Benefits of sulfate New fertilizer Polysulphate Readily available sulfur plus potassium, magnesium and calcium for better crops Benefits of sulfate 3 19.2% S 14% K2O 3.6% Mg 12.2% Ca Mined in the UK, ICL is the first – and only – producer in The need for sulfur application the world to mine polyhalite, marketed as Polysulphate™. Sulfate is now established as a major fertilizer requirement for arable crops and grassland. Yet most farmland never receives a routine application. Sulfur fertility has historically not been a major concern for growers on most soils, as soil organic matter, atmospheric deposition, manure application and incidental sulfur contained in fertilizers have typically supplied sufficient sulfur for crop production. However, reductions in the amount of sulfur contributed by these factors combined with increased sulfur removal with greater crop yields have made sulfur deficiencies more common. According to The Sulphur Institute, it is estimated that about 20% of arable lands in North America suffers sulfur deficiency at present. Benefits of sulfate 5 Historically, in industrialized countries arable crops and grassland had never required sulfate applications. Coal-burning had always ensured plenty of sulphur was supplied via atmospheric deposition. Regulation has ensured this deposition is now a fraction of what it used to be. As a result, large areas of farmed land are sulphur deficient, particularly those with lighter soils or lower rainfall. NATIONAL EMISSIONS OF SULFUR DIOXIDE (SO2) IN USA 35,000 30,000 25,000 2 20,000 15,000 ‘000 tons SO ‘000 10,000 5,000 0 Livestock requirements 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 Like arable crops, grassland needs sulfate fertilizer – it’s a vital input to ensure a healthy ruminant diet. Even where manure Nitrogen (N) and sulfur (S) are both essential constituents of plant and animal protein, so now that sulfur is no longer freely available from the and slurry are returned to the land, extra applications are atmosphere, wherever nitrogen fertilizers are applied there is likely to be a often needed. need for a balancing sulfate fertilizer to ensure yield and quality. In the UK, only around 10% of grassland currently receives sulfate fertilizer. Legumes such as peas, beans, alfalfa/lucerne and clover, which rely on But a shortage will reduce grass yield and efficient nitrogen utilization, atmospheric nitrogen but are now deprived of similar sulfur, will now increase nitrate loss and reduce sugar content and digestibility1. Grass almost certainly respond to a sulfate fertilizer. grown for silage is particularly liable to sulfur deficiency. This booklet introduces a sulfate fertilizer, PolysulphateTM. This new product is mined in the UK, and with 19.2% S, provides a reliable and readily available new source of sulfate. 1 G. Fisher, J. Buss et al., 2011, Grassland Report, British Grassland Society, UK 4 Benefits of sulfate 7 As with arable crops, grass also requires a balance between nitrogen and DAILY LIVEWEIGHT GAIN OF LAMBS INCREASES sulfur for its protein content, and a lack of sulfur will lead to reduced yields AS FEED N:S RATIO IMPROVES and to increased levels of non-protein nitrogen in the feed (see chart). Source: Rendig and Weir, J. Anim. Sci. 16(2) BENEFICIAL EFFECT OF S-FERTILIZATION ON NON-PROTEIN 0.17 N CONTENT OF GRASS Source: Baker A.S. et al. Sulfur Inst J. 9(1), 14-16 0.15 25 R² = 0.85324 0.13 20 0.11 15 Daily liveweight gain – pounds 10 0.09 17:1 16:1 15:1 14:1 13:1 12:1 11:1 N : S ratio in grass 5 N:S ratio of feed 0 1.4 1.2 1.0 0.8 0.6 0.4 0.2 IMPROVED N:S RATIO INCREASES D-VALUE OF FEED FOR DAIRY COWS Source: Bouchard and Conrad, J. Dairy Sci. 56 Non-protein nitrogen content – NPN % Research on silage carried out by IGER at North Wyke (now part of 72 Rothamsted Research, UK) found dry matter yields increased by 35% over three cuts on sandy loam soil where sulfate was applied2. Nitrate losses were cut by up to 82%, while the true protein and soluble sugars content of 70 the silage were boosted by 25% and 30% respectively. Perhaps even more importantly, the microbes in the rumen also need the 68 correct balance of nitrogen and sulfur. If the grass is short of sulfur they will not be able to use all of its potential feed value. This means that the actual Apparent D-value of feed digestibility (D-value) of the feed is reduced and part of the feed value is 66 wasted (see charts). 