Shade Tolerant Crops

Chris Lent

Chris Lent

Moderator
For grazing and soil health purposes under ground mounted PV, it will be important to know about the shade tolerance of various forage or cover crops. I saw this review on the Association for Temperate Agroforestry site that looks at past studies of the shade tolerance of herbaceous forbs and legumes. https://www.aftaweb.org/latest-news...-groundcovers-for-agroforestry-plantings.html Does anyone have other sources of information on this topic?
 
By using vertical solar array fencing it is less important to know about shade tolerant crops. Because
you set the solar fence to your equipment width and as the solar fence uses only 6 inches of width itself, most crops can be grown with normal yields. By using drip irrigation even produce can be grown but in recent days we have been informed that a linear irrigation system can be installed and running a GPS for alignment with the vertical solar bifacial fence. for raising potato, onion and alfalfa crops.
 

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Chris, being that the vertical solar fence is 6-8 inches wide, I was wondering if Goat's Rue would be a plant to seed under the solar fence. It doesn't grow very tall an lots of sun shines under the vertical solar fence.
Have you had any experience with this cover crop. Will it stay where you plant it? We want to stop erosion
and keep the soil covered under the vertical solar fence.

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William, A perennial crop would be nice for the vertical solar application. I don't have personal experience with Goat's Rue, but found a Utah Extension piece about it that identified it as an invasive. And it also says that it can grow to 80 inches, which, if true, may interfere with the solar panels. A low growing clover might be a good choice. As a biennial it would need to be reseeded occasionally, but it would be attractive to some pollinators as a side benefit. I'll see if I can find any more information on specific covers that might be good for that application. Here's the extension piece I made reference to.
extension.usu.edu

Goatsrue (Galega officinalis) Identification and Management in Pastures and Croplands

Goatsrue is an aggressive invasive plant and a declared Utah state noxious weed (Category 1B). It was introduced into the Cache Valley in 1891 and spread through the irrigation canals, streams, and rivers of the Bear River drainage. Cache County has one of the largest goatsrue infestations in...
extension.usu.edu extension.usu.edu
 
Chris, the clovers sound like a good answer, but there are so many. The produce growers using the vertical solar fence would love for extra bee's for pollination in crops like cukes. Their was some data posted somewhere that pollinators like lower wind conditions like the vertical solar fence provides. In the attachment above there is vertical solar fencing for honey production. Your help is very much appreciated.
farmfoodfamily.com

51+ Different Types Of Clovers With Names, Facts and Pictures

Clover is also called a trefoil and is a member of the legume or pea family. It has at least 300 recognized clover species. While it is mostly confused with shamrock, the shamrock is considered as the suckling clover.
farmfoodfamily.com farmfoodfamily.com
 
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Chris, Vertical Solar fence benefits are hugh, as a very little amount of clover seed will be needed to seed a 8 inch strip, a half mile long. The pollinators will help the produce grower and seed crops like canola. Vertical Solar fence benefits will put more solar on more agriculture land yet because of a so little land loss. One other thing is that the Vertical Solar fence benefits is there are no moving parts, no snow loads to worry about, and they will fit any width equipment.
 
I can definitely see there are benefits to the vertical solar configuration. In my area of the country (PA), when I see a low growing clover, it's usually White Dutch Clover. That may be a good choice for seeding under a solar fence.
This is getting off the Solar Crop thread topic, but do you have any energy production figures on vertical solar as compared to more conventionally installed solar?
 
Good Morning Chris, each piling is 7 foot apart, so a 1- 400 watt solar panel between each piling at 26 solar panels long will produce 10.4 KW like in the dairy pasture picture in the attachment above in this forum. With a double panels system in the same length, it would take 52 bi-facial solar panels and they would generate about 20.8 KW. If you use a ground mount system, it takes about 100 square feet of land to produce 1 KW as the vertical solar fence producing 10 KW only uses 94 square feet at 8 inches wide. The Vertical Solar Fence is the best solar structure for agriculture this day and age. You can see this on the web
et-sun dot com on the about page.
 
Thanks for your reply. Panels are tested under standard testing conditions (STC) to come up with a wattage rating. Those conditions don't usually exist when a panel is installed. There are also other efficiency losses that occur in an installed pv system. So panels rarely produce there rated wattage when installed in a system. One thing that affects efficiency of a panel is the angle of incidents of the sun light hitting the panel surface. The optimal angle is considered to be 90 degrees. The sun light won't be hitting a vertically installed panel at 90 degrees, so a vertical pv installation will not produce it's rated wattage. A good calculator for estimating the output of a pv system is NREL's PVWatts. https://pvwatts.nrel.gov/
 
Chris, the vertical bi-facial fence panels collect energy from sunup to sundown, but very little during the noon time, but still perform 30% better as tested at the Sandia National Laboratories.
 

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Chris, was asked a question about growing corn between solar fences which can be very tall. I was told to not worry about the corn height shading out the solar fences because the corn industry is cutting the corn height almost in half with short-stature corn. This breakthrough will make the solar fences even more profitable per acre. The Stine Seed Co. company in Iowa has the first variety's out and have the same yield curve as tall corn. The low growing clovers will really work in this environment.
 
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Joe, I read the info you posted and what I see is that the ROI is too low for the average Midwest and Great Plains farmer for elevated solar structures. The farmer of today does not to go back to farming with 4 and 6 row equipment. Those elevated solar structures cost's is too high and maintaince is a high risk job like cleaning. The vertical bifacial solar fence has the advantage forever, as it can be installed at the lowest cost, matches the farm equipment size of even the largest 4WD equipment, and is the lowest maintaince in many different weather coniditions.
One other big reason is the low amount of land use as good crop land is expensive wheather you are a livestock, grain crop or produce farmer. Organic growers may want to seed a cover crop, but with a 6-8 inch width of solar fence, the cost is mininial even on a grazing operation. With your ag background you should do well in the solar industry.
 
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thanks for your insight and experienced analysis.. QUESTION from a previous post, what is the orginal source of that bifacial solar output graph above ? ___________ I want to read the story . I have a person trying to dispute the benefits of solar fence output, so I need some good stats and data to use in my discussion to convince her of the PV output advantages of solar fence. I already told her of the logistic benefits for farming between solar fence row, residential dog or privacy solar fences, and so on .. thanks.
 

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Got a request from Edward, a produce grower , of which he doesn't want any spreading crops planted on his valuable crop land under his solar fence. Chris, is there a cover crop you would recommend for him with his 8 inch wide solar fence that powers his packing house and coolers. He is organic and has a single row solar panel fence.
 

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Sounds like a nice system for powering a packing house and coolers. I'd be interested to talk to Edward about how big the system is and how it's working for him. I'm thinking a mix of low growing cover crops that minimizes maintenance, attracts pollinators, and that can enhance soil quality would be ideal. I don't know Edwards location which would influence his choice of cover crops. He could talk to a seed company that specializes in cover crop mixes. Some have developed solar seed mixes specifically for use under solar panel installations.
 
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