{"id":930,"date":"2010-02-11T11:44:14","date_gmt":"2010-02-11T16:44:14","guid":{"rendered":"https:\/\/extension.umaine.edu\/cranberries\/?page_id=930"},"modified":"2019-09-10T00:30:45","modified_gmt":"2019-09-10T00:30:45","slug":"cranberry-nutrition","status":"publish","type":"page","link":"https:\/\/extension.umaine.edu\/cranberries\/growing-cranberries\/cranberry-nutrition\/","title":{"rendered":"Common Cranberry Plant Nutrition Questions"},"content":{"rendered":"<p>Courtesy of Teryl R. Roper.\u00a0 \u00a9 2008.\u00a0<em>(during his time at\u00a0the Dept. of Horticulture, Univ. of Wisconsin-Madison)<\/em><\/p>\n<hr \/>\n<h3><strong>Nitrogen [N]:<br \/>\n<\/strong><\/h3>\n<p style=\"text-align: left\"><span style=\"color: #008000\"><strong><em><span style=\"color: #000000\">See also<\/span><\/em><\/strong><\/span>: <span style=\"color: #008000\"><strong><a href=\"https:\/\/catalog.extension.oregonstate.edu\/em8741\" target=\"_blank\" rel=\"noopener noreferrer\">Nitrogen for Bearing Cranberries in North America<\/a><span style=\"color: #000000\"> (Oregon State University)<\/span><\/strong><br \/>\n<\/span><\/p>\n<ul style=\"text-align: left\">\n<li><em><strong>What is Nitrogen used for?<\/strong><\/em> Nitrogen in the ammonium form is used in the formation of amino acids.\u00a0 Amino acids are assembled in appropriate order to form proteins.\u00a0 Enzymes that mediate plant metabolism and regulate uptake and movement through membranes are proteins.\u00a0 Proteins as enzymes are essential for energy capture and sugar formation via photosynthesis.<\/li>\n<li><em><strong>Do N fertility guidelines vary by cultivar?<\/strong><\/em> The optimum tissue level is the same.\u00a0 The optimum rate for Stevens is 20 lbs N\/a [18 kg\/ha].\u00a0 The optimal rate for Stevens in Wisconsin research was different for different soils.\u00a0 A sand soil did best one year at 40 pounds [36 kg] and a peat-based bed did best at 20 pounds [18 kg].\u00a0 In all cases 20 pounds [18 kg] was better than 0 pounds N\/a.\u00a0 Stevens appears to be a bit more forgiving of above optimal N than Searles.\u00a0 Wisconsin has recently increased the range for tissue test N for Stevens so the range is 0.9 to 1.3%N.\u00a0 Other cultivars remain 0.9 to 1.1 %N<\/li>\n<li><em><strong>What is the optimum timing for N application?<\/strong><\/em> Research in Wisconsin has shown that the best time to apply N on Stevens is:\u00a0budbreak, peak bloom, fruit set, and preharvest.\u00a0 Data for Searles were inconclusive.\u00a0 The optimal rate for bearing beds was 20 lbs\/A [18 kg\/ha].\u00a0 Interestingly, there were no treatment effects the first year as the buds for that crop were already in place.\u00a0 The treatment effects appeared in year 2 as a result of N fertilization in year 1.\u00a0 This is common in fertility experiments.<\/li>\n<li><em><strong>How much N comes from thunderstorms?<\/strong><\/em> In rural Wisconsin precipitation amounts to about 10-15 lbs N\/A. However, this N is NO3-, not NH4+ and so is less useful for cranberries.\u00a0 Further, this natural precipitation is also present in all fertility studies, so this should not be counted as part of the 20 lbs N\/A.<\/li>\n<li><em><strong>After application how long does it take for the N to be in the young fruit?<\/strong><\/em> Actually you don\u2019t want it in the fruit, you want it in the leaves so it can be used to make sugars that will cause the fruit to grow.\u00a0 In field studies using 15N we can find 15N in the uprights by 24 hours after application.\u00a0 It takes<br \/>\nabout 1 week before this levels off, depending on the air and soil temperature.<\/li>\n<li><em><strong>Can I estimate N released from organic soils?<\/strong><\/em> Mineralization, the process through which organic N is released as ammonium, is microbe-mediated and therefore the process is temperature dependent.\u00a0 Further, soils must not be \u201cwet\u201d, just moist. During hot weather (&gt;85\u00b0F; &gt;30\u00b0C) postpone or eliminate N applications to peat beds as much N will be mineralized.