The recent trial results reported in the 2008 Primary Industries (copied to you in a bulletin) showed that there are a lot that farmers could learn by analysing trial results. For example, in the Merriwagga site, it appeared that due to low yield, the cost of extra nitrogen (as ulphate of ammonia or urea) and the cost of doubling the rate of MAP at sowing (presumably around $40.00/ha) was a loss over and above the observed yield loss. This minimum loss of over $40/ha especially hurts when we find that with an integrated program (BSN and Plasma), the net return was $68/ha or compared to the double rate MAP it was at least a loss of $108 .00/ha ($68.00+$40.00).

There are numerous reasons for the lack of response to nitrogen and phosphorus as observed in the trial. The high soil reserves of nutrients and low rainfall are some of the common reasons. Let us for a while disregard the statistics and assume that the drop in yield when the MAP rate was doubled or the nitrogen rate was increased was a probable/expected response. Searching for an explanation we find that high phosphorus inputs at sowing reduces zinc and copper uptake (Bolland and Baker 1988, Aust. J of Exp. Agric. 28, P 765; Zhu et al Annals of Botany 2001 P 941). Similarly, overdosing of nitrogen or high soil nitrogen could reduce the transport of copper from the old leaves to the developing head (RFBrennan 1993, Aust. J of Exp. Agric. 33, P 901) at critical stages of maturity that soil uptake of copper is limited due to firstly drying soil conditions and secondly reduced root activity. While the scenario may vary in different situations, this result highlights the significance of fertiliser integration (e.g. utilizing soil, seed and foliage) that allows the grower to prime the seed, use sufficient fertiliser at sowing and keep the means to apply foliar spray during the season; especially when all could be achieved with no increase in fertiliser budget. Fertiliser integration is scientifically sound and particularly relevant in Australian conditions with high nutrient variability in seed and soil reserves.Priming the seed with BSN and the ability to correct nutrient deficiency during dry spells by foliar spray are useful tools that should not to be missed. While replicated randomized trials give confidence when the treatment is statistically significant, the lower the yield response, the greater is the chance of it not being statistically significant. The alternate option is to extract useful information from simple trials.