Aglime and Lupins
Long Term Average
Our extensive trial programme has shown that, on average, lime has no effect on lupin yields in the long term (over 12 years). This is the conclusion from Aglime of Australia’s long term field trial programme which is designed to identify benefits and problems associated with our product, Aglime, under commercial farming conditions and different rotations in the central and northern wheatbelt.
Since the Aglime trial program commenced in 1981, we have measured a total of 405 plots from 38 trials at 17 locations where farmers sowed lupins over limed plots. Overall, yield in control plots (which are not limed) are no different when compared with the yields of limed plots. These results are summarized in the figure below.
It clearly can be seen that lupins tend to be variable in yields regardless of the soil pH. (Most of the plots with pH levels over 5.0 in this graph were limed and below 5.0 were not limed.)
Effect of location and season
At all of the 17 locations there is also no effect of aglime on lupin grain yield. However, in any one-year at some locations there have been occasions when either significant increases or decreases in lupin yields have occurred. For example, at one location, lupins showed no effect from liming in the 2nd season, then responded negatively in the 6th season and positively in the 8th season after liming. However, the average effect of aglime on lupins at that location was 0%.
Negative responses in lupins to lime may arise from reduced uptake of certain nutrients including potassium, copper, zinc and manganese and farmers should ensure that these nutrients are not limiting when liming in a wheat/lupin rotation. Chris Gazey (Agriculture WA) in 1997 has shown clearly that a depression in lupin yields after liming was prevented by applying potassium after sowing and spraying manganese at podding because the soil was deficient in these nutrients
Low manganese levels may also lead to split and shrivelled seed. In Chris’ trial, the seed problem was made worse where potassium was applied without manganese. Overcoming the potassium deficiency increased the yield potential and diluted the low manganese reserves even further. It also appears that sulfonylurea herbicides may carry over under certain conditions and affect early lupin growth.
However, liming can also increase lupin yields possibly through increased nitrogen availability early in the season before the lupin plant has nodulated or through improved soil wetting and water infiltration. As lupins are more tolerant of aluminium toxicity than wheat, liming is likely to have less effect on lupins than wheat. To get the best results from liming, especially if lupins are in the rotation, it is essential to ensure nutrients are at good levels (particularly potassium, manganese, zinc and copper) and sulfonylurea herbicides are applied according to the label.
Aglime of Australia encourages clients to tissue test regularly to ensure nutrients, particularly trace elements, are not limiting yield.
To get the best results from liming if lupins are in the rotation, it is essential to ensure:
• Nutrients are at good levels (particularly potassium, manganese, zinc and copper)
• Sulphonyl urea herbicides are applied according to the label