The pre-work tour and site survey. In this snapshot, Professor Bomford is identifying problems with spotty germination, located in some of the terrace garden plots. |
Professor Bomford discussing the reasons for spotty germination of beets and carrots; they were directly sown by hand last week and a few weeks prior to that. |
Masa applying anti-fungal organic pesticide to suppress the development of early onset powdery mildew in our cucurbits. |
Harvest bins drying outside under the mid-day heat, this picture was taken near the end of class. |
Thursday June 30th: @ The Gilbert Road Orchard Site
Wireworm Suppression study in corn patch in planting block AB1
Figure # 2: Sami Adbul's Experimental Design Plot Summer 2015 at the Gilbert Road Orchard in AB2 Block; comparing the ENF v. DSM to control endemic wireworm populations in Winter Wheat cover-crop. |
Third year students must first complete a basic statistics class in order to understand how statistical methods are both determined and applied in research projects. After completing this introductory course, successful agriculture students must then enrole in the Experimental Design class. The objective of this class is to create and design their own experimental study. Senior 4th year student Abdul Sami, originally from Afghanistan, became curious about wireworms and Integrated Pest Management (IPM) options available to kill them.
Adbul, observed that conventional methods of using synthetic pesticides was a non-sustainable management solution to kill resident larva populations; therefore Abdul Sami, reviewed the existing body of literature on wireworm management techniques. Doing so he was lead to believe that there were two suitable organic management techniques that he could further investigate.
The first option was to find and use rapeseed meal. It is sold commercially as Defatted Seed Meal (DSM). This would later prove to be a problematic solution; as Professor Bomford would discover, the source of canola, the primary ingredient in DSM was likely GMO. As it turns out, it is very difficult to source organic canola in 2016; it is an open-pollinated crop and is planted at such a large scale, in the Canadian prairie provinces that it makes sourcing a legitimately organic crop of canola difficult, if not impossible. Having determined DSM, as his first wireworm control method, Adbul Sami and Professor Michael Bomford were next able to approach local agricultural company Enterra Feed Corporation. They sought some Black Solider Fly (BSF) frass for use in their study.
The BSF, Hermetia illucens is a large fly native to the tropics and South America. The feces of the BSF are called Frass. It has been demonstrated through peer reviewed studies, that Frass makes both an effective fertilizer, with an NPK content of 3-2-4 and also an organic insecticide (Vickerson et. al, 2015) (Enterra Feed Corporation, 2016). This frass or digestate [in layman's terms the poop of the BSF larva] is exceedingly nutrient dense and has the advantage of a low C:N ratio. This allows plants to uptake nutrients in soil solution very quickly, compared to other leading organic fertilizers. The process of soil absorbing nutrients from fertilizers and then translocating these nutrients, to plants through their network of fibrous roots, helps plants, to uptake nutrients when the soil is saturated with water. We call this process mineralization (Enterra Feed Corporation, 2016).
A 2013 study carried out on Vancouver Island conducted by Temple et. al at the Amara Farm in Courtenay had one main objective; it sought to compare the efficacy of mineralization obtained from Enterra Natural Fertilizer (ENF) against two other comparable organic fertilizer products. The farming site used in the experiment was of marginal agricultural to provide a better contrast for the success or failure rate of each fertilizer option. The ENF was compared against composted poultry litter (EPL) and worm castings (WC) in three different trials and the results were pretty clear cut; ENF's rate of N mineralization was 60% greater than either CPL or WC (Temple et. al, 2013). Not only was nitrogen mineralized at a greater rate than occurred in the two other competing organic fertilizer products, so too was phosphorous and potassium minerals.
