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.
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Transcript 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.
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.
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 place
Provide water and some needed nutrients
Oxygen for root growth
Major Components of Soil
Physical
Properties
Chemical Properties
Air
Water
Physical Properties
Sand, Silt and Clay
Soil Particle Sizes
Sand = 2 mm to 0.05 mm
Silt = 0.05 to 0.002 mm
Clay = less than 0.002 mm
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
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
Less
pH
loam soil with high organic matter
than 28% clay ideal
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 6.8
Soil 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 amendments
Liming 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 done
Must know dimensions of high tunnel
Calculating Application Rates
Practice Problem 1
Recommendation 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 2
Recommendation 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 Manure
Compost Application Problem Handout
Given:
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 7.5
Ec (electric conductivity or salinity) – 5.0 or less
C:N Ratio – recommend an initial of 30:1
Bulk Density – Soilds/moisture content
Expressed
as lbs/yd3
Useful in determining rate of application
Heavy Metals – Zn, Cd, Ni, Pb, Hg, Mo, As, Cr, Co
Overall Nutrient Profile – essential plant nutrients
Salinity
Salt buildup in high tunnel soils is prevalent issue
Particularly
when cover is left
on year round
Leave 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
Limit
not over fertilize
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?