Effects of tillage, stubble, gypsum, and nitrogen fertiliser on cereal cropping on a red-brown earth in south-west Queensland

Abstract

We describe effects of a range of fallow and crop management practices on soil properties and crop growth in wheat and grain sorghum on a red-brown earth in south-west Queensland. Results from the first 4 years of the experiment, which commenced in 1983, have been published. This paper reports results from the next 6 years. No tillage (NT) and reduced tillage (RT), combined with stubble retention, resulted in better soil-water storage during fallow but less soil nitrate-nitrogen (N) at sowing than observed with more frequent and aggressive mechanical tillage treatments such as discing, and stubble removal. In drier growing seasons, when N application often resulted in yield reductions in wheat, NT and RT with stubble retention resulted in higher grain yields than other treatments in both crops. In a wetter growing season, when N application resulted in yield increases, wheat yields under NT and RT with stubble retention were lower than those of other treatments, even at the highest rate of N application, indicating that factors such as plant disease were also affecting yields. With stubble retention, average yields of 6 wheat crops were 12% higher under NT and reduced blade tillage, and average yields of 4 sorghum crops were 20-30% higher under NT, than other tillage treatments. Gypsum application resulted in an average yield increase of 15% in both crops under conventional disc tillage with stubble retention. In wheat, NT and RT with stubble retention were generally associated with lower grain protein concentration, and N application was necessary to maximise profitability of these practices.

Subsoil constraints to grain production in the cropping soils of the north-eastern region of Australia: an overview

“…Dalal (1989) showed that stubble retention and no-tillage reduced both ESP and salt levels in a black Vertosol (Table 3). Similar effects of these practices have been observed on a red-brown earth soil (red Chromosol) in southern Queensland (Thomas et al 1995) and in long-term zero-tillage trials on grey and black Vertosols of northwest NSW (W. Felton, pers. comm.…”

“…5). Highly mobile ions, such as NO 3 -, have been shown to concentrate deeper within the soil profile (Thomas et al 1995;Turpin et al 1998) concentration of NH 4 + has also been reported between soil depths of 1.2 and 3 m; however, in some Vertosols, the source of this deposit is unknown (Page et al 2002).…”

Soil carbon change and its responses to agricultural practices in Australian agro-ecosystems: A review and synthesis

“…Agricultural systems modelling facilitates scenario analyses by specifying different combinations of management options, and the investigation of the impact of long-term climate variability and future climate change on agricultural systems productivity and soil C dynamics. An agricultural systems model with well-tested crop and soil modules enables the exploration of the interactions among agricultural practices in regulating soil C dynamics (Thomas et al, 1995;Heenan et al, 2004;Hooker et al, 2005;Al-Kaisi et al, 2005;Wang and Dalal, 2006;Poirier et al, 2009) across space and time, which is otherwise impractical through conducting field experiment because of the large spatiotemporal variability in both climate and soils and the possible management options.…”

Performance of Jatropha curcas L. in Semi-arid Zone: Seed Germination, Seedling Growth and Early Field Growth

“…Different patterns of response of gypsum have been reported on growth and yield of different crops. Gypsum treatment to the soil is reported to increase yield of low bush blueberry (Sanderson et al, 1996), wheat and sorghum (Thomas et al, 1995) and corn and alfa-alfa (Toma et al, 1999). However, Viator et al (2002) could not obtain any response of gypsum on yield and root growth in sugarcane and described that short duration…”