A review of the soil science research legacy of the triumvirate of cotton CRC

Abstract

For nearly two decades (1994–2012) a series of three consecutive Cooperative Research Centres (CRC) dealing with cotton production provided the impetus and financial support for a substantial body of soil science research in eastern and northern Australia. Focusing on the most commonly utilised soil for irrigated crop production, the Vertosol, CRC-affiliated soil researchers undertook detailed soil inventories of cotton-growing valleys in New South Wales, and tackled a range of applied soil research questions that faced the entire Australian cotton industry. Across the broad categories of soil mapping and characterisation, soil physical condition, salinity and sodicity, soil chemical fertility, and soil carbon and biota, some 120 CRC-affiliated research papers were published in peer-reviewed journals during the years of the CRC. Findings from this body of research were fed back to the industry through conferences, extension workshops and materials, and to a lesser extent, the peer-reviewed publications. In certain cases, underpinning basic research was carried out concurrently with the more applied research, meaning that the cotton CRC were effectively supporting advances in the discipline of soil science, as well as in sustainable cotton production. A feature of the soil research portfolio over the span of the three cotton CRC was that priorities shifted according to the interplay of three factors; the natural maturation of research topics and the concomitant evolution of cotton farming systems, the rising importance of environmental implications of agricultural land use, and the emergence of carbon as a national research priority. Furthermore, the commitment of the CRC to education resulted in the involvement of undergraduate and postgraduate university students in all aspects of the soil research effort. A legacy of the triumvirate of cotton CRC is a wide-ranging body of both applied and basic knowledge regarding the physical, chemical and biological attributes of Australian Vertosols used for irrigated agriculture.

When does organic carbon induce aggregate stability in vertosols?

“…Research into the structural characteristics of vertosols in agricultural situations has revealed various problems including low aggregate stability (Cattle and Field, 2013;Prebble, 1987;Yates, 1972), low infiltration (Little et al, 1992) and high surface crusting and sealing (Pillai-McGarry and Collis-George, 1990), leading to severe sheet erosion (Junor et al, 1979) and crop yield declines (Yates, 1972). In contrast with other soil types where subsoils are wetted slowly by percolation through the surface soil, the subsurface aggregates in vertosols are rapidly wetted through cracks to appreciable depths (>1 m).…”

“…Organic matter has been considered less effective in determining soil aggregate size distribution and stability than other soil physico-chemical characteristics in vertosols (Charman and Roper, 2000;Coughlan and Loch, 1984;Coughlan et al, 1987;Dalal, 1989;Dalal and Bridge, 1996;Freebairn et al, 1996;Prebble, 1987;Reichert and Norton, 1994;Smith, 1984;Yates, 1972;Yates and McGarity, 1984). However, several authors have acknowledged that the use of cover crops, minimum tillage and stubble retention are generally beneficial for vertosol structural conditions (Cattle and Field, 2013;Ringrose-Voase and Nadelko, 2013).…”

“…This has implications for subsoil structure, infiltration and erosion (e.g. tunnelling) (Cattle and Field, 2013).…”

Subsoil Microbial Diversity and Stability in Rotational Cotton Systems

“…The majority of Australian cotton is grown in Vertosols, where minimum tillage and rotational crops are utilised to improve soil structure, promote and protect soil organic carbon (SOC), introduce and optimise nutrients in the system and suppress disease [20][21][22]. In soils that are considered low in OM and natural nutrient sources (compared to northern hemisphere soils), there is an increasing need to find innovative ways to maintain and enhance these depleted soil resources to meet the demands of a growing global population [23,24].…”

Lessons from extension activity related to cotton rotation impacts on soil—A scientist's perspective

“…Within the Australian cotton industry, soil-related extension was initially undertaken with the development and promotion of SOILpak (Daniells, Larsen, Mckenzie, & Anthony, 1996). As an extension vehicle, SOILpak was generally seen as a success, going through three updated editions and forming the basis of subsequent COTTONpaks (Cattle & Field, 2013). The extension of SOILpak was facilitated through industry development officers, but these positions were largely lost due to the 2001-2009 millennial drought (Dijk et al, 2013), which affected most agricultural sectors (Heberger, 2012) and resulted in a disconnection between farmers and research within the Australian cotton industry.…”