Wolf Trax treatment shows the benefit from early nutrition

Early last spring, I reported on some research that looked at the use of Wolf Trax dressing as a source of trace element supply for cereal production.

This involves the application of the trace nutrient(s) on the base fertiliser so as to have an early supply and to have the nutrient(s) distributed through the soil to enable early and continued availability in the early stages of plant growth.

Wolf Trax trace elements are applied to the fertiliser, which should be spread in advance of planting and incorporated into the seedbed.

The objective is to have the nutrient present and available to the plant to prevent the appearance of deficiency symptoms. In theory, if deficiency symptoms can be prevented, the benefit should be higher than the benefit which could accrue from foliar application on the appearance of symptoms.

In 2015, field research continued, this time on two sites likely to have deficiency. This was conducted by Dr Edna Curley from NUI Galway and involved replicated trials which compared the use of Wolf Trax with one or two foliar applications.

The manufacturers of Wolf Trax claim that the product can only replace the initial application, which is usually applied after the onset of symptoms when loss of yield potential may have already occurred.

The focus of this research was manganese (Mn), but other elements can also be applied. Following the results from recent years, future trials will evaluate a wider range of nutrients and crops, including combinations of micro-nutrients. The 2015 results are very interesting and raise even more questions for the future.

Two separate trials were conducted on sites around Athy in Co Kildare. The treatments were broadly similar and applied to spring barley, but treatments were not identical in the two trials.

Both sites had high soil pH and one was very low in soil Mn while the other was higher in Mn, but which frequently showed Mn deficiency symptoms.

One of the trials used seedbed incorporated NPK fertiliser (treated or untreated with Wolf Trax Mn), while the other had its NPK applied when the tramlines were visible, along with the Wolf Trax treatments.

So the question was asked as to whether the fertiliser dressing could function fully when applied as an early topdressing?

In essence, the trials compared no Mn treatment with standard-practice two foliar applications and with three treatments dressed with Wolf Trax Mn.

One of the latter received no subsequent foliar treatment, the second received a foliar Mn spray at GS 12/13 and the third received two foliar treatments, the second at GS 30/31.

Trial 1: Fertiliser applied in the seedbed

This site had high soil organic matter (10% to 15%), a pH of 7.7 and a soil manganese reading of <25 mg/litre. The yield results from the different treatments are shown in Figure 1.

Firstly, it can be seen that the treatment with no manganese had a very high yield at 8.45t/ha. Secondly, the standard double foliar spray treatment added nothing to yield, while the fertiliser treated with Wolf Trax Mn gave a significant yield increase. Interestingly, foliar treatments on top of the seed dressing appeared to depress grain yield.

These results are interesting and reinforce my belief that waiting for symptoms to appear may already have resulted in lost yield potential, which is prevented by the seedbed fertiliser treatment.

The yield from the follow-up sprays on the Wolf Trax were not significantly lower than the fertiliser dressing only, but neither were they significantly higher than the untreated.

And comparing treatments, the Wolf Trax-treated fertiliser treatment yielded 0.33t/ha over the double foliar treatment, which meant a higher yield at lower cost.

Trial 2: Fertiliser applied tramlines visible

This method of fertiliser application was standard practice on this farm and so was used as the method of Wolf Trax application at this site.

This site also had a high soil pH of 7.8, along with high soil P and low soil K (index 2). The soil Mn level was found to be 114mg/l, which is regarded as high index 2.

In this trial, the compound NPK fertiliser was applied post-emergence of the crop when the tramlines were visible.

This meant that the Wolf Trax treatments on the fertiliser were also applied post-crop emergence and on the surface. This could mean an additional risk, as nutrients applied on top may not be available to plant roots if the weather was to remain dry post-application.

One extra treatment was used in this trial. One treatment had the NPK incorporated into the seedbed, followed by two foliar sprays, to have a comparison with other trial sites.

The other five treatments were: NPK post-emerge only (no Mn); NPK post-emerge followed by two foliar treatments; and then three NPK treatments treated with Wolf Trax Mn and applied post-emergence. One of these received no further Mn; the second received a foliar Mn early (GS12/13); the third also received a follow-up foliar spray, but applied late at GS30/31.

Yield was also very good in this trial, but the consequences of not applying Mn in any form is shown by the untreated yield in Figure 2.

In this trial, all Mn treatment products produced a significantly higher yield than the untreated plot (the bar on the left in Figure 1).

Yield received a significant boost where the NPK was incorporated into the seedbed and followed by two foliar Mn sprays.

While not significant, this treatment was better than where the NPK was applied after the tramlines were visible, followed by the same two foliar treatments. In this case, it seems that the major difference, although not significant, is due to the placement of the fertiliser in the seedbed.

Where the Wolf Trax Mn was applied with the fertiliser on top, yield level was broadly similar to where no Mn was applied with the NPK post-emergence, but where two foliar sprays of Mn were applied.

The highest-yielding treatment was where the post-emergence-applied Wolf Trax was followed by an early foliar spray. When this follow-up foliar spray was delayed to GS30/31, the yield boost was lost.

The results from these trials show the benefit of having the Mn present and available from the commencement of plant growth.

The Wolf Trax-only treatments all performed well, but only in some instances was there a significant benefit from a follow-up spray.

Indeed, the question arises as to whether the standard GS30/31 treatment may be negative for yield. Could it be that the application of an element to a plant that is already adequately supplied with that nutrient is generating a negative consequence?

If this is the case, then this needs to be clarified as quickly as possible, as it is key to the efficient use of Wolf Trax trace element dressings.

Previous research has indicated that a small amount of well-timed product can be very beneficial.

Trace elements are costing growers a lot of money and it is essential that we know how to use individual products to best advantage.