Introduction
In the 2021 growing season an experiment was conducted in which a border of native plants (mostly stinging nettel and goose foot) were allowed to grow around a 150cm wide bed of potatos. The purpose of this experiment was to observe the effect of these growing conditions on the behavior of the potato bugs. The result was that no potato bug larve were found on the plants as long as the native plant border was intact. This result was attributed to preditory insects inhabiting the native plants and controling the potato bugs. This is a follow up of that experiment.
In this follow up experiment three parameters will be changed:
1) Plants that are of a more useful plants than nettels and goosefoot will be used as border plants. For instance borage. Borage is known as a „bee magnet“ because of its abundant flowers. In addition, to the flowering period of borage being relative longer than many garden plants, more than one generation of Borretch can be grown in a season.
2) There will be companion planting among the potatos with other useful vegetables such as pole beans, corn and sweet potatoes.
3) A mulch environment will be created that consists of a larger percentage of wood chips. This will creat a condition that is more favorable to the growth of fungus.
The symbiotic relationship between a mycorrhiza fungus and plants has been shown to be beneficial. Not only does the mycorrhizal fungus allow essential nutrients (such as phosphorous, nitrogen and Co.) and water to be more available to the plants they are in association with [1-6], it also increase plant growth [5,6] and the nutritional value of the vegetables [6,7]. In addition, as shown in research done by Schoenherr, et al. it is also able to increase the plants resistance to attack by herbivore insects [8].
Establishment of the growing bed
The growing bed, let it be refered to as KB-2 is to be established in an area where no potatos have grown before. The ground had been mulched over in 2021. In the 2022 season the native plants had grown through the mulch cover. This was desired. Not only are they providing more mulch for the bed when they are mowed down they are also keeping active roots in the ground and thus assist in maintaining the soil food web.
Fig. 1 View of KB-2 from the north end of the bed
Fig. 2 View of KB-2 from the south end of the bed. Note that in this portion of the bed a layer of grass mulch has prevented the native plants from growing. The mulch here was put on thicker than on the north side of the bed in the background where the native plants are seen growing.
Fig. 3 KB-2 after the mowing of the native plants.
After Mowing the native plants the Borretch and Chamomile can be seen. These are two of the desirable species of plants that are known to attract predatory insects like lady bugs.
A layer of mulch consisting mostly of wood chips covered by a layer of grass clippings and other assorted organic material will now be applied to the mowed area. This layer will have a thickness of approximately 20cm and, in addition to serving as a food source for the mycorrhiza fungus will also serve as compost as it is degraded. The wood chips that are being applied below are a mixture of poplar and pine.
Fig 4. Wood chip mulch being applied
The size and shape of the wood chips allows for airflow through the layer and it is unlikely that the bed will become anaerobic.
References
1) O’Keefe, D. M., and D. M. Sylvia. “Chronology and Mechanisms of P Uptake by Mycorrhizal Sweet Potato Plants.” The New Phytologist, vol. 122, no. 4, (1992), 651–59. .
2) Govindarajulu M, Pfeffer PE, Jin H, Abubaker J, Douds DD, Allen JW, Bücking H, Lammers PJ, Shachar-Hill Y. „Nitrogen transfer in the arbuscular mycorrhizal symbiosis“. Nature. (2005) Jun 9;435(7043):819-23.
3)Liu, Caixia, Sabine Ravnskov, Fulai Liu, Gitte H. Rubæk, and Mathias N. Andersen. “Arbuscular Mycorrhizal Fungi Alleviate Abiotic Stresses in Potato Plants Caused by Low Phosphorus and Deficit Irrigation/Partial Root-Zone Drying.” The Journal of Agricultural Science 156, no. 1 (2018): 46–58.
4) Chifetete, Varaidzo W. and Joanna Felicity Dames. “Mycorrhizal Interventions for Sustainable Potato Production in Africa.” Frontiers in Sustainable Food Systems, vol. 4, (2020), Article 593053
5) Begum N, Qin C, Ahanger MA, Raza S, Khan MI, Ashraf M, Ahmed N, Zhang L.„Role of Arbuscular Mycorrhizal Fungi in Plant Growth Regulation: Implications in Abiotic Stress Tolerance“. Front Plant Sci. (2019) Sep 19;10:1068.
6) Bhantana, P., Rana, M.S., Sun, Xc. et al. „Arbuscular mycorrhizal fungi and its major role in plant growth, zinc nutrition, phosphorous regulation and phytoremediation“. Symbiosis 84, (2021), 19–37
7) Baslam, M.; Garmendia, I.; Goicoechea, N. „Enhanced Accumulation of Vitamins, Nutraceuticals and Minerals in Lettuces Associated with Arbuscular Mycorrhizal Fungi (AMF): A Question of Interest for Both Vegetables and Humans“. Agriculture (2013), 3, 188-209.
8)Schoenherr, A.P; Rizzo, E.; Jackson, N.; Manosalva, P.; Gomez, S.K.; „Mycorrhiza-Induced Resistance in Potato Involves Priming of Defense Responses Against Cabbage Looper (Noctuidae: Lepidoptera)“, Environmental Entomology, Volume 48, Issue 2, April (2019), 370–381.