Interpreting a Compost Analysis

The incorporation of compost into your production spaces is a great way to recycle nutrients and carbon back into the soil, turning waste into something that will feed future crops and soil microbes. The variety of materials incorporated into compost, however, is highly variable. Plant residue, municipal solid waste, food processing waste, pulp or paper mill solids, manure and seafood wastes are all contenders for being included in a compost. The range of materials, each with their own broad ranges of nutrient concentrations, makes it a highly inconsistent product between batches, even where the supplier remains consistent. This variation in composition is going to have implications for nutrient management planning year to year - we can't necessarily apply the same volume from year to year and expect the same impact on our soils. 

In order to approach our nutrient management and compost applications with increased accuracy, it is recommended to submit compost samples for analysis. Nova Scotia's provincial lab services offer this as an option, and the report will break down the nutritional composition of the compost for next season's planning. Once we can better quantify the amount of nitrogen (and other key nutrients) in the compost, application volumes and a plan for additional supplementation throughout the growing season can be put together to meet the crop needs, and reduce accidental over-fertilization. 

For greenhouse soils, where all overhead precipitation has been excluded, compost analysis is especially important. Some composts tend to run high in salts (ex. calcium, magnesium etc), and while these are crucial nutrients for crop production, it is important that they are not being over-supplied to the soils. With a lack of a seasonal reset via rain and snow in protected spaces, these salts can accumulate quickly over time, impacting crop health and productivity. 

Now that we have the data...what does it mean?!

The Department of Agriculture has an interpretation document outlining the line items included in a compost analysis report and the impact that each nutrient has on crop production. Once you have a good understanding of what is included in the report, Perennia has created a fact sheet that provides further information on some of the metrics included, and the implications that these metrics have on our nutrient management plan. Below is a brief summary of some of the information presented in the factsheet, but I highly recommend you check it out for yourselves! 

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Finished composts typically contain low levels of a wide variety of nutrients (though this is highly dependent on the materials included in the mix). This lower level of nutrients can translate to a tendency to apply large volumes of compost, however this can lead to excessive levels of certain nutrients in the soil in some cases. It is typically recommended that compost is not the sole fertility source for crops, but one of a handful of additives that come together to provide the target nutrient ranges for the crop in question. 

C:N Ratios

The amount of carbon present in a compost, in relation to nitrogen, impacts nutrient cycling, and how quickly nutrients will become plant available. Composts typically range from 8:1 - 30:1. If your compost has a ratio:

•  >40:1, there is a good chance that any nitrogen that is present in the soil/compost will be 'tied up' through the process of breaking down carbon. This can lead to nitrogen deficiencies in your crop.
• 12-22:1, there is more nitrogen available than the microbes need, meaning it will become plant available more readily
• 25-32:1, it will slowly become plant available over the course of a few years.

Nitrogen

The provincial lab analysis of compost reports on total nitrogen in the sample, however nitrogen has many forms in compost. 'Organic nitrogen', which is the nitrogen included in microbial, animal and plant tissues, is not immediately plant available. It must be mineralized in the N cycle before a plant is able to take it up and use it for growth. The rate of mineralization is difficult to forecast, as it is dependent on a handful of variables (temperature, moisture, C:N ratio of the compost). When compost is the only source of nitrogen in a production system, it is challenging to match the times of peak demand for the crop, with the availability of high amounts of useable (i.e. mineral) N. 

'Mineral nitrogen', specifically ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N), are the plant-available forms of nitrogen. While these are key forms for plant production, they are easily lost to the environment if they aren't immediately taken up.

How do we know the amount of available nitrogen that is present in our compost analysis? Low N composts typically have low mineral (readily available) nitrogen. High N composts usually carry a fair amount of NO3-N, which is immediately plant available. Take a look at the table below, which estimates the breakdown of organic and mineral N based on your C:N ratio, and the total N (% dry weight). This chart was taken from Perennia's fact sheet linked above, and sheds some light on the percentage of organic, or plant -unavailable, nitrogen in a compost. 

From here, we can calculate how much compost we need to add in addition to our other amendments, in order to meet the target N needs of the crop in question. 

