{"id":117,"date":"2018-06-19T09:49:53","date_gmt":"2018-06-19T13:49:53","guid":{"rendered":"http:\/\/site.extension.uga.edu\/benhillcoag\/?p=117"},"modified":"2018-06-19T09:49:53","modified_gmt":"2018-06-19T13:49:53","slug":"cotton-fertility","status":"publish","type":"post","link":"https:\/\/site.extension.uga.edu\/benhillcoag\/2018\/06\/cotton-fertility\/","title":{"rendered":"Cotton Fertility"},"content":{"rendered":"

Fertility<\/strong> (Glenn Harris)<\/p>\n

Replacing Nutrients Leached by May Rains<\/strong>
\nIt seems like every time we get a lot of rain I hear people say \u201cwell, I guess I lost all my
\nfertilizer\u201d. While nutrient leaching (nutrients dissolved in water moving downward out of
\nthe root zone of plants) is a legitimate concern, especially on our sandy Coastal Plain soils
\nof South Georgia, this statement is not exactly true. First, not all fertilizer nutrients are
\nmobile in soil. Phosphorous for example is usually considered immobile and most
\npositively charged elements or cations, like calcium and magnesium adsorb to the cation
\nexchange capacity of the soil and do not leach readily. Most micronutrients are held by
\norganic matter and\/or pH and do not move. Therefore, nitrogen, sulfur and boron are the
\nmost \u201cmobile\u201d in soil. Even then, they have to be in the right form, namely the negatively
\ncharged nitrate, sulfate or borate forms. By the way, this is why most soil testing labs like
\nUGA do not routinely test for nitrogen, sulfur and boron in soils. They are considered
\n\u201ctransient\u201d, i.e. they can be there one day and (after a big rain) not be there the next. Oh,
\nand what about potassium? Potassium is more mobile than phosphorous but contrary to
\nsome current thinking, it is NOT as mobile as nitrogen, sulfur and boron.<\/p>\n

So the next question is \u201chow much fertilizer do I need to put back\u201d? There is no easy
\nanswer to this question because it depends on which nutrient, which form of nutrient, how
\nmuch you put out, what soil type (i.e. how sandy) how much rain you got etc. But let\u2019s for
\nexample take the case of cotton fertilized in South Georgia before the heavy rains in May
\nthis year. Hopefully most growers followed soil test recommendations and put about 30
\npounds of nitrogen, 10 pounds of sulfur and the recommended P and K at planting. The P
\ndidn\u2019t move much at all, the K may have moved some but it is likely still where roots will
\nget it eventually. So that leaves N and S. Even if you lost half of your N and S you would
\nonly have to replace 15 pounds of N and 5 pounds of S. This can easily be done at N
\nsidedressing time between first square and first bloom. Boron can be foliar fed any time
\nbefore first bloom. Our recommendation is for 0.5 lb B\/a and can be tank mixed with
\nherbicide or growth regulator sprays. Bottom line is look to maybe sidedress on the earlier
\nside, replace about 10-20 lbs N\/a and include S with your sidedress N.<\/p>\n

Fertilizing Late or June Planted Cotton \u2013 Reduce N Rates<\/strong>
\nDue to the heavy late-May rains, a higher percentage of Georgia cotton is going to be
\nplanted late, in June, this year. The tendency is to think \u201chey its late, I need to rush this
\ncotton so I am going to put higher rates of N out at planting\u201d. This is actually the opposite
\nof what you should do! While it is always important to get off to a good start, if you get off
\nto TOO good of a start with extra N at planting, you could interfere with the
\n\u201cvegetative\/reproductive\u201d balance and reduce yields. In other words, you want the plant to
\nshift from vegetative (\u201cgrowing stalk\u201d) to reproductive (flowering\/fruiting) as quickly as
\npossible (as early as 5 nodes) since there is not as much time to flower and put on fruit
\nbefore frost.<\/p>\n

So how much do I reduce my N rate by and when? On page 76 of the UGA Cotton Production
\nguide, it is recommended to reduce your total N rate by 25-30% . It is not stated, but I would
\nrecommend taking some off of both preplant and sidedress applications if possible. So
\ninstead of roughly 30 lb N\/a at planting and 70 at sidedress for May planted cotton for a total
\nof 100 lb N\/a\u2026.consider 20 lb N\/a at planting and 55 lb N\/a sidedress for June planted cotton.
\nIf you put out 30 lb N\/a in early May before the rains and don\u2019t plant until June, you still
\nshould have about 10-20 lb N\/a available so could just plan on an early N sidedress.<\/p>\n","protected":false},"excerpt":{"rendered":"

Fertility (Glenn Harris) Replacing Nutrients Leached by May Rains It seems like every time we get a lot of rain I hear people say \u201cwell, I guess I lost all my fertilizer\u201d. While nutrient leaching (nutrients dissolved in water moving downward out of the root zone of plants) is a legitimate concern, especially on our […]<\/p>\n","protected":false},"author":234,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20,26],"tags":[],"class_list":["post-117","post","type-post","status-publish","format-standard","hentry","category-cotton","category-fertility"],"_links":{"self":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/117","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/users\/234"}],"replies":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/comments?post=117"}],"version-history":[{"count":1,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/117\/revisions"}],"predecessor-version":[{"id":118,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/117\/revisions\/118"}],"wp:attachment":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/media?parent=117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/categories?post=117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/tags?post=117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}