Dr. Meriam Karlsson, PI

Kendra Calhoun, Co - PI

OBJECTIVES:
This project aims to provide food alternatives to remote communities in rural and urban Alaska and to test specific apple varities for cold weather tolerance with the use of high tunnel technology.

 
OUR PLAN:
Recent cold climate technology research involving the use of high tunnel structures has proven to be highly successful (http://plasticulture.cas.psu.edu/). These tunnels, which can vary in size, can extend the growing season in cold climates, enabling farmers to increase their annual yield (Heidenreich et al. 2007, Jett L. W. 2007). We will be testing fruit tree establishment and productivity in high tunnels in extreme cold conditions, similar to conditions in rural villages in Alaska.
 

SO FAR:

We constructed two high tunnels and planted over 200 apple trees and a handful of other fruit trees and berries in 2007. We lost one of the high tunnels (winter of 2010) and will not be replacing it. Many of the trees inside survived the collapse and we are interested in seeing if they will survive the winter without protection. We have just completed our 4th growing season (2011). 

APPLE VARIETIES:

We have been testing over 30 apple varieties both inside and outside of the high tunnels. These varieties include the following:

8919, Prairie Sensation (18-10-32), 18-8-9, 21-61-69, Advance, Alice, Altaiski Sweet, Arbordale, Arctic Red, Brookland, Carroll, Chinese Golden Early, Collet, Garland, Golden Uralian, Goodland, Heyer 12 and 20, Lee 12, 17 and 20, Norcue, Norda, Norhey, Norkent, Norland, Norson, Northland, Novosibirski Sweet, Parkland, PF-12, Prairie Magic, Prairie Sun, Red Heart, Rescue, September Ruby, Summer Red, Trailmen and Ukalskoje Nalivnoje.

All our varieties are grafted on a Siberian roostock that is winter hardy to about 40 below zero.

Our trees were grafted by Dan Elliott who has a small orchard in Wasilla. We also obtained our rootstock from Lawyler Nursery out of Montana.

OTHER FRUIT:

BERRIES:

We planted several berries both inside and outside of the high tunnels, but only the Sea Berry (female), Honey Berry and an Arctic Raspberry survived inside the high tunnels.

Red Currant, Black Currant (Ribes rubrum / Ribes sativum, Ribes nigrum)

-Cherry Red and Black September

Honey Berry (Lonicera caerulea var. edulis)

-Blue Bird, Blue Sky, Blue Belle, Berry Blue

Arctic Raspberry/ Nagoon Berry (Rubus arcticus L. subsp. X stellarcticus)

-Anna, Sophia, Beta, Valentine

Sea Berry / Sea Buckthorn Berry (Hippophae rhamnoides)

-Baikal, Male Sea Berry, Orange Delight, Siberian Splendor, Sunny

ADDITIONAL FRUIT TREES:

The following additional fruit trees were planted in the high tunnels only and none survived the first winter:

Asian Pear (Pyrus pyrifolia) Raja P. Bet, Seuri OHXF 513

Plum (Prunus x domestica) Bavay's Gage, Shropshire Damson

Cherry (Prunus avium) Crown Jewel, Crimson Passion

Berry and additional fruit tree materials were obtained from Dan Elliott (Wasilla, AK) and One Green World (Molalla, OR). (This is not intended as an endorsement of the services or products.)

LOCATION:
Our site is located at the University of Alaska, Fairbanks Experiment Farm (http://www.uaf.edu/salrm/afes/).

HIGH TUNNEL CONSTRUCTION:
We began preparing the site in early May of 2007, shortly after the spring thaw. Once we determined the location and orientation of the high tunnels, they were measured and staked out accordingly (42’ by 96’). Once the side wall posts were pounded in and leveled, construction began.

Once the tunnels were constructed, the plastic was installed  (see film) and the site was prepared for planting. Each tunnel was planted with 60 apple trees, 15 per 4 rows. In addition to the high tunnels, two exterior plots were planted in a similar design. (See the full first year report for planting design/map here : First Year Report)

PLANTING:

Holes were dug twice as deep and wide as the 1/2 gallon or 1 gallon pots that the trees came in. Pre planting, a bit of topsoil was added and the hole was watered. Trees were planted in and a small circular catchment was made around the tree. The trees were then watered in. A small amount of low nitrogen root stimulating fertilizer was added to the water, and the topsoil also contained very low nitrogen (Risse’s Triple R).

