Optimizing Alfalfa Production

Nutrient ZincIronCopperManganese

Low< 0.8< 0.3< 0.2< 1.0

Marginal0.8 - 1.03.0 - 5.0

Adequate > 1.0> 5.0> 0.2> 1.0

Documentation of sulphur de�ciency in alfalfa continues to increase. Phil Kaatz, forage crop educator at Michigan State University conducted a state wide survey in 2015 to determine the sulphur status of alfalfa. “Plant tissue samples were collected from �elds located across the state. A total of 52 samples were analyzed from 2nd, 3rd, and 4th cuttings. Of the tested samples 38% were found to be de�cient in sulphur; de�cient was de�ned as less than 0.25%. Another 14% of the samples fell into a range that was barely adequate (0.25-0.27% S)” (Rankin, 2016). A Wisconsin assessment of S in alfalfa revealed 80% of plant tissue samples in 2015 contained inadequate S for optimum yield response according to Dr. Dan Undersander, Extension Forage Agronomist at University of Wisconsin.

Undersander also shared that “we’ve seen an extra 1 – 1.5 tons of production with the addition of sulfur”. “Forage yields were increased by sulphur fertilization on the S-de�cient site near Lake Park, MN (Table 3.0). Forage yield was increased 80-88% by sulfur fertilization in 2005 and 41-50% in 2006. Forage yield of the elemental sulfur treatment in 2005 was higher than the check, but not as great as the other sources. However, in 2006 the yield with elemental sulfur was similar to other sulfur sources. The additional year to break down the elemental sulfur allowed adequate sulfur for the environmental conditions” (Meyer, 2006). An alfalfa trial conducted at The Ohio State University over 4 years resulted in elemental S yielding 9% greater than the Tri-State recommendations for P and K. The elemental S treatment responded with 51% increase over the control treatment (Figure 1.0). Forage samples from the sulphur treatments had 2% higher protein content. (Sulc et al., 2013).

Plant tissue sampling and analyses is a recommended management tool that is encouraged to monitor plant nutrient status. Thirty plant samples should be collected from top 6 inches at late bud to beginning bloom growth stage. Alfalfa removes signi�cant amounts of nutrients from the soil and tissue analyses can provide an in-season nutrient uptake demand. If the tissue analysis reveals that one or more nutrients are de�cient then management decisions can be implemented to correct the situation. Table 2.0 provides required plant tissue values for alfalfa.

Treatment � CheckZinc Sulphate Gypsum S-15Elemental Sulfur

2.74.95.15.14.2

3.24.74.84.54.3

Tons Dry Matter/AC

2005 2006

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J 00 0 000000 0 0 000 00

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Harvesting is a critical part of the management ---------------------- process to insure the forage quality obtained in _M_a_tu_r_it_y_S_ t_a_g __ e ____ C_P ________ R_F_Q __ the crop growth and development is maintained

Table 4.0 Alfalfa Quality at Various Maturity Stagesl

Vegetative 24-27 230-300 until consumed by the animal. "The quality ofBud 22-26 160-250 alfalfa decreases as the plant transitions fromEarly Bloom 18-22 125-180 vegetative to reproductive stages TableMid-Bloom 14-18 100-150Late Bloom 9_13 90_110 4.0. However, yields increase during this

---------------------- transitional phase. In general, alfalfa cut in the

1 Adapted from Lacefield et al. CP = Crude Protein RFQ = Relative Feed Quality

Conclusion

range of late bud to early bloom growth stage will result in acceptable yields of high quality feed with minimal effect on stand persistence. Good quality alfalfa should contain from 17-20% crude protein (CP) and 60-65% total digestible nutrients (TON). Six tons of good alfalfa hay contains more digestible energy than 150 bushels of corn and more protein than 2 tons of soybean meal" (Lacefield, et al. 2009).

Alfalfa is a high demanding crop from a management and crop nutrient viewpoint. Properly managed alfalfa stands can provide 6 or more years of pro fitable productivity. The plant nutrient status must be evaluated annually by soil sample analyses and plant tissue analyses due to its high feed value and high nutrient removal rate. Corrective action can be taken between cuttings with appropriate fertilizer applications. Sulphur has value in an alfalfa nutrient management plan. TIGER-SUL products that can meet alfalfa sulphur nutrient requirements include TIGER 90CR and TIGER XP. If micronutrients are needed TIGER-SUL has wide range of micronutrient products. The most prevalent micronutrient requirement is boron and TIGER-SUL Micronutrients Boron 2% can be utilized. The harvest process influences the quality of alfalfa. Harvest timing dramatically affects protein content, feed value, and animal palpability. Since alfalfa is a deep rooted perennial crop it can greatly reduce soil erosion potential, nutrient runoff potential, and enhances soil quality. The inclusion of TIGER-SUL products in an alfalfa nutrient management program provides slow release S and micronutrients that will contribute to optimum productivity and minimal impact on the environment. These factors exceed the requirements to fit into the 4R best management practices strategy.

References: Hancock, D.W. 2009. Alfalfa Management in Georgia. University of Georgia Extension Bulletin 81350 Koenig, R. et al. 1999. Fertilizer Management for Alfalfa. Utah State University - Extension Publication AF-FG-01

Lacefield, G. et al. 2009. Growing Alfalfa in the South. National Alfalfa & Forage - Alliance.

Meyer, D. 2006. Is Sulfur Fertilizer Needed for Alfalfa Production? North Dakota State - University Forage Focus-Hay. Rankin, M. 2016. Added Evidence to Monitor Alfalfa Sulfur. Hay & Forager Grower Ritchey, E. et al., 2014. Fertilizer Management in Alfalfa. University of Kentucky - Extension Publication AGR-210.

Sulc, Mark. 2013. Alfalfa Response to Sulfur, Gypsum, and Reduced Rates of P& K. - The Ohio State University Extension. Presentation.