Reading the tea leaves - nutrient trends in Australia

Transcription

1 Prediction is very difficult, especially about the future. Neils Bohr Reading the tea leaves - nutrient trends in Australia Rob Norton, ANZ Regional Director, IPNI Better Crops, Better Environment through Science Agronomy Community, April 14, 2011

2 Nutrient Issues in Australia Big picture issues Understanding of nutrient balances Desktop study building on the NLWA 2001 Data in this study was collected 1994 to 1996 most recent information!?!? Some P balances done more recently Gourley Dairy farms, Cordell Continental, Wong WA (unpublished as yet) WA SA Vic Tas NSW Qld N +/~ ~/- - + ~/+ ~/- P ~/+ ~ -/~ + ~/- - K ~ - - S +/~ ~/+ ~/+ + ~/+ -/~

3 Nutrient Imbalances a big part of the challenge in an open system Vitousek et al., 2009, Science

4 Major changes in fertilizer costs or crop prices Climate change induced shifts in cropping patterns, yields, soil processes Genetic changes that alter crop yields and NUE Changes in crop species due to bioenergy Changes in plant parts harvested due to bioenergy Manure composition changes due to distillers grains Application of bioash Government policy

5 1987 P removal to use ratio by 8-digit hydrologic unit 2007

6 Applications of NuGIS Guidance in nutrient management education A basis for science-based guidance in marketing of fertilizers and nutrient management related services A tool for integrating nutrient balances in water quality and nitrous oxide emission modeling Factual spatial and temporal input into environmental policy development involving plant nutrients Being considered for India, Canada, Brazil, others

7 Case study from the ANRA Audit Victorian Dairy All nutrients were in positive balance

8 Nutrient and sediment loss from horticulture Runoff from a small vegetable production enterprise in the Hawkesbury catchment (NSW). Measured water, N and P loss from the study area. Over 2 years losses were: 19 t sediment/ha/y sediment (1 topsoil) 11 kg P/ha/y (on soil) 127 kg N/ha/y (in water) Bareness over summer and large nutrient loads associated with high losses. E. Hollinger et al. / Agricultural Water Management 47 (2001) 227±241

9 Farm gate N & P balance

10 Farm gate K & S balance

11 Nutrient and sediment loss from horticulture Runoff from a small vegetable production enterprise in the Hawkesbury catchment (NSW). Measured water, N and P loss from the study area. Over 2 years losses were: 19 t sediment/ha/y sediment (1 topsoil) 11 kg P/ha/y (on soil) 127 kg N/ha/y (in water) Bareness over summer and large nutrient loads associated with high losses. E. Hollinger et al. / Agricultural Water Management 47 (2001) 227±241

12 Nutrient balance survey Desk-top audit Based on ABARE production figures State & Small area data (NRM Zones) With nutrient densities as proposed by Reuter (used on ANRA survey). Estimated a farm gate nutrient removal in product. Using FIFA fertilizer input figures 2002 to 2009 State figures only P, K and S only estimated to look at N need to estimate N fixation rates THIS IS A WORK IN PROGRESS AND RESULTS ARE PRELIMINARY

13 kt P removed State by State P removals at farm gate NSW Vic Qld WA SA Tas NT Fruit Grain Livestock Sugar Vegetable

14 kt K removed State by State K removals at farm gate No K return for sugar included in this balance a significant proportion of K is likely to be returned to cane fields as various mill byproducts NSW Vic Qld WA SA Tas NT Fruit Grain Livestock Sugar Vegetable

15 P & K Balance by State ( ) Nationally P +278 kt K -149 kt WA +81 kt P -3 kt K NT +1 kt P 0 kt K Qld -3 kt P -36 kt K SA +45 kt P -33 kt K NSW +69 kt P -62 kt K Vic +73 kt P -25 kt K Tas +13 kt P +11kt K

