Soil Fertility Management for Forage Crops 25 th Annual FL Cattlemen’s Institute and Allied Trade Show

Soil Fertility Management for Forage Crops25th Annual FL Cattlemen’s Institute and Allied Trade Show Maria L. Silveira Soil and Water Science University of Florida – Range Cattle REC

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Essential Elements for Plants • Primary nutrients: Nitrogen, Phosphorus, Potassium • Secondary nutrients: Calcium, Magnesium, Sulfur • Micronutrients: Zinc, Manganese, Iron, Copper, Boron, Molybdenum, Chlorine • Carbon, Hydrogen, and Oxygen

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Soil Fertility and Forage Production • Soil fertility management is a continuous process that begins before forages are established Yield will be limited by the element in shortest supply in relation to plants needs

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Soil Fertility and Forage Production

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Soil pH

pH 5.7 pH 5.6 M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC pH 4.4 pH 4.3

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Effect of soil pH on fertilizer efficiency

Target pH for different forage crops grown on mineral soils1 1C. G. Chambliss, G. Kidder, and R. Mylavarapu. 2003. Liming for Production of Forage Crops in Florida. EDIS SS-AGR-46.

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Characteristics of liming materials Lime, calcite, dolomite, calcitic and dolomitic limestone, aragonite. •  ECCE = effective calcium carbonate equivalence ECCE 100% ECCE 40% ECCE 10% Photo: University of Nebraska

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Importance of Soil Test

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Soil Test • Soil sample collection: representative of the entire area of interest • Minimum of 15-20 subsamples • Differences in soil type • Areas managed or cropped differently • Areas that clearly have some type of problem

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Soil Test • Handling and submitting your soil sample 1. Samples are thoroughly mixed 2. Sub-sample should be placed in a clean and properly labeled soil sample bag 3. Samples should be delivered to lab as soon as possible after collection

Soil Fertility and Forage Production SOIL TEST RESULTS AND THEIR INTERPRETATION - Target pH: 5.5 - pH (1:2 sample:water): 5.1 - A-E Buffer Value: 7.3

Tissue Test Photo: Dr. C. Mackowiak 60”

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Tissue Test Critical range Crop Yield Deficient Low High Excess Sufficient Tissue concentration

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Plant Tissue Sampling • Sample collection and handling are crucial • Bahiagrass should be sampled prior to seed head emergence • The four uppermost leaf blades should be sampled • Critical P concentration for bahiagrass = 0.15% Photo: Dr. C. Mackowiak

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Changes in Fertilization Recommendations for Established Bahiagrass Pastures 1.Soil sampling is recommended for the entire State • 2. Soil pH • ≥ 5.5 (if pH is below 5.3, lime should be applied) • When necessary, lime should be applied at least 3 to 6 months prior to fertilization • 3. Phosphorus fertilization • Phosphorus fertilization is recommended when soil test is very low or low in P and tissue concentration is < 0.15%

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Changes in Fertilization Recommendations for Established Bahiagrass Pastures Low N option (50-60 lb N/A) - K is not recommended - Apply 25 lb P2O5/A if soil tests very low or low in P AND tissue concentration is below 0.15% Medium N option (100 lb N/A) - Apply 50 lb K2O/A if soil tests very low or low in K - Apply 25 lb P2O5/A if soil tests very low or low in P AND tissue concentration is below 0.15%

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Changes in Fertilization Recommendations for Established Bahiagrass Pastures High N option (160 lb N/A) - Apply 80 lb K2O/A if soil tests very low or low in K. Apply 40 lb K2O/A if soil tests medium in K. - Apply 40 lb P2O5/A if soil tests very low or low in P AND tissue concentration is below 0.15%

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Summary

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC Flow Chart – Bahiagrass Recommendations Soil Sample Plant Tissue Sample Soil test P, K, Ca, Mg, lime requirement Soil test P, K, Ca, Mg, lime requirement and tissue test Soil pH < 5.3 Soil pH > 5.3 No P fertilizer Soil tested very low or low in P Soil tested medium or high in P Tissue P < 0.15% Tissue P ≥ 0.15% No P fertilizer P recommendation No P fertilizer

M. Silveira, Soil and Water Science, UF/IFAS Range Cattle REC THANKS Questions?

Soil Fertility Management for Forage Crops 25 th Annual FL Cattlemen’s Institute and Allied Trade Show