Template:Chapters 7.8
7.8 - Manure tea field spraying and seed application
Nick Moroz, University of Guelph, Canada
Suggested citation for this chapter.
Moroz,N. (2022) Manure tea field spraying and seed application. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org
Compost “Teas” can Prevent Disease
Compost teas - an umbrella term that includes manure teas - are preventative measures: they reduce the possibility of plant infection from occurring. Preventative measures contrast with curative measures, with the latter aiming to address plant diseases as they occur within a field. Although the benefits of preventatives measure are not directly seen, these measures can save money and resources over time. Preventative measures can decrease the probability of pathogenesis in a field, reducing the need for insecticides to control plant epidemics that could have been controlled by preventative treatment in the first place.
Compost tea may reduce the need for multiple field applications of fungicides or bactericides later in the growing season. Aggravated use of pesticides is often damaging to the local environment and poses a health hazard to farmers using these applications without advanced safety equipment. Subsistence farmers interested in conserving crop health can consider compost teas as a safe preventative measure, although these teas are generally considered to be less effective than commercial pesticides.
Compost or Manure “Tea” Mechanism to Reducing Pathogenesis
Compost or manure “teas” - composed of compost, manures, and other organic materials - are organic approaches to reducing pathogens, most notably fungi and bacteria. There are multiple beneficial mechanisms that allow these teas to reduce pathogenesis of crops. First, compost teas contain a variety of beneficial microbes in the compost or manure that outcompete pathogenic microbes for nutrients secreted by plants in both the roots and leaves (Ingham & Alms, 2003; Scheuerell, 2004). Plant exudates, both from roots and leaves, help grow disease-suppressing bacteria and fungi in the compost tea, fighting off pathogens (Ingham & Alms, 2003; Scheuerell & Mahaffee, 2002). Unfortunately pesticides and inorganic fertilizers can kill the beneficial microbes, leaving plant exudates for the disease causing microbes (Ingham & Alms, 2003).
Second, compost teas contain soluble nutrients that feed beneficial microbes within the teas themselves and also feed the plants after application of the “tea” (Ingham & Alms, 2003; Scheuerell, 2004). High nutrient concentrations promote beneficial microbe growth, plant resiliency, and increase retention of nutrients in the soil around the plants, reducing fertilizer demands (Ingham & Alms, 2003). Because of these mechanisms, compost teas are often sprayed onto the soil or used as a leaf spray (foliar).
Methods of Compost Tea Production and Application
Compost tea is produced by mixing compost (or manure in manure teas) with water and culturing for a defined period (Scheuerell, 2004). There are two major methods for producing these teas: actively aerating (aerated compost tea, ACT) or not (non-aerated compost tea, NCT) (Scheuerell, 2004). Finally, teas are made with or without additives that are intended to increase microbial population densities during production (Scheuerell, 2004). These are a number of other parameters besides the role of aeration that impact compost tea production and their suppressive properties (Scheuerell & Mahaffee, 2002). These include choice of compost feedstock, compost age, water ratio, fermentation time, added nutrients, temperature and pH, and these are outlined in table 1 (Scheuerell & Mahaffee, 2002). Each of these properties influences the suppressive capabilities of compost teas (Scheuerell & Mahaffee, 2002). Simple procedures/recipes can be found on wikihow (http://www.wikihow.com/Make-Manure-Tea).
A variety of parameters to consider for application are dilution ratio, equipment, timing, and rates of application (Scheuerell & Mahaffee, 2002). Application to soils and/or plants can be done with spray equipment and all types of irrigation systems, if useful (Steven J. Scheuerell). The application system determines the need for filtering compost tea and it should be noted that some filters could reduce microbial populations (Scheuerell, 2004). It should be noted that the research reflects that there is no one ideal compost tea and application factor for all host-pathogen systems (Scheuerell & Mahaffee, 2002.
In summary, these are several methods for producing compost or manure teas to choose from, depending on the scale of production and available financial resources for buying brewing equipment or constructing a homemade brewer (ATTRA, 1998). Methods include the Bucket-Bubbler, Tough, and Commercial Tea Brewer Methods (ATTRA, 1998). Two methods, found at ATTRA, are listed here and can be further researched if needed at ATTRA (ATTRA, 1998).
