1 / 16

Avocado Leaf and Soil Tests Interpretation

Avocado Leaf and Soil Tests Interpretation. By Lindsay Heard Brenmark Horticultural Consultants . Avocado Leaf and Soil Tests. Nutrient status - Nutrient corrections -Trends Soil Texture Light Soils – Ash Pumice Nutrient Leaching – High in light soils

livingston
Download Presentation

Avocado Leaf and Soil Tests Interpretation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Avocado Leaf and Soil Tests Interpretation By Lindsay Heard Brenmark Horticultural Consultants

  2. Avocado Leaf and Soil Tests • Nutrient status - Nutrient corrections -Trends • Soil Texture Light Soils – Ash Pumice • Nutrient Leaching – High in light soils • High Cropload Trees; Nitrogen, Potassium, Boron • Nutrient deficiencies – Limiting Production • Phytophthora Control • Healthy Roots – Good nutrient uptake • Irrigation or Mulch – Increased root growth

  3. Soil pH (Potential Hydrogen) • Reference to Acidity or Alkalinity • Soil pH 5.0 is 10 times acidic as pH 6.0 • Soil pH below 7.0 pH - Acidic • Soil pH above 7.0pH - Alkaline • Soil pH range Avocados 6.2-6.5pH • Lime Calcium Carbonate – Increase soil pH • Lime slow to increase soil pH • Fine particle size – increase soil pH quickly • Gypsum (Calcium Sulphate) - Neutral - Will not increase pH

  4. Nitrogen Leaf – Shoot growth Chlorophyll (leaf greening) Role for synthesis of plant hormones Target Leaf Levels Autumn N 2.6-3.0% 2011 Autumn Leaf N Higher compared to 2010: N 2.7-3.0% Avoid excess N – high tree vigor – decreased fruiting – especially young avocados 4-6Yrs

  5. Available Nitrogen N Soil Tests Snap shot of Nitrogen soil level Subject to soil moisture – plant growth rates High Available N level over dry summer Low soil moisture - low bacteria - microbe activity - Increased Available N soil level Good soil moisture - High grass growth - soil bacteria will use Available N in soil Long grass – low available N used – Available N increases over low rainfall summer months NZ Organic Matter soil levels 5 -10% High composting at soil surface

  6. Available Nitrogen N Soil Tests Organic Apples – Hawkesbay Observation: Long grass in late summer resulted in Nitrogen Spike - High Vegetative - Shoot growth Organic Matter soil levels – high composting – Soil Bacteria using Available N Lowest available N levels BOP – Irrigated Avocados Good soil moisture – Available N used by bacteria and absorbed by roots Available N used by soil bacteria to breakdown bark (high carbon) and organic matter NZ Organic Matter soil levels 5 -10%

  7. Cation Exchange Capacity CEC Number of sites in soil for cations to attach;- Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na) Organic Matter increases CEC levels Low CEC soils (8-15 CEC) Pumice Vocanic Ash – South of Te Puke Low CEC soils apply fertilisers on little and often basis – high leaching factor High CEC (20-30 CEC) – Volcanic Loam - Clay – Peat soils High capacity for nutrients to be applied and retained

  8. Volume Weight (Vol/Wgt)- Bulk Density Is weight of a known volume of air-dried and ground soil. Provides indication of physical characteristics Low Vol/Wgt soils (0.6-0.7) Pumice Ash Soils – South of Te Puke Low Vol/Wght soils - apply fertilisers on little and often basis - high leaching factor High Vol/Wght (0.7-1.0): Clay - Silt Loam - Sandy Soils soils Clay – Silt Loams Vol/Wgt: High capacity for nutrients to be applied and retained

  9. Boron • Pollen vigor – pollen viability • Monitor Leaf and Soil Boron trends • Apply Boron in February - Start of high root growth period • Apply Boron onto leaf or bark mulch • Boron subject to leaching in high rainfall climates • Solubor 21% B - Granubor (Borax Pentahydrate) 14.5%B • Granular Boron - Calcium Oxide Boron 10-14.0% B • Boron Foliar Applications – Apply if leaf B 35ppm or below. • Low Boron uptake by Zutano rootstock • Dusa Rootstock - Good Boron uptake - caution for Boron rates

  10. Boron Leaf Levels

  11. Boron Soil Levels

  12. Thank You • Questions • Lindsay Heard Brenmark Horticultural Consultants

More Related