MFS Soils Club - 2017 test results Richard Simpson (CSIRO) Todays - PowerPoint PPT Presentation

MFS Soils Club - 2017 test results Richard Simpson (CSIRO) Todays agenda: 1. Highlights from the 2017 soil test results 2. Sulphur-management experiments beginning 2018 3. Results from this year’s P -response experiments 4. New thoughts on soil sampling strategies 5. Overview of the RnD4Profit: P efficient pastures project ………. and MFS’s role in it

Highlights from the 2017 soil test results “Erratic” critical Colwell P estimates - an artefact created when PBI tests are not done ( ignore! ) Colwell Phosphorus critical P 35 30 25 Phosphorus Phosphorus (Colwell) 20 Colwell P (Colwell) mg/kg 15 Critical Colwell P 10 (estimated) 5 0 2009 2011 2013 2015 2017 2019

Annual numbers of soil tests “attributed’ to soil type in the MFS soil database: Basalts soils: ave = 76 (range: 36-117) Granite soils: = 76 (45-119) Shale/slate soils: = 25 (14-44) • There are also many “transition” soils that sit between basalt and granite or shale soils and, most importantly, many soils with no attributed origin. • Some effort to record the origin of more of the soils in the database will improve our ability to probe the data. • Todays talk focuses mainly on basalt & granite soil results because of the strength of the data that is available to us. (Shale soil results are usually similar in nature to those from the granite soils.)

How we interpret the data: All data - basalt soils 30 2010 2011 25 2012 2013 20 2014 KCl 40 -S 15 2015 2016 (mg/kg) 10 2017 5 S deficient 0 0 1 2 3 4 5 6 P fertility index P deficient (1) P fertility index = current Colwell P critical Colwell P (2) Critical Colwell P is estimated from the PBI of the soil

All data - basalt soils 30 2010 2011 25 2012 2013 20 2014 KCl 40 -S 15 2015 (mg/kg) 2016 10 2017 5 0 0 1 2 3 4 5 6 P (Colwell) fertility index Basalt soils (ave 76 paddocks tested) 100% 80% 60% % deficient 40% pdks P 20% 0% 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

All data - basalt soils 30 2010 2011 25 2012 2013 20 2014 KCl 40 -S 15 2015 (mg/kg) 2016 10 2017 5 0 0 1 2 3 4 5 6 P (Colwell) fertility index Basalt soils (ave 76 paddocks tested) 100% 80% S 60% % deficient 40% pdks P 20% 0% 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Note the dramatic shift in S results between 2016 and 2017: 2016 data - Basalt soils 2017 data - Basalt soils 30 30 25 25 20 20 KCl 40 -S 15 15 (mg/kg) 10 10 5 5 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 P (Colwell) fertility index P (Colwell) fertility index

Basalt soils (ave 76 paddocks tested) 100% 80% S 60% % deficient 40% pdks P 20% K 0% 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

All data - granite soils 30 2010 2011 25 2012 2013 20 2014 KCl 40 -S 2015 15 2016 (mg/kg) 2017 10 5 0 0 1 2 3 P (Colwell) fertility index Granite soils (76) 80% P 60% % deficient 40% pdks 20% 0% 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

All data - granite soils 30 2010 2011 25 2012 2013 20 2014 KCl 40 -S 2015 15 2016 (mg/kg) 2017 10 5 0 0 1 2 3 P (Colwell) fertility index Granite soils (76) S 80% P 60% % deficient 40% pdks 20% 0% 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

• Similar trends I P and S results to tse for the basalt soils. • Big change in potassium (K) result associated with a change to the Colwell K test ( With MFS help, we will investigate this further as it does alter perceptions of the incidence of K deficiency .) Granite soils (76) S 80% P 60% % deficient pdks 40% K ‘Colwell K’ test 20% ‘Available K’ test in use (with conversion factor applied) 0% 2008 2010 2012 2014 2016 2018

What has happened to SULPHUR in 2017 ? The options: Was the lab having a “bad day”? (1) The ‘control’ soils we resend to the lab every year indicate there was probably a big change in methodology in 2012, but they do not indicate that the 2017 result is due to measurement error. "How Good" - granite soil "How Good" - basalt soil 12 14 12 10 Soil 10 8 test ? 8 ? result KCl 40 -S 6 6 (mg/kg) 4 KCl 40 -S 4 2 2 0 0 1/01/2010 1/01/2011 1/01/201231/12/20121/01/2014 1/01/2015 1/01/2016 1/01/2017 1/01/2018 1/01/2019 1/01/2010 1/01/2011 1/01/201231/12/20121/01/2014 1/01/2015 1/01/2016 1/01/2017 1/01/2018 1/01/2019 2010 2011 2012 2013 2014 2015 2016 2017 2018 2010 2011 2012 2013 2014 2015 2016 2017 2018

What has happened to SULPHUR in 2017 ? The options: (1) The lab was having a “bad day”  (2) There was a lot of S-fertiliser applied on the Monaro in 2017? Bibbenluke (John Murdoch) Response of soil test: pre- & post- S application 40 maintenance 30 application = 16 kg S/ha Change 20 ???? in S test value 10 2015/16 (mg/kg) 0 0 10 20 30 40 -10 -20 S applied (kg/ha)

