Basic Fertility By Clif Little OSU Extension

1. Basic Fertility By Clif Little OSU Extension Mg Def.

2. Important Nutrient Management Tools: • Soil Test • Plant Tissue

6. Next two slides provided by Van Slack

9. SOIL TEXTURE Soil texture is the relative volume of SAND, SILT and CLAY particles in a soil. Soil texture affects the water-holding capacity of soil, movement of water through the soil and ease of cultivation. PARTICLE SIZE Sand is visible, silt particles are the size of talc and clay particles are microscopic.

12. Coarse-textured soils: Sands, loamy sands and some sandy loams. • Medium-textured soils: Loams, sandy loams, silt loams, some sandy clay loams and clay loams. • Fine-textured soils: Clay, sandy clays, silt clays, silty clay loams and clay loams.

13. Cation exchange capacity (CEC)is a measure of the soil's ability to hold exchangeable cations such as hydrogen (H+), calcium (Ca++), magnesium (Mg++), potassium (K+), sodium (Na), iron (Fe) and aluminum (Al). CEC is measured in terms of milliequivalents (meq) per 100 grams of soil • Soil Texture • CEC Range • Sands 5-15 • Silts 8-30 • Clays 25-50 • Organic soils 50+

14. The base saturation for calcium should be 60% or above. • Magnesium should fall in the range of 10%-15%. • Potassium should be in the range of 1%-5%. High potassium levels can reduce the uptake of magnesium.

15. Crop Response To Nutrients Sufficient Toxic • • • • • • • • • • • • (micro-nutrients) • • • • • • • % YIELD • • • • Deficient •• 0 SOIL NUTRIENT CONCENTRATION

16. OHIO STATE FERTILIZER K RECOMMENDATIONS Critical Level K2O, Lbs./A Maintenance Breakpoint Forages = 75 + (2.5 X CEC) & Corn Silage Build Up Maintenance Draw Down SOIL TEST K, ppm

17. RELATIVE AVAILABILITY OF ELEMENTS pH of Mineral Soils

18. Element deficiency Symptom N Old Leaves turn yellowish (*) P Old Premature leaf fall-off Calcium New Damage and die off of growing points Yellowish leaf edges Mg Old Yellow spots (*) K Old Withering of leaf edges and tips S New Similar to nitrogen deficiency Iron New Leaves turn yellow Greenish nerves enclosing yellow leaf tissue First seen in fast growing plants Mn (**) Dead yellowish tissue between leaf nerves Copper (**) Dead leaf tips and withered edges Zinc Old Yellowish areas between nerves, Boron New Dead shoot tips, Mo Old Brownish areas along edges.

21. Structural: C, H, O Macronutrient: N, P, K, Ca, Mg, S Micronutrient: Fe, Mn, B, Mo, Cu, Zn, Cl, Ni

22. Phosphorus • Promotes root development • Stimulates blooming

23. PhosphorusSoil Levels Optimum levels P50-80 (lb/acre)or25-40 ppm P Def.

24. Phosphorus Fertilization • Phosphorus regulates the uptake of Mg and Ca. • P and K losses are minimal.

25. Implications of Phosphorus Use: • Applications of P & K can be made at anytime. However, spring P applications as ammonium phosphates can be very economical as this allows for application of P & N (ie. DAP).

26. Potassium • Essential for plant health • Important in disease resistance

27. Potassium Soil Test Values CRITICAL LEVELS: ppm K = 75 + (2.5 x CEC) ie. CEC = 15 75 + (2.5 x 15) = 112 ppm K Or 270 lbs K20/acre approx. range: 112 - 162 ppm K

28. The nutrient probably required in the largest quantities. Nitrogen

29. Nitrogen is a constituent of all living cells and is a necessary part of all proteins, enzymes, and metabolic processes involved in the synthesis and transfer of energy.