\u00a0 There is no &#8216;formula&#8217; to determine mineralization.<\/li>\n<li><em><strong>Can I estimate N released from peat below a 6-8\u201d sand lift?<\/strong><\/em> Cranberries are relatively shallow rooted.\u00a0 In my opinion little to no N would be available to cranberries under a 6-8\u201d sand lift.<\/li>\n<li><em><strong>Foliar applications?<\/strong><\/em> Foliar N applications have their place.\u00a0 They are most effective when uprights are growing poorly or look pale.\u00a0 Foliar applications are expensive, but will \u201cgreen\u201d vines up in a short time.\u00a0 However, cranberry uprights cannot absorb sufficient N through the leaves to meet their full N requirement.\u00a0Granular fertilizer applications will still be required to meet N requirements of vines.<\/li>\n<li><em><strong>Fall applications to enhance bud set?<\/strong><\/em> A fall application is included in the best fertilizer timing protocol described above.<\/li>\n<li><em><strong>What about drainage and leaching?<\/strong><\/em> Ammonium N does not leach appreciably (but may leach or run off in surface water<br \/>\nif a significant rain event quickly followed application).\u00a0 When pH is 5.5 or below there is no significant nitrification.\u00a0 Drainage is important because NH4 uptake is energy dependent and oxygen is required for this process.\u00a0 When soils are saturated air is excluded and the root zone becomes anaerobic leading to no N uptake.<\/li>\n<li><em><strong>What about slow-release products for new beds?<\/strong><\/em> We have done that research using Ammonium sulfate, SCU, MEU, Milorganite (biosolids) and composted chicken manure.\u00a0 All treatments were adjusted to provide the same amount of N, P, &amp; K.\u00a0 Our results show that none of the slow release products performed as well as ammonium sulfate; not even close.\u00a0 We did not test osmocote as it is very expensive.<\/li>\n<li><em><strong>At what soil temp does N uptake begin?<\/strong><\/em> About 50\u00b0F [10\u00b0C].<\/li>\n<li><em><strong>Are there guidelines for optimum growth of current-season uprights?<\/strong><\/em> Some of this work has been done in Massachusetts.\u00a0 We have not done that work in Wisconsin.\u00a0 My opinion is that it would be highly variable based on location, crop load, etc.\u00a0 However, the Massachusetts recommendations are:<\/li>\n<\/ul>\n<table style=\"text-align: left\" border=\"1\" width=\"70%\">\n<thead>\n<tr>\n<th style=\"text-align: center\" scope=\"col\"><strong>Cultivar<\/strong><\/th>\n<th style=\"text-align: center\" scope=\"col\"><strong>Optimum growth before early bloom<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: center\">Early Black<\/td>\n<td style=\"text-align: center\">50-60 mm\u00a0\u00a0 (2-2.5 in)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">Howes<\/td>\n<td style=\"text-align: center\">45-55 mm\u00a0\u00a0 (1.75-2 in)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">Ben Lear<\/td>\n<td style=\"text-align: center\">55-65 mm\u00a0\u00a0 (2-2.5 in)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">Stevens<\/td>\n<td style=\"text-align: center\">60-70 mm\u00a0\u00a0 (2.5-2.75 in)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3><strong> Phosphorus [P]:<\/strong><\/h3>\n<p><em><strong>See also <\/strong><\/em><strong><a href=\"https:\/\/scholarworks.umass.edu\/cgi\/viewcontent.cgi?referer=https:\/\/www.google.com\/&amp;httpsredir=1&amp;article=1010&amp;context=cranberry_factsheets\" target=\"_blank\" rel=\"noopener noreferrer\">Phosphorus for Bearing Cranberries in North America<\/a> (Univ. of Massachusetts)<\/strong><\/p>\n<ul>\n<li><em><strong>What is the role of P in cranberry plants?<\/strong><\/em> P is very important to plant metabolism.\u00a0 P is a primary constituent of the genetic material of plants and animals (DNA).\u00a0 It is also critical in energy transfer (ATP\u00e0ADP).