Soil Research at the Northfield Research Laboratories (1964–1990)

Doug Reuter

The Vision & Development of the Northfield Research Laboratories

In September 1964, Departmental research staff in the Soils Branch with other research groups relocated from the Simpson building in Gawler Place to new research facilities at Northfield. These modern facilities were designed by the late Allan ‘Teddy’ Beare (Chief Soils Officer and Soil Conservator), Peter Barrow (Senior Agronomist) and Ted Carter (OIC Kangaroo Island Research Centre) on land where Sir Ross & Keith Smith landed their Vickers-Vimy bomber on their epic flight from England to Australia in 1919.

The Premier, Sir Thomas Playford, officially opened the Laboratories in January 1965. It was a gala event attended by many farmer dignitaries, who no doubt held great expectations of how this government and wheat industry investment would assist SA rural industries.

The vision for this new facility had several facets. Following WWII, agricultural land development in SA expanded rapidly but with relatively little knowledge about the requirements of the soils and the farming systems being used. Recognising this, in the 1950s the Department offered cadetships for students to undertake agricultural science degrees at the University of Adelaide as a means of strengthening its future research and extension arms. Thus, by the early 1960s new graduates were starting their careers within the Department, which in turn prompted the need for new facilities for the new age of farming.   

The first OIC at Northfield was Peter Barrow closely followed by Reg French, who both orchestrated the beautification of the grounds (including gum trees planted by the Women’s Agricultural Bureau in June 1967) and progressive extension of many additional facilities. This wonderful new facility was a vast improvement on the abysmal conditions we endured at Gawler Place and importantly brought together Departmental researchers across several scientific disciplines (weeds, entomology, field crop and pasture agronomy, plant breeders, horticulture, soil research). Rapidly an excellent esprit de corps developed amongst Northfield staff.

Across Folland Avenue, the Department’s dairy research group established their facilities and the Northfield Dairy Research Farm under the leadership of John Feagan. Bill Bussell managed the farm. Paul Heap developed the Northfield Pig Research Centre and Rip van Velsen and David Cartwright established the Northfield Horticultural and Commonwealth quarantine glasshouse complex.

Northfield staff were supported by an excellent group of administration staff.  The first Senior Clerk was Trevor Roberts, followed by Alan Stevenson, Peter Phillipou and John Earle. Other staff who worked at Northfield at various times included Sue Standish, Di Green, Ian Tonkin, Stuart Matthews, Mary Siggers, Bev Brazel, Adrienne Twisk, Desma White and Carol Wood (receptionist). Len Hill was caretaker and gardener.

In November 1985, Northfield celebrated its 21st birthday, with a symposium held at the Enfield Civic Centre. Northfield achievements were presented and in 1986 were subsequently published in a special issue of the Departmental journal ‘Agricultural Record’. 

In 1993, the Northfield facilities closed and staff relocated to the Waite campus (soils, agronomy, plant breeding, genetic resources, entomology, weeds and horticulture), Flaxley (dairy research) and the Roseworthy campus (pig and livestock research), primarily because the Government required the land for suburban housing. The sale of Northfield land was invested in building new facilities at these sites.

Soil Research at Northfield

Until 1978, Reg French led the Soil Research Group as Principal Research Officer (Soils) with energy and vision. He was ably assisted by Dr Alan Clarke who took on the responsibility for pasture research in the Mt Lofty Ranges and the South East region. Alan later became Director of the Toowoomba Wheat Research Centre. Doug Reuter was appointed PRO (Soils & Nutrition) and OIC Northfield Laboratories from 1979 to 1990. Bob Hannam then became leader of the Soil group until it transferred to the Waite campus.

An extensive area of the new Laboratory complex at Northfield was devoted to soil research, including a soil and plant analytical laboratory with sample preparation areas. But when we arrived the analytical cupboard was very bare and our field research equipment was either non-existent or antiquated. But this situation was quickly addressed by a major injection of funds from the Department’s Marginal Wheat Fund.

In a single afternoon meeting chaired by Reg French (PRO Soils), soil researchers ordered laboratory equipment (including an auto-analyser, atomic absorption spectrophotometer, XRF spectrophotometer, spectrophotometer, carbon induction
furnace, and electronic balances) and a set of mobile field equipment (truck, seeder and plot harvesters for crops and pastures). These expensive purchases served the Department exceptionally well during the following 30 years.

Indeed prior to the Northfield relocation, almost all of our analytical needs were undertaken by the Department of Chemistry in Kintore Avenue, Adelaide, where Dean Harvey and his staff provided excellent support. A small soil laboratory existed in the Simpson’s building run by Jill Wishart (nee Mead). But Alan Beare foresaw a
need for his staff to have their own analytical capability. This included providing analytical services to regional research projects and Departmental advisory staff.

