The optimum P2O5tato route to extra yield
Independent research has demonstrated the importance of phosphorus for tuber bulking. The longer the phosphorus level in the crop is maintained the greater the yield potential. Yield potential is increased by around 0.5 t/ha for each extra day that the phosphorus level in the petiole is kept above 0.22%. However the level of phosphorus in the petiole peaks at tuber initiation and then declines as the season progresses. In northern European conditions the phosphorus level normally arrives at 0.22% around 100 to 110 days after planting. Any "premature deficiency" incurs a yield penalty of 0.5 tonnes per hectare per day.
Predicting the P2O5tato requirement. If prediction of the P2O5 requirement can be made early in the season then the 0.5 tonnes per hectare per day through the bulking phase can be saved - or gained. Phosyn has the answer in its petiole analysis databank and range of effective foliar phosphates.
Megalab potato petiole programme. Since 1993 we have been analysing potato crops and our petiole analysis database currently stands at over 5000 samples and continues to rise. Biometric analysis of results allows us to establish phosphorus values early in the season which are equivalent to the critical figure of 0.22% at 100 days after planting. The Phosyn petiole Megalab system now becomes much more PROACTIVE because when a petiole sample is analysed we are asking the question "Will this crop make it to 100 days after planting before the phosphorus level drops below 0.22% ?". Another benefit is that normally only one sample per season is needed rather than the regular, repeated samplings normally required.
Taking a petiole sample. The sample is made up of around 80 petioles. The forth petiole from the growing point is taken and the leaflets should be immediately stripped off. Sampling can be carried out any time after tuber set has taken place, which normally means around sixty days after planting. Samples analysed by Phosyn Laboratories are automatically put through the