organic high tunnel fertility research

Organic High Tunnel Fertility Research

Terrance T. NennichExtension Professor

Vegetable and Small Fruit ProductionUniversity of Minnesota Extension

[email protected]

© 2009 Regents of the University of Minnesota

High Tunnel Research Sites in Minnesota

Experiment StationsGrower Cooperators


Why Organic Fertility Research in High

Tunnels?

The Concept


Organic soil fertility studies

The purpose of this study is to measure the amount of soil nutrients, used buy tomatoes and cucumbers in a very high production system in high tunnels.


The Organic Systemin High Tunnels

As in any organic production system, chemicals and other commercial crop inputs are traded for excellent management.


Crookston Organic Tunnel

What we did?

What Happened


Water Testing

Consider testing the water for at least nitrates .

The Crookston high tunnel was being watered by the city water supply.


Soil Texture Amending

The soil texture at the Crookston site was a very heavy clay. ( Red River Mud)

We desired to change to a sandy clay loam.

To do this we added about one cubic yard of sand for every 100 square foot.


Concerns from Previous High Tunnel Experiences 1999-2006

Enough soil fertility between residual and applied application to meet plant growth and yield.

What is left at the end of the growing season for future production


Soil texture

The goal was to have a soil organic matter of at least 5% and ideally 6-7%.

In order to accomplish this we added about ½ yard of composted horse manure per 100 Square ft.


Soil FertilitySoil fertility must start out very high with enough organic matter to prevent leaching of nutrients. In this case horse manure was used

It is very difficult to add enough soil nutrients organically after plants are established

However there are some products that can help.


Test the Sand

Test for Basics- pH

- Other nutrients are ok but not as important


Compost/Manure

Use only very well rotted manure

Don’t assume that compost is high in nutrients.

Do regular soil test plus micros

May need to do a dilution test if the nutrients areextremely high (off the chart)


Test the compost

Horse Beef Plant

N 2418 1410 321

P 407 310 106

K 2321 1830 482


Test Soil Before Planting

After all incorporation and soil amending is done test the soil before planting.

– In high tunnels test 9-10 inches deep.


Planting Beds

Planting beds were raised 1 inch (from 4 to 5 inches)Width of the beds were increased 4 inches (from 16 to 20 inches)

– This increased the soil volume of the beds by approximately 55%, increasing available nutrients and soil moisture to the plants.


Additional Fertilization

A organic fish solution of a 4-1-1 was used that was compatible with the drip tape.

The fish solution would be used on a continuous flow basis

The rate would start at about 2 oz/100 running ft. of tape and increased to 6 oz as the nutrient needs of the plants increased.


Plant Spacing Spacing between rows would remain the same at 48 inches.

Plant spacing in the row would be increased to allow for more air flow and hopefully more natural disease control.

Alternate plant spacing would be used to maximize nutrient availability and increase air flow around the plants.

Hopefully the individual plants would compensate with increased yield.


Plant Spacing

In row plant spacing would be increased to :

– 24 inches for indeterminate tomatoes such as Coba and Ultra Sweet.

– 18 inches for determinant tomatoes such as Sunstart, Sunshine, and Mountain Spring.


Plant Spacing

– Cucumber varieties would be increased to 18 inches.

– Peppers would remain the same 2 rows on a bed planted 18 inches in a staggered configuration


Alternate Spacing


Plant Pruning

Reasonable plant pruning practices would be done to increase earliness, size and allow more airflow for disease control.

– Determinate tomatoes would have 2 punning – Indeterminate tomatoes would have moderate

continuous pruning

– Christmas tree method pruning would be used to control side growth.


Soil Nutrient Research2007

Before planting soil was tested at 0-6 inches6-12 inches12-24 inches

Soil was retested for each crop after season production.

All plots were fertilized equally


Tomato Results 2007

Variety CobraFirst harvest June 21Total Yield 37 Pound/plantCulls 4 Pound/PlantMarketable 3.89 Pound sq/ftTotal Yield 4.63 Pound sq/ft Acre Yield 101 ton acre



Cobra Tomatoes0-6 inch soil depth

N P KBefore Season 335 330 1050

After Harvest 11 215 235


Cucumber Results2007

CucumbersAll the fruit from all 26 cucumber plants were weighed and evaluated for quality. All data is in pounds per plant.