Laboratory chemists and technicians were appointed progressively and included Bob Brooks (the first laboratory manager), Jim Jacka (his successor), the late Walter Binder, Peter Mulhlan, Jenny Anderson, Gita Tynk, and John Gouzos. Dennis Heanes was appointed research chemist and developed a number of laboratory procedures. His organic carbon test is known throughout Australia as the ‘Heanes method’. In 1984, the laboratory processed 35,000 analyses annually. Later, some instruments were computerised and analytical output increased even further.

Graduate technical staff, who worked on various soil research projects, included Graham Wishart, Noel Pederson, Brian DuBois, Jeanette Jennings, and Steve Hughes. 

Technical support for field programs was also provided through the appointment at various times of Jim Griggs, the late Angus Weir, Bob Abbott, John Riggs, David Kruger, Grant Gowling, Rod Karger, Steve Harper, Bob Beare, Neil Schubert, Rick Darling and Chris Schulte. Their practical and diverse skills and commitment were invaluable assets. This included building and modifying field and laboratory equipment, perhaps the most notable being the mobile rainfall simulator, designed and built by Noel Pederson for estimating soil erosion potential in farmer’s paddocks.

John Ellis (Senior Departmental biometrician) and his staff in head office provided appropriate and efficient experimental designs for our research. In the early days, they statistically analysed all research results. But by the mid 1970s, Northfield had gained a programmable calculator for performing statistical analyses. Peter Gibson and Denis Elliott wrote many of the programs required. By the 1980s, two computer rooms at Northfield were furnished with a server and a series of computer modules.

In 1993, Northfield soil researchers transferred to the Waite campus and became part of the Cooperative Research Centre for Soil and Land Management, a joint venture between the Department, CSIRO and The University of Adelaide. Regrettably, we lost our laboratory analytical facilities in relocating to the Waite.

Soil Research Programs & Achievements (1964 – 1990)

Both applied research (seeking solutions to existing farming problems) and strategic research (developing initiatives, technologies and tools for the future) were undertaken, with emphasis being given to understanding causes for measured yield responses.

Over the years, the Northfield Soils group published a large number of reviews, scientific papers and conference papers and addressed a large number of farmer meetings.

Water use efficiency (WUE) in crops

Possibly the most significant concept with direct on-farm utility was the development of a simple calculation for estimating the efficiency by which crops acquired and used growing season rainfall to produce yield. Reg French and Jeff Schultz pioneered the concept of WUE following years of field trials at many SA farm sites (including intensive monitoring of soil water fluxes under wheat grown on long and short fallows at three sites by Jeff Schultz). The concept is universally called the ‘French-Schultz model’ across southern Australia. Using this tool, farmers, advisers and consultants are now able to compare crop yields in relation to rainfall in any year and estimate how close the yields approached near-optimal yields or their ‘yield potentials’. Alleviation of site constraints led to improved WUE. Later, equations for pasture growth were developed.

In 1987, Reg received the prestigious C.M. Donald medal from the Australian Society of Agronomy largely for the WUE concept and received a sustained, standing ovation from hundreds of Australian agronomists.

Mapping the distribution and properties of agricultural soils

During this era, members of the Soils Branch published several regional soil maps. These included the soils of Yorke Peninsula and northern areas (Reg French, Bill Matheson, and Alan Clarke); Counties Albert, Alfred and Eyre (John ‘Soils’ Potter, Ken Wetherby and David Chittleborough); southern Mallee region (Andy McCord); a revision of Reg French’s original 1958 soil map of Eyre region  (Peter Jeffery and Brain Hughes, with major contributions from Ken Wetherby); coastal soil in the SE region (David Zimmerman and Mark Seeliger) and a soil survey of the Padthaway region (Ken Wetherby and David Armstrong).

These essential soil information bases have been progressively refined and extended in all agricultural regions by David Maschmedt and his group who resided at Northfield from 1985 - 2003.

Developments in Fertiliser Advice and Technology

Many SA farming soils are renowned for their inherent infertility and fragility.  Historical observations and information gained from early field trials on different soil types were broadly consolidated by the late Newton Tiver (Chief Agronomist) and published in the 1955 Journal of Agriculture ‘Deficiencies in South Australian soils’. Often multiple deficiencies were recognised and some classical ‘world-first’ discoveries were made, especially with trace elements. But during the post war era more land was being rapidly cleared for agriculture. Fertiliser requirements, including type of fertiliser (nutrients applied), the rate, frequency and most efficient method of application were also needed for these diverse soils and farming systems.

The fertiliser industry, especially Adelaide & Wallaroo Fertilizers Ltd (AWFL) and more recently Pivot and Hifert often supported Departmental research programs by either co-sponsoring or providing experimental fertiliser products for testing. Of course they also manufactured and imported fertiliser products used in farming. Industry research grants were sought more actively from the mid 1970s.

