{"id":1149,"date":"2017-06-01T07:48:16","date_gmt":"2017-06-01T11:48:16","guid":{"rendered":"https:\/\/gallandt.wordpress.com\/?p=1149"},"modified":"2018-03-07T13:42:35","modified_gmt":"2018-03-07T18:42:35","slug":"comparing-solarization-occultation","status":"publish","type":"post","link":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/","title":{"rendered":"Comparing Solarization & Occultation"},"content":{"rendered":"

Comparing Solarization & Occultation<\/strong><\/p>\n

Grace Smith, Undergraduate Student<\/p>\n

Sonja Birthisel, PhD Student in Ecology and Environmental Sciences<\/p>\n

Eric R. Gallandt, Professor of Weed Ecology and Management<\/p>\n

 <\/p>\n

We have seen increased interest in using black plastic silage tarps for stale seedbed preparation, a technique known as occultation or tarping.\u00a0 Our prior research suggests that solarization using clear plastic can also be used to create an excellent stale seedbed. We conducted two experiments to compare solarization to occultation, and during our second experiment measured the impacts of these practices on the soil microbiome.<\/p>\n

 <\/p>\n

Photo showing a summer 2016 field experiment comparing solarization and occultation,<\/em><\/p>\n

\u00a0<\/em>Rogers Farm, Old Town, ME<\/em><\/p>\n

 <\/p>\n

Experiment 1<\/strong><\/p>\n

In the first experiment, we rototilled, irrigated the soil, and applied solarization and occultation (securing plastic edges tightly by clipping them to metal pipe) for seven weeks starting in April of 2016.\u00a0 Two weeks after plastic removal in early June, we counted emerged weeds.\u00a0 There was significant weed emergence in control plots, but zero weed emergence following both solarization and occultation.<\/p>\n

 <\/p>\n

\"BlogPostFig2.jpg\"Weed emergence measured two weeks after plastic removal<\/em>\u00a0in control, occultation and solarization treatments<\/em><\/p>\n

 <\/p>\n

The field in which this experiment took place had been amended with compost before the trial began in April and was very high in organic matter (17.9%).\u00a0 This meant that we were actually performing \u201cbiolsolarization\u201d \u2013 that is, coupling solarization with addition of organic amendments.\u00a0 Past studies suggest that biosolarization is often more effective at controlling pests than regular solarization, so this may have contributed to the excellent weed control we measured.<\/p>\n

\u00a0<\/strong><\/p>\n

Experiment 2<\/strong><\/p>\n

We were curious how solarization and occultation compared when applied for shorter treatment periods, so we conducted a second experiment starting in early July of 2016. As before, we rototilled, irrigated, and applied plastic.\u00a0 This time we included seven treatments: solarization for two, four, and six weeks; occultation for two, four, and six weeks; and a control.\u00a0 Organic matter in this field was 3.7%, which is more typical than in our first experiment.\u00a0 We measured weed emergence two weeks after plastic removal for each treatment, and found that solarization created a better (less weedy) stale seedbed than occultation for all treatment durations.<\/p>\n

\"BlogSolarization resulted in an effective stale seedbed at all treatment durations;\u00a0<\/em>occultation suppressed weeds at two and six weed durations only<\/em><\/p>\n

 <\/p>\n

Surprisingly, more weeds emerged after four weeks of occultation than two weeks.\u00a0 We think this was because overall 2015 was a very dry summer, but there was abundant rainfall during the two weeks between removing plastic and counting weeds in the four week treatments, which likely encouraged weed germination.\u00a0 The fact that the solarization plots did NOT respond the same way to rain suggests that solarization may have impacted weed seeds in the seedbank more dramatically than occultation, likely through a combination of direct seed death, fatal germination, and forcing seeds into dormancy.<\/p>\n

 <\/p>\n

Soil temperatures were consistently highest in the solarized plots, intermediate in the occultation plots, and lowest in the controls.\u00a0 We expected this trend based on the physics underlying these soil heating techniques: clear plastic allows energy from the sun\u2019s rays to directly heat water in the soil underneath, while black plastic absorbs the sun\u2019s energy and re-radiates some heat to the soil below, but the energy transfer is not as efficient.<\/p>\n

\"BlogPostFig4.jpg\"Soil temperatures, measured at 2 inches depth during six weeks of treatment, were highest under solarization, intermediate under occultation, and lowest in the control<\/em><\/p>\n