First, the Bucket-Fermentation Method: compost tea is made by immersing a burlap sack filled with compost into a tank with occasional stirring for 7-10 days, resulting in a compost water extract rather than a “brewed” compost tea (ATTRA, 1998). This is a hundreds of years old method for making basic watery compost tea (ATTRA, 1998).
Second, the Commercial Tea Brewers: These brewers contain a compost leachate basket with drainage holes placed in a tank with water and microbial food sources (ATTRA, 1998). A pump also supplies oxygen to aerate the compost tea while brewing in the tank (ATTRA, 1998). Although this method may be too expensive for a subsistence farmer, it may be affordable for a community.
Aerated and Non-aerated Compost Tea
As mentioned, the two major methods for producing compost teas are aerated compost tea (ACT) or non-aerated compost tea (NCT). This parameter is especially important because producing compost tea with or without aeration and nutrient additives was shown to affect total bacterial population counts as well as bacterial metabolically activity (Scheuerell, 2004). The main distinction between NCT and ACT is that NCT uses greater quantities of compost than ACT, usually without separate nutrient additives, and can be produced from several days to several weeks (Scheuerell, 2004). In contrast, ACT is aerated and uses composts, water, and nutrient additives to significantly increase microbial populations over a 12-36 hour period (Scheuerell, 2004). Compost is supplied aeration through technologies such as an aquarium pump (Lanthier & Advising, 2007). The higher oxygen supply stimulates growth of aerobic microbe populations that assist in compost tea disease suppression and nutrient supply, and these microbes may not survive low oxygen conditions (Lanthier & Advising, 2007).
Most research has focused on the plant disease control properties of compost tea, with most studies pointing to the efficacy of NCT as compared to ACT (Scheuerell, 2004). This review paper outlines the number of NCT studies that showed disease suppressive properties compared to ACT studies (Scheuerell & Mahaffee, 2002).
Case Studies
There are multiple examples in the literature to support the claims that both NCT and ACT can be effective in disease suppression (Scheuerell & Mahaffee, 2002; Martin, 2014; Haggag & Saber, 2007; Al-Dahmani, Abbasi, Miller, & Hoitink, 2003). Due to the volume of studies that reflect this, examples are outlined in table 2. Supposedly, like NCT, increasing the populations of both the total and active bacteria in ACT will generally lead to heightened plant disease suppression (Scheuerell, 2004). In one study, NCT used for seed sterilization prevented pea seeds from “damping-off” caused by the microbe Pythium ultimum and also helped the plant to grow after germination (Scheuerell & Mahaffee, 2002). Although less research has been conducted on soil-borne disease suppression (as compared to foliar disease suppression) with compost teas, this is an often-practiced technique used by organic farmers (Scheuerell & Mahaffee, 2002
Critical Analysis and Summary
Use and application of compost teas in practice are rapidly expanding and outpacing the capacity for traditional scientific research to document the effects of these teas (Scheuerell, 2004). As with many biotechnologies, compost teas are not the single solution to complex problems, such as unsustainable farming, and often their efficacy is limited compared to commercial pesticides (Scheuerell, 2004). However, these teas may be integrated into organic farming systems as a carrier of plant nutrients and beneficial microbes to manage diseases, especially when pesticides use is not a possible solution. Subsistence farmers should be informed of how compost teas may impact their production systems (Scheuerell, 2004)
As some microbes in manure teas can be human pathogens, these “teas” must be used with caution. Microbes in compost teas are thought to be the most importance factor assisting in plant disease suppression despite a limited understanding of the microbes that provide this protection (Scheuerell & Mahaffee, 2002). This limit in knowledge, along with a lack of reporting standards, likely contributes to the variability in compost tea research findings (Scheuerell & Mahaffee, 2002).