In the main field study, of most relevance to Abdul Sami and by our extension our Agro-ecosystems class are the three rates of ENF and how they were applied in 1.2 m x 1.5 m test plots at a low rate of 5 t/ha or a high rate of 10 t/ha in comparison to control plots which received no ENF application. The ENF treatments were applied and incorporated at a depth of 15 cm, plots were then levelled off with shovels and rakes and covered with jute coffee sacks and left for two weeks to for mineralization to occur (Temple et. al, 2013, 4). In Addul Sami's trial, four replicates and three treatments were used, the control where neither DSM or ENF were applied and incorporated into the soil. Each plot that received an application of either DSM or ENF was 2m wide by 5 m long, secondly ENF which was applied at a rate of 7 t/ha and lastly the DSM which was applied and worked into the soil at an application of rate of 6 t/ha (Sami 2015)
There were two major take-away lessons from the Temple et. al study in 2013 that were relevant to Abdul Sami's research which provided the foundations for our latest study, which we set up just this past Thursday at the Gilbert Road Market Garden site. Firstly, the rate of mineralization of the ENF is slow burning, "by day 56 [after application and incorporation] for the ENF was still increasing, whereas the nitrogen levels of the other fertilizers had levelled off (Temple et. al, 2013)." Extrapolating this line of thinking, we can take this as incidental evidence of the latency of the fertilizer product and its corroborating role as an organic insecticide meant to repel and kill resident wireworm populations in an agricultural field of study.
The second take away from the Temple et. al study is the correlation between high EC (Electrical Conductivity) and sodium content, greater than either WC or CPL. Okay, so at does this mean, you may ask? Well, to break things down, we will firstly need to explain the role of assessing EC in your soil as a farmer. EC will give you a snapshot of the water in your soils ability to carry an electrical current, remember that all nutrients absorbed in soil solution are taken up by plants roots in ionic form as either cations or anions. Therefore a healthy soil, will be able to carry an ample electrical charge according to research conducted out of Clemson University, the article I read online went on to explain that an ideal EC level in soil solution is between 200 uS/cm and 1200 uS/cm.
We can deduce soil health problems if EC levels fall either above 1200 uS/cm or below 200 uS/cm.
ENF in some field studies has problematically tested too high in EC content s problematically had to as a result of high sodium content.
High sodium content in the composition of ENF can show evidence of over application causing salinization in the soil. Salinization is a four-letter word among farmers because it contributes to immobilization of nutrients in soil rather than their release to nearby plants. According to Reed Radley, head scientist at Enterra Feed Corporation and co-author of the Temple et. al study, steps have been taken to limit or prevent incidents of salinization caused by over-application of ENF. They now request that growers assess their existing NPK levels in soil before applying ENF, if the soil shows evidence of pre-existing nitrogen freely available in the soil, they request that the grower reduce the amount of frass applied and incorporated into the soil to reduce the incidences of soil sterility and on the production end they have streamlined this process by relying on: "the same feedstock suppliers, and trying to maintain variety in the input feedstock to even out feedstock quality, and hence stabilize the frass numbers (Radley, email correspondence, 2016)".
Herein lies an applicable takeaway from Radley's e-mail explanation to myself, perhaps it is the sodium load causing isolated incidences of increased soil salinity create a toxic environment for which the wireworm can no longer survive and as a result die off. In Enterra's patent application for it's ENF product, chief technology officer states that: "the frass may be applied at a rate of at least 5 tonnes per hectare, for example at a rate that kills at least 50% of the insect pest. (Vickerson et. al, 2015)". Regardless of the cause of toxicity caused by application and incorporation of ENF Abdul Sami choose to apply at a rate of 7 tonnes per hectare.
The other key thing Abdul Sami did in constructing the methodology of his study was comparing existing wireworm populations to those after incorporation and mineralization of both the ENF and DSM products. In the discussion section of his report, Sami concludes the following: "wireworms were seven times more abdundant in control plots than DSM plots and four times more abundant in control plots than ENF plots" (Abdul, 2015 p. 10). He concludes that their was a key limiting factor in his study scale, he says that the trial should be replicated at a larger size and with larger buffers between plots. This is where the Spring 2016 Agro-Ecosystem II's class involvement comes into play.