\u00a0<\/strong><\/p>\n

To explore the impacts of solarization and occultation on the soil microbiome, we measured soil biological activity before, during, and after four weeks of treatment. \u00a0A soil microbiome consists of tiny organisms such as bacteria, archaea, fungi, and protists that are essential to plant life. Beneficial microorganisms convert nitrogen from the air into ammonium in order to render it useable by plants; protect against harmful microorganisms; and simply crowd out harmful microorganisms. Soil biological activity is essentially a measure of how much the soil is breathing, and is considered to be an indicator of good soil health.<\/p>\n

 <\/p>\n

\"figureSoil biological activity was not significantly impacted by solarization or occulataion during treatment, but two weeks after plastic removal, soil biological activity was reduced in the solarized plots.\u00a0 Shown here are data from 0-1 inch soil depth.<\/em><\/p>\n

\u00a0<\/em><\/p>\n

Treatment did not significantly affect soil biological activity during<\/em> treatment, but soil biological activity was reduced in solarized plots two weeks after plastic removal. \u00a0Soil depth (0-1 inch, 1-2 inches, and 2-4 inches) did not impact these results. \u00a0It is possible that during solarization, natural selection changed the composition of microorganisms present in the soil, favoring heat-loving species.\u00a0 After plastic was removed, the heat loving microorganisms could have been at a disadvantage and declined in population faster than they were replaced by other moderate-temperature-loving species, so the overall soil biological activity decreased temporarily as a result. \u00a0We expect that if we had been able to measure again a month or two after plastic removal, we might have seen soil biological activity return to pre-treatment levels.<\/p>\n

 <\/p>\n

Beyond stale seedbed creation, occultation and solarization could be useful small-scale methods for terminating no-till cover crops.\u00a0 New research at UNH is looking into this<\/a> application, with early results suggesting that occultation may have an edge when it comes to subsequent weed suppression.<\/p>\n

\u00a0<\/strong><\/p>\n

Conclusions<\/strong><\/p>\n

Overall, these two experiments suggested that solarization and occultation can both create effective stale seedbeds, but solarization appears to be more consistently effective than occultation at shorter treatment durations<\/em>.\u00a0 Solarization may negatively impact soil biological activity, though we expect effects to be temporary; we\u2019ll be posting results soon describing two more experiments that take a closer look at the impacts of solarization on soil microbes.<\/p>\n

\n

This work was made possible by a grant from the Maine Food and Agriculture Center<\/i><\/p>\n","protected":false},"excerpt":{"rendered":"

