Calcium is an important micronutrient for plant growth.

Calcium has a major role in the formation, structure and stability of cell membranes as well as being an important signalling molecule. Through its function as a signalling molecule, calcium is involved in nutrient uptake, the heat stress response and disease mitigation. Calcium deficiency can lead to the deterioration of cell membranes and consequently cell and tissue death. Although calcium is an essential micronutrient, deficiencies are rarely observed in cereals since in most cases the calcium concentration in the soil is sufficient for the demand of the crop. 

Calcium has an important role in meristematic growth, and so symptoms of calcium deficiency appear in new growth. Unlike many other micronutrient deficiencies, calcium deficiencies do not lead to chlorosis, and instead the dark green colour is maintained. Necrotic spotting around the middle of the leaf of newest growth occurs, and this spotting expands and the lead then collapses before unrolling. In oilseed rape, deficiency causes stunting of new growth in stems, flowers and roots. Symptoms range from distorted new growth to black spots on leaves. Yellow leaf margins may also appear. 

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Connected Content

Crop Nutrition

Plants need around 12 essential mineral nutrients to grow: Nitrogen (N), Phosphorous (P), Potassium (K), Magnesium (Mg), Sulphur (S), Calcium (Ca), Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B) and Molybdenum (Mo).

Grain nutrient analysis

Analysing grain for all 12 nutrients can be an effective tool to improve nutrient management, providing information on crop nutrient status and nutrient offtakes.  It can indicate whether your crops are getting hold of the nutrients they need, or whether you can save on future fertiliser use.

Managing Nutrients Better

Share your ideas and experience of how to improve nutrient efficiency and reduce dependence on artificial fertilisers

Fertiliser

This Topic doesn't yet have a Stewarded summary, but connected groups, content and organisations show below. Click the 'Ask to Join' button if you would like to be a Steward for this Topic and provide a summary of current knowledge and recommend useful resources, organisations, networks and projects. "Like" this Topic if you would like to see it prioritised for providing a wikipedia style summary.

Nutrient Management

Managing nutrients effectively is crucial for our soils, crops, livestock and environment. There are many resources and initiatives available to help. 

Envirolizer

We help farmers grow naturally stronger plants, increase crop yields & immunity, and eliminate over-reliance on the use of harmful chemicals.   envirolizer® is a natural mineral plant growth enhancer and adaptogen.  It contains finely micronized and augmented natural calcite. Fully certified as organic input and fulfils the requirements of Demeter International as well as listed in the EU Input Lists. The farmers' ultimate solution for plant growth, made from 100% Natural Minerals.

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Configure the meta tags below.

Use tokens to avoid redundant meta data and search engine penalization. For example, a 'keyword' value of "example" will be shown on all content using this configuration, whereas using the [node:field_keywords] automatically inserts the "keywords" values from the current entity (node, term, etc).

Browse available tokens.
Basic tags

Simple meta tags.

The text to display in the title bar of a visitor's web browser when they view this page. This meta tag may also be used as the title of the page when a visitor bookmarks or favorites this page, or as the page title in a search engine result. It is common to append '[site:name]' to the end of this, so the site's name is automatically added. It is recommended that the title is no greater than 55 - 65 characters long, including spaces.
A brief and concise summary of the page's content, preferably 150 characters or less. Where as the description meta tag may be used by search engines to display a snippet about the page in search results, the abstract tag may be used to archive a summary about the page. This meta tag is no longer supported by major search engines.
Advanced

Meta tags that might not be needed by many sites.

Geo-spatial information in 'latitude; longitude' format, e.g. '50.167958; -97.133185'; see Wikipedia for details.
Geo-spatial information in 'latitude, longitude' format, e.g. '50.167958, -97.133185'; see Wikipedia for details.
Robots
A comma-separated list of keywords about the page. This meta tag is used as an indicator in Google News.
Highlight standout journalism on the web, especially for breaking news; used as an indicator in Google News. Warning: Don't abuse it, to be used a maximum of 7 times per calendar week!
This meta tag communicates with Google. There are currently two directives supported: 'nositelinkssearchbox' to not to show the sitelinks search box, and 'notranslate' to ask Google not to offer a translation of the page. Both options may be added, just separate them with a comma. See meta tags that Google understands for further details.
Used to rate content for audience appropriateness. This tag has little known influence on search engine rankings, but can be used by browsers, browser extensions, and apps. The most common options are general, mature, restricted, 14 years, safe for kids. If you follow the RTA Documentation you should enter RTA-5042-1996-1400-1577-RTA
Indicate to search engines and other page scrapers whether or not links should be followed. See the W3C specifications for further details.
Sets a cookie on the visitor's browser. Can be in either NAME=VALUE format, or a more verbose format including the path and expiration date; see the link for full details on the syntax.
Tell search engines when to index the page again. Very few search engines support this tag, it is more useful to use an XML Sitemap file.
Control when the browser's internal cache of the current page should expire. The date must to be an RFC-1123-compliant date string that is represented in Greenwich Mean Time (GMT), e.g. 'Thu, 01 Sep 2016 00:12:56 GMT'. Set to '0' to stop the page being cached entirely.
Open Graph