What has happened to SULPHUR in 2017 ? The options: (1) The lab was having a “bad day”  (2) There was a lot of S-fertiliser applied on the Monaro in 2017? Bibbenluke (John Murdoch) Response of soil test: pre- & post- S application 40 30 2017 Change 20 in S test value 10 2015/16 (mg/kg) 0 0 10 20 30 40 -10 -20 S applied (kg/ha)

What has happened to SULPHUR in 2017 ? The options: (1) The lab was having a “bad day”   (2) There was a lot of S-fertiliser applied in 2017 (3) Environmental conditions in 2017 have favoured S-mineralisation, conservation and/or retention ? Basalt soils Granite soils 100% 100% 2012 2011 2016 2014 80% 80% 2013 2012 % of 2011 2015 2015 2013 2016 paddocks 60% 60% 2010 2010 that were 2014 2017 S- defic’nt 40% 40% 2017 ( 0-10 cm topsoil ) 20% 20% 0% 0% 300 400 500 600 700 200 300 400 500 600 700 Total Jan-Aug rainfall (mm, Nimmitabel ) Total Jan-Aug rainfall (mm, Bombala )

New sulphur management experiments planned for 2018 1. Deep soil nutrient profiles will be measured during autumn at 15 sites,  particularly aiming to determine where S is ending up in soil profiles . (5 sites on each of the basalt, granite and shale-based soils) mg/kg meq K/100 g 0 0.5 1 0 10 20 0 Colwell P -10 Potassium -20 -30 Granite-based soil MCP-sulphur Soil -40 Erosion paddock (1999) depth -50 (Connemara, via Tarcutta) (cm) -60 -70 -80 -90 -100

2. Pasture response to S-fertiliser at all 15 nutrient profile sites  Does the 0-10 cm S soil test adequately indicate S responsiveness?  What value should we place in deep S? 3. Soil test response to gypsum at 6 nutrient profile sites  How much gypsum is required to raise KCl 40 - S test by 1 unit? … to assist fertiliser rate planning and calculations

Where to next with this study? Potential experiment sites will initially be identified using the Soils Club database. Nancy will follow up ( probably Feb 2018 ) to ask if people with the right soil types wish to participate . Soil sampling begins AUTUMN, ….after it has rained and the soil is ‘soft’.

Initial results from this year’s P-response expts Underpinning philosophy: soil tests should assist pasture management …. NOT ….“stamp collecting” CASE STUDY: Figure 1: Colwell Phosphorus, "Ring-a-bells", Quinburra “Ring -a- bells” paddock, Quinburra (Ron & Mandy Horton) 35 critical Colwell P Critical Phosphorus (Colwell) 30 Colwell P (estimate 25 mg/kg Phosphoru Colwell P 20 Colwell P (Colwell) mg/kg 15 10 100 kg super/ha 200 kg/ha 100 kg super/ha 200 kg 5 Fertiliser application every year super/ha reverts to 100 kg super/ha 0 2009 2010 2011 2012 2013 2014 2015 2016 2017 2010 2011 2012 2013 2014 2015 2016 2017

Soil test response to P application: 4 sites laid out in autumn 2017 • Quinburra PBI = 85 (Ron & Mandy Horton), • Redcliff PBI = 100 (Ned & Annie Kater), • Bibbenluke PBI = 200 (John & Kate Murdoch & family) • Shirley PBI = 330 (John & Sally-Anne Cottle) P-fertiliser experiment, Quinburra

Soil test response to P application 2017 180 160 Shirley: PBI = 330 140 y = 0.47x + 108.3 120 100 Colwell P (late spring) 80 Bibbenluke: PBI = 200 y = 0.33x + 48.9 3kg P/ha (mg/kg) 60 to raise Quinburra: PBI = 85 y = 0.33x + 28.5 Colwell P 40 by 1 unit Red Cliff: PBI = 100 y = 0.31x + 20.8 20 0 0 20 40 60 80 P applied (kg/ha)

Soil test response to P application 2017 180 Table 1. from “Five Easy Steps…….” 160 50 100 200 300 Shirley: PBI = 330 PBI value of topsoil 140 y = 0.47x + 108.3 120 100 Colwell P *EXTRA (late spring) 80 2.7 2.7 2.9 3.0 Bibbenluke: PBI = 200 kg P/ha to raise y = 0.33x + 48.9 3kg P/ha Colwell by 1 unit (mg/kg) 60 to raise Quinburra: PBI = 85 y = 0.33x + 28.5 Colwell P * P in excess of maintenance amount which must also be applied 40 by 1 unit Red Cliff: PBI = 100 y = 0.31x + 20.8 20 0 0 20 40 60 80 P applied (kg/ha)

Back to the case study: 2014: Colwell P = 20 mg/kg, 100 kg super (9 kg P)/ha maintained this critical Colwell P = 32 mg/kg 3 kg P/ha must be applied to raise Colwell P by 1 unit Fertiliser rate was increased to 200 kg super/ha/yr i.e. 9 kg P (maintenance) + 9 kg P for increase Therefore – expected Colwell P to increase by 3 units/yr …..and it should take 4 years to reach critical P.