high tunnel fruit and vegetable production
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High Tunnel Fruit and Vegetable Production. Lesson Five: Soil Management and Fertility. Objectives. Recall soil’s physical and chemical properties and how they affect nutrient management. Calculate the fertilizer needs in a high tunnel based on soil test recommendations. - PowerPoint PPT PresentationTRANSCRIPT
LESSON FIVE: SOIL MANAGEMENT
AND FERTILITY
High TunnelFruit and Vegetable Production
Objectives Recall soil’s physical and chemical properties
and how they affect nutrient management. Calculate the fertilizer needs in a high tunnel
based on soil test recommendations. Identify characteristics of compost and what
affects the decomposition rate. Recognize salinity issues associated with
high tunnel production.
Soil Management Considerations
Site location is key to high tunnel production Sunlight Drainage Wind protection
Soil type is of less importance Can grow in modified raised beds and soilless
media
In this lesson, assuming that structure is moveable and soil management is key consideration
Importance of Soil
Anchor plant in placeProvide water and some needed nutrientsOxygen for root growth Major Components of Soil
Physical Properties Chemical Properties Air Water
Physical Properties
Sand, Silt and Clay
Characteristics of A High Clay Content Soil: High water-holding ability High cation exchange capacity Low infiltration rate Warms up slowly in the Spring Resists change to pH
Soil Particle SizesSand = 2 mm to 0.05 mmSilt = 0.05 to 0.002 mmClay = less than 0.002 mm
Physical Properties
Characteristics of a High Sand Content Soil: Low water-holding capacity Some nutrients are prone to leaching Warms up quickly in the Spring Shows a rapid change in pH
Good location for high tunnel (soil standpoint) Well-drained loam soil with high organic matter
Less than 28% clay ideal pH of 6.5 on upper part of landscape Northwest windbreak
Chemical Properties
17 elements are needed by plants Three are never limiting 14 may or may not be in adequate amounts
Depend upon soil type and pH
Ideal pH for most vegetables: 6.2 to 6.8Soil tests and plant analyses can
determine if essential nutrient levels are adequate
pH and Liming Recommendations
Adequate pH is single most important soil amendment factor
Low pH can be improved through amendmentsLiming Sources
Ground Limestone Calcite (CaCO3) Dolomitic [CaMg(CO3)2]
Calcium Oxide (CaO) Calcium hydroxide (Ca(OH)2)
pH and Liming Recommendations
Use agricultural limestone Requires certification
Be careful, do not over apply: Change in pH, detrimental to plant growth Decrease in availability of P Deficiencies in Fe, Mn, Zn and sometimes
Cu Reduced root uptake of B
pH and Liming Recommendations
In most soil tests, N is not reported May request report of N content for high
tunnels
Be careful not to purchase more than needed Calculate fertilizer needs
Calculating Application Rates
Always determine need based on soil test recommendations
Most recommendations give in lbs/acre 43, 560 square feet in an acre
If applying compost 1 cubic yard = 182 gallons 1 inch of surface compost over 1,000 ft2 =
3.1 yd3
Must have an analysis of compost doneMust know dimensions of high tunnel
Calculating Application Rates
Practice Problem 1Recommendation from soil test: 1 lb. N/1000 ft2 Utilizing 24-4-12 pre-mix fertilizer High tunnel dimensions: 24x48
1) Divide amount recommended by percentage in mix - 1 lb/1,000 ft2 / .24 = 4.16 lb/1000 ft2
2) Determine square feet of high tunnel- 24 x 48 = 1,152 ft2 / 1000 = 1.152
3) Multiply recommended application by adjusted size of high tunnel
- 4.16 lbs x 1.152 = 4.79 lbs of 24-4-12 mix
Calculating Application Rates
Practice Problem 2Recommendation from soil test: 1.5 lbs K/1000 ft2
Utilizing 0-0-60 premix fertilizer High Tunnel dimensions: 20 x 36
1) Divide amount recommended by percentage in mix- 1.5 lbs K/1000 ft2 /.60 = 2.5 lbs/1000 ft2
2) Determine square feet of high tunnel- 20 x 36 = 720 ft2 720/1000 = .72
3) Multiply recommended application by adjusted size of high tunnel
- 2.5 lbs/.72 = 1.8 lbs of 0-0-60 mix
Calculating Application Rates
Problem 3 – Utilizing Compost ManureCompost Application Problem HandoutGiven:
Nitrogen recommendation is 60 lbs per acre High tunnel dimensions are 21 ft x 96 ft 1 cubic yard = 182 gallons 1 inch of surface compost over 1,000 ft2 =
3.1 yd3
Compost analysis
Organic Matter
Soil organic matter is derived from: Decomposition of organic residues
+excretions from microorganisms
and microbial cells
End product called humus
Organic Matter
Decomposition Rate Depends On: Environmental conditions Particle size of organic material Cultivation frequency Depth of tillage Irrigation Type of organic matter Crop rotation
Organic Matter
Benefits of Adding Organic Matter to Soil: Provides a nutrient reservoir of N, P, and S Retains nutrients in an available form Increases aggregate formation Increases soil porosity
Organic Matter
Considerations when adding organic amendments to the soil They are highly variable in composition &
quality No standards for labeling exist Make sure you analyze each load or
shipment They are more expensive to transport,
store, purchase and apply Some may contain sewage sludge
Compost Chemical Analysis
pH – 6.0 to 7.5Ec (electric conductivity or salinity) – 5.0 or lessC:N Ratio – recommend an initial of 30:1Bulk Density – Soilds/moisture content
Expressed as lbs/yd3
Useful in determining rate of applicationHeavy Metals – Zn, Cd, Ni, Pb, Hg, Mo, As, Cr, CoOverall Nutrient Profile – essential plant nutrients
Salinity
Salt buildup in high tunnel soils is prevalent issue Particularly when cover is left
on year roundLeave sides rolled up in winter
Snows and late winter rains leach salt from root zone
Symptoms of High Soil Salinity Root dieback, root tips burn off Plant stunting Leaf burn Wilting
Salinity
High Salinity in Root Zone May Result From: Poor placement of fertilizer Fertilizer salts mainly due to K and nitrate Evapotranspiration greater than irrigation Too much fertilizer applied High water table
Salinity
To Reduce High Salt Levels: Monitor salt levels with the Ec test Place tunnel on well-drained site, add tile line Be careful with nutrient applications,
Do not over fertilize Limit use of organic sources containing manures Keep sides rolled up in winter Leach salt downward in soil profile via irrigation Constant watering with trickle irrigation
techniques
Soil Management & Fertility: In Review
Why is soil management and fertility important to growing produce in a high tunnel?
What are the physical properties of soils? From the standpoint of soil physical properties,
what is ideal for the placement of a high tunnel?
How do soil chemical properties influence nutrient management?
Why is soil pH important to plant health? What is the ideal soil pH for most vegetables?
How can soil pH or nutrient value be altered?
Soil Management and Fertility: In Review
Why is it important to calculate fertilizer applications? What are some characteristics of compost? What influences the decomposition rate of compost? What are benefits of adding organic matter to soil? What should be considered before applying compost? Why is salinity an issue for high tunnel production? What happens when soil salinity gets too high? What can be done to reduce salt levels in soils?