36:1 20:1 14:1 12:1 N:S ratio of feed 2 L. Brown, D. Scholefieldet al., 2000, The effect of sulfur application on the efficiency of nitrogen use in two contrasting grassland soils, Journal of Agricultural Science, Vol 135 6 Sources of sulfate 9 Sulfur from manure and slurry Sulfur in soil and in the plant Farmyard manure and slurry contain significant quantities of sulfur. When fresh much of this becomes Sulfate behaves like nitrate in the soil. In the plant nitrogen available to the plant. But in storage the activity of and sulfur are both essential building blocks for proteins. anaerobic bacteria can reduce the sulfate to sulfide and Sulfur deficiency will severely reduce the efficient use of combine it into organic complexes. These cannot be nitrogen and limit protein synthesis. utilized by plants, but gradually oxidize back to sulfate Sulfur can only be taken up by plants from the soil solution as sulfate. over time. As with readily-available nitrate, it can be liable to loss through leaching. Spring application of sulfate fertilizer is therefore recommended so that There is little reliable data on the actual availability the plant can take it up during the period of active growth, as with nitrate. of sulfur in stored manures, so it is therefore best to Sulfur is required together with nitrogen for the formation of proteins and consider it as contributing to overall soil reserves, rather uptake timings are similar. than supplying sufficient nutrient for the current crop. Some atmospheric Sulfate in deposition of S fertilizer Uptake Dung/urine Crop residue Crop Mineral S Sulfate in S in organic in the soil soil solution material Desorption Immobilization Adsorption Mineralization Leaching 8 Sources of sulfate 11 Elemental sulfur While sulfate fertilizer is immediately available to the crop, applications of elemental sulfur must be converted to sulfate by bacterial activity in the soil before it becomes available. The time taken for this oxidation is unpredictable and may take many months, so the sulfate required by the crop may not be available when needed. Protein synthesis Sulfur is required for many growth functions in plants – like nitrogen it is principally an essential constituent of protein. There is therefore a close relationship between the quantities of nitrogen and sulfur in crops, with most taking up about 1 pound of sulfur for every 12 pounds of nitrogen. SULFUR UPTAKES BY WHEAT, POTATO AND CABBAGE 20 90 18 80 16 70 Once taken up, unlike nitrogen, sulfur does not move against the 14 60 transpiration stream and cannot be taken from older leaves, for example, 12 50 to support new growth. So a sufficient and continuous supply is needed in 10 40 the soil to satisfy all the needs of the growing crop. 8 30 6 Wheat Signs of deficiency include the yellowing of young leaves or new growth. By 4 Potato 20 contrast, yellowing from nitrogen deficiency affects the older leaves first. Wheat and potato – lb S/ac Wheat and potato – lb Cabbage Sulfur in Cabbage – lbS/ac 2 10 Sulfur-deficient oilseed rape can also have purpling and upward cupping of 0 0 1 2 3 4 5 6 7 9 8 10 11 12 13 14 15 16 17 18 19 young leaves, delayed and prolonged flowering, pale-colored flowers, and Week of sampling in spring fewer, smaller pods. Brassica crops, such as oilseed rape, cabbage and kale, require much more sulfate. They need extra sulfur for the production of glucosinolates, which are used within the plants as a defense mechanism. 10 Polysulphate 13 BOULBY MINE STRATIGRAPHY JURASSIC SURFACE 0 Sea level 100 200 Iias shales 300 Penarth Group 400 PERMIAN STRATA 190 million years 500 Mercia Mudstones 1000 Halite with mudstone interbeds TRIASSIC 600 Halite 700 Anhydrite POTASH Marl (clay) 800 MINE 1100 Halite Introducing Polysulphate Sherwood Sandstone LEVEL 900 Anhydrite Polysulphate is a new fertilizer, high in sulfate, available in its natural state, and mined in the UK. A unique benefit is its Dolomite PERMIAN 1000 Anhydrite additional natural content of other macronutrients. 225 million years 1200 1100 Halite POLYSULPHATE Polyhalite Polysulphate comes from the polyhalite layer of rock, over 3,300 ft below 1200 MINE LEVEL the North Sea off the North Yorkshire coast in the UK. Deposited 260 Anhydrite million years ago, it lies 490-560 ft below the potash seam at the Cleveland Permian Evaporites 1300 Potash Boulby Mine. 1300 1400 Dol/Lst The main Polysulphate seam was reached in September 2010, bringing the (lower evaps) first samples up to the surface. It is estimated there are one billion tons CARBONIFEROUS 1500 available from this one source. Polysulphate is available as both a granular and powder product. The 1400 2-4mm granular product has excellent spreading characteristics and is an ideal fertilizer to apply alongside straight nitrogen. Depth below surface in meters 1500 12 Trials information 15 Polysulphate contains How Polysulphate performs • 19.2% S as sulfate • 14% K2O as from sulfate of potash • 3.6% Mg as from magnesium sulfate Proprietary and independent trials work have shown • 12.2% Ca as from calcium sulfate Polysulphate to be as good as the best sources available of the principal nutrients it contains.