The Open Graph meta tags are used to control how Facebook, Pinterest, LinkedIn and other social networking sites interpret the site's content.

The Facebook Sharing Debugger lets you preview how your content will look when it's shared to Facebook and debug any issues with your Open Graph tags.

The URL of an image which should represent the content. The image must be at least 200 x 200 pixels in size; 600 x 316 pixels is a recommended minimum size, and for best results use an image least 1200 x 630 pixels in size. Supports PNG, JPEG and GIF formats. Should not be used if og:image:url is used. Note: if multiple images are added many services (e.g. Facebook) will default to the largest image, not specifically the first one. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly.
The URL of an video which should represent the content. For best results use a source that is at least 1200 x 630 pixels in size, but at least 600 x 316 pixels is a recommended minimum. Object types supported include video.episode, video.movie, video.other, and video.tv_show. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically.
A alternative version of og:image and has exactly the same requirements; only one needs to be used. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly.
The secure URL (HTTPS) of an image which should represent the content. The image must be at least 200 x 200 pixels in size; 600 x 316 pixels is a recommended minimum size, and for best results use an image least 1200 x 630 pixels in size. Supports PNG, JPEG and GIF formats. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically. This will be able to extract the URL from an image field if the field is configured properly. Any URLs which start with "http://" will be converted to "https://".
The type of image referenced above. Should be either 'image/gif' for a GIF image, 'image/jpeg' for a JPG/JPEG image, or 'image/png' for a PNG image. Note: there should be one value for each image, and having more than there are images may cause problems.
The date this content was last modified, with an optional time value. Needs to be in ISO 8601 format. Can be the same as the 'Article modification date' tag.
Links an article to an author's Facebook profile, should be either URLs to the author's profile page or their Facebook profile IDs. Multiple values may be used, separated by a comma. Note: Tokens that return multiple values will be handled automatically.
The date this content was published on, with an optional time value. Needs to be in ISO 8601 format.
The date this content was last modified, with an optional time value. Needs to be in ISO 8601 format.
The date this content will expire, with an optional time value. Needs to be in ISO 8601 format.
Twitter Cards

A set of meta tags specially for controlling the summaries displayed when content is shared on Twitter.

Notes:
  • no other fields are required for a Summary card
  • Photo card requires the 'image' field
  • Media player card requires the 'title', 'description', 'media player URL', 'media player width', 'media player height' and 'image' fields,
  • Summary Card with Large Image card requires the 'Summary' field and the 'image' field,
  • Gallery Card requires all the 'Gallery Image' fields,
  • App Card requires the 'iPhone app ID' field, the 'iPad app ID' field and the 'Google Play app ID' field,
  • Product Card requires the 'description' field, the 'image' field, the 'Label 1' field, the 'Data 1' field, the 'Label 2' field and the 'Data 2' field.
A description that concisely summarizes the content of the page, as appropriate for presentation within a Tweet. Do not re-use the title text as the description, or use this field to describe the general services provided by the website. The string will be truncated, by Twitter, at the word to 200 characters.
By default Twitter tracks visitors when a tweet is embedded on a page using the official APIs. Setting this to 'on' will stop Twitter from tracking visitors.
The URL to a unique image representing the content of the page. Do not use a generic image such as your website logo, author photo, or other image that spans multiple pages. Images larger than 120x120px will be resized and cropped square based on longest dimension. Images smaller than 60x60px will not be shown. If the 'type' is set to Photo then the image must be at least 280x150px. This will be able to extract the URL from an image field if the field is configured properly.
The MIME type for the media contained in the stream URL, as defined by RFC 4337.