We have essentially replicated Abdul Sami's study in a larger spatial area, relocating his space of study from AB2 block to AB1, where the crop under observation is now corn instead of winter wheat. As we are only using one variable ENF, instead of ENF and DSM, there is little need for a 1 m buffer between test plots.
Our study was conducted on a 150 square meter corn field, divided into eight plots, measuring 19 square meters each (5 metres in width x 3.75 metres in length). We applied 21 kg of ENF to each of four plots, leaving the remaining four plots untreated in randomized complete block design. The application rate was 11 t/ha (21 kg / 19 square meters x 1 t / 1,000 kg x 10,000 square meters / ha).
Our class did not sample for wireworms before applying and incorporating the ENF into the soil of AB1 test plots. I will bring up the methodology for sampling wireworm populations over the lifecycle of the corn transplants (likely the next two months) and how we can record and compare data over the next few weeks. Additionally we need to consider that unlike the Temple et. al study we did not allow mineralization of the ENF to occur in a covered environment for two weeks before transplanting our corn starts, they were becoming root bound and this was not an option for us. It will be very interesting to see how this study progresses over the coming weeks. I can honestly say, that it has gotten me to feel excited about the scientific method and data collection in general. This is a shocking revelation for me to offer up because I am more interested in the practical hard-nosed business of agriculture, meaning putting shovels in the soil and what not. Perhaps, this experiment will change my point of view, time will tell.
Anna Rawlings tilling in the weeds which have overtaken AB1 planting block, this would have taken forever by hand even with a half-dozen student and teacher farmhands to assist. |
Erecting and marking off the study area in planting block AB1 |
Professor Michael Bomford explain the proper technique for removing a corn seed plug from a 72 cell tray, we had about 1000 plugs to transplant last Thursday afternoon. |
Student Leanne Ejack, removes corn plugs with the blunt end of # 2 HB pencil and gives them to Professor Bomford whom plants them in the ground at 12' intervals in parallel rows. |
Our class attempt at the Ford assembly line model of corn transplanting. |
Leanne Ejack and Professor Bomford transplanting more corn seedlings, when will it end? |
Me (Stafford Richter) excitedly pumping my fists in the area after completing the transplanting of another row of corn transplants. |
Sami, Abdul, December 2015. The use of Canola Seed Meal
and Enlltruterra Natural Fertilizer for Controlling Wireworm. Kwantlen
Polytechnic University, Sustainable Agriculture and Food Systems.
Agricultural Solutions,
n.d. The why and how to testing the Electrical Conductivity of Soils. https://www.agriculturesolutions.com/resources/92-the-why-and-how-to-testing-the-electrical-conductivity-of-soils
Enterra Feed Corporation, 2016. Natural Fertilizer. http://www.enterrafeed.com/products/natural-fertilizer/
Sheppard, D.C J.K.; J.K. Tomberlin, J.A. Joyce, B.C. Kiser
& S.M. Sumner.
2002. Rearing Methods for the Black Soldier Fly (Diptera:
Stratiomyidae). J.
Med. Entomol. 39(4): 695-698
Temple, D.W., R. Radley, Baker-French. and Richardson F. November
2013. Use of Enterra Natural Fertilizer (Black Soldier Fly Larvae
Digestate) As a Soil Ammendment. http://www.certifiedorganic.bc.ca/programs/osdp/I-172_Frass_Research_Final%20Report.pdf
Vickerson, A, R. Radley, B. Marchant, O. Kaulfuss & T. Kabaluk
February 2015. Hermetica illucens frass production and use in plant nutrition
and pest management. http://www.google.com/patents/WO2015013826A1?cl=en
E-mail Correspondence. Monday July 4th 2016. Stafford Richter and
Reed Radley.
Great post, Stafford! Thanks for all the interesting information.
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