Picture Based Lesson to Train Farmers
For the South Asian version (pictures only, text for you to insert), click this link for lesson 8.8a:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8a_south_asian.pdf
For the South Asian version (pictures only, text for you to insert), click this link for lesson 8.8b:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8b_south_asian.pdf
For the East/South Asian version (pictures only, text for you to insert), click this link for lesson 8.8a:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8ae.s.a.pdf
For the East/South Asian version (pictures only, text for you to insert), click this link for lesson 8.8b:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8be.s.a.pdf
For the Sub-Saharan Africa/Caribbean version (pictures only, text for you to insert), click this link for lesson 8.8a:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8asubsaharan_africa_carribean.pdf
For the Sub-Saharan Africa/Caribbean version (pictures only, text for you to insert), click this link for lesson 8.8b:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8bsubsaharan_africa_carribean.pdf
For the Latin-America version (pictures only, text for you to insert), click this link for lesson 8.8a:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8alatin_america.pdf
For the Latin-America version (pictures only, text for you to insert), click this link for lesson 8.8b:http://www.sakbooks.com/uploads/8/1/5/7/81574912/8.8blatin_america.pdf
For North Africa And Middle East version (pictures only, text for you to insert), click this link for lesson Chapter 5. 7.8a:http://www.sakbooks.com/uploads/8/1/5/7/81574912/7.8_a_n._africa_middleeast-1.pdf
For North Africa And Middle East version (pictures only, text for you to insert), click this link for lesson Chapter 5. 7.8b:http://www.sakbooks.com/uploads/8/1/5/7/81574912/7.8_b_n._africa_middleeast-2.pdf
Source: MN Raizada and LJ Smith (2016) A Picture Book of Best Practices for Subsistence Farmers: eBook, University of Guelph Sustainable Agriculture Kit (SAK) Project, June 2016, Guelph, Canada. Available online at: www.SAKBooks.com
Resources Moving Forward
ATTRA Sustainable Agriculture link is a quick guide to a variety of compost tea production systems. Retrieved from: https://attra.ncat.org/attra-pub/viewhtml.php?id=125
ATTRA notes on compost teas. Retrieved from: https://attra.ncat.org/attra-pub/summaries/summary.php?pub=125
Notes for compost teas and other pathogen treatments seen here: http://www.growseed.org/seedtreatments.html
Compost Tea: Principles and Prospects For Plant Disease Control: good literature on ACT and NCT with tables. Retrieved from: http://www.tandfonline.com/doi/pdf/10.1080/1065657X.2002.10702095
Outline of compost teas titled: Compost tea and its impact on plant diseases. Retrieved from: http://crophealth.com/wp/wp-content/uploads/2012/04/CropHealthcom-Sustainable-Compost-Tea-and-plant-diseases-2007-BCOrganicGrower-COABC.pdf
References
1. Appropriate Technology Transfer for Rural Areas, ATTRA. (1998). Notes on Compost Teas. National Center for Appropriate Technology (NCAT). Retrieved from: https://attra.ncat.org/attra-pub/viewhtml.php?id=125
2. Al-Dahmani, J. H., Abbasi, P. A., Miller, S. A., & Hoitink, H. A. (2003). Suppression of bacterial spot of tomato with foliar sprays of compost extracts under greenhouse and field conditions. Plant disease, 87(8), 913-919.
3. Gea, F. J., Navarro, M. J., & Tello, J. C. (2009). Potential application of compost teas of agricultural wastes in the control of the mushroom pathogen Verticillium fungicola. Journal of Plant Diseases and Protection, 116(6), 271-273.
4. Haggag, W. M., & Saber, M. S. M. (2007). Suppression of early blight on tomato and purple blight on onion by foliar sprays of aerated and non-aerated compost teas. Journal of Food Agriculture and Environment, 5(2), 302.
5. Ingham, E., & Alms, M. (2003). Compost tea. Soil Foodweb Incorporated.
6. Lanthier, M., & Advising, C. (2007). Compost tea and its impact on plant diseases. BC Organic Grower, 10(2), 8-11.
7. Martin, C. C. S. (2014). Potential of compost tea for suppressing plant diseases. CAB Rev, 9(32), 1-12.
8. Scheuerell, S., & Mahaffee, W. (2002). Compost tea: principles and prospects for plant disease control. Compost Science & Utilization, 10(4), 313-338.
9. Scheuerell, S. J. (2004, September). Compost tea production practices, microbial properties, and plant disease suppression. In International Conference on Soil and Compost Eco-Biology