1. Pasture fertiliser programs

In the early 1960s, John Burford examined responses by perennial pastures to applied potassium (K) fertilisers in the Mt Lofty Ranges. He also developed and calibrated a unique soil test for detecting K deficiency (see below). This was the first ‘available’ soil test developed in SA.

Alan Clarke also showed that even insoluble rock phosphate applied to the acidic Mt Compass sand rapidly moved down the soil profile.

By the early 1970s, Departmental fertiliser research in the higher rainfall areas of the SE region became a priority, although earlier pioneering research by Dr David Riceman (CSIRO) and colleagues and later by Kelvin Powrie (University of Adelaide) in the Robe and Coonalpyn Downs areas, together with the coast disease research with sheep at Robe was well known. Dale Lewis and Tony Meissner were appointed to Struan Research Centre and with Alan Clarke (based at Northfield) commenced research on the phosphorus (P), sulphur (S) and K needs of pastures in the South East region.

Dale conducted an extensive soil chemical survey of sandy soils in the region to establish the rate of accumulation or depletion of applied P and S (and other soil properties) under grazing on land that had been developed for a variable number of years. He and Alan (with assistance from Lewis Auhl) also investigated P & S fertiliser requirements on a range of other SE soils, including some longer-term trials. Tony Meissner and Alan Clarke conducted a series of medium-term trials examining rates, timing and residual benefits of K fertiliser applications to pastures. Both programs were used to calibrate soils tests for high rainfall pastures (see below) and fertiliser guidelines for graziers.

Other nutritional investigations in the SE region were also pursued, including some classical field work by Jock McFarlane calibrating critical levels of copper (Cu) in sub clover, strawberry clover and wheat (see below).

In 1980, a soil analytical laboratory was established at Struan to assist the expanding research activities in the SE region.
Denis Elliott transferred from Cleve to Northfield in 1970 and with Bob Abbott investigated nitrogen (N) fertiliser requirements of perennial pastures and hay crops grown in the Mt Lofty Ranges. This work continued until 1979 under Commonwealth Extension Services Grants and the findings were widely promoted to dairy farmers and graziers throughout the higher rainfall regions of SA. In their experiments, rates up to 200 kg N/ha were applied several times between winter and spring to a maximum of 800 kg N/ha/year. The main conclusions were: autumn applied N (50 kg N/ha) increased pasture yield for only a 2 month period, but repeated applications maintained productive responses, especially in grass pastures; N fertilised sod-sown oats out-yielded pastures in autumn and winter; and single dressings (50 – 100 kg N/ha) in early spring increased hay and silage yield by 1.3 to 2 t/ha. In the final two years, two rates of N (0 and 100kgN/ha) were contrasted at 200 sites.

A collaborative research program was formed between the Department and CSIRO Division of Soils (Dr Kevin Tiller and Richard Merry). An initial survey of acidic soils and their chemical properties was made in the Mt Lofty Ranges with the assistance of local District agronomists and Departmental soil surveyor, David Maschmedt. Many soils had acidic subsoils. Subsequently, medium-term field experiments were established to examine pasture responses to rates of lime applied to representative acidic soils in the Mt Lofty Ranges, Kangaroo Island and in the SE region. Departmental advisers selected the sites and coordinated extension for the program. Sue Hoppo and Tim Hodge established the field trials and Alan Richards conducted analytical and glasshouse work at CSIRO. While lime responses were recorded at most sites, too much lime induced trace element deficiency at some sites. A new lime requirement soil test was developed for predicting rates of lime applications for different acidic soils.

Bob Hannam and Peter Marrett also showed that repeated applications of copper (Cu) fertiliser were required on dairy pastures grown on the alkaline peat soils at Eight Mile Creek. These soils had high molybdenum status, inducing Cu deficiency in dairy herds. 

2. Crop fertiliser programs

In the mid to late 1960s, Chris Rudd and Reg French examined phosphatic (P) fertiliser requirements in wheat and medic pastures at a range of sites within the SA cereal belt. Chris also tested the relative effectiveness of different P fertilisers (none outperformed single superphosphate or ‘super’) and different methods for applying super to crops (drilling super at sowing was best). Variations in super granule size had negligible impact on yield. Soil P tests were calibrated for wheat and medic (see below).

Andy Mc Cord (Murraylands) with support from staff at Northfield also conducted a series of P fertiliser rate trials in the Netherton area of the southern Mallee to better define soil P test standards for wheat. Ken Wetherby (Cleve) conducted a similar program on the Eyre region.

Between 1967 and 1972, the ‘National Soil Fertility Program’ was initiated in a joint venture between CSIRO Division of Soils, Departments of Agriculture in all southern Australian States and the fertiliser companies. In SA, N, P, K, and S fertiliser requirements for wheat and higher rainfall pastures were investigated on representative soils throughout SA. Soils were sampled to depth by CSIRO and they also analysed large numbers of soil tests together with statistical analyses. Ron Tuckwell and Bob Freak organised the cereal field trials (conducted over 3 years) with assistance from regional Soil Branch staff. Richard Merry (CSIRO) coordinated 28 pasture field trials in the SE region and the Mt Lofty Ranges with assistance from Alan Clarke.

