1. Micronutrient Management Dorivar Ruiz Diaz Soil Fertility and Nutrient Management

2. Outline  Overview micronutrients  Factors to be considered  S, Zn, Cl, and Fe  Deficiency symptoms  Fertilization strategies and management  Current studies

3. Essential Micronutrients  Minor elements or trace elements  Increased interest in micronutrients – Higher crop yields and micronutrient removal rates – Declining soil organic matter, a major source of most micronutrients – N, P and K fertilizers contain lower amounts of micronutrient impurities  Excessive levels can cause toxic effects on plants  In Kansas: Fe, S, Zn, and Cl.  Other micronutrients: B, Mg, Cu, Mn, and Ni.

4. Organic Matter  Important source of most micronutrients.  Simple organic compounds as chelates.  S, Zn and B deficiencies are more likely to occur in soils low in O.M.  Deficiencies of Cu and Mn are most common in peat soils.

5. Soil pH and micronutrient availability  Soil pH affects availability of micronutrients.  In general the solubility and availability of micronutrients are greatest in acid soils and lowest in high pH calcareous soils.  Exception is Mo.  In some soils, high levels of soluble Fe, Al and Mn may be toxic to plants.

6. Sulfur (S) Photos by Brian Lang, IA

7.  Soil situations and climatic conditions aggravating deficiency symptoms – Coarse textured soils (sandy soils) – Low organic matter soils – Cold, wet soils – Slow release of S from organic matter – Low atmospheric deposition  No application from – Manure – Other fertilizers Sulfur Deficiencies

8. S N

9. 10 kg SO 4 /ha = 3 lb S/acre Sulfur Deposition

10. Corn Response to Sulfur J. Sawyer, 2007

11. Wheat S Rec. (Lb/A) = (0.6 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits Corn and Sorghum S Rec. (Lb/A) = (0.2 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits Soybean S Rec. (Lb/A) = (0.4 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits Subsoil S may be significant. Profile soil test for S, 0-24 inches, also good for nitrate and Cl. Sulfur Fertilizer Recommendation

12. Zinc (Zn)

13. Zinc  Frequently deficient micronutrient  Absorbed by plant roots as Zn ++  Involved in the production of chlorophyll, protein, and several plant enzymes  Deficiency symptoms –Most distinctive in corn with new leaves out of whorl turning yellow to white in a band between the leaf midvein and margin

14.  Sensitive crops – Corn, sorghum  Soil Situation – Low organic matter, high pH (>7.4), eroded soil – Coarse texture, restricted rooting –High P application in conjunction with borderline or low zinc availability – High soil P alone does not create deficiency  Climatic Conditions – Cool and wet soil Zinc Deficiencies

15. Phosphorus and Zinc  Zn deficiency impairs plant P regulation.  Large amounts of starter applied P can enhance Zn deficiency if soil Zn is low and no Zn fertilizer is applied. P2O5P2O5 ZnYieldLeaf tissue lb/acrebu/acreP, %Zn, ppm 001010.1412 0101020.1624 800730.7310 80101620.4117 Adriano and Murphy, KSU

16. P and Zn Effects On Corn Yields P2O5P2O5 Zn B’castStarter Lb / A Corn Yield (Bu/A) 00 107 010121115 40012193 4010 139140 St. Mary’s, KS – Kansas State University

17. Wheat response to foliar Zn and Cu western Kansas 1 lb/acre Zn 1 lb/acre Cu Control B. Olson, 2009 Soil Test YearSiteVarietyCopperZinc - - - - ppm - - - - 20071Danby1.01.3 2Jagalene1.0 3Wesley1.00.7 4Jagalene0.70.8 20081Jagalene0.60.2 2Ike1.01.2 3TAM1111.20.6

18. Wheat response to foliar Zn and Cu western Kansas B. Olson, 2009 TreatmentYield 20072008 - - - - - bu/acre - - - - Zinc6342 Copper6540 Control6342 LSD (0.05)NS

19. Zinc Fertilizer Recommendation Corn, Sorghum and Soybeans Zinc Recommendation Zn Rate = 11.5 – (11.25 × ppm DTPA Zn) If DTPA Zn > 1.0 ppm then Zn Rec = 0 If DTPA Zn <= 1.0 ppm then Minimum Zn Rec = 1

20. Application Methods  Broadcast –Preferred to correct a low Zn soil test –5 to 15 pound will increase soil test for a number of years –Inorganic Zn is more economical than chelates at these rates  Band –Very efficient method of applying Zn –0.5 lb Zn/Acre of inorganic Zn is generally sufficient –Annual applications will be needed for low testing soils

21. Chloride (Cl)

22.  Wheat, corn, sorghum deficiencies in Kansas  Deficiencies most likely in higher rainfall areas with no K application history - central and eastern part of state  Soluble, mobile anion  Addition of KCl – Increased yields with high levels of available K – Reduced incidence of plant disease – Internal water relationships, osmotic regulation, enzyme activation and other plant processes

23. Chloride fertilization for wheat and sorghum, in Kansas Chloride rateWheat yield (Var. 2145) lb/acrebu/acre 066 1071 2071 3073 LSD(0.05)= 3 B. Gordon, 2009

