A simple on-farm pasture test is an effective way to identify a molybdenum deficiency in pastures.
Molybdenum ( Mo) is necessary for clover growth, but testing for this trace element can be difficult.
Where there is a deficiency, it is often difficult to find enough clover to sample without the leaves being contaminated with soil. The soil distorts the results by elevating Mo and nitrogen content.
Even without soil contamination, the results of a Mo test can also be difficult to interpret as nitrogen also needs to be taken into consideration.
A Beef + Lamb New Zealand factsheet, produced as part of the Hill Country Futures research programme, outlines a simple protocol for setting up pasture test strips in three to five representative paddocks to identify a mo deficiency.
The test areas should be marked-out strips of pasture of about five metres long and two metres wide containing at least 10 percent clover.
Ideally, the location could be GPS marked before 500 grams of granular Mo (10% Mo) is spread evenly over the 10 square metres.
It is then just a matter of observing the strip over a six-to-12-month period.
If the clover in the majority of the strips is more vigorous than the clover outside the strips, then it is recommended that 100 grams of Granular Mo (10% Mo) per hectare or 50g/ha of sodium molybdate is added to the next fertiliser application.