16 P & K Balance by State per fertilized hectare ( ) Nationally P +6.4 kg P/ha* K -3.4 kg K/ha* WA kg P/ha NT kg P/ha -4.6 kg K/ha Qld -1.2 kg P/ha kg K/ha -0.4 kg K/ha SA +2.6 kg P/ha -1.9 kg K/ha NSW +7.6 kg P/ha -6.9 kg K/ha K Vic +9.3 kg P/ha -3.2 kg K/ha No K return for sugar included in this balance a significant proportion of K is likely to be returned to cane fields as various mill byproducts. * per fertilized ha ABS Census Tas kg Pha kg K/ha

17 Dahlen IPL Trial Long Term P long term P management Soil P 2007 Soil P 1996 Estimated P balance/year 2010 Canola P Removal 1.44 t/ha 2.76 t/ha 3.07 t/ha 2.89 t/ha 7 kg P 17 kg P 21 kg P 22 kg P

18 Colwell P values IPL labs (<160 PBI) Location and Soil Type Colwell P (mg/kg) <20 20 to 35 >35 Harden Red & Brown Loams 10% 19% 71% Horsham Grey & Brown Clay Loams 24% 32% 44% Maryborough Red & Brown Clay Loams 10% 28% 62% Cummins Red & Brown Sandy Loams 4% 45% 51% Moree Gray &Brown Clay/Clay Loams 82% 13% 6% Dalby Gray &Brown Clay/Clay Loams 62% 25% 13% Emerald Gray &Brown Clay Loams 52% 14% 34% Gunnedah Gray &Brown Clay Loams 14% 37% 49% Huge district variation in soil P levels emphasises the need for soil testing

19 Phosphorus BMP for wheat Developed along with a N BMP From a GRDC collaborative project Key issues are soil testing to know if the paddock is in P balance or not. Fertilize to replacement + demand from soil PBI Soil test important Better Fertilizer Decisions Crops Robust calibrations Good sampling

20 From soil test values to investments

21 How much P to apply? Maintenance of fertility = keep same DSE and Colwell P How much is needed to meet the present stocking rate demand? 0.5 kg P/DSE - exported in produce 0.3 to 1.0 kg P/DSE lost through leaching, soil erosion 0.1 kg P/DSE in soil fixation (PBI) Pasture type/rainfall /grazing system Increase in fertility = increase DSE and Colwell P How much is needed to raise the test value to meet the extra demand? Soil test response to added P eg 100 PBI 2.7 kg P to raise Colwell 1 unit. eg 300 PBI 3.0 kg P to raise Colwell 1 unit. For example kg P/DSE 100 wethers = 1 t of SSP

22 Changes in soil K test levels ANRA v IPL Lab 2010 % less % 16% 25% 44% 18% ANRA Audit up-scaled soil test values to regional value 9 Mha with test levels below 120 mg/kg = 10% of area Lowest values in WA (25%) & Qld (12%) State < >600 Vic 3% 9% 12% 24% 33% 11% 8% SA 4% 13% 11% 20% 26% 14% 12% QLD 18% 30% 12% 12% 19% 7% 3% NSW 1% 4% 17% 9% 41% 18% 9% TAS 3% 9% 19% 30% 30% 4% 5%

23 No surprises here then Declining K use nationally (& NZ) Not quite as drastic as the left WA still the big K state Largest negative balance in Qld Review K use in Qld Mike Bell project on K & P profile enrichment

24 S Removal in Australian Agriculture 48% removed in Grains, 42% in Livestock

25 Notional farm gate S balance S inputs from current fertilizers Most superphosphate applied to pastures. DAP/MAP used for grain Notionally Australia is in positive S balance Not included in this balance Added S from mined/biproduct gypsum (4 Mt mined) Atmospheric input 4.5 ± 2.1 kg S/ha/y (NLWA 2001) S input from irrigation depends on watershed position 247 kt S/y +2.9 kg/ha/y 113 kt S/y

26 Soil S levels ANRA Audit 2001 Nationally 11% < 5 mg/kg KCl-40 (mg/kg) Crop Pasture <8 52% 43% % 30% >12 28% 27% New South Wales 25% < 5 mg/kg Victoria 3% < 5 mg/kg 2010 Draws Soil on S test data values from mid-1990 s (top 10 cm) for Victoria, South Australia, New Requires South Wales revision (~1200 and review tests) current IPNI ANZ project