Reg French and Jeff Schultz also measured nutrient uptake in a range of crops at different stages of growth. The grain nutrient data for these crops are still used widely to replenish nutrients removed in harvested grain.

Doug Reuter teamed with Terry Heard (Agronomy Branch), with assistance from Angus Weir, Cyril Schubert and Bob Puckridge, to investigate barley crop failure on highly calcareous soils at Warooka. This research program, conducted between 1963 and 1969, tested a range of experimental fertilisers manufactured by AWFL. The main problem was identified as manganese (Mn) deficiency and was corrected by applying Mn and copper (Cu) homogeneously blended with superphosphate at sowing followed by two or three Mn foliar sprays. In the final year of this program, Clipper barley (which replaced Prior barley in 1968) yielded 3.4 tonnes/ha.

This work gave confidence to local barley growers, was extended to other calcareous soils in SA and as well laid the foundation for the use of foliar sprays to correct trace element deficiencies in annual crops in SA.

AWFL subsequently developed four refined foliar products for correcting Mn, Cu, zinc(Zn) and iron (Fe) deficiency. This was needed because the crude manganese sulphate used in the first year at Warooka dissolved slowly and blocked farm-spraying equipment.

Trace element foliar sprays were also used to identify potential micronutrient deficiencies on other soil types. Field trials by Doug Reuter confirmed Mn and Cu deficiencies also occurred on other calcareous soils in SA and mild Zn deficiency existed in crops grown on the black earths at Freeling and Saddleworth. Responses to Fe were not observed. 

In the early 1970s, Peter King examined potential trace element deficiencies in cereal crops grown on different land units in the Wharminda and Stokes area of Eyre region. Responses to foliar sprays of Cu, Zn, Mn, Fe, molybdenum (Mo), and boron (B) were tested in wheat. Yield responses varied greatly across sites with the largest response being to Cu, but deficiencies of other trace elements were confirmed at some locations. Cu soil tests were calibrated.

In 1963, Peter Marrett reported the correction of Fe deficiency in pastures and barley crops grown on rendzina soils in the lower SE. Barley yields were increased 700 % by applying foliar Fe sprays. Subsequently (1976), Mark Seeliger and David Moss corrected Fe deficiency in pea crops grown on rendzina lunettes in the SE region by using two foliar Fe sprays, three weeks apart. Symptoms were most severe under waterlogged conditions, were less evident in drier years and partially disappeared as the soil dried out in spring.

Jock McFarlane, Trent Potter and Dale Lewis also diagnosed and developed corrective measures for molybdenum (Mo) deficiency in sunflower crops. Dale and Jock also reported the first world evidence of Mn deficiency in safflower (grown on black rendzina soils) and its correction by Mn foliar sprays.

In six intensively monitored field trials, Bob Hannam, Bill Davies, John Riggs and Robin Graham (University of Adelaide) in the early 1980s demonstrated that a single aerial spray of Mn at mid-flowering on the main axis of sweet lupin crops markedly improved seed yield (from zero up to 2.5 tonnes/ha) and corrected a seed disorder known as ‘splitseededness’. Much of this work formed part of Bob Hannam’s PhD thesis and included work by the use of ultra-low volume Mn sprays applied by aircraft. The trials showed that although lupins did not exhibit any symptoms, there was a critical need for Mn during seed development, since Mn was not redistributed within the plant. There was a strong relationship between this disorder and Mn levels in seed. A plant test for predicting Mn deficiency at mid flowering was also developed. Many of these findings were later adopted in WA. 

In the early 1960s, Grant Baldwin, Doug Reuter and the late Don Winn examined the efficacy of applying urea foliar sprays to wheat crops. Don’s laundry copper at Balaklava was needed to dissolve the urea!

Between 1981 and 1982, Denis Elliott and his team conducted 22 field trials comparing responses to N fertiliser rates applied at sowing, broadcast during early tillering or stem extension or split between sowing and early tillering. In the majority of trials, tillering and split applications were either equivalent or superior to N applied at sowing, and especially on light textured soils. N applied at stem elongation produced inferior yield responses. Plant tests for diagnosing N deficiency in wheat were developed.

Between 1990 and 1992, 123 field trials were conducted in the cereal zone examining responses to N applied to wheat and barley crops grown in different rainfall zones and following different rotational sequences. Rates of applied N and time of application were evaluated. This large program, co-sponsored by Top Australia (previously AWFL), was supervised by Denis Elliott and involved participation by Drs Xu, Nigel Wilhelm, Lewis Auhl and Chris Dyson. Responses in yield and grain protein varied considerably with site soil N status and seasonal conditions, but barley crops were more responsive than wheat, because barley usually followed a cereal whereas wheat usually followed grain legumes or pasture in rotations. Mineral N levels (0 – 60cm depth) were calibrated and found to reasonably predict crop responses to applied N.

