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Plant Nutrients Assessment of Nutrient Needs Visual inspection of crops for deficiency symptoms Damage could have occurred already Symptoms may not be.

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Presentation on theme: "Plant Nutrients Assessment of Nutrient Needs Visual inspection of crops for deficiency symptoms Damage could have occurred already Symptoms may not be."— Presentation transcript:

1

2 Plant Nutrients

3 Assessment of Nutrient Needs Visual inspection of crops for deficiency symptoms Damage could have occurred already Symptoms may not be reliable Tissue testing for nutrients in plants May uncover problems that soil test misses Soil tests to measure nutrient levels Growers depend on this method to determine lime and fertilizer needs

4 Soil Testing Soil sampling Soil testing Soil Interpretation Recommendation

5 Take a Good Soil Sample to Help Make Good Decisions

6 Taking a Soil Sample Rotation field 1 Permanent Pasture Low Spot Rotation field 2 Sampling Depth Conventional tillage: 6-9 inches No till: Use special pH sample in top 2” Sod or pasture: 2-3 inches Tree Crops: inches Sampling Area Should not exceed 10 acres For row crops

7 Soil Test Results pH: Acid, Neutral, Alkaline (How much of a nutrient is available) Soil Test Index: (How high or how low a nutrient is in the soil) Soil Test Rating: VL, L, M, H, VH, EH

8 Soil Test Rating Soil Test Explanation Index Very Low (H)0-50 Severe deficiency Low (L) 60-70Moderate deficiency Medium (M) Near optimum: some fertilizer recommended High (H) Adequate for most crops Very High (VH) Two to four times the amount considered adequate; none should be applied Extremely High (EH)410+ Excessive; none should be applied Phosphorus, Potassium, Magnesium, calcium

9 Additional Resources (1) Nitrogen Fertilizer Recommendation for Corn in Iowa (2) Iowa State University Soil Testing Lab (3) Extension Publications.

10 Plant Food Elements Used in Large Amounts Macronutrients Used in Small Amounts Primary NutrientsSecondary Nutrients Micronutrients Nitrogen (N)Calcium (Ca)Iron (Fe) Phosphorus (P)Magnesium (Mg)Manganese (Mn) Potassium (K)Sulfur (S)Zinc (Zn) Copper (Cu) Boron (Bo) Chlorine (Cl) Cobalt (Co)

11 Nitrogen Nitrogen is a primary component of proteins and is part of every living cell. Functions of Nitrogen Speeds growth Vigorous growth, large leaves, and long stem internodes. Required for the formation of dark green pigment: chlorophyll. Promotes better production of chlorophyll hence it is required for better source of forage, feed and human nutrition. Plants use water best when they have ample nitrogen.

12 Excess Nitrogen Soft, weak easily injured growth  Stems are weaker and more easily to lodge Soft growth is more prone to diseases and insects Overly rapid growth slows maturity and ripening of many crops N promotes vegetative rather than reproductive growth of flowers and leaves. Over-fertilized tomato plants promote lush growth but few fruits

13 Nitrogen deficiency Slow growth and stunting Plants lack dark green color of well fed plants: Chlorosis

14 Phosphorus Functions Phosphorus is part of chromosomes and genes and so it is involved in plant reproduction and cell division. P spurs early and rapid growth and helps a young plant develop its roots P helps plants resist cold and diseases P speeds up crop maturity P aids blooming and fruiting P improves the quality of grains and fruits

15 Phosphorus Deficiency There is stunted growth but plants could remain green. Plants have a purple tint to leaves and stems, starting on lower Older leaves

16 Potassium (Potash) Activates enzymes needed in the formation of protein, starch cellulose and lignin. Functions It is important in the formation of thick cell walls and strong, rigid plant stems. Regulates the opening and closing of pores in the leaf through which water, oxygen and carbon dioxide pass. Important in the development and ripening of fruits like apples or tomatoes Needed for proper growth of root and tuber crops

17 Potassium Deficiencies Seen less often than the other primary nutrients. Shortages occur primarily in sandy heavily leached soils. “Marginal scorch” or burnt edges of lower, older leaves