\u00a0 It is critical to transferring three carbon sugars from the chloroplast into the cytoplasm where it can be used for metabolism or\u00a0growth or can be exported to other organs.<\/li>\n<li><em><strong>Do we have guidelines about P timing?<\/strong><\/em> There are some guidelines, but the research behind them is incomplete.\u00a0\u00a0The recommendation is no P until late spring, and then apply 20 lbs actual P (45 lbs P2O5) in 2-3 doses (I\u2019d prefer\u00a03).\u00a0 We also know that H2PO4- reacts readily with iron, aluminum and manganese ions in soils to form insoluble\u00a0compounds and that these reactions occur rather quickly.\u00a0 Frequent light application of P is better than one or two large doses.<\/li>\n<li><em><strong>About how much P should be applied during a year?<\/strong><\/em> Research shows no response to added P fertilizer beyond 20 lbs P\/a\/yr [18 kg P\/ha\/yr].\u00a0 This is about 45 lbs P2O5\/a\/yr [40 kg\/ha\/yr].\u00a0 Sandy soils may need more P.\u00a0 I believe we are over-applying P by using fertilizers like 6-24-24.\u00a0 We recommend that cranberry fertilizers not exceed an N:P ratio of 1:2.<\/li>\n<li><em><strong>Are there cultivar differences in P requirements or timing?<\/strong><\/em> There is no research in this area [as of 2007\/2008].<\/li>\n<li><em><strong>Do sandy soils require more P than organic soils?<\/strong> <\/em>Due to the fact that\u00a0phosphorus is an anion (negatively charged), soil type is less critical.\u00a0 Research results show similar results of P fertilization on sand or peat-based soils. The amount and availability of iron, aluminum and manganese are more important in my opinion.<\/li>\n<li><em><strong>Should I worry about leaching or runoff?<\/strong><\/em> Phosphorus does not leach and would not be any more likely to go\u00a0through a sandy soil than it would a mineral or organic soil.\u00a0 Runoff is a concern if a significant rain event were to quickly follow a fertilizer application.\u00a0 There is also some evidence that P can leach from uprights when a bed is flooded (as for harvest).<\/li>\n<li><em><strong>Should P fertilizer be added after spring frost season?<\/strong><\/em> Yes, that is the right timing, but irrigation for frost protection is only peripherally involved.\u00a0 P is released as soils begin to dry out but are still cool after the winter flood melts.\u00a0 Once the soils warm, P is not released as quickly.\u00a0 It is coincidental that frost protection ending and soils warming occur at the same time.<\/li>\n<li><em><strong>Do large levels of natural iron disrupt P uptake?<\/strong><\/em> They don\u2019t directly disrupt P uptake, but rather the iron forms\u00a0 insoluble compounds with the P and makes it unavailable for uptake by cranberry roots.<\/li>\n<li><em><strong>What available fertilizers contain P?<\/strong><\/em> See the table below.\u00a0 Phosphoric acid can be used as a foliar P source, but\u00a0should not be applied during flowering or on fresh-fruit plantings.\u00a0 Rock phosphate is almost insoluble and is not a\u00a0good P source.<\/li>\n<\/ul>\n<hr \/>\n<h3><strong>Potassium [K]:<\/strong><\/h3>\n<ul>\n<li><em><strong>What is the role of K in plant growth?<\/strong><\/em> <span style=\"color: #000000\">Potassium does not have a direct role in plant metabolism.\u00a0 It is not involved in proteins or membranes.\u00a0 It is primarily used to balance charges and as an osmoticant (used to move water from place to place).\u00a0 K is also\u00a0important to stomata opening and closing and in the movement of sugars from one place to another.<\/span><\/li>\n<li><em><strong>What is the optimum timing for K application?<\/strong><\/em> <span style=\"color: #000000\">Since K+ will leach, it is important to have frequent light applications of K as opposed to 2-3 large applications at &#8216;critical&#8217; times.\u00a0 In Wisconsin research, different timings for K fertilizer did not affect yield or rot.<\/span><\/li>\n<li><em><strong>Do I need more K on sand than peat beds?<\/strong><\/em> <span style=\"color: #000000\">Research does not show differences in K response on sand or peat-based soils.