AS A graingrower should you opt for liquid fertilisers to replace conventional top-dressing?
If early Agriculture WA trials are any indication, the answer is a resounding yes, with the usual caution that you should hold your own trials to establish a good learning curve on placement.
In six field trials established last year, banding or on-furrow applications of a commercial product, Flexi-N, resulted in greater plant growth and nitrogen uptake than Flexi-N applied with a boomspray or urea top-dressed.
In some trials, banding or on-furrow Flexi-N increased grain protein but in most cases, the short season limited grain filling and differences in grain yield between the placement treatments were not significant.
But some aspects of the trial work certainly will encourage more farmers to seriously evaluate liquid fertilisers. It is considered to be only a matter of time before liquid fertilisers becomes accepted practice in broadacre farming in WA.
The trials showed Flexi-N was safer to band than urea and there were positive signs of better plant growth.
At Mullewa, stored subsoil moisture from summer rain contributed to grain filling and yields responded significantly to nitrogen application, increasing from 2.1t/ha at nil to about 3.3t/ha at 40kgN/ha.
At Carnamah, at 108kgN/ha, wheat protein increased significantly from 10.5pc with urea top-dressed to 14.3pc with Flexi-N banded.
At Westonia, dry conditions severely limited crop responses to nitrogen with little significance in yield and protein differences between the placement treatments.
At Varley, at 80kgN/ha, the various treatments produced similar yields (2.7 to 3t/ha) but protein contents were 1-2pc greater where Flexi-N was banded or applied on-furrow.
At Arthur River, at the high nitrogen rate, Flexi-N banded produced the best yields and there was little difference between the other Flexi-N placements and urea top-dressed.
At Mindarabin, the late sowing and dry spring limited canola podding and seed filling considerably. It was impossible to draw any conclusions from the yield data but plant weight and nitrogen uptake data at 15 weeks after sowing indicated an advantage of on-furrow and banding Flexi-N compared with application through a boomspray.
In a further three wheat trials to study the responses to late foliar applications of Flexi-N, protein content increased by 0.5 to2pc with applications of Flexi-N at flowering (21 and 42kgN/ha).
At Yuna, Flexi-N was superior to urea when applied wholly at sowing. Applications of Flexi-N at the flag leaf stage( when the crop was showing signs of moisture stress) caused considerable leaf scorching. Late applications caused a significant yield reduction and failed to increase protein content.
Grain yields at Buntine (up to 5t/ha) were excellent because of stored subsoil moisture and timely sowing. There were no significant differences between grain yields with urea and Flexi-N.
Applications of Flexi-N at flowering had no effect on grain yields but improved protein by 0.5 to 1pc.
York was severely inhibited by a late break and dry spring conditions. Differences in yield between urea and Flexi-N treatments were not significant.
The application of Flexi-N at flowering increased protein by up to 2pc but reduced yields by about 8pc and significantly increased screenings.