27 Soil S levels 2010 (Pre-sowing ie before May 2010) Location and Soil Type KCl 40 Wheat (mg/kg) KCl 40 Canola (mg/kg) <3 3 to 5 >5 <12 >12 Harden Red & Brown Loams 11% 33% 56% 80% 20% Horsham Grey & Brown Clay Loams 23% 18% 59% 68% 32% Maryborough Red & Brown Clay Loams 0% 8% 92% 74% 26% Cummins Red & Brown Sandy Loams 12% 44% 44% 74% 26% Moree Gray &Brown Clay/Clay Loams 17% 20% 63% Dalby Gray &Brown Clay/Clay Loams 15% 23% 62% Emerald Gray &Brown Clay Loams 27% 19% 54% Gunnedah Gray &Brown Clay Loams 10% 26% 63% Soil depth 0-10 mobility of S in profiles, maybe need a deeper soil test as routine when request nitrate, also request sulphate. Role of organic sulphur should the budget include mineralised S.

28 Variable P, generally low S 6% 20% 40% 34% (<200 PBI & 60 mg/kg) Pasture soil tests from the Armidale region IPL Labs, Low P = Low S, High P = likely low S

29 Fertilizer responses to P and S Mar-Jul Jan-Mar Dec-Jan Aug-Dec P Recovery 35% 36% 40% 50% Source, Flavel, Guppy & Blair, 2010 World Soil Science Congress. Old Redgrass. Wallaby Grass, Bluegrass, Kangaroo Grass, over sown with sub, white & red clovers. UNE

30 S deficiency in Australia History of S deficiency in pastures. Deficiencies first seen in NSW at Lockhart. Soils naturally low in S. Declining soil OM levels Reduced use of single super clear trend to AP s High demand for S by canola. Typically on Red Brown Earths. Pale petal colour.

31 Role of Ammonium Sulphate Tauhid Khan - PhD Is Ammonium sulphate an enhanced S source compared to gypsum? Does it enhance P uptake (eg through root zone acidification?) What role is there for co-placement of N and S in canola (and wheat). Biomass Urea/Gypsum compared to Ammonium Sulphate pots/canola Biomass yield (g/pot) P 0.05 a b c a b c N content (g/pot) P 0.05 a a b a b c 0 AS UG Nil 4 weeks 6 weeks Days after sowing 0.00 AS UG Nil 4 weeks 6 weeks Days after sowing

32 Ammonium sulphate Urea + Gypsum Gypsum Nil Ammonium sulphate Urea + Gypsum Gypsum Nil Urea Results: Yield variations in different soil types Changes of canola grain yield variation in sandy and clay loam soils Sandy soil Clay loam soil Grain yield (t/ha) P 0.05 a a a b a bc bc bc c Agronomic N efficiency Sandy soil AS= 26 kg grain/kg N UG=14.4 grain/kg N Clay loam soil AS= 12 grain/kg N UG= -2.5 grain/kg N N and S treatment

33 2010 Ammonium sulphate responses Suggestion that the S response from gypsum was not as good as the S reponse from sulphate in AmS

34 Nutrient Audit - wheat Critical issue is the nutrient contents of produce removed Reuter values: Evaluate this for wheat Took 70 sites from the NVT experiments from 2008 & 2009 Two cultivars Yitpi & Gladius Species N P K S Ca Mg Wheat (11%) * Wheat (0%) * Analysed for nutrient densities with ICP-OES - Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Se, Ti and Zn. Grain yield and N contents reported through NVT analyses Soil test values reported through NVT

35 Effect of site, year and cultivar on nutrient content N P K S States Regions Culitvars Year (SA only) P values from AnoVar for data sets Significant differences among N, P, K and S contents among regions, but states compensated for these differences. So nutrient budgets between regions can be quite different. Significant differences between these two cultivars for grain P and K offtakes. Not possible to investigate the interaction among site/year/cultivar