<\/span><\/li>\n<li><em><strong><a id=\"how-much-k\"><\/a>How much K is required annually?<\/strong><\/em> <span style=\"color: #000000\">Research showed yield differences related to K rate in only 1 of 4 years.\u00a0 There was no relationship between K rate and tissue K.\u00a0 Interestingly, yield was reduced at high K rates (240 lbs K2O\/a)[215 kg\/ha].\u00a0 60-100 lbs K2O\/a\/yr [55-90 Kg\/ha] appears sufficient.\u00a0 High K was correlated with decreased Ca, Mg, &amp; Fe.\u00a0Apparently, high K applications exchanged other cations off the exchange sites in the soil. I would determine that through tissue testing in the late summer.<\/span><\/li>\n<li><em><strong>Are there cultivar differences in K requirement?<\/strong><\/em> <span style=\"color: #000000\">Not that I am aware of.<\/span><\/li>\n<li><em><strong>Can I minimize K leaching on sandy soils?<\/strong><\/em> <span style=\"color: #000000\">The only approach I know of is to be cautious with other cation nutrients (Ca, Mg, Fe) and then over time an organic duff layer will form.\u00a0 This layer will have more exchange sites and will hold onto K (&amp; other cations) better than sand alone.<\/span><\/li>\n<li><em><strong>What forms of K are available?<\/strong><\/em> <span style=\"color: #000000\">See the question below that asks: What is the difference between 0-0-50 and 0-0-60?<\/span><\/li>\n<li><em><strong>Is one better than another on sandy soils or new plantings?<\/strong><\/em> <span style=\"color: #000000\">In all cases potassium sulfate is preferred over potassium chloride.<\/span><\/li>\n<li><em><strong>Can I optimize K uptake in soils with high Ca &amp; Mg?<\/strong><\/em> <span style=\"color: #000000\">Frequent light applications of K would allow it to be more available than 1-2 heavy applications.\u00a0 K will compete with Ca &amp; Mg for exchange sites.\u00a0 Overapplication of Ca &amp; Mg will reduce K availability.\u00a0 However, see also the answer up above for the question: <em><strong><a href=\"#how-much-k\">How much K is required annually<\/a>?<\/strong><\/em><\/span><\/li>\n<li><em><strong>Foliar applications of K during bloom &amp; early fruit set?<\/strong><\/em> <span style=\"color: #000000\">Research shows no effect of timing on yield.\u00a0 Research also shows no effect of different products when applied at the same rate of K.<\/span><\/li>\n<li><em><strong>What is the difference between 0-0-50 and 0-0-60?<\/strong><\/em> <span style=\"color: #000000\">0-0-50 is potassium sulfate (KSO4) and 0-0-60 is potassium chloride (muriate of potash, KCl).\u00a0 Cranberries are sensitive to chloride, so the sulfate form is generally preferred.\u00a0 However, research in Wisconsin has shown that at normal application rates (&lt;400 lbs\/a) both the chloride and sulfate forms provided equal results and no plant injury was observed.<\/span><\/li>\n<li><em><strong>Will high application rates of potassium result in larger or better colored fruit?<\/strong><\/em> <span style=\"color: #000000\"> Research shows that yield, fruit number, fruit size, and fruit color do not vary by rate of K application.<\/span><\/li>\n<\/ul>\n<table border=\"1\" width=\"90%\">\n<thead>\n<tr>\n<th scope=\"col\" width=\"50%\">Fertilizer<\/th>\n<th scope=\"col\">Chemical formula<\/th>\n<th scope=\"col\" width=\"20%\">Analysis<\/th>\n<th scope=\"col\" width=\"15%\">Solubility<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Triple superphosphate<\/td>\n<td>Ca(H<sub>2<\/sub>PO<sub>4<\/sub>)<sub>2<\/sub><\/td>\n<td>0-46-0<\/td>\n<td>87%<\/td>\n<\/tr>\n<tr>\n<td>Diammonium phosphate<\/td>\n<td>(NH<sub>4<\/sub>)<sub>2 <\/sub>HPO<sub>4<\/sub><\/td>\n<td>18-46-0<\/td>\n<td>100%<\/td>\n<\/tr>\n<tr>\n<td>Monoammonium phospate<\/td>\n<td>NH<sub>4<\/sub>H<sub>2<\/sub>PO<sub>4<\/sub><\/td>\n<td>11-48-0<\/td>\n<td>100%<\/td>\n<\/tr>\n<tr>\n<td>Ammonium polyphosphate (dry)<\/td>\n<td>NH<sub>4<\/sub>H<sub>2<\/sub>PO<sub>4<\/sub>+(NH<sub>4<\/sub>)<sub>3<\/sub>HP<sub>2<\/sub>O<sub>7<\/sub><\/td>\n<td>10-34-0<\/td>\n<td>100%<\/td>\n<\/tr>\n<tr>\n<td>Ammonium