NSW DPI soil scientist Nilantha Hulugalle says after two years of research, the long term benefits of sowing cotton into standing wheat and vetch stubble are starting to appear.

Cotton production could be increased by as much as two bales per hectare when cotton is sowed into wheat and vetch stubble if early research results are confirmed in the long-term.

The powerful combination could also make it possible to significantly reduce fertiliser use, according to NSW DPI.

The effects of rotation crops and stubble management on soil quality, carbon sequestration, deep drainage, nutrient leaching, yield and profitability are being examined as part of a major research project by the Cotton Catchment Communities Cooperative Research Centre.

One of the aims is to develop rotation systems under permanent beds, using stubble retention to improve soil quality, minimise erosion and retain moisture.

DPI soil scientist at Narrabri, Nilantha Hulugalle, said after two years of research the long term benefits of sowing cotton into standing wheat and vetch stubble were starting to appear.

'Standing wheat stubble can store up to 75 mm more winter rainfall than when the soil surface is bare, because it improves rainfall infiltration and reduces evaporation,' Dr Hulugalle said.

'While vetch doesn’t provide early season water conservation benefits because it uses moisture in the winter, the nitrogen benefits are significant enough to justify the extra effort.

'I suspect we may be able to greatly reduce fertiliser use and manage the crop so that it is applied on a needs basis much later in the season.'

Dr Hulugalle said some disadvantages relating to crop management needed to be addressed.

'Blocking of 'gas knives' by wheat stubble during application of anhydrous ammonia was overcome by attaching coulter discs to the front bar of the gass rig to cut through the stubble.

'Herbicide costs were very high, but we were able to significantly reduce herbicide usage by adopting a band sprayer.'

This story appears in Agriculture Today.