36 P, K and S contents - P K S 3329 ± ± ±220 S contents do not vary so much P and K values do vary significantly Bell reported similar results from CQ

37 Grain P contents What drives grain content? Tested grain yield No Tested soil ph No Tested Soil P content No Therefore To do a reasonable P balance need actual grain P contents -

38 Difference between estimates and actuals 2010 canola at the Dahlen site Measured yield and actual grain P contents Reuter grain P content estimate = 5.1 kg P/t of grain Actual content varied with P rate significantly P rate Yield t/ha Estimated P removal Actual P content Actual P removal

39 Wheat grain N:S ratio S RESPONSIVE S UNRESPONSIVE Inadequate N SE Australian N/S 2009 n=140 (2*70) Randell et al. (1981) AJAR 32,

40 Grain Nutrient Levels (all in mg/kg) P K S Ca Mg Zn Fe Cu B International CV 53% 20% 24% 61% 33% 41% 62% 61% 71% Australia Australia CV 21% 14% 12% 21% 10% 32% 19% 25% 58% International Values taken from IPNI survey of 130 samples from India, China, Canada, USA, Russia. Australian values taken from IPNI survey of 130 samples from NVT experiments in 2009 from Southeastern Australia. Lowest values in Mallee and EP samples (19 mg/kg) Desired range for human health on grains based diet 35+ mg/kg

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43 Zinc essential for life World Map Zinc Deficiency Soils Humans

44 Zinc essential for life Examples of Zinc Deficiency Wheat Rice plants in paddy field Severe Zn deficiency Zn treated plot Pictures: Potash & Phosphate Institute; Int l Rice Research Institute

45 Response to Zn Yield Response to 7.5 kg Zn 2 of 6 sites Grain Zn Increase on 5 of 6 sites DTPA Zn test available but difficult to find yield responsive sites Peck et al 2008

46 Grain Zinc Content regional values State Region Zn (mg/kg) NSW South East 23.0±2.4 South West 23.5±2.4 SA Lower EP 18.7±2.0 Mid North 25.4±1.8 Murray Mallee 19.2±1.6 South East 24.5±2.2 Upper EP 26.0±1.4 Yorke Penn. 22.2±2.0 Vic Mallee 18.9±1.7 North Central 25.5±3.4 North East 28.8±3.4 Wimmera 27.3±2.2 Total Mean 23.0±7.3 Regions with alkaline soils not unexpected

47 Zn/Fe Baseline levels & Target Levels Wolfgang H PFEIFFER

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49 Zinc and seed vigour Zinc seed content versus concentration High content important for early vigour <500 ng Zn per seed critical value Seed size & grain zinc concentration is important 15% below critical Low Zn level in seed from various locations Consider Zn application for seed crops improve vigour Zn Content (ng/grain)

50 New areas for thought Post-harvest evaluation of nutrient status in grain P removal maps become P replacement maps Zn content of grain become diagnostic for future Zn responses XRF analyses developed on from ICP now hand-held XRF great potential for in-field low cost grain nutrient analyses. N:S ratios give direction for potential S responses Nutrient balances will become more important as monitoring tools mining versus pollution. A NuGIS exercise for Australia would be interesting but reliable nutrient input data is scarce (fertilizer & manures/feeds). Is it time to revisit a collaborative soil test summary last done as ANRA (1998) and then as a single report in 2003 (Rayment)

51 Ha per sample Samples per year, millions Ha per sample s NA Soil sampling and sampling intensity in selected countries s 2000s Estimates based on best available data s Ag holdings/sample U.S. 0.5 India Years reported Argentina Australia Brazil China India Russia U.S NA

52 Concluding Comments Manage or be managed Regulations on nutrient management Reef Regulations on sugar industry in the wet tropics Use of soluble P fertilizers on the Swan coastal plain. Fertilizer management in the Mississippi Basin Regulations on N use on particular dairy pastures in New Zealand. Right source, right rate, right time, and right place is a simple slogan that integrates a century of science and experience into nutrient stewardship. Research backstops the principles of 4Rs with science, but the stakeholders decide what is right.

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