polyphosphate (liquid)<\/td>\n<td>NH<sub>4<\/sub>H<sub>2<\/sub>PO<sub>4<\/sub>+(NH<sub>4<\/sub>)<sub>3<\/sub>HP<sub>2<\/sub>O<sub>7<\/sub><\/td>\n<td>15-62-0<\/td>\n<td>100%<\/td>\n<\/tr>\n<tr>\n<td>Ordinary superphosphate<\/td>\n<td>Ca(H<sub>2<\/sub>PO<sub>4<\/sub>)<sub>3<\/sub>+CaSO<sub>4<\/sub><\/td>\n<td>0-20-0<\/td>\n<td>85%<\/td>\n<\/tr>\n<tr>\n<td>Phosphoric acid<\/td>\n<td>HPO<sub>4<\/sub><\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>Rock phosphate<\/td>\n<td><\/td>\n<td><\/td>\n<td>low<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3><strong>Calcium &amp; Magnesium:<\/strong><\/h3>\n<ul>\n<li><em><strong>What role does calcium play in cranberry production?<\/strong><\/em> Calcium is known to be important in holding cell walls together in plants.\u00a0 It is also important in membrane integrity and permeability.\u00a0 Calcium is immobile in plants once it reaches its \u201cfinal resting spot\u201d.\u00a0 A constant low level supply of calcium is important.\u00a0 Plants get calcium from other fertilizers (triple or ordinary superphosphate), water, and from the mineral fraction of soils.<\/li>\n<li><em><strong>What does Magnesium do for cranberry production?<\/strong><\/em> Magnesium is essential to create and maintain chlorophyll for photosynthesis and it is involved in several enzyme systems.\u00a0 Mg is required, but at low levels compared to N, P, or K.<\/li>\n<li><em><strong>Will I see a yield response to added Ca?<\/strong><\/em> One research project showed increased yield with applications of CaB at fruit set.\u00a0 However, they did not separate applications of Ca &amp; B, so we can\u2019t tell which element caused the response.\u00a0 Boron is known to be critical for flower development and pollen germination and growth.\u00a0 In my opinion, B was the limiting nutrient in these studies.\u00a0 However, when we look at several years of tissue test results submitted to the UW soils lab we found very few samples that were below the critical value\u2014suggesting that calcium is seldom a limiting factor.\u00a0 The same is true for magnesium.<\/li>\n<li><em><strong>How much calcium and magnesium are required in a season?<\/strong><\/em> There is not a good answer to this other than to say not very much.\u00a0 The requirement is likely met through water and other fertilizers.<\/li>\n<li><em><strong>Will calcium applications during bloom increase fruit set?<\/strong><\/em> I know of no research data suggesting that\u00a0 applications of calcium alone during bloom will increase fruit set or yield (fruit set ? yield).\u00a0 See also the section\u00a0for the question above that asks: <em>Will I see a yield response to added Ca?<\/em><\/li>\n<li><em><strong>Is gypsum an excellent form of calcium and will it lower soil pH and enhance soil drainage?<\/strong><\/em> 1) gypsum (CaSO4) is an excellent source of calcium for cranberries, 2) gypsum will NOT lower soil pH, 3) gypsum will enhance soil drainage on sodic soils by exchanging Ca++ for Na+ ions on the soil.\u00a0 I don\u2019t know of any sodic cranberry soils in Wisconsin.<\/li>\n<li><em><strong>What soils will benefit most from calcium applications?<\/strong><\/em> Sodic soils.\u00a0 <strong><em>What are the effects on soil?<\/em><\/strong> Gypsum will enhance soil drainage on sodic soils by exchanging Ca++ for Na+ ions on the soil.\u00a0 This reduces soil clumping and opens channels through the soil.\u00a0 I don\u2019t know of any sodic cranberry soils in Wisconsin.<\/li>\n<li><strong><em>What calcium forms are available?<\/em><\/strong> See the table below. <em><strong>Which are cheapest?<\/strong><\/em> Lime is cheapest, but has the generally unwanted effect of raising pH.<\/li>\n<li><em><strong>Is there an optimum timing for calcium and magnesium applications? <\/strong><\/em>I know of no research data indicating an optimum timing for Ca or Mg application for cranberry.