Fertilizers: Types, Use, and Methods of Monitoring Fertilizer Status in Nursery Operation UCCE

Transcription

1 Fertilizers: Types, Use, and Methods of Monitoring Fertilizer Status in Nursery Operation

2 Presented by: Donald J. Merhaut, Ph.D. Extension Specialist for Ornamental and Floriculture Crops 5

3 And: María de la Fuente Maria s title and photo

4 Overview II. Developing Fertilizer Programs A. Irrigation Water B. Planting Media C. Crop Type D. Cultural Practices

5 Crop Media Cultural Practices Irrigation Water

6 Variables Affecting Nutrient Availability in Nursery Production Systems 1. Concentration of nutrients 2. Form of Nutrients 3. Antagonistic agents 4. Beneficial agents

7 Overview II. Developing Fertilizer Programs A. Irrigation Water B. Planting Media C. Crop Type D. Cultural Practices

8 A. Irrigation Water Source municipal, reclaimed, recycled, well, surface Storage capacity of tanks, basins Recycling water treatment Fertigation

9 Nutrient Availability in Water 1. Concentration of nutrients 2. Form of Nutrients 3. Antagonistic agents 4. Beneficial agents

10 Nutrient Availability in Water

11 Nutrient Availability in Water 1. Concentration of nutrients presented in reports 2. Form of Nutrients

12 Nutrient Availability in Water 1. Concentration of nutrients 2. Form of Nutrients 3. Antagonistic agents 4. Beneficial agents

13 Water Quality Electrical Conductivity X ph X Bicarbonates - X Sodium Adsorption Ratio (SAR) Not an issue in container production Sodium - X Chloride - X Boron X Pathogens - X

14 Electrical Conductivity Definition: estimates the amount of total dissolved ions in the water. Note: EC ~ 640 ppm TDS (Total Dissolved Solids) Effects (ds/m) EC < 0.7 okay EC caution EC > 3.0 Danger Note: adding fertilizer will increase EC. *Consider crop sensitivity *Fertilization method -CRF or LF

15 Water Acidity Acid/Alkaline Definition: H + and OH - ions in water Range = 1-14 Optimum: Effects in soil * Root damage * Nutrient availability from soils - leaching and precipitation Note: soils have a buffer capacity.

16 Dissolved Alkali Chemical Concentration (meq/l) Alkalinity Definition: concentration of bicarbonates (HCO - 3), carbonates (CO 3 ) compounds dissolved in the water. *Measures water s ability to neutralize acids. - Media ph influenced - Nutrient and chelate integrity Ideal OK large pots Alkalinity (meq/l) Alkalinity

17 Bicarbonates (Alkalinity) Measurements and Conversions: 1) meq CaCO 3 /L 2) mg CaCO 3 /L 3) ppm CaCO 3. 1 meq CaCO 3 /L = 50 mg CaCO 3 /L 1 ppm CaCO 3 = 1 mg CaCO 3 /L 1 mg CaCO 3 /L = 0.02 meq CaCO 3 /L 1 meq CaCO 3 /L = 60 ppm HCO 3 1 ppm HCO 3 = meq CaCO 3 /L 1 ppm HCO 3 = 0.83 mg CaCO 3 /L Concentrations: < 1.5 meq/l okay > 8.5 meq/l Severe

18 Sodium Adsorption Ratio (SAR) In Field Soils ONLY Definition: Amount of sodium in water relative to calcium and magnesium SAR sodium / ( calcium magnesium) / 2 Problem: Dispersement of clay in soils causing impermeability SAR < 6 okay SAR > 9 Danger Solution: Calcium and/or magnesium additions

19 Sodium Concentration Definition: Concentration of sodium in water Problem: Sodium toxicity in plant Range: Overhead < 69 ppm (3 meq/l) - okay > 69 ppm - questionable *Competition with Potassium, Calcium, Magnesium for uptake into plant

20 Chloride Concentration Definition: Concentration of chloride in water Problem: Chloride toxicity to plant Range: Overhead *< 100 ppm (3 meq/l) - okay Surface *<140 ppm (4 meq/l) - okay

21 Boron Concentration Definition: Concentration of boron in water Problem: Toxicity can occur in plants Ranges: * < 0.5 ppm - very sensitive lemon, blackberry * ppm - sensitive avocado, orange * ppm - less sensitive sunflower, lupine

22 Overview II. Developing Fertilizer Programs A. Irrigation Water B. Planting Media C. Crop Type D. Cultural Practices

23 Planting Media - Nutrient Retention 1. Container Volume 2. Absorption 3. Adsorption

24 Nutrient Retention in Media 1. Container Volume 2. Absorption 3. Adsorption

25 Container Volume Media shrinkage is the loss in volume of the media because organic products decay quickly or clay leaches out of containers. Wood products with high cellulose content break down quickly, rather than barks and products that contain lignins and tannins Media that breaks down `shrinks will increase potential of nutrient runoff because: 1) nutrient storage capacity of media is reduced. 2) WHC of media is reduced. 3) root volume potential is reduced.