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Utilizing and understanding the tools available to us is a key step in maximizing on-farm productivity, and the inputs invested on the farm. Compost analysis, along with soil tests and water tests, are great ways to quantify and characterize our key production components, and figure out how they can work together to hit our crop-specific nutrient targets without overshooting them. 

For those who are interested in better understanding their compost analysis results, check out Perennia's fact sheet here, or contact your commodity specialist for further discussion! 

-Talia 

Finishing up 2023

 As we finish up our 2023 growing seasons, it is time to re-visit our standard cleaning procedures. Throwing out the old and preparing for the new is one of the most important components to protected production.

While this is going to look different for those in soil-based systems compared to those who are set up hydroponically, there are some key practices that can be adapted to any protected space:

1. Removing ALL organic matter from the greenhouse, and greenhouse vicinity
• dried up leaves, old soil, dirty pots and growing supplies are perfect hiding spots for pests and disease to overwinter. Its important that you eliminate as much potential habitat and food source as possible
• Don't hesitate to do this in stages. Clean out the big stuff, and come back a second and third time to get rid of the bits and pieces that were not picked up the first few times. 
• Do not leave piles of plant material or old soil next to your greenhouse. As much as these serve as habits inside the production space, they will do the exact same thing outside. No matter how well the inside is cleaned, if you have a major source of insects just steps away from the greenhouse...there will be problems
2. Collect all old growing supplies from the year, and remove from the space for cleaning. Pots, carrier trays, pruners, clips, support stakes/string etc. should be dealt with to reduce pathogen and pest load into the new production cycle. Pots, carrier trays and pruners can all be sterilized and re-used, but be aware of the cleaning agent used here - some are going to cause more harm than good! Wooden stakes, while tempting to re-use these, cannot properly be sterilized because they are highly porous. Disease transfer from year to year from re-using stakes is possible.
3. Consider swapping out ground cover if you are using something more substantial than plastic mulch! While this isn't something typically tackled on a yearly basis, following a heavy disease year it can be worth considering getting a new cover put over the ground. If you are considering this, remove the old cover before going forward with suds and sanitizer! That way your ground layer will be scrubbed back to a base layer of clean, and you can be confident that nothing is hiding out in tiny cracks and crevices throughout the old ground cover.
4. Lets get soapy!
• Giving all growing surfaces a soapy scrub is going to grab hold of any bacterial, viral and fungal agents that are still in the space and wash them away. 
• The best strategy for washing a greenhouse is to start at the top and work down - and this includes your ceiling! Failure to wash the top of the grow space creates a disease bank that can literally rain down on your future crop.
• Once you have applied your soap, give the production space a thorough rinse and allow it to air dry
5. Once you have allowed the space to airdry after cleaning, it is time to bring in the big guns- Sanitizer! There are a lot of sanitizers on the market to chose from, but they do have a few things in common:
• Contact time is important. Different products have different required contact times in order to be effective. Be sure to check what the required contact time is for your product of choice, and do your best to adhere by that. Otherwise there is no guarantee that the product will sterilize to the degree that you are hoping for
• Organic matter will de-activate sterilizing agents. Any of those leaves or soil bits that got left behind in pots and seeding trays will actually render your product useless. 
• Consider how corrosive your cleaning agent is. Bleach is effective, but does impact the longevity of growing equipment, both for plastics and other materials.
• TEMPERATURE. Sanitizer efficacies significantly decrease at lower temperatures. While it is difficult to justify heating a protected space for cleanout, it is a key factor in maximizing your product efficacy.

Here are a few other considerations for your end-of season wrap-up:

-Once the production space and tools have been cleaned, be conscious of what is coming into the space. Just because you aren't actively growing plants, doesn't mean you are immune to accidental spread! Clean clothes/shoes/growing supplies should be the only thing that enter the space for as long as possible to maintain the clean slate.

-For those who are growing in soil, producers should consider removing plastic on spaces that are not being used for production. The lack of rainwater coming onto your tunnel soils will result in the accumulation of salts in the soil. One of the best ways to tackle this is to allow the snow and rain that come with the winter to run through the soil. Come growing season, this will allow for better uptake and use of supplemented nutrients, and less stress caused by buildup over time. Plastic removal can be a pain, so even doing so every few years is going to be hugely beneficial. For more information on soil salinity in high tunnels, check out this fact sheet!