Comparing Solarization & Occultation Grace Smith, Undergraduate Student Sonja Birthisel, PhD Student in Ecology and Environmental Sciences Eric R. Gallandt, Professor of Weed Ecology and Management   We have seen increased interest in using black plastic silage tarps for stale seedbed preparation, a technique known as occultation or tarping.\u00a0 Our prior research suggests that solarization […]<\/p>\n","protected":false},"author":1032,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-1149","post","type-post","status-publish","format-standard","hentry","category-news"],"yoast_head":"\nComparing Solarization & Occultation - Weed Ecology and Management - University of Maine<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Comparing Solarization & Occultation - Weed Ecology and Management - University of Maine\" \/>\n<meta property=\"og:description\" content=\"Comparing Solarization & Occultation Grace Smith, Undergraduate Student Sonja Birthisel, PhD Student in Ecology and Environmental Sciences Eric R. Gallandt, Professor of Weed Ecology and Management   We have seen increased interest in using black plastic silage tarps for stale seedbed preparation, a technique known as occultation or tarping.\u00a0 Our prior research suggests that solarization […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\" \/>\n<meta property=\"og:site_name\" content=\"Weed Ecology and Management\" \/>\n<meta property=\"article:published_time\" content=\"2017-06-01T11:48:16+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-03-07T18:42:35+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"960\" \/>\n\t<meta property=\"og:image:height\" content=\"720\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\"},\"author\":{\"name\":\"\",\"@id\":\"\"},\"headline\":\"Comparing Solarization & Occultation\",\"datePublished\":\"2017-06-01T11:48:16+00:00\",\"dateModified\":\"2018-03-07T18:42:35+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\"},\"wordCount\":958,\"commentCount\":0,\"image\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg\",\"articleSection\":[\"News\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\",\"url\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\",\"name\":\"Comparing Solarization & Occultation - Weed Ecology and Management - University of Maine\",\"isPartOf\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg\",\"datePublished\":\"2017-06-01T11:48:16+00:00\",\"dateModified\":\"2018-03-07T18:42:35+00:00\",\"author\":{\"@id\":\"\"},\"breadcrumb\":{\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage\",\"url\":\"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg\",\"contentUrl\":\"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg\",\"width\":960,\"height\":720,\"caption\":\"figure comparing soil activity\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/umaine.edu\/weedecology\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Comparing Solarization & Occultation\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/umaine.edu\/weedecology\/#website\",\"url\":\"https:\/\/umaine.edu\/weedecology\/\",\"name\":\"Weed Ecology and Management\",\"description\":\"University of Maine\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/umaine.edu\/weedecology\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"\",\"url\":\"https:\/\/umaine.edu\/weedecology\/author\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Comparing Solarization & Occultation - Weed Ecology and Management - University of Maine","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/","og_locale":"en_US","og_type":"article","og_title":"Comparing Solarization & Occultation - Weed Ecology and Management - University of Maine","og_description":"Comparing Solarization & Occultation Grace Smith, Undergraduate Student Sonja Birthisel, PhD Student in Ecology and Environmental Sciences Eric R. Gallandt, Professor of Weed Ecology and Management   We have seen increased interest in using black plastic silage tarps for stale seedbed preparation, a technique known as occultation or tarping.\u00a0 Our prior research suggests that solarization […]","og_url":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/","og_site_name":"Weed Ecology and Management","article_published_time":"2017-06-01T11:48:16+00:00","article_modified_time":"2018-03-07T18:42:35+00:00","og_image":[{"width":960,"height":720,"url":"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"Written by":"","Est. reading time":"5 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#article","isPartOf":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/"},"author":{"name":"","@id":""},"headline":"Comparing Solarization & Occultation","datePublished":"2017-06-01T11:48:16+00:00","dateModified":"2018-03-07T18:42:35+00:00","mainEntityOfPage":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/"},"wordCount":958,"commentCount":0,"image":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage"},"thumbnailUrl":"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg","articleSection":["News"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/","url":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/","name":"Comparing Solarization & Occultation - Weed Ecology and Management - University of Maine","isPartOf":{"@id":"https:\/\/umaine.edu\/weedecology\/#website"},"primaryImageOfPage":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage"},"image":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage"},"thumbnailUrl":"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg","datePublished":"2017-06-01T11:48:16+00:00","dateModified":"2018-03-07T18:42:35+00:00","author":{"@id":""},"breadcrumb":{"@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#primaryimage","url":"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg","contentUrl":"https:\/\/umaine.edu\/weedecology\/wp-content\/uploads\/sites\/354\/2017\/06\/blogpostfig2.jpg","width":960,"height":720,"caption":"figure comparing soil activity"},{"@type":"BreadcrumbList","@id":"https:\/\/umaine.edu\/weedecology\/2017\/06\/01\/comparing-solarization-occultation\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/umaine.edu\/weedecology\/"},{"@type":"ListItem","position":2,"name":"Comparing Solarization & Occultation"}]},{"@type":"WebSite","@id":"https:\/\/umaine.edu\/weedecology\/#website","url":"https:\/\/umaine.edu\/weedecology\/","name":"Weed Ecology and Management","description":"University of Maine","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/umaine.edu\/weedecology\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"","url":"https:\/\/umaine.edu\/weedecology\/author\/"}]}},"taxonomy_info":{"category":[{"value":2,"label":"News"}]},"featured_image_src_large":false,"author_info":{"display_name":"","author_link":"https:\/\/umaine.edu\/weedecology\/author\/"},"comment_info":0,"category_info":[{"term_id":2,"name":"News","slug":"news","term_group":0,"term_taxonomy_id":2,"taxonomy":"category","description":"","parent":0,"count":7,"filter":"raw","cat_ID":2,"category_count":7,"category_description":"","cat_name":"News","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/posts\/1149","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/users\/1032"}],"replies":[{"embeddable":true,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/comments?post=1149"}],"version-history":[{"count":4,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/posts\/1149\/revisions"}],"predecessor-version":[{"id":2386,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/posts\/1149\/revisions\/2386"}],"wp:attachment":[{"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/media?parent=1149"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/categories?post=1149"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/umaine.edu\/weedecology\/wp-json\/wp\/v2\/tags?post=1149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}