Best management for N & S in canola and wheat Rob Norton - PowerPoint PPT Presentation

Best management for N & S in canola and wheat Rob Norton http://anz.ipni.net

Nutrition – the way forward • You get nothing for nothing …… . – If produce is removed, nutrients go with it – if not replaced, then the soil reserves go down. It is soil not the “Magic Pudding”. • Address the limiting factor …… – What is limiting production – until that is addressed, then no extra response. Its no good pumping up the tyres if the tractor is out of fuel. • There are no silver bullets …… . – If something sounds too good to be true – then it probably is.

Where to start you nutrition program: Make a realistic estimate of demand … .. MSF N site in July 2011 – Yield Prophet estimates

Aim to at least balance output with input • Demand for ~N twice the offtake, S about offtake. • 25 mm rain gives ~ 0.3 t/ha canola or 0.45 t/ha wheat • 25 mm rain means 21 kg N for canola, 18 kg N for wheat.

Why canola needs more S than wheat • Wheat 10% protein 15:1 N:S • Canola 20% protein 7:1 N:S

N & S deficiency in wheat

Sulfur A Johnson IPNI T Jensen, IPNI H Burns, NSW DPI

Why S? MAP/DAP Fertilizer %P %S Superphosphate 8.8 11.0 TSP 20.7 1.0 DAP 20.0 1.6 MAP 21.9 1.5

So what to do? • Select the right source/product, apply it at the right rate, and at the right time and in the right place! • 4 Rights of nutrient management.

The Right Rate - Soil test Crop Deficient Marginal Adequate Pasture <5 5-10 >10 Canola <12 12-18 >18 Wheat <3 3-5 >5 KCl-40 (mg/ Crop Pasture kg) <8 52% 43% 8-12 20% 30% >12 28% 27% 2010 Soil S test values (top 10 cm) for Victoria, South Australia, New South Blair 1993 P&S Wales (~1200 tests)

Problem with leaching & soil tests - - - • Sulfate mobile = SO 4 Soil Colloid Leaching - - • Sulfate supplied – Mineralisation OM – Oxidation S • Improved tests; – Appropriate depth – Take account of some part of the other S sources.

Strategies for S • Spread out the need through the whole rotation – Higher S rates in the cereal phase (more tolerant of seed placed fertilizer) – Canola/Wheat/Barley – use 10/15/15 to meet total demand. – Depends on soil type/S mobility – Use high rates up front (eg gypsum) – Elemental S • +Bentonite

Improving S nutrition To apply 20 kg S/ha • Gypsum (~200 kg/ha) • Surface applied • Variable quality • Cheap (?) • Ammonium sulphate (100 kg/ha) • Fertilizer damage to seedlings (machinery) • See http://anz.ipni.net/anz0042-en Share ¡or ¡similar ¡mixing ¡point Inverted ¡T ¡or ¡similar ¡narrow ¡point/opener ¡ (2.5 ¡cm ¡spread) ¡(7.5 ¡cm ¡spread) Opener ¡type ¡and ¡row ¡spacing ¡ (cm) 15 22.5 30 15 22.5 30 Light ¡(sandy ¡loam) ¡ 50 ¡ 35 ¡ 25 ¡ 150 ¡ 100 ¡ 75 ¡ texture ¡ Medium ¡(loam/clay ¡ 75 50 40 230 150 110 loam) ¡texture

Banding fertilizer away from seedrow • Particularly important for N and S • (includes MAP) • Band fertilizer away from seed – Band 2-3 cm away – Side or Side & Below – Mid-row band • P/K source in seed row.

Right place & right time • Ammonium Sulfate, Potassium sulfate • Where the plant can get it – – Root zone – control release rates to avoid leaching • In synchrony with plant demand – ability to recover from nutrient stress – eg Canola S Sowing 5-6 Leaf Buds Stem applied Visible Elongatio Kg/ha n 10 1.73 1.62 1.56 1.41 LSD 40 2.15 2.26 2.11 2.19 0.43 Hocking et al., 1996

Right product • Deliver sulfate to the rootzone at the right time Product N P K S Superphosphate 0 8.8 0 11 MAP 10.0 21.9 0 1.5 DAP 18.0 20.0 0 1.6 Triple Superphosphate 0 20.7 0 1.0 Ammonium Sulphate 20.2 0 0 24 Sulphur Bentonite 0 0 0 90 Sulphate of Potash 0 0 41 18 • A range of S fortified products – sulfur coated urea, sulfur coated MAP & DAP. • Usually coated with S 0 (elemental) which requires oxidation to release sulfate & it all happens at once! • Nutrient co-location can be important (P/S – Friesen 1989)

Alternative sources of S Particle Size µ % S oxidised • S 0 oxidation rapid with fine 2 weeks 4 weeks <75 80 82 particles 75-125 61 81 – Good for sulphate release 125-175 36 68 – Bad for handling 175-400 15 36 • Two new processes that 400-840 5 14 incorporate S 0 into existing 840-2000 2 5 2000-4000 1 2 products at manufacture 12:18:0:10 N:P:K:S Up to 14% S 50:50 S 0 :SO 4

50 kg/ha Urea (23 N) 80 kg/ha SOA (17N, 19S)

Ammonium Sulfate Gypsum + urea 30 N + 35 S

Canola response to AmS v U+G Source Yield Yield Yield P2009 P2010 H2010 AmS 1.55a 1.93a 2.03a U+G 1.08b 1.93a 1.67ab Nil 0.90b 1.72b 1.29b Soil Test KCl40 Pira 2009 2.5 Pira 2010 2.7 Horsham 2010 1.5

Ammonium sulphate • Traditional fertilizer – seen as a better S source than gypsum.( Root Zone acidification, Coplacement of N/S, Reduced N loss). • As a plant fertilizer – not enough N – looking at Urea/ Ammonium Sulfate fluids or co-granulated UAS fertilizers, compared to UAN/ATS fluids

N losses via volatilization: Turner et al. 2012 (Nutrient Cycling in Agroecosystems,93, 113-126) • 2 expts in Wimmera – 23% N loss from urea – 12% N loss from UAN – 12% N loss from AS – Rain 9 DAF – 13% N loss from urea – 3% N loss from AS – Rain 1 DAF

Summary • Make a realistic yield estimate • Deep soil test • Care with S and N in-furrow with canola – especially light & dry soils, wide rows. • Compared to cereal crops, canola requires a greater supply of S – N:S 7:1 canola; 15:1 wheat • Applying all the required S in the seed-row for canola is difficult because of excess N coming from the ammonium phosphate and ammonium sulphate portion of a possible seed-row blend. • There are alternative ways to supply sufficient S and avoid excess N in the seed-row.

New/Old Products • Evidence from Trials – Appropriate controls – Replicated – Randomised – Repeatable – Reasonable • Mass balances? • Magic or special? • Laws of physics/chemistry • Test it yourself, be sceptical – its your $ and your reputation. • Ask “ How do you know that? ”