-Looking to maximize the performance of over-wintered cover crops? Unheated, double poly inflated greenhouses are not going to give enough protection from those cold winter nights. The addition of one or two layers of ground cover can work wonders for your cover crop, reducing large fluctuations in temperature and buffering against cold snaps. It also helps to protect soil moisture for your cover crop. As our day lengths turn around, these plants will see a huge boost in productivity in February and March, increasing the amount of in-house biomass generated to be worked back into the soil before bringing in the cash crop. 

Row cover is best installed after a cold snap or two in the greenhouse space. This should function to kill some of the pests that may still residing in the space, before adding the additional layer of protection

Here's to a fresh start!

Posted by: Talia Plaskett

Join us tomorrow to be a part of the minor use pesticide priority selection process

 The session for field and greenhouse vegetable crops will take place virtually via Zoom on Wednesday, November 22 from 10 AM to 12 PM. 

Perennia’s minor use representative, Michelle Cortens, and the provincial minor use coordinator Deney Augustine Joseph will briefly outline the process. Then as a group you will be guided through the different crops to assess the priority pest control needs for insects, weeds/growth regulators, and diseases. If you have potential solutions on your radar (products registered in other crops or for other uses) or have heard of products you might be interested in, please bring those along as well.

 Any grower is welcome to attend, so if you know of someone who would like to attend please let me know so I can include them on the contact list. If you can’t make the meeting, please send us your critical pest issues and any potential solutions for consideration at the meeting.

The selected priorities will then be submitted on behalf of the province and used in ranking the national priorities.

If you are interested in attending, please contact tplaskett@perennia.ca or tmorcom@perennia.ca for the meeting link and password.

 - Tim

Q&A with CropLife - Happening November 22 at 1pm AST

The Protected Agriculture Stewardship Standards are new on the block and apply to any crops grown in structures such as greenhouses, shade houses, hoop houses, high tunnels, containers and warehouses. These standards were established to assist protected producers in the identification and mitigation of risks associated with the application of conventional and biological pest control products. With the implementation of these standards starting January 1, 2024, there is not much time to get things sorted.  

Join Perennia’s Protected Crop Specialist and Dr. Justine Taylor for a session dedicated to answering your questions about these new standards! Dr. Taylor is the executive director of stewardship and sustainability for CropLife Canada.  In this role Justine supports both industry stewardship efforts as the executive director of the Agrichemical Warehousing Standards Association and contributes to the larger sustainability efforts of Canada’s plant science sector. Justine comes to this role after nearly 10 years in the greenhouse sector covering science and government relations issues for the Ontario Greenhouse Vegetable Growers. A keen supporter of collaboration, Justine contributes to several cross-sectoral initiatives and sits on several local volunteer boards in her home town of Windsor, Ontario. Justine holds a Ph.D. from the University of Alberta with a focus on analytical chemistry.

Check out our website for more information and registration options. Questions can be submitted beforehand or during the live event to provide clarity on the new standards and how they affect your farm.

Hope to see you there!

-Talia

Annual Selection of Minor Use Pesticide Priorities

Please save the date for our annual selection of minor use pesticide priorities for Nova Scotia crops. The session for field and greenhouse vegetable crops will take place virtually via Zoom on Wednesday, November 22 from 10 AM to 12 PM. 

Perennia’s minor use representative, Michelle Cortens, and the provincial minor use coordinator Deney Augustine Joseph will briefly outline the process. Then as a group you will be guided through the different crops to assess the priority pest control needs for insects, weeds/growth regulators, and diseases. If you have potential solutions on your radar (products registered in other crops or for other uses) or have heard of products you might be interested in, please bring those along as well.

 Any grower is welcome to attend, so if you know of someone who would like to attend please let me know so I can include them on the contact list. If you can’t make the meeting, please send us your critical pest issues and any potential solutions for consideration at the meeting.

The selected priorities will then be submitted on behalf of the province and used in ranking the national priorities.

If you are interested in attending, please contact tplaskett@perennia.ca or tmorcom@perennia.ca for the meeting link and password.

-Talia

NEW Guidelines Surrounding the Purchase of Pest Control Products in Protected Spaces

Attention Protected Producers! There is a new national standard on the block.