<\/li>\n<li><em><strong>What options are available to supplement magnesium?<\/strong><\/em> Dolomitic limestone is the cheapest, but has the unwanted effect of increasing soil pH.\u00a0 Epsom salts (MsSO4 \u2022 7H2O) or potassium magnesium sulfate (SulPoMag) are acceptable.<\/li>\n<li><em><strong>Does soil pH affect Ca or Mg availability?<\/strong><\/em> Mg is less available as soil pH declines.\u00a0 If tissue tests indicate low or declining Mg in tissue you\u2019ll want to check the soil pH.\u00a0 If it is much below 5.0 you can make the Mg more available by applying a little bit of lime to increase the pH to 5.0 to 5.5.<\/li>\n<\/ul>\n<hr \/>\n<h3><strong>Micronutrients:<\/strong><\/h3>\n<ul>\n<li><strong><em>Should I consider applying micronutrients such as zinc, manganese, copper and boron?<\/em><\/strong> As the class\u00a0name suggests, these elements are required in very small amounts.\u00a0 You should add them if a tissue test suggests they are low or declining.\u00a0 I have not seen tissue test reports showing deficiencies in any of these elements.\u00a0 The one exception may be boron during flowering to fruit set.<\/li>\n<li><em><strong>Have there been any studies showing the benefits of applying the above micronutrients?<\/strong><\/em> There is very little field research with micronutrients.\u00a0 It is difficult to do and unless replicated many times the effects are usually too small to find with the natural variability of cranberries.\u00a0 There have been some laboratory studies to determine the critical tissue value for these elements.\u00a0 These values are reflected in our current tissue test recommendations.\u00a0We have also looked at toxicity of these elements and while they may become toxic, the concentrations that affect vegetative growth are ~100 fold higher than what we have found in routine tissue tests.<\/li>\n<li><em><strong>About how much of these elements are needed for optimum crop production?<\/strong><\/em> I\u2019m not sure that is the correct question.\u00a0 Much of these elements are retained in the perennial portions of the vines and little is harvested with the crop.\u00a0 Further, our soils typically contain adequate amounts of these elements.\u00a0 The question isn\u2019t how many pounds per acre [Kg\/ha], but how many ounces per acre [g\/ha].\u00a0 Further, if your tissue tests show sufficient levels of micronutrients adding micros probably is not necessary (with the possible exception of B).<\/li>\n<\/ul>\n<hr \/>\n<h3><strong>pH Management:<\/strong><\/h3>\n<ul>\n<li><em><strong>When is the best time to apply sulfur for pH management?<\/strong><\/em> Small doses of no more than 100 lbs\/a [90 kg\/ha] are best.\u00a0 These can be effective once soils have dried and warmed in the spring.\u00a0 Fall applications of sulfur would be less effective (depending on the length of fall and the temperatures after harvest) because the reactions that release H+ ions are microbe mediated and thus are temperature dependent.\u00a0 Early spring applications would not have an effect until the soils warm.<\/li>\n<li><em><strong>Is there a general rule for calculating the number of pounds of sulfur per acre required to reduce soil pH by 1 point?<\/strong><\/em> There are some general rules, but all of these are mediated by the soil type and carbonate concentration in the soil.\u00a0 The table that follows gives some guidelines.<\/li>\n<\/ul>\n<table border=\"1\" width=\"90%\">\n<thead>\n<tr>\n<th style=\"text-align: center\" scope=\"col\"><strong>Initial pH<\/strong><\/th>\n<th style=\"text-align: center\" scope=\"col\"><strong>Sand or Loamy <\/strong><strong>Sand<\/strong><\/th>\n<th style=\"text-align: center\" scope=\"col\"><strong>Sandy Loam or <\/strong><strong>Loam<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><\/td>\n<td style=\"text-align: center\">lb.\/acre<\/td>\n<td style=\"text-align: center\">lb.