Peter Gibson developed procedures for measuring the quantity of N fixed by grain legumes, such as lupins, and established a sophisticated N fixation laboratory at Northfield. In a classical piece of inter-disciplinary research, he and senior entomologist, Peter Allen examined the effects of sitonia weevil larvae on N fixation in annual medics. In a field trial they showed that a larvae density of 2000/ m2 unexpectedly did not affect N fixation. In subsequent laboratory experiments they showed that medics compensated for damaged nodules by either increasing the efficiency of N fixation in undamaged nodules or producing new nodules (depending on grazing intensity).

In 1984, cereal farmers in SA began using high analysis fertilisers, such as DAP and MAP for the first time. Experience in WA indicated that this change in fertiliser practice could induce severe Zn deficiency in crops, because these refined fertilisers contained much lower levels of Zn contamination (~100 mg Zn/kg) than single superphosphate (~ 400 mg Zn/kg). Bob Hannam, Nigel Wilhelm (recruited to Pt Lincoln) and John Riggs commenced a research program on several soil types, and discovered severe Zn deficiencies still persisted in cereals, field peas and medic pastures. At Lameroo (Jim Byrne’s farm), yields of medic were nearly quadrupled by applying Zn in rotation trials. In following years at this site the farmer applied Zn and observed marked improvements in soil structure, water infiltration, sheep carrying capacity and crop and pasture yields. Diagnostic plant tests were developed and new methods for correcting Zn deficiency were assessed – cultivating soils following a Zn spray before sowing was most efficient. The residual effectiveness of soil applied Zn (2.5 kg Zn/ha) lasted for 3 years (calcareous clays); 5 – 7 years (calcareous red brown earths); and from 3 – 10 years (mallee loams). 

Bob Hannam and University of Adelaide colleagues also showed at Lameroo that severe Zn deficiency intensified Rhizoctonia damage in cereals (i.e. undernourished crops were more susceptible to a root disease). Following this Zn research program, sales of Zn fertilisers in SA increased four fold.

In 1971, Mark Seeliger and Reg French reported changes in soil chemical properties in fertiliser treatments of the non-irrigated grape vine experiment conducted at the Nuriootpa Viticultural Research Centre. After 23 years of annual N, P and K fertiliser applications, they showed that broadcast applications of superphosphate were inefficient because it took 8 years for the applied P to reach the vine feeder root system at 15 to 30 cm depth. Ammonium sulphate applications resulted in soil acidification to a depth of 45 cm and reduced vine vigour and yield. Soil pH values below 5.5 depressed yield. Soil K levels were adequate where no K fertiliser was applied and applied K had no effect on yield.

3. Livestock trace element requirements

In the early 1970s, the Director of Agriculture (Marshall Irving) directed that new trace element investigations with livestock were needed and encouraged collaboration between the Department and veterinary researchers in the Institute of Medical and Veterinary Science (IMVS).

A project team was formed comprising Doug Reuter, Bob Hannam (returned from army service in Vietnam), John Riggs and David Kruger (DA) and Geoff Judson and Tom Benson (IMVS). Later Locky McLaren and Jock McFarlane joined the team for work in the SE region. Alan Harris (Departmental wool adviser) graded wool at shearing time. This unusual mixture of skills worked well on several projects

Initial investigations were on lateritic (ironstone) soils on Kangaroo Island and Fleurieu Peninsula (8 sites) where the residual value of Cu applied up to 13 years ago was found to still be adequate for sheep production – wethers did not respond to Cu injections and blood and liver Cu levels were also satisfactory over two years. [A long-term grazing trial conducted on virgin lateritic soil at Parndana by Ted Carter and Henry Day had previously shown that super and Cu were essential for sheep and pasture production]. Graziers were advised not to re-apply Cu.

Similar findings in sheep and pastures were also recorded in later trials conducted in the SE region where Co had not been applied for up to 23 years. These trials and trials in the southern Mallee also examined the need for cobalt (Co) in weaners and suckling lambs. Vitamin B12 injections were also shown to an efficient means of treating Co deficiency in suckling lambs and this practice has now been adopted widely for preventing Co deficiency in prime lambs.

The distribution of steely wool in SA (a symptom of Cu deficiency in sheep) was also mapped for 1972 - 1975 and compared to the widespread occurrence found in a similar survey conducted by John Lee (CSIRO) between 1939 and 1946. Affected areas in the 1970s had contracted considerably to that observed in the earlier survey, indicating that Cu fertiliser had been widely used.

In 1988, a Department Technical Report (‘Trace Elements in South Australian Agriculture’) was published collating contemporary knowledge of where trace element disorders in plants and livestock had been discovered in SA over the years.