26 Nutrient Retention in Media 1. Container Volume 2. Absorption 3. Adsorption

27 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

28 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

29 Water Holding Capacity (WHC) Substrate blends should be selected to retain water, but provide pore spaces for aeration. *WHC of most ideal substrates and media usually range between %. Silt and clay add WHC, but cause aeration problems and will slowly leach out in runoff, clogging container bottoms and drainage basins. Increasing WHC increases the ability of the media to hold dissolved nutrients at the roots, instead of leaching out of containers.

30 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

31 Hydrophilic Hydrophobic Properties Some substrates, such as dry peat, will repel water. To correct or avoid this problem: *Never allow medium to dry out completely if it contains hydrophobic substrates *Add a surfactant to increase wettability. *Blend peat with another substrate, such as sand, coir or bark products to minimize hydrophobic properties. *Provide irrigation that uniformly wets media throughout container.

32 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

33 CEC (meq/l) Cation Exchange Capacity (CEC) - Adsorption The total amount of positively charged ions that a substrate can adsorb The Anion Exchange Capacity (AEC), ithe amount of negatively charged ions that can adsorb onto the substrate, is about 1-5% of the CEC for most media ~ almost nonexistent. This is the reason anions, such as nitrates and phosphates, easily leach out of media and soils and are a problem in watershed management.

34 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

35 Anion Exchange Capacity (AEC) - Adsorption The total amount of negatively charged ions that a substrate can adsorb The Anion Exchange Capacity (AEC), the amount of negatively charged ions that can adsorb onto the substrate, is about 1-5% of the CEC for most media ~ almost nonexistent. This is the reason anions, such as nitrates and phosphates, easily leach out of media and soils and are a problem in watershed management.

36 Absorption and Adsorption Properties Water Holding Capacity (WHC) Hydrophobic / Hydrophilic Properties Cation Exchange Capacity (CEC) Anion Exchange Capacity (AEC) Media/Substrate Types

37 Substrate Types Organic amendments and substrates *Manures do not provide slow release of nutrients. Nutrient release is quick. *Barks do not provide nitrogen or phosphorus and could actually tie up nutrients. *Wood products, like sawdust and ground pallets, break down quickly and tie up nutrients. *Rice hulls and shells breakdown slowly. Mulches such as barks and wood do not add nitrogen to the soil. In fact, these products add so much carbon, that additional nitrogen may be needed, as wood decomposition is a sink for nitrogen. Manures add nitrogen, phosphorus and other nutrients, so this can increase the risk of nitrogen and phosphorus in runoff.

38 Substrate Types Inorganic amendments and substrates *Sand and silts help with drainage, but smaller particle sizes may reduce drainage. *Clays will move to bottom, and will either clog containers or will cause milky suspension in water. *Vermiculite, a superheated mineral, excellent WHC, aeration, CEC but easily smashed or compressed if handled improperly. *Calcined clays, provide WHC, CEC, and aeration Sands, if too fine, will reduce drainage and porosity. This will inhibit root growth and increase the risk of nutrient leaching and runoff. Clays, while contributing to CEC, usually percolate to container bottoms and cause reduced drainage. Consider calcined clays instead to increase CEC and mitigate nutrient runoff.

39 Inorganic amendments Increases amount of large pores Reduces water retention Improve drainage and aeration Common Materials: Perlite, Vermiculite, Calcined Clays Other materials: pumice, ashes, and pea gravel

40 Perlite Mineral Silica of volcanic origin Grades used in container media are ground first and then heated until the added water vaporizes to form an expanded light substance powder The lightness and uniformity useful to increase aeration and drainage Perlite is very dusty when dry and has a tendency to float to the top of a container during irrigation Potentially toxic levels of Fluoride Moderate cost Effective amendment for substrates

41 Vermiculite Mica ore produced by heating at about 745 C Plate-like expanded particles, have a very high water retention capacity and aid in the aeration and drainage Excellent cation exchange capacity and buffer as well as the ability to supply potassium and magnesium Less durable than sand and perlite Chemical and physical properties are very desirable for substrates in containers

42 Calcined Clays Formed by heating the mineral montmorillonite clay to about 690 C Ceramic-like particles formed are six times heavier than perlite Have a relatively high cation exchange capacity and water retention This material is a durable and useful amendment