\/acre<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">7.0<\/td>\n<td style=\"text-align: center\">800<\/td>\n<td style=\"text-align: center\">2500<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">6.5<\/td>\n<td style=\"text-align: center\">650<\/td>\n<td style=\"text-align: center\">2000<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">6.0<\/td>\n<td style=\"text-align: center\">525<\/td>\n<td style=\"text-align: center\">1500<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">5.5<\/td>\n<td style=\"text-align: center\">350<\/td>\n<td style=\"text-align: center\">1000<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center\">5.0<\/td>\n<td style=\"text-align: center\">170<\/td>\n<td style=\"text-align: center\">500<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<ul>\n<li><em><strong>How many pounds of sulfur per acre should I apply to maintain my current soil pH?<\/strong><\/em> That depends on how alkaline your water supply is.\u00a0 If your water does not contain much carbonate it won\u2019t take much if any sulfur to manage pH.\u00a0 This question would need to be answered on a bed-by-bed and water-source basis.<\/li>\n<\/ul>\n<hr \/>\n<h3><strong>General Questions:<\/strong><\/h3>\n<ul>\n<li><strong><em>Each season I see many small aborted berries at harvest time.\u00a0 What do I need to do to set more fruit &amp; size these berries for harvest? <\/em><\/strong> Is there a problem with pollination, fertility (amount\/timing), heat stress or blossom injury?\u00a0 While all of the above factors can affect fruit set and size, in my opinion it is not any of these that limits fruit set and production.\u00a0 My research clearly showed that most of the carbohydrates that support fruit set and growth come from leaves on the current season growth above the fruit.\u00a0 When we measure photosynthesis on these leaves through a season and then do some math it appears that on average, a cranberry upright produces enough carbon to set and grow to maturity, 2 fruit.\u00a0 Good overall management will give you the best chance of setting and keeping as much fruit as possible.\u00a0 Having enough, but not too much N is important.\u00a0 Good pollination is critical, as is frost protection.\u00a0 But none of these individually will increase production.\u00a0 In my opinion this phenomenon is not a fertility issue.<\/li>\n<li><strong><em>Each season (especially hot, dry years) I see \u201cyellow areas\u201d appear in producing beds (mostly Stevens, sometimes Ben Lears), is this a sign of poor fertility, drainage, or leaching concern, heat stress or disease?\u00a0 What is suggested for treatment?<\/em><\/strong> In my opinion this is not strictly a fertility issue, but is a sign of stress.\u00a0 I have also seen it in hot periods.\u00a0 We typically don\u2019t see the symptoms in the Spring or in cool years.\u00a0 Being careful with irrigation and using the sprinklers to cool the vines during the heat of the day can reduce the stress.\u00a0 Good drainage is also essential.\u00a0 However, time and cool weather are also effective at reducing symptoms.<\/li>\n<li><em><strong>Have you ever heard of manganese deficiency in cranberry?<\/strong><\/em> I have not.\u00a0 I don\u2019t recall seeing manganese deficient in tissue tests.\u00a0 <em><strong>Is it possible, and under what conditions?<\/strong><\/em> It is possible.\u00a0 Conditions that would favor manganese deficiency are high pH and organic soils.\u00a0 The condition could be exacerbated by heavy doses of calcium as the calcium would fill up the cation exchange sites in the soil and Mn could be lost.\u00a0 <em><strong>How do I know if I have it?<\/strong><\/em> By taking a tissue test.<\/li>\n<li><strong><em>Growers in BC plant into sawdust.\u00a0 Is this a reasonable alternative? Will the sawdust hold water and nutrients better?\u00a0 Will herbicides work better?<\/em><\/strong> BC growers use sawdust because it is cheap and readily available.\u00a0 This is aged softwood sawdust.\u00a0 In my experience it does not hold water or nutrients any better or worse than other organic soils.