $20 - $40/A Herbicide will cost $8 - $25/A Lbs/bermuda/ac N = 34 lbs/ac John Boyd, U of Arkansas

32 Herbicides, Mowing and Bermudagrass Yield Lbs /ac Heavily infested with wooly croton and ragweed Baumann Texas A&M

PASTURE WEEDS

Blackberry (bush-type)

Blackberry Control Remedy - 1 qt/A Pasturegard - 2 qt/A Cimarron oz/A ( injury to Bahia) Telar oz/A Do not mow within 1 yr of treatment Blackberry is most sensitive when blooming

Dogfennel Control Weedmaster – application rate is highly dependant on DF size. – up to 12 inches – 2 pt – 12 to 24 inches – 3 pt – >24 inches – not recommend WM Often inconsistent control.

Dogfennel control Pasturegard – 2 pt will relatively good control on DF up to 24-30”. 3 pt never misses, even on big stuff. Price keeps PG from being used more often

Cleanwave Active ingredient: fluroxypyr Volatility: moderate Use rate: 14 oz/A (for now) Price: ~ $0.50 per ounce.

Control of 3’ tall dogfennel Herbicide% control 6 WAT $/A Cleanwave (14oz) + 2,4-D (3pt) 9012 Weedmaster (2 pt)508 Weedmaster (3 pt)8012 Weedmaster (4 pt)9016

Cleanwave + 3pt 2,4-D

Weedmaster 2 pt

Weedmaster 3pt

August dogfennel treatment – Useless, right??? Brent Sellers, Univ. of Florida

5 months later – this field will exploded with grass in spring Brent Sellers, Univ. of Florida

5 months later – this field will exploded with grass in spring Treatment with Pasturegard 3 pt/A ($23/A) more than doubled grass production. Is it worth it to you? Brent Sellers, Univ. of Florida

Prickly Pear

Prickly Pear Control Do not mow! These reproduce veg. and the mowed pads can root and colonize. Herbicides -Remedy + basal/diesel fuel – spray one at a time. -Pasturegard is same as Remedy -2,4-D is not effective -What about Cleanwave?

Before

After

Recommendation Cleanwave at 50 oz/A. We applied in the fall (October). Spring applications????

Florida Pusley

Control of 6” pusley HerbicideRatePusley Control (%) 2 weeks8 weeks Cleanwave14 oz/A1418 Weedmaster3 pt/A5670 Pasturegard3 pt/A4884 Forefront2 pt/A5590 Forefront + CW2 pt + 14 oz7399 Forefront + PG2 pt + 1 pt90100

Sedges Outrider – sulfosulfuron Use rate: 1.33 oz/A Cost - $20/A 0 day grazing, 14 day haying restriction Safe on established Bermuda and Bahia

TSA Control % Control HerbicideRate3 MAT6 MAT12 MAT Remedy1 qt Pasture gard 1.5 qt oz959085

Horsenettle Remedy - 2 pt at bloom – Acceptable control but somewhat weak Milestone is excellent – Use at least 3 oz/A, 5 oz is better.

Wild Radish

Control of Wild Radish 2,4-D 1 pt University of Georgia

Thistle Control

>90% Thistle Control Growth StageHerbicide$/A Rosette2,4-D$6 BoltingWeedmaster$12 FloweringMilestone$20

What about BIG weeds

Milestone is the best option

References Dr. Obreza, Soil and Water Science Dr. Ferrell, Weed Science Dr. Sellers, Weed Science