24. Wheat response to Cl and fungicide application Overley wheat yield Chloride rateNo fungicideFungicide lb/acre - - - - - - - - bu/acre - - - - - - - - - 04854 105762 206064 306064 LSD(0.05)= 3 B. Gordon, 2009

25. Grain Yield ChlorideMarion Co.Saline CoStafford Co. Rate Site ASite BSite ASite BSite CSite DSite ASite BAvg. lb/a- - - - - - - - - - - - - - - - - - - - - bu/a - - - - - - - - - - - - - - - - - - - - 0458051898370736469 20478554899075807074 Soil test Cl, lb/a (0-24") 77142271471512 *Average over either 12 or 16 varieties. Soil test Cl, lb/a (0-24") Chloride Fertilization on Wheat

26. Cl Fertilizer Recommendation Profile soil ChlorideChloride recommendation ppmlb/acrelb Cl/acre < 4< 3020 4 - 630 - 4510 > 6> 450 Wheat, corn and sorghum

27. Iron (Fe)  Iron in the plant – Catalyst in the production of chlorophyll – Involved with several enzyme systems  Deficiency symptoms – Yellow to white leaf color – Symptoms first appear on the younger leaves – Wide range of susceptibility of different crops Sorghum, field beans and soybeans are more sensitive than corn and alfalfa Varieties differ within crops

28. Iron Deficiency

29. Iron Deficiency - Causes  Iron deficiency is caused by a combination of stresses rather than a simple deficiency of available soil Fe  Soil Chemical Factors –pH, carbonates, salinity (EC), available Fe (DTPA- Fe), high nitrate-N. –Cool, wet soils  Biotic factors –Variety, SCN, root rotting fungi, interplant competition.

30. Effect of soil nitrate?

31. The nitrate theory  Iron is part of the chlorophyll molecule  Iron taken up as Fe +++ (ferric)  Iron in chlorophyll exists as Fe ++ (ferrous)  High concentrations of nitrate-nitrogen inhibit conversion of Fe +++ to Fe ++

32. Irrigated soybean

33. Nitrogen application and iron chlorosis G. Rehm, 2007

34. Soybean population and iron chlorosis 2.0 1.5 1.0 Iron chlorosis score 5= Dead; 1=Green Neave, 2004

35. Soybean population – yield Neave, 2004 Loc.1Loc.2 0 10 20 30 40 50 bu/acre

36. Soybean Fe Study - 2009  Varieties (2): high and low IDC tolerance.  Seed treatment: with and without 0.6 lb/acre of EDDHA Fe (6.0%).  Foliar treatments: – 0.1 lb/acre EDDHA Fe (6.0%) – 0.1 lb/acre HEDTA Fe (4.5%) – No foliar treatment  4 locations with 5 replications

37. Objectives  Evaluate fertilization strategies.  Determine soil parameters (diagnostic): – Fe, Mg, P, K, Ca, OM, OC, TN, pH, EC, Carbonates, nitrate-N.  Determine “optimum” plant tissue level.  Evaluate possible interaction of parameters, both in soil and plant. – Possible Fe-Mn interaction?

38. Soybean seed treatment with Fe chelate

39. Seed coating treatment

40. Chlorophyll meter readings

42. Plant height at maturity

43. Treatment Average yield W/O Seed coating39 6% Foliar40 4.5% Foliar37 No39 W/ seed coating50 6% Foliar52 4.5% Foliar49 No49 Var AG3205: Low IC tolerance Soybean grain yield

44. Var AG2906: Very Good IC tolerance Treatment Average yield W/O Seed coating36 6% Foliar35 4.5% Foliar38 No35 W seed coating50 6% Foliar47 4.5% Foliar52 No52

45. Are these yield values significantly different? EffectF ValuePr > FSignificance Variety2.110.1487NS Seed trt69.6<.0001S Foliar0.050.9553NS Var*Seedtrt0.190.6616NS Var*Foliar2.10.1268NS Seedtrt*Foliar0.10.9004NS Var*Seed*Foliar0.270.7631NS

46. Common Iron Fertilizers Fertilizer Source Iron Sulfate Iron Chelates Other Organics Manure - best Fe (%) 19-40 5-12 5-11 ??

47. Manure source IronManganeseBoronZincCopper -----------------lb/wet ton--------------------- Dairy solid0.50.060.010.030.01 Swine solid19.01.090.040.790.50 Poultry3.00.610.080.480.66 -----------------lb/1000 gal--------------------- Dairy liquid0.90.110.030.110.12 Swine liquid2.50.230.061.030.62 Average animal manure micronutrient content

48. Summary  Fe deficiency potential can not be explained well by a single soil parameter.  Development of an “ soil index” may be the best alternative.  Foliar treatment seems to increase the “greenness” effectively. But seed coating provides higher yield increases.  Select a soybean variety that is tolerant to Fe chlorosis.  Avoid excessive application of nitrogen fertilizer to the crop that precedes soybeans in the rotation.

49. Summary  Increased interest for foliar application of nutrients.  Tissue test can provide good indication for micronutrient needs.  Increased interest for mixing micronutrients with fluid fertilizer for band application.  Seed coating with micronutrients is an alternative.

50. Questions? Dorivar Ruiz Diaz ruizdiaz@ksu.edu 785-532-6183 www.agronomy.ksu.edu/extension/