32. Nitrogen: Plants showing signs of nitrogen deficiency are usually dwarfed and spindly, with light green or somewhat yellow leaves. These leaves soon yellow, die, and may drop off.

33. Table 2. Nitrogen available from previous crop (lb/acre) Previous Crop N. Credits Corn, Small Grain 0 Soybeans 30 Grass Sod/Pasture 40 Forage LegumeAvg stand (3 plants/ft2) 40 + [20 X (plants/ft2)] max.140 Source: Extension Bulletin E-2567 Nitrogen Credits

40. Secondary and micronutrients of concern in Ohio are magnesium, boron and manganese. Sulfur and zinc also may be of concern, but evidence is not available documenting overall deficiencies in the state. Calcium and magnesium usually are deficient on acid soils. Magnesium can become deficient with the application of excessive potassium. The addition of calcitic or dolomitic lime generally solves most calcium and magnesium deficiency problems

41. Applying Plant Nutrients First Priority: Correct Soil Acidity

42. Sources of Acidity • Leaching of basic cations, Ca, Mg, K, Na • Cations removed by plants • Organic matter decomposition • Fertilizers, ammonium nitrogen releases H

43. pH MAINTENANCE • Use soil testing • Little benefit from lime applied if pH > 6.5

44. Soil Test Calls for Lime. What Do You Buy?Do You Need Ca, Mg, or Both?

45. Types of Lime Calcitic lime or high calcium lime (50%-56% CaO, 1%-4% MgO) is the most soluble form and is used when calcium is low and magnesium high. It generally reacts the fastest and is the most common form available in some areas. Magnesium or hi-mag lime (32%-42% CaO, 5%-15% MgO) is intermediate in solubility and should be used where pH, calcium and magnesium are low. The continued use of liming materials high in magnesium increases the base saturation of magnesium and decreases calcium saturation, which may result in deficiencies of calcium during stress periods. Dolomitic lime (30% CaO, 20% MgO) should be used where magnesium is particularly low. However, this is the least soluble of the materials. Hydrated lime (60% CaO, 12% MgO) reacts most rapidly with the soil, but the effect is only temporary. This material is caustic to humans and plants, and care must be taken not to burn plants. Hydrated lime should be used only in emergencies, when rapid changes are needed in soil pH.

46. Acid neutralizing values for aglime materialsCalcium carbonate equivalent, % • Calcium carbonate 100 • Calcitic limestone 85 to 100 • Domomitic limestone 95 to 108 • Marl (selma chalk) 50 to 90 • Calcium hydroxide (slaked lime) 120 to 135 • Calcium oxide (burnt or quick lime) 150 to 175 • Calcium silicate 86 • Basic slag 50 to 70 • Ground oyster shells 90 to 100 • Cement kiln dusts 40 to 100 • Wood ashes 40 to 50 • Power plant ashes 25 to 50 • Gypsum (land plaster) none

47. Fertilizing • Soil test tells you to put on 2 lbs of Nitrogen per 1000 sq feet. You but 46-0-0 how much fertilizer do you need to spread? • 2 lb N / .46 = 4.37 lbs per 1000 sq feet

48. Soil test says to apply 20 lbs per Acre P2O5 • Choose a fertilizer. 0-46-0 • 20 lbs rec./ .46 = 43.7 lbs/ A needed • If you were to convert this to 100 sq feet. • 43.7 / 435 = .1

49. Methods of Fertilizer Application Varies with plants and planting method

50. Liquid vs Dry Fertilizers Liquid fertilizers are equivalent to dry fertilizers when applied in amounts that supply an equal amount of plant nutrients Liquid fertilizers are easier to handle than dry fertilizers. Certain pesticides can be mixed with liquid fertilizers, and they also can be applied through irrigation water. However, foliar feeding should not be thought of as a substitute for regular fertilization because of the amount of fertilizer required for growth. Sufficient amounts of fertilizer applied to the leaves would result in the burning of the plants, and the use of multiple applications is not economically practical.