4. Diagnostic Tests

Soil Tests

Chris Rudd and Reg French in the mid 1960s compared several standard soil P tests against their yield response data for wheat and medic and found the Colwell soil P test (developed by Dr Jeff Colwell, CSIRO in Canberra) to be superior. This test is now used universally across Australia. Dale Lewis calibrated the Bray 1 soil test in his SE work on pastures, but later also showed that this test was highly correlated with the Colwell P test on non-calcareous soils.

In 1975, the Department published a special Bulletin entitled ‘Superphosphate in SA – its importance to crops and pastures & guidelines for efficient use’, which summarised much of the past research findings for cropping and higher rainfall pasture zones. Subsequently, all data from soil P calibration studies in SA (580 field trials) were summarised and published in the Australian Journal of Experimental Agriculture in 1995.

Two K soil tests were developed and calibrated for pastures – one in the Mt Lofty Ranges (John Burford), the other (called the Colwell soil K test) in the SE region by Tony Meissner and Alan Clarke. Both these tests used sodium as the displacing ion for exchangeable soil K, and the calibrated critical level (below which K soil status is considered to be deficient) was essentially similar for both tests and regions.

Denis Elliott and his colleagues also calibrated a soil test for estimating soil N status (mineral N measured to 60 cm soil depth) in cereal trials conducted between 1990 and 1992 (see above).

Peter King calibrated three soil tests for Cu in his cereal trial work on Eyre region.

Alan Richards and his CSIRO colleagues developed a lime requirement test for acidic soils (see above).

In the SE region, Dale Lewis and Leigh Sparrow calibrated a soil test (extractable K/Ca + Mg ratio) for identifying the likelihood of cattle being affected by grass tetany.

In 1999, an Australian manual on soil testing was published, entitled ‘Soil Analysis: an interpretation manual’. Departmental staff contributed soil test criteria and chapters on different soil tests to this technical manual.

Plant tests

In 1981, the Department hosted the First National Workshop on Plant Analysis at Goolwa, which attracted many of Australia’s nutrition specialists. The meeting recommended that all plant analysis tests and criteria be assembled into a publication and disseminated widely within Australia. This was accomplished by a group of Australian nutritionists in1986 with the publication of ‘Plant Analysis: an interpretation manual’. This technical manual exposed many knowledge gaps needed for interpreting multi-nutrient plant analyses in different plant species.

During the 1980s, Departmental staff at Northfield and in some regions developed several plant testing research programs, mostly supported by industry grants. New plant tests were developed including: P in wheat, barley, medic, sub clover and field peas; N in wheat and barley; Cu in sub clover and strawberry clover; Zn in sub clover, medic, faba beans and wheat; Mn in wheat, barley, lupins and safflower; and S in sub clover. Much of this work started with detailed glasshouse studies conducted at Northfield to identify the most sensitive plant parts for sampling and detecting plant nutrient status. For some nutrients, analysis of nutrients in young leaves was found to be superior for diagnosing deficiencies in field crops and pastures. Key Northfield and regional researchers involved in this work were: Denis Elliott, Sue Hoppo, Alan Richards, Reddy Gogu, Bob Hannam, Nigel Wilhelm, Dale Lewis, Jock McFarlane, Dennis Heanes and Doug Reuter with excellent support from the field and laboratory staff.

In 1997, a second edition of the Plant Analysis manual was published, citing these and many other new plant tests developed by Australian and overseas research.

In 1986, the Department replaced the SA Soil Analysis Service (established in 1976) with the SA Soil and Plant Analysis Service (SASPAS). This farmer service still operates on a fee-for-service basis.

Other tests

Peter King is credited with developing the first bioassay test for detecting cereal cyst nematode (CCN) during his work at Coonalpyn. He also developed a simple test for gauging the severity of water repellence in sandy soils during his research on re-establishing aphid-resistant lucerne on repellent sands in the upper SE region.

Jeff Schultz and Reg French discovered a strong correlation between water use by wheat crops and silicon uptake in shoots at grain maturity. A large proportion of plant silicon resided in wheat glumes at maturity.

Dr Geoff Judson and Jock McFarlane also published a review in the 1998 issue of the Australian Journal of Experimental Agriculture summarising a range of tissue, blood and pasture tests for diagnosing mineral disorders in livestock.

Northfield and regional soil researchers also organised soil and plant testing workshops for regional advisers and agribusiness.

A fertiliser decision support model was developed by Tony Smith and Chris Dyson to assist farmers decide the most economic rate of P fertiliser to apply to crops after they had tested their soil. However, this tool was not widely used in SA.

5. Signals from the RPAC

In about 1980/81, the Research Policy Advisory Committee (RPAC) convened a meeting with senior Departmental staff. They indicated that farming systems in the cropping zones were likely to change in the future from the traditional cereal – pasture rotations. Farmers were beginning to crop more intensively and crop rotations were likely to become more diversified. They foresaw new soil management and agronomic practices might be required for these new systems to become sustainable. Importantly, what new Departmental research programs could be initiated to support these significant changes in land use? A lively debate ensued!