\u00a0 It might be useful for growers planting into alkaline soils, but in those sites the water is\u00a0typically alkaline so I don\u2019t think this is a long-term solution.\u00a0 The biggest drawback to sawdust is keeping it from floating when beds are flooded.\u00a0 BC growers are in the process of sanding heavily to keep their bogs from floating.\u00a0 They don\u2019t flood to make ice in the winter.\u00a0 I don\u2019t know if herbicides would work better or worse.<\/li>\n<li><em><strong>Why soil and tissue tests in Aug\/Sept. rather than Spring?<\/strong><\/em> There are two reasons to take tissue tests in the late summer as opposed to Spring.\u00a0 The first is that tissue concentrations of elements (particularly N) change rapidly in the spring.\u00a0 That means that the date or stage of development at which the sample is taken has a large effect on the tissue concentrations found in the uprights.\u00a0 In the summer these elements don\u2019t change much so the exact date or stage of development is much less critical.\u00a0 The second reason is that you should think of fertility as a July-to-July process rather than a May to August process.\u00a0 A fall tissue test tells you if your fertility program was effective for the year for bud formation and points out areas where adjustments may have to be made for the following year.\u00a0 If you make this \u201cparadigm shift\u201d then the fall collection makes more sense than a spring sample.<\/li>\n<li><em><strong>Should I irrigate after a fertilizer application?<\/strong><\/em> I think it is prudent to irrigate after applying fertilizer, especially fertilizer with K (the possible exception being a foliar application of micronutrients that may be best absorbed through the leaves).\u00a0 About 1\/10 of an inch [2.5 mm] of water should be sufficient to wash granules off the vines, solubilize the fertilizer and get it into the top soil layer, yet not enough to leach nutrients through the soil.<\/li>\n<li><em><strong>Should I consider using blended rather than manufactured fertilizer? <\/strong><\/em> Blended fertilizers are less expensive than manufactured fertilizers.\u00a0 The primary drawback is that blended fertilizers have different particle sizes\/densities and some elements may settle out in shipping and they may behave differently in pneumatic delivery tubes on booms.\u00a0 I think the cost savings exceed this minor drawback.\u00a0 Be careful that when a dealer blends a fertilizer for you that they use ammonium nitrogen.<\/li>\n<li><em><strong>Should I fertilize in the fall?\u00a0<\/strong><\/em> <a href=\"https:\/\/extension.umaine.edu\/cranberries\/grower-services\/cranberry-management-calendar\/fall-fertilizer\/\"><strong>Fall Fertilizer<\/strong><\/a><\/li>\n<\/ul>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>Courtesy of Teryl R. Roper.\u00a0 \u00a9 2008.\u00a0(during his time at\u00a0the Dept. of Horticulture, Univ. of Wisconsin-Madison) Nitrogen [N]: See also: Nitrogen for Bearing Cranberries in North America (Oregon State University) What is Nitrogen used for? Nitrogen in the ammonium form is used in the formation of amino acids.\u00a0 Amino acids are assembled in appropriate order [&hellip;]<\/p>\n","protected":false},"author":60,"featured_media":0,"parent":236,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"templates\/page-withsidebar.php","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":""},"class_list":["post-930","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Common Cranberry Plant Nutrition Questions - Cooperative Extension: Cranberries - University of Maine Cooperative Extension<\/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:\/\/extension.umaine.edu\/cranberries\/growing-cranberries\/cranberry-nutrition\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Common Cranberry Plant Nutrition Questions - Cooperative Extension: Cranberries - University of Maine Cooperative Extension\" \/>\n<meta property=\"og:description\" content=\"Courtesy of Teryl R. 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