Sweet SuccessFirst Harvest June 21Total Yield/Plant 65.12Culls 8.0MKT/sq/ft 9,52Total sq/ft 10.85

Total Yield Acre = 472,628 or 236 tons.



Sweet Success Cucumbers0-6 inch soil depth





The 2008 research question was:

If the soil fertility is at high levels before planting will additional yield be obtained by adding a organic approved fertilizer to the irrigation water at a continuous flow rate through the season?


Soil Nutrient Research 2008

The plots (rows) were divided in two, one half fertilized through drip tape, the other half received no supplemental fertilization

Tomatoes from both plots were weighed and evaluated during the growing season.


2008 Soil Amending

Enough manure based compost was added to raise the beginning soil nutrient levels to very high.


Fertilized PlotAdded 10 gallons of a 4-1-1 fish solution

evenly through drip tape

- per acre nutrients added were - N 280- P 70- K 70



Before planting soil was tested at 0-6 inches6-12 inches12-24 inches

Soil was retested for each crop after season production.


Tomato Results2008

Variety Yield fertilized Yield Unfertilized

Cobra 49 Pounds/Plant 45Pounds/Plant269,500 Pounds/Acre 247,500 Pounds/Acre134 Tons Acre 123 Tons/Acre


Soil Nutrient Research 2008Fertilized PlotsCobra Tomatoes

0-6 inch soil depth




Soil Nutrient Research 2008Unfertilized Plots





Soil Nutrient Research 2008Fertilized plotsCobra Tomatoes

6-12 inch soil depth




Soil Nutrient Research 2008Unfertilized plots





Soil Nutrient Research 2008Fertilized Plots





Cucumber Results2008

CucumbersSweet Success

Fertilized Unfertilized

18 Pounds/Plant 13 Pounds/Plant132,000 Pounds/Acre 95,329 Pounds/ Acre66 Tons/Acre 48 Tons/Acre

There was considerably less yield in 2008, plants were removed early.

.



Fertilized Plots






Unfertilized Plots






Fertilized PlotsSweet Success Cucumbers





Soil Nutrient Research2008 Unfertilized Plots






Fertilized plotsSweet Success Cucumbers





2009 Soil Fertility Results

As in 2008 the high tunnel was divided into two areas for fertigated and unfertigated


Compost Fertility Composition2009

N 2418P 407K 2321S 120B 7.0


Cucumber Yields 2009

Variety : Sweet Success

Fertilized, Yield per plant = 42 pounds

Not Fertilized ,Yield per plant = 28 pounds


Preplant Soil Test.2009

N P K0-6 630 198 8476-12 285 160 25012-24 60 100 150


Cucumbersafter harvest fertilized/drip tape

N P K0-6 inch 81 lb/ac 189 230

6-12 inch 44 lb/ac 150 140

12 – 24 inch 32 lb/ac 70 90


Cucumbers After harvest not fertilized/drip tape

N P K0-6 36 lb/ac 106 896-12 26 lb/ac 64 10012-24 24 lb /ac 51 81


Tomato Yields 2009

Variety: Cobra

Fertilized/drip tape : 31 pounds/plant

Not fertilized 25 : pounds plant.


Tomatoes after harvestfertilized/drip tape

N P K O-6 inch 47 lb/ac 134 916-12 inch 28 lb/ac 108 14512-24 inch 34 lb/ac 52 217


Tomatoes after harvest not fertilized/drip tape

N P k0-6 inch 28 lb/ac 97 726-12 inch 30 lb/ac 85 11912-24 inch 54 lb/ac 95 128


Is Organic Production Feasible?

The 2007, 2008, and 2009 research and demonstration projects show that organic production in high tunnels works well and can be very profitable if certain production practices are followed and high nutrient levels are maintained and supplied.


Organic Production Concerns

1. Adequate fertility to supply nutrient needs of high yields in the high tunnel.

- Special precautions will be needed the second and subsequent years.

2. Plant spacing may need to be increased

3. Air flow and keeping plants dry


Organic Concerns/Recommendations

4. Continual feeding of plants even if a small amount of nutrients.

5. Special precaution to take out all old plant debris.

6. Extreme water management.


Organic Concerns/Recommendations

7. Seed selection

8. Learn early disease identification

8. Have organic approved crop protectants on hand


Questions

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