DOUBLING TANJIL lupin row spacing can give yield increases in paddocks that have typically had low lupin yields and related improvements in gross margin. That's just one of the results from row-spacing trials conducted by the Western Australian NoTillage Farmers Association (WANTFA).
The trials involved eight growers from the central and northern wheat belt during 2000 and 2001. They sowed Tanjil lupins at the 'normal' row spacing (18-25 cm) and twice the normal row spacing under the guidance of Farm Focus Consultants. Seeding rates were adjusted to try to have both treatments ending up with the same number of plants per hectare.
Grower Gordon Curtis of 'Binnaburra', 25 km north of Kellerberrin, saw his yields climb from 1.24 t/ha to 1.42 t/ha by doubling his row spacing from 9 inches (23 cm) to 18 inches (46 cm). He considers this to be a good result with most growers in the district aiming to get 1 t/ha.
Mr Curtis saw a further benefit in the increased number of plants in the wider rows, which forced the lupins to grow higher to compete for light. The result was that the pods in the wider rows averaged 4 cm higher off the ground.
"This makes harvesting a lot easier as the pods came into the header a lot better," says Mr Curtis.
Lupins grown in the ' normal' row spacing were so low in places that Mr Curtis found he was battling to get the header comb underneath the pods.
Mr Curtis says there is room for improvement on determining the best seeding rates for the district. A trial is planned for this coming season. "We actually ended up with 74 plants/m2 in the wide-spaced rows, which is higher than the recommended 40-60 plants/m2 says Mr Curtis. "Just doubling the seeding rate clearly isn' t good enough."
Plant density in lupins sown at normal row spacing was still high at 62 plants/m2 Concurrent WANTFA lupin trials have confirmed that simply doubling the row spacing in otherwise low-yielding crops is perhaps the most effective strategy for WA growers. Other strategies, such as skiprow configurations, can give yield penalties. (Skip row involves two rows of crop, then missing a single row (single skip) or missing two rows (double skip); double row is one single row at twice the row spacing.)
Best for low-yielding crops
The trial results suggest that increasing row spacing is worthwhile only for sites likely to yield less than 2 t/ha. At higher yields it seems that increasing row spacing does not increase yields. "This confirms grower observations that the benefits of wide rows are greatest for low-yielding crops," says Bill Crabtree, WANTFA's scientific officer.
Based at Meckering, these trials showed a very poor yield response to double and triple skip-row configurations. And very wide (84 cm) row spacings also had reduced grain yields (see table).
However, Mr Crabtree says a late sowing in mid-June might help explain the reduced yields observed in the Meckering trial s. Trials of lupins sown with a extra-wide 1-metre row spacing at the same site early in May yielded 1.9 t/ha, which is better than yields from the 84 cm rows.
"These treatments also indicated a strong benefit from the highest seeding rate of 70 kg/ha," he says. The Meckering trials confirmed growers' observations of increases in pod height, of 10- 18 per cent, in the wider row spacings (see table).
Also noticeable was a difference in pod height from one side of the row to the other in east- west running rows. The lowest lupin pod heights were up to 20 cm high on the south side of the rows compared with 10 cm on the north side, a difference noted by growers in their on farm trials.
Mr Crabtree says the trials also showed that wider rows give less soil disturbance and easier stubble management, which are likely to stimulate fewer weeds. Other benefits include the potential for wide rows to help in controlled traffic, allow cheaper knockdown herbicide application between the rows, create more aeration in the crop canopy, and allow selective and more expensive pesticides to be banded in the crop row.
WANTFA and individual farmers will do more work with the wide rows at the Meckering site in 2002. Growers will further test the time of sowing for different row spacings, with some initial results being presented at a field day on 17 September 2002.
With no measurable difference in grain quality or screenings, the future looks bright for wide row spacings for lupins in WA.
Acknowledgments: Funding is from BEELINE Technology. GRDC, CSBP future farm, Elders, and Farm FOCLlS clients. Agritech Crop Research conducted the Meckeril1g trials, Bowden and Lance took plant and soil samples. Consultant Mr Geoff Fosbery supervised the trials.
Program 4 Contact: Mr Bill Crabtree 08 9622 3395