The QLD Department of Agriculture and Fisheries (DAF) recently completed a demonstration site on a cane farm near Freshwater to determine if different species and varieties of legume produce different amounts of nitrogen.
The project also analysed the legumes resistance to Root Knot Nematodes (RKN) on sandy soils.
DAF senior agronomist Derek Sparkes explained that green manure legumes were commonly used in the sugarcane farming system to break the monoculture, providing a break for cane pests and diseases.
“The green manure legumes provide excellent soil cover during the wet season as well as providing nitrogen for the plant cane crop,” Mr Sparkes said.
“Cane crops grown on sandy soils have a tendency to be infected with RKN which may also infect many other crops such as legumes that are commonly used as break crops.
“The purpose of the study was to see which of the available legumes showed the most resistance to RKN.
“We looked at nine different species, or varieties of legumes and compared the outcomes.
“We found that all the legume crops were well-grown and there were similar amounts of nitrogen fixed per hectare in the above ground part of the plant (around 150 – 180 kg nitrogen/ha; based on measured and N concentration data in ‘six-easy-steps’).
“Despite all the crops looking very healthy, there was a wide variation in the health of the roots and root galling.
“Although it is hard to draw firm conclusions from this study, soybeans like Stuart and A6785, as well as sunn hemp and peanuts, appear to have more fine roots, less root galls and low RKN numbers in the soil after four months of crop growth.
“We are keen to share the technical findings of the study with local canegrowers, who can call 13 25 23 to get more details.”
Source: QLD Government