Approaches to Soil & Compost Testing
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1. The document discusses approaches to soil and compost testing, providing lessons learned and case studies from the NYC Compost Project. 2. A case study of nutrient management at Queens Farm is presented, showing how soil testing led them to reduce their annual compost application rate from 4 wheelbarrows per bed to 1-5 gallon bucket per bed. 3. Another case study discusses unexpected high fecal coliform results from compost made at a "Salt Lot", which could indicate contamination from warm-blooded animals. The document explores ways to identify the potential source.
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Approaches to Soil & Compost Testing
- 1. 1 2019 Cultivating Community Compost Forum Monday, May 13, 2019 Leah Retherford, NYC Compost Project Hosted by Big Reuse Approaches to Soil & Compost Testing
- 2. 2 Overview • Background • Lessons • Technical Assistance for Compost Requests • Case Study 1: Queens Farm Application Rates • Case Study 2: Salt Lot Compost • Following our own Advice
- 3. 3
- 4. 4 Lessons Learned ● Soil Tests are Tools ● Find and use experts that work for you ● Start with “I don’t know”, especially with unexpected results ● Share Information
- 5. 5 NYC Compost Project Hosted by Big Reuse: Technical Assistance • One of seven Compost Projects • Part of a community scale composting network. • Mission: To rebuild NYC’s soils by providing New Yorkers with the knowledge, skills, and opportunities they need to make and use compost locally.
- 6. 6 NYC Compost Project Hosted by Big Reuse: Technical Assistance • Compost is not soil • A little goes a long way, a maximum of an inch annually of screened compost is plenty. Build your soil fertility slowly • Calculate the amount they need for their growing area • Recommend soil testing ◦ Contamination ◦ Track nutrients and organic matter • Other
- 7. 7 Nutrient Management at Queens Farm
- 8. 8 Nutrient Management at Queens Farm
- 9. 9 Nutrient Management at Queens Farm Compost Application Rate Prior to 2011: 4 wheel barrows per 180’ x 4’ bed Math: 1 wheelbarrow = ~4 ft3 4 x 4 ft3 = 16 ft3 compost/ 720 ft2 = 0.022 ft * 12 inches/ft = 0.27 inches annually 0.022 ft * 43,560 ft2 = 958 ft3/acre or ….. 958 ft3 * 1 yd3/27 ft3 = 35 yd3 of compost/acre from Compost Test: 1 yd of compost = ~1000 lbs 35 yd3 x 1000 lbs wet compost = 35,000 lbs x 0.59 (dry solids content) = 20650 lbs dry solids 20650 lbs x 0.00614 (total P) = 127 pounds P annually
- 10. 10 Nutrient Management at Queens Farm *New* Compost Application Rate: 1 -5 gallon bucket per 180’ x 4’ bed Math: 1 -5 gallon bucket = ~0.67 ft3 0.67 ft3 compost/ 720 ft2 = 0.00093 ft * 12 inches/ft = 0.011 inches annually 0.00093 ft * 43560 ft2 = 40 ft3/acre or ….. 40 ft3 * 1 yd3/27 ft3 = 1.5 yd3 of compost/acre From Compost Test: 1.5 yd3 x 1000 lbs wet compost/ yd3 = 1500 lbs x 0.59 (dry solids content) = 886 lbs dry solids 886 lbs x 0.00614 (total P) = 5 pounds P annually
- 11. 11 Unexpected Results: The Salt Lot
- 12. 12 Unexpected Results: The Salt Lot Fecal Coliform: facultatively anaerobic, rod- shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal Coliform and Salmonella are “indicator bacteria”. They need higher temperatures to be reduced or destroyed and if they are not present than other pathogens have also been reduced. -Carmen Thiel Lab Manager UW Oshkosh
- 13. 13 Unexpected Results: The Salt Lot Guilty?
- 14. 14 Unexpected Results: The Salt Lot
- 15. 15 NYC Compost Project Hosted by Big Reuse: Technical Assistance
- 16. 16 Thanks and call me if you want to talk more about this.
Editor's Notes
- Background: Not a Soil scientist have used soil and compost tests as a practitioner Americorps member in Detroit, provided resources to urban gardeners one of those resources were soil tests, primarily to check for the lead contamination Formerly was the farm manager at the Queens County Farm Museum -used soil test to manage farm nutrients As the Project Manager for the NYC Compost Project we use compost tests to evaluate the compost we make and we also recommend people using our compost, test the soil they are growing in.