43 Overview II. Developing Fertilizer Programs A. Irrigation Water B. Planting Media C. Crop Type D. Cultural Practices

44 Crop Type 1. ph Tolerance 2. Salt Tolerance 3. Phosphorus Tolerance

45 Crop Type - ph Media ph acid vs. neutral +/- associated with micronutrient uptake efficiency of plants Calcifuge - Acid media ~(4.5 to 6.0) *Azalea *Snapdragon *Blueberry *Vinca *Pansy *Ferns Chlorosis of new growth Calcicole slightly Acid to Neutral Media ( ) *Marigold *Zonal geranium *Many herbaceous and perennials Necrosis/chlorosis on margins of oldest leaves

46 Crop Type - EC Electrical Conductivity (EC) +/- associated with soils and water of native habitats Low EC tolerant ~ 2.0 ds/cm *Azalea *Blueberry *Avocado *Ferns *Orchids *Alpine natives *Plants native to well drained soils *Plants native to highly organic soils, sandy or gravelly soils *Seedlings and newly rooting cuttings necrosis of oldest leaves, root dieback Halophyte -High EC tolerant ~ *Plants from brackish waters *plants native to salt flats and areas of poor drainage

47 Crop Type - Phosphorus Phosphorus sensitive crops *plants native to Australia (old leached soils) -Proteoid Roots P and Fe responsive * plants native to nutrient poor, organic soils - Mycorrhizae associated roots *Australian plants *Ericaceous plants *Myricaceae CA myrtle *Legumes *Eleagnaceae Eleagnus, silverberry, fragrant olive *Avocado *Ferns *Orchids *Alpine natives *Plants native to well drained soils *Plants native to highly organic soils, sandy or gravelly soils *Seedlings and newly rooting cuttings Banksia ericifolia Chlorosis, necrosis and rosetting of new growth Australian plants Mycorrhizae colonization unsuccessful in high fertility programs

48 Overview II. Developing Fertilizer Programs A. Irrigation Water B. Planting Media C. Crop Type D. Cultural Practices

49 Cultural Practices 1. Irrigation 2. Container/Media 3. Plant

50 Cultural Practices 1. Irrigation 2. Container/Media 3. Plant

51 Irrigation and Water Management Water Quality Irrigation Methods Irrigation Timing Water recycling

52 Water Quality If you must use poor quality, reclaimed water (high salts), consider these options (based on observations not science): Drip instead of overhead -prevent salt build up on foliage some species more sensitive than other species. Clogged emitters will be added problem. Shading vs. Sun even for full sun plants (no info on post full sun tolerance of crop) Well drained media get water to plants, keep salts out. Pot in Pot culture - keeping roots cool and preventing media dry-out. Increase % Leaching - Typically recommended 25%

53 Irrigation Methods Optimizing Fertilizer efficiency Granular Fertilizer Programs Overhead impact, boom - Liquid Fertilizer Programs Hand watering Drip/Microspray Subirrigation/Capillary mats/flood Irrigation Hydroponic systems

54 Irrigation Timing 1. Pulse irrigation 2. Time of Day 3. Seasonal considerations Pulse irrigation short irrigation episode prewets media, especially if medium is slightly hydrophobic Time of Day nights and no wind reduce evaporation loss with overhead irrigation, but watch foliar diseases with night wetness on foliage. Seasonal lower radiation levels during short days means lower evapotranspiration, even with high temperatures.

55 Water Recycling Optimizing Fertilizer efficiency Saves ~ 50% of fertilizer *Monitor EC *Blend with fresh water *Fortify with fertilizer *Sanitize to kill Pathogens

56 Cultural Practices 1. Irrigation 2. Container/Media 3. Plant

57 Container Media Aeration Substrate blends should be formulated to provide oxygen in the root zone. Proper aeration is required for respiration of the root system. A healthy root system optimizes nutrient uptake potential.

58 Media/Fertilizers Media and fertilizer mixing should be done on impervious surfaces to prevent nutrient leaching Clean any media and fertilizer spills Store all fertilizers in a cool, dry location During heavy rain events, cover and/or store any unused media and fertilizer to prevent leaching Properly dispose of empty fertilizer and media bags Follow all regulations regarding storage, use and disposal of fertilizers and media

59 Cultural Practices 1. Irrigation 2. Container/Media 3. Plant

60 Timing of Fertilizer Applications Seasonal Variability Spring vs. summer in conjunction with plant growth Winter rains vs. summer droughts leaching with winter rains Stage of Plant Development Active vegetative growth and flowering seedlings vs. mature plants Cultural management pruning transplanting Plant Health roots vs. shoots

61 Special Thanks to: *William Darlington: Senior Consultant, Waypoint Analytical Labs in Anaheim, CA. *Dirk Holstege: Director, UCDavis Analytical Laboratory *Leticia Macias: Program Representative Univ. of CA Nursery & Floriculture Alliance (UCNFA) +++ The mention of trade names or commercial products in this presentation does not constitute endorsement or recommendation for use.

62 The End

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