Crops

Maize best-suited for two-crop cotton rotation: study

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Maize is a suitable rotation crop for irrigated cotton in a two-crop sequence, but is of little additional benefit in a cotton/wheat/maize sequence, according to NSW DPI research.

Scientists reported that a maize rotation introduced into irrigated cotton crops improved lint yields and reduced GHG emissions but had little impact in a minimum-tilled cotton/wheat rotation.

Lead researcher Nilantha Hulugalle, now at ANU’s Fenner School of Environment & Society, said the research followed the increasing use of maize as rotation crops in cotton farming systems. “Although sowing winter cereal crops in rotation with irrigated cotton is practised by many Australian growers, summer cereals such as maize are sown more frequently than previously,” he said. “Our objective was to quantify the impact of sowing maize rotation crops on soil properties, greenhouse gas emissions, incidence of black root rot (BRR) disease and crop yields.”

Through research funded by the Cotton Research and Development Corporation at the Australian Cotton Research Institute near Narrabri, the team sowed maize into an on-going long-term experiment, during which a flood occurred.

They found higher concentrations of minerals such as exchangeable calcium and magnesium under the maize plots after the flood, which might have helped reduce BRR, but that the concentrations dissipated after a few years. Likewise, soil organic carbon (SOC) was higher only in the soil surface layer and only three years after maize was first sown, but did not lead to any increase in SOC storage.

Dr Hulugalle worked with NSW DPI’s G. Nachimuthu, K. Kirkby, P. Lonergan, V. Heimoana, M. D. Watkins and L. A. Finlay.

Source: Soil Research 58(2) 137-150 https://doi.org/10.1071/SR19242