IRRIGATION:

Trees were watered by hand throughout the first growing season. Each tree received 2 gallons of water weekly until September when watering was reduced to every other week. The exterior plots received less watering when there was significant rainfall.

During the second season, drip irrigation was installed inside and outside of the tunnels. Each tree was set up with two 1/2 gallon/hr emitters and received water weekly for 1-2 hours. Again, the exterior plots received less water when there was high rainfall and watering was tapered off in September to every other week. In both seasons, we tried to ensure the ground around the trees was well saturated before freeze up which usually occurs in early to mid October.

MAINTENANCE (during the growing season):
Tunnels and plots are weeded daily by hand and rototilled once a week. To keep weeds down around plots and tunnels, the entire site gets tilled once a month with a tractor. Extra care is taken to keep the area around the trees weed free. No chemicals have been used for weed control. It is particularly difficult to keep the tunnel edges and sides weed free since rainfall runoff in these areas is common. In the second season corn was planted in the fields surrounding the site, which seemed to reduce weeds somewhat. We are hoping to plant some cover crops between the tunnels to help with weed control. We are also considering putting grass in between the rows, which will require mowing, but may reduce weeds considerably and help to retain moisture.

WINTER PREPARATION AND MAINTENANCE:

At the end of each growing season, the end walls are installed, usually in mid October. Metal pipes are installed along the bottoms of the end wall material to help weight them down. Trees inside the tunnels are covered with 1 m pieces of reflective insulation and covered with straw (12 inches).  The first winter, 40 trees in each tunnel and exterior plot were covered with either Tubex or a Treepee shelter.

6 ml visqueen was added wherever needed primarily to the sides and corners of the high tunnels. Duct tape and Tyvek tape were used to secure the visqueen before the first frost.

Throughout the winter, the high tunnels are cleared of snow as needed and checked regularly for rips and tears in the covering. We also check for critter activity and make repairs to the structure as needed. We have been collecting climate data inside and outside of the high tunnels since October 2007.

CLIMATE DATA:

We have been collecting climate data at our site since the Fall of 2007.

We currently have the following equipment in use:

Two HOBO weather stations, set up inside a tunnel and in one exterior plot, measuring:

    -Air temp and RH
    -Soil temp (5 inches – 10 inches)
    -Soil moisture
    -Wind speed
    -Solar Radiation
    -Photosynthetic Active Radiation
   

10 HOBO micro stations (five inside a tunnel, five in an exterior plot), placed on random trees, measuring:

-Air temp and RH

-Soil temp between 5 and 10 inches

The adjacent graph shows the min and max soil and air temperatures for the 2007 - 2008 season, high tunnels vs. exterior plots.

We noticed that the soil temperatures outside stayed above zero the entire winter while air temperature outside seemed to fluctuate more when compared to the high tunnels.

Soil temperatures in the high tunnels were generally colder than outside despite our attempts to provide some insulation. Natural snowfall seemed to provide better insulation for our trees. However, air temperatures in the high tunnels were generally higher (10 - 15 degrees higher) throughout the winter.

SURVIVAL DATA 2008:

The first season, we had 80 % survival in the high tunnels and 68 % in the exterior plots.

Some of our highest survivors after the first season were (alive/dead):

            Altaiaski Sweet 6/1                             Nova Siberski 6/1

            Arctic Red 8/0                                     Parkland 7/1

            Brookland 4/1                                     Prairie Magic 5/3

            Carroll 3/0                                           Prairie Sun 5/2

            Golden Uralian 6/2                              Red Heart 6/2

            Goodland 6/2                                      Trailmen 7/1

            Heyer 12 8/0                                       Ukalskoje 7/1

            Heyer 20 5/2                                       18-10-32 7/0

            Lee 17 5/2                                           8919 8/0

Kendra Calhoun

Cooperative Extension Service

University of Alaska Fairbanks

PO Box 756180

Fairbanks, AK 99775

klcalhoun@alaska.edu

907-474-5420

Funded by:

Western Sustainable Agriculture Research and Education (SARE) SW06-111