18 Secondary Nutrients Calcium Functions of Calcium Required by plants mainly to build cell wall Crispness of apples come from calcium pectate in the fruit cells Ca largely controls soil pH and helps in the formation of soil structure Calcium plays a role in protein formation and carbohydrate movement in plants

19 Calcium Deficiencies Commonly appear in fruits and vegetables. Apple growers prevent “water core” (collapse of cell walls) in apples by spraying trees with Ca. This is similar to “blossom end rot” in tomatoes. Soil dries out and slows movement of Ca to roots during rapid root development. Ca deficiency cause misshapen roots on root vegetables.

20 Magnesium Functions of Magnesium It is an essential ingredient in chlorophyll formation Each chlorophyll molecule has one magnesium atom at the center Magnesium activates a number of important enzyme systems Mg is involved in protein, carbohydrates and fat synthesis

21 Sulfur Functions of Sulfur Needed in the formation of proteins and chlorophyll Aids in the formation of nodules in legumes and seed production S improves stress tolerance. Alfalfa, members of the mustard family and members of the onion family need much sulfur. The pungent flavors derive from sulfur compounds

22 Sulfur Deficiencies Stunted growth Older leaves are pale green – similar to N-deficient plants

23 Micronutrients These form special organic-metal molecules called Enzymes. Enzymes activate biological reactions in living systems. The difference between enough and too much can be quite narrow, sometimes only a few pounds per acre Please apply elements with caution

24 Effect of pH on nutrient availability

25 Iron Iron is part of many enzymes necessary for the formation of chlorophyll It is an abundant element in rocks and soils but it is also one of the most commonly deficient micronutrient Functions of Iron

26 Symptoms of Iron Hunger “Chlorosis”: Yellowing of interveinal leaves. Mainly new leaves

27 Manganese Functions of Manganese Speeds up germination and crop maturity Helps uptake of several other nutrients Functions in chlorophyll development

28 Symptoms of Manganese Deficiency Dwarfing Chlorosis on new leaves

29 Zinc Functions of Zinc Needed in the metabolism of protein Involved somehow in the production of chlorophyll

30 Symptoms of Zinc Deficiency Fruit crops including peaches and citrus are sensitive to zinc deficiency Field crops also include corn, soybeans, cotton, and potatoes Symptoms include spots on leaves Chlorosis between veins is also common

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32 Fertilizers Added to the soil to provide essential nutrients to plants Fertilizer Material Chemical compounds or mixtures containing nutrient Mixed fertilizer Weed and Feed fertilizers Liquid fertilizers Fertilizer Spikes Slow-release fertilizers

33 Fertilizer Grade: %N % Phosphate (P 2 O 5 ) % Potash K O 2

34 Some Popular Fertilizer Grades Available in Alabama Fertilizer Grade % of all Grades sold in Alabama % % % % % % (diammonium phosphate) 5% % % % <18%

35 Examples of Fertilizer Calculations Recommendation: 120 Ib N, 60Ib Phosphate, 60 Ibs potash per acre Fertilizer Grade: Before Planting 60/13% percent = 461 pounds / acre of Amount needed Analysis of source Size of Garden : 50 x 20 = 1,000 square feet 1 acre = 43, 000 square feet 1,000 square feet = 1,000 / 43,000 = acres Fertilizer needed = x 461 pounds per acre = 0.6 Ib

36 Examples of Fertilizer Calculations Recommendation: 120 Ib N, 60Ib Phosphate, 60 Ibs potash per acre Fertilizer Grade: Sidedressing Use ammonium nitrate ( ) Amount needed per acre = 60 / 34% = 176 pounds Size of Garden = acres Amount required for side dressing = x 176 = 4 pounds

37 Recommendation: “Per 50 ft x 20 ft garden apply 6 pounds of at planting and sidedress with 4 pounds of ” Fertilizer Grade Available: At Planting 6 Ib (expected) x 8 (required) / 13 (available ) = 3.7 Sidedressing 4 x 8 / 13 = 2.5 Ib,


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