Tim Marshall was born in WA on 26 March 1907. His family moved around the farming districts of Boulder, Pingelly, and Wickepin, and then into Perth after his father enlisted in World War 1 between 1915 and 1918. He attended Perth Boys School, and Perth Modern School on a Coombe scholarship, then studied at the University of WA for his BSc(Agr).
	Irrigation soils
	On graduation he joined the new CSIR Division of Soils in Adelaide in February 1929, where he worked under the direction of JA Prescott (Chief of Soils Division and Professor of Agricultural Chemistry, University of Adelaide, Waite). He worked closely in the field with JK Taylor to survey the soils of the irrigated lands of the Murray River system, including soil profile examinations, soil analyses, detection of salinity and the preparation of reports and soil maps for each area. In the course of his work he studied soil physical properties and, encouraged by Prescott, obtained an MSc(Agr) in 1933 from the University of Adelaide, with a thesis entitled ‘The correlation between field estimates of texture and the mechanical composition of soils’. In 1936 he went to the University of California Berkeley to work with the soil physicist, GB Bodman, supported on a senior research studentship of the Science and Industry Endowment Fund). New developments in water retention and movement in unsaturated soils, soil structure and clay mineralogy provided tremendous stimulation for his future work, and he produced a PhD thesis entitled ‘The water-conductivity functions of a kaolinitic and a montmorillonitic soil colloid’.

Family

He returned to Adelaide in 1938 and married a bright young Masters graduate, Ann Nicholls, who also studied at UCB after graduating from University of Melbourne, and who eventually became an accomplished lecturer (and Chair) of the Department of Geography, University of Adelaide. They had three daughters, one of whom (Judy) died as a young child, and the other two of whom are highly successful research academics (Professor Jenny Graves and Professor Marilyn Gray (Lyn) Richards). In the early years after he returned to Adelaide, he reported on advances in soil physics and clay mineralogy at the winter school of soil science organised by JA Prescott in Adelaide in 1939. This event, and a second that he ran in 1945, were important as forerunners for the Australian Society of Soil Science, bringing together soil scientists from all over the country.

World War 2

Tim’s work in CSIR Adelaide focussed primarily on soil surveying, but early in 1942 (after Japan entered WW2) the Chairman of CSIR (ACD Rivett) sent him to Townsville to help the US Army on soils at sites suitable for aircraft landing strips. (He recalled that flying with American pilots was more terrifying than any threat from the Japanese). He examined sites in northern and western Queensland and western NSW for development of an inland channel for Army supplies. Because of the shortage of bitumen, Portland cement was proposed as a soil stabiliser and he determined the amount of water and cement and the degree of compaction required for sites at Bourke and Roto, NSW. In 1944 he went with the Australian Army north along the new road between Alice Springs and Darwin to study soils being irrigated with bore water to grow fresh vegetables for the Army. The Army then sent him to the Kimberley region where he joined GH Burvill and his group from WADA and CSIRO to conduct soil surveys for irrigation on the Ord River, with particular emphasis on soil water relations, for which he took field measurements using instruments made of improvised gear. After WW2 in 1945 he wrote up several CSIRO Divisional Reports on soil-cements and the irrigation possibilities in northern Australia. Notably, in a more general report on possible irrigation developments, he was the first to express concern about the stress being placed on water of the Murray-Darling system for crops like rice, which made extravagant demands on water.

Photo: CS Piper, JK Taylor, CG Stephens, University Chancellor Sir William Mitchell, TJ Marshall, JA Prescott, HC Stace, c. 1940. Source: A history of the CSIRO Division of Soils: 1927 - 1997 by KE Lee.

Soil physics section

In 1945 he became leader of the soil physics section of CSIRO Soils Division and was a great mentor for many Australian soil scientists. He worked with GB Stirk on soil-water relations associated with infiltration and drainage, and with GB Clark to show that annual cultivation decreased soil organic matter content and soil structural stability under wheat. He also worked with GD Aitchison, JS Colville, CG Gurr and JW Holmes, MW Hughes (among others) to tackle field methods for measuring water content and retention in soils (tensiometers, adsorbent blocks, neutron moisture meters). The work of the SOIL PHYSICS SECTION had a widespread influence on the design of foundations for houses on expansive soils, and on our understanding of water balances under pastures and forests and the contribution of water to groundwater systems. At the same time, he worked in the laboratory with AV Blackmore, WW Emerson, DL Farrell, EL Greacen, JW Holmes, DS McIntyre, K Norrish, JP Quirk, GB Stirk, and DR Williamson in Adelaide on the basic principles of soil composition, swelling of clay minerals, aggregate stability and soil strength and root growth, leaking of farm dams, improvement of irrigated land, water balance, water transmission, physico-chemical studies of aggregate stability, and salinity. In 1947 he completed earlier work on a diagram relating particle size distribution to field descriptions of texture, which was adopted as a standard for Australia. He was able to show there were inconsistencies and probably errors in the texture diagram of the USDA Bureau of Soils. With JP Quirk he developed a method for measuring the stability of structural aggregates of dry soil and with CG Gurr he measured the movement of water as liquid or vapour in unsaturated soil and the effect of a temperature gradient on this. He also developed a new form of an equation relating permeability to pore size distribution and water content which fitted published data for sands, and devised a plummet balance for particle size analysis1. The output of the soil physics section under Marshall’s direction brought it a high international reputation, with results that advanced the understanding of the principles of water movement and the stability and strength of soils as they affect plant growth. In 1959 the Commonwealth Agricultural Bureau published his small book ‘Relations between water and soil’, which grew into the textbook ‘Soil physics’ published by Cambridge University Press with JW Holmes (1979), then again with JW Holmes & CW Rose (1996).

Leadership roles

He became Assistant Chief (and Acting Chief) of CSIRO Soils Division, and also served as President of the SA Branch of ASSSI (1957) and then as President of ASSSI during the 1968 Congress of the International Society of Soil Science in Adelaide, organised with JK Taylor and EG Hallsworth. For ISSS he served as vice president of the Soil Physics Commission and President of the Technology Commission. He was awarded a Fellowship of the AIAST (1964), the Prescott Medal of the ASSSI (1974) and Honorary Life Member of ASSSI in 1989. Most recently he was awarded the Order of Australia Medal in 2000. After 40 years in Adelaide, he and wife, Ann moved to Victoria in 1983 to build a cluster of three family homes with their daughters and families in Eltham. In this environment he continued working and publishing in soil physics, and formed a good relationship with the LaTrobe University library in Melbourne. He enjoyed the challenge of taming the Eltham clay to grow tree fruits and vines, and later cared for Ann through five years' illness to her death in 2001. He delighted in his four grandchildren and three great-grandchildren. His final contributions to soil science included a publication in the Australian Journal of Soil Research at the age of 98 (Particle-size distribution of soil and the perception of texture. AJSR, 41: 245-249. 2003) and a video interview for the 50th Anniversary of ASSSI in May 2005. The week before his death, he completed his biography of JA Prescott for the Australian Dictionary of Biography. Even at the age of 101 Tim made his mark on a wide range of people and will be truly missed in the soil science community as a great friend and mentor.

Written by Cam Grant with help from Tim Marshall’s daughters, Prof. Jenny Graves & Prof. Lyn Richards