The Protected Agriculture Stewardship Standards were established to assist protected agriculture operators in the identification and mitigation of risk associated with pesticide application. This set of standards was drafted by a multi-stakeholder committee including CropLife Canada in collaboration provincial and federal grower groups. Health Canada's Pest Management Regulatory Agency (PMRA) and Agriculture and Agri-Food Canada (AAFC) acted in an advisory capacity to guide development of the standards.

The standards apply to any crops grown under structures, such as greenhouses, shade houses, hoop houses, high tunnels, warehouses, containers etc. This new motion requires a certificate in order to purchase any pest control products registered for use in protected spaces effective January 1, 2024. This includes biological-based products, as well as conventional chemistries. 

There are two general streams associated with this new set of standards:

Category 1PA -> Protected Ag Operators using any closed loop irrigation/chemigation systems. A closed loop system is one where any excess irrigation/chemigation liquid delivered to the crop is captured via trough. drainage tile, or other similar conveyance system. Operators using these systems are referred to as Category 1Pa Operators. 

NOTE: warehouse production structures and freight container growing operations with no subterranean plumbing and continuous flooring are excluded from this group

Category 2PA -> Protected Ag Operators not using closed loop irrigation/chemigation systems are referred to as Category 2PA Operators. 

The path forward looks different depending on which of the two streams your particular farm falls into.

A few additional tidbits:

-For those who have both types of irrigation/chemigation on their farm, a category 2 waiver is not needed. Follow through the path for Category 1PA. 

-For farms that have multiple locations/addresses - 

• A site spanning multiple address that are adjacent to one another will be considered a single site
• Multiple addresses that are NOT adjacent to one another will each be treated as a separate assessment, and a separate registration must be completed. 

-What happens if I am currently a Category 2PA operator, and we install a closed loop system in all/some of our operation?

•     When a category 2 waiver is completed, the operator agrees to terms, including notifying the AWSA of any changes in use, scope, or category. In these cases, the operation should be audited for compliance with the Standards. Once successfully audited, a certificate will be issued which renders the original category 2 waiver redundant. 

Stay tuned for details on an upcoming virtual Q&A session with a representative from CropLife in the next month! This will be a great opportunity to get clarity on the new standards effective January 1, 2024. Deadline to Register is December 31, 2023. 

In the meantime, feel free to explore AWSA's page on the Protected Agriculture Stewardship Standards and the resources provided there. 

-Talia 

Just a Reminder...it's Soil Sampling Season!

 Soil testing is a great way to understand the current nutritional status of your production space. When taken properly, the sample will give information on which nutrients are already present in the soil, the degree of nutrient availability (through CEC and pH values) and make suggestions on lime applications where needed. This information can then be used to determine the best inputs for efficient and economical crop production in the upcoming year. 

Soil sampling can be done any time of year, however most producers opt to take them in the fall immediately following harvest. The results generated through soil analysis can vary depending on the time of year, but they typically don't change a lot from the fall to the following spring. This timing also allows for a larger window to develop the fertility plan for the following season, and allows slow-acting amendments such as lime, and elemental sulfur to work their magic before the next batch of plants move in. Whichever time of year you chose to soil sample though, it should remain consistent over the years. Outdoor crops see a recommended interval of testing every 2-3 years, but protected soils (tunnels, greenhouses, etc.) should be tested on a yearly basis as it is more susceptible to big changes from year to year compared to a field soil. 

Unsure of what test you should be submitting? The field soil test is suitable for all soils, including those contained in tunnel/protected spaces. If you are a hydroponic producer, with crops grown in containers or grow bags containing soilless substrate (Ex. Sunshine mix, Promix etc), or are looking to get your potting mix tested for nutritional breakdown, then you are looking for the greenhouse soil paste analysis, listed as G1P on the general submission form for Nova Scotia's lab. 

For information on how to take a soil test, check out Perennia's latest guideline here. 

Once we have our soil test, what do all these values mean?

There are a handful of resources available to you to help interpret your soil results:

• Perennia's Soil Test Report Interpretation for Nova Scotia
• Nova Scotia's Analytical Lab's Soil Test Interpretation Ratings for Nova Scotia Crops

As always, if you have any questions regarding your soil test, feel free to reach out to your commodity specialist for further discussion.

Happy sampling folks!

-Talia