A follow up meeting in August 1982 was convened by RPAC in which research priorities were canvassed from 12 leading farmers from four regions in the cropping zone. A large number of issues were identified, prioritised and published in Departmental Technical Report 23 - ‘Report on Workshop – research priorities for the cereal/sheep zone – a farmer’s point of view’. A range of soil issues rated highly.

Of course, RPAC original predictions were correct and challenging. Eventually, two broad initiatives were undertaken that were supported by industry grants. Firstly, long-term soil management trials were either established or maintained to examine rotational and farming systems issues and secondly, productivity and soil health were surveyed on farms that had changed their systems of land use (called the ‘monitoring’ program).

Long-term trials

At Coonalpyn, Peter King and Bob Beare established a 4-year rotation trial in 1976 on Dean Elliott’s farm to examine practices for overcoming limitations caused by root diseases, low N status and weeds. A technology package was developed that resulted in large wheat yield increases following grain legume crops. Root diseases in wheat were less severe after grain legumes than after volunteer or sown pastures.
Jeff Schultz also had already established a rotation trial in 1977 at Tarlee on Ian and John Rhode’s farm that compared productivity and soil health parameters under eight 2-year continuously cropped rotation sequences. The soil was a hard-setting red brown earth. Three stubble management and tillage treatments and three N fertiliser levels were superimposed on the rotations. This trial ran for 20 years. Large numbers of SA and interstate farmers visited this classical trial and many soil researchers took samples for separate studies.

The trial demonstrated that wheat yields, protein values and gross margins without applied N were markedly superior following grain legume crops (especially faba beans) than continuous cereal rotations employing N fertiliser applications. Wheat yields following sown legume pasture were superior to wheat following volunteer pasture. Wheat yields following long fallow were often high, but this superiority declined with time. Most rotations were exploitive on soil organic matter, especially where stubble residues were removed, but the un-grazed sown pasture-wheat rotation had a positive effect where residues were retained.

With time, herbicide resistant ryegrass and soil acidification (especially at high rates of N fertiliser) emerged as issues to be resolved. In 1996, Mike Krause calculated gross margins for the treatments across the first 18 years that showed large treatment differences.

In 1976, with various external sources of funding, Bob Fawcett and Noel Pederson (with assistance from various research and technical staff) established a series of tillage-rotation trials across SA, where conventional cultivation was compared to reduced and zero (no-till) tillage treatments together with various stubble handling systems. Residual herbicide activity in soil was also studied by Tim Herrmann. These long-term trials were conducted at Lameroo (on Fred Maynard’s farm), Coonalpyn (Dean Klitscher), and Halbury (Greg and Ashley Robinson) and medium term trials were conducted at Tailem Bend (Ray Bald), Balaklava (Dean Hill) and Coonalpyn (Gordon Lutze). A Shearer trash worker, mulch treaders, wide shares and narrow points on seeders were used.

Again yield responses and soil chemical and physical variables were monitored. Yields were essentially similar across the systems studied (some tillage systems and machinery used were modified over time), except where weed control had been ineffective. Water infiltration into soils improved under reduced tillage and stubble retention.

During this period, new herbicides became available for weed control for the new tillage, rotation and stubble handling systems – herbicides were replacing soil cultivation. Tim Herrmann (now with Rural Solutions) concentrated on studying the soil incorporation of Trifluarlin and Avadex into crop stubbles and the residual impacts of herbicides, such as Glean and Ally, on the establishment and health of following crops. 

In 1984, Tim also established a 10-year rotation trial (wheat-barley-grain legume) at Tarlee (on Mark Hill’s farm) on sloping land to examine stubble retention loads (0.5 to 5 tonnes/ha) and four tillage practices (no-till; direct drill; reduced tillage and conventional tillage) on crop productivity and soil physical properties. Stubble retention increased grain production by 15 %, this being attributed to higher soil organic N status, better soil structure and rainfall infiltration. Using Noel Pederson’s rainfall simulator David Mallinda and showed that stubble retention and no-till reduced soil erosion potential – at least 60 – 75 % soil cover (2 – 3 tonnes/ha of crop stubble) was required to protect sloping soils from erosion. 

Bob Fawcett was also involved in a six year ‘scalping’ trial conducted at the Mortlock Experimental Station at Mintaro (managed by Ian Bidstrup) where the impact and management options from removing soil to various depths (up to 25cm) were assessed under different tillage, fertiliser regimes and rotations. Soil removal markedly depressed crop yields. 

Bob Fawcett and Noel Pederson also organised the very popular annual ‘Tillage systems, Rotations, Nutrition and associated Root diseases’ workshops where the latest findings from soil and agronomic research projects conducted by the Department and other agencies were presented.

Up to 130 people attended these meetings including interstate researchers. Departmental advisers, agribusiness and leading farmers raised observations on emerging farming system issues.

Collectively, the Departmental Soil & Land Management team at Northfield (Bob Fawcett, Tim Herrmann, David Malinda, Gerry Davies, Jeremy Cocks, Peter King and Noel Pederson) received two National awards for their contributions towards conservation farming. These were: the 1991 National Landcare Award for Conservation Land Management and the1992 Banksia Award for Conservation R&D (Category Agribusiness).

Denis Elliott and Dr Angus Alston (University of Adelaide) also established a long-term P rotation experiment (1985 – 1993) on the Mallala farm of Jack Angus that had a moderate soil P status. This trial had 192 plots and examined the most efficient method of applying four levels of P fertiliser (0 – 50 kg P/ cycle) to a 2-year wheat-medic rotation. Two levels of N fertiliser and two tillage systems (conventional and reduced tillage) were also superimposed. Trends in soil P pools across treatments were monitored. Applying P fertiliser to the wheat phase of the rotation was more efficient than applying it solely to the pasture phase. Split applications (50 % to wheat and 50 % to pasture) produced intermediate yield trends. Small and slow declines in soil P levels occurred where no P was applied but increased appreciably in the organic and inorganic soil P pools where P fertiliser was applied regularly.   

CSIRO Division of Soils established a long-term rotation trial (1976 – 2001) at Robin Manley’s mallee farm at Mallala to examine the effects of rotations and tillage systems on root diseases, especially Rhizoctonia. Another rotation trial at David Shannon’s farm at Kapunda (1983 – 1992) investigated rotational effects on soil physical condition and soil biological health.

Monitoring programs

Three monitoring programs were established in the mid 1980s in the mid North region (Peter Wegner and Cathy McDowell), the Eyre region (Tony Adam) both projects monitoring cropping systems. On Yorke Peninsula, Jo Crosby monitored pasture condition. The Northfield Soil laboratory provided analytical support for each project. Farm paddocks were selected on the number of years of continuous cropping and an area within each paddock was sampled intensively for weeds, disease and pests, soil and plant nutritional status, soil structural stability, crop yield and grain protein. Statistical packages were used to associate these variables with farming practices used by farmers.

For example, in the mid North survey (77 red brown earth paddocks sown to wheat were sampled between 1985 and 1986), measured parameters varied widely between sites as did crop yields and WUE. Many original hypotheses were overturned by the data. The conclusions reached were that high cropping intensity (up to 25 years) and high soil disturbance was associated with higher wheat yields, mainly due to improved control of grassy weeds that were hosts to cereal root diseases. However, intensive cropping was also associated with poorer soil structure, lower soil organic matter levels and many crops were deficient in N as only limited N fertiliser had been applied by farmers.

6. ‘Protein for Profit’ – declining wheat protein levels

In 1989/90, the Australian Wheat Board sought advice on what factors were responsible for declining protein levels in wheat delivered to SA and interstate silos, since this was now affecting the marketing of wheat overseas. The AWB introduced a premium price schedule for higher protein deliveries of wheat. 

Over the years, many research projects had routinely tested harvested grain for protein, even though farmers received no payment incentive. In a program called ‘Protein for Profit’, coordinated by the Soils group at Northfield, available SA data from all research agencies were scanned to identify what farming practices were associated with variations in wheat protein levels. Ultimately, five Departmental technical publications were prepared by agency specialists and released in 1990. The topics covered included: protein trends at SA silos; impacts of protein on baking quality; the physiology of protein and starch deposition in wheat endosperms; effects of soil N dynamics on grain protein; and the effect of farming practices on protein levels. These findings were discussed at a technical workshop held at the Waite, (attended by interstate researchers) and farmer meetings were subsequently held to explain what had been learned about this issue. Inadequate soil N supply to crops was seen as the major constraint, but changes in wheat variety selection were considered to have had only minimal impact.

Looking back

As I look back over this era (1963 – 1990) in the Department of Agriculture, the work undertaken by the Northfield soil staff produced outcomes that ultimately help shape the evolution of modern farming systems and practices in the cropping and higher rainfall pasture zones of SA. Many programs of work were done collaboratively with regional research and advisory staff and with other agencies and we were certainly encouraged by the enthusiasm, excellent innovations and goodwill of farmer co-operators and farming communities in general.

I also record that as a new graduate entering the Department we were privileged to enjoy the strong leadership and wisdom of our senior research and advisory staff. They encouraged us to seek higher training (to sharpen our skills) and to publish our research findings (or perish). Teamwork was the essence of success and enduring friendships were made. As one of my colleagues recently said:

‘If your career was in agricultural research, Northfield was the best and most enjoyable place to be’.

Prepared by Doug Reuter (June 2007) with valuable inputs from Denis Elliott, Bob Hannam, Bob Fawcett, Tim Herrmann, Dale Lewis, and Peter Allen.