- There are lots of ways to evaluate your soil and compost that don’t involve a test -smell, feel, weight, how it looks. But sometimes soils and compost can look very similar but be very different. Soil tests -similar to a microscope can help us see or observe a quality of soil or compost that we can’t detect otherwise Lab tecnhicians, soil scientists at companies, partners. Soil scientists -in my experience -are similar to composters and farmers and like to share resources and what they’ve learned. Just like teachers, Different experts work for different people. Find ones that work for you. Call people -an open-ended conversation can give you a much greater depth of info. I like experts who don’t make me feel bad about what I don’t know. Mamonides quote. “Teach yourself to say I don’t know and you will progress” Problem solving technique, when you start with “I don’t know” it saves a lot of time because you are immediately asking questions and begin to look for resources. When you feel like you have all the answers from the start or you already know exactly what is going on you can get in your own way of learning and progressing. It’s ok to not know. I am going to cover some simple math and show a lot of tests, that can be intimidating for some, but the more you interact with soil tests the more you realize they are just a tool that you can use to better understand the soil or compost you are working with. You may be or be becoming an expert and sharing info., even if it is just through a question or a problem can help others
- One of the main ways we help rebuild NYC’s soils is by distributing compost All New Yorkers requesting compost from us for the first time receive a technical assistance call. This is maybe the only time we are interacting with gardeners and stewards in a year so it is a great opportunity to provide some education about using compost and we provide the same info for everyone even if they are professional gardeners.
- Wrong year, but similar to the ones we took in 2011. Sent this to our organic soil amendment dealer, Fertrell. Where I got to know one of my experts Orin. Winter calls. He would answer all my questions even though we bought very few amendments and most of my questions were about fields that we didn’t apply any amendments. The thing that stood out to him on the first test was the high levels of P. He said that if we were located along the Chesapeake Bay our farm would be shut down with P levels this high. This was shocking to me -innocent organic farmer not a polluter. He explained that when manures and composts heavy with manures have phosphorus in higher ratios. And if farmers use these manures to meet their N requirements they will end up with excess P. QCFM on top of having year round livestock also had a seasonal petting zoo so for decades lots of manure was being put on a relatively small growing area. It wasn’t all my fault.
- Next we looked at our compost test and calculated how much P was being added to our field based on our application rate.
- Going to go over this quickly, but if you would like to look at it with me later more slowly Thats sounds like fun, and you can check my math. ¼ inch annually of compost, not that much. Orin basically said that if we continue at this application rate our P levels would never decrease.
- So we changed our compost application rate drastically We worried this would affect our plants with so much less N being applied. Also used covered crops, tilled in plant debris where we could, mulches, and rotated crops. Things grew fine - didn’t notice any major effect on our crops. Still used our compost, but spread it more widely on lawns and pastures that had received very little compost over the years. Orin’s advice - continue to grow vegetable intensively with this new application rate and your P levels will go down. Also -every year he would ask me how our plants grew. Farmer observations along with the soil test were the best feedback loop.
- The Salt Lot -one of two compost sites we manage. Started operating in late January 2018. First compost test from our beautiful pristine site and we are about to have our first giveback event, not to mention we are busy as usual. We are definitely reaching PFRP. I personally have made compost with much less careful situtations, but that first time you get the information it’s hard not to panic a little but and worry you are doing something wrong. Start with I don’t know. Helped that our good friends at Earth Matter had told us that they had an issue where they were failing the fecal coliform tests way back in 2015 and that the issue was how they were sending samples.
- So we get on the horn with Carmen and Greg from Univ of Wisconsin and Devin, Operations Coordinator, starts asking a ton of questions about why we might have failed and we learn a lot. Sma
- So we get on the horn with Carmen and Greg from Univ of Wisconsin and Devin, Operations Coordinator, starts asking a ton of questions about why we might have failed and we learn a lot. Small sampling size could easily be contaminated by wildlife (~1/2yard) A likely source of fecal coliform contamination are birds. Bird feces are "loaded with fecals." Also a family of cats on the SL site the public health threat is low. Generally fecal coliform bacteria can't last too long (day or two) outside of their ideal conditions (mammalian gut) so it is likely safe. Thinks if it is a one-off and the other tests pass that we have nothing to worry about, the public health risk of this compost is pretty low Discussed with our team felt comfortable distributing compost from different batches We did two more tests of different batches pretty immediately and passed both
- We did two more tests of different batches from the Salt Lot, pretty immediately and passed both But it was a good learning experience and a reminder to not overreact, ask more questions, and better to know that you have a problem than to not know.
- Followed our own advice and tested soil we planned on growing in at our new QB site. Really high lead Called our soil expert and came up with a plan to remediate so our site would be safe for staff and volunteers
- Soil mixing -Office of Environmental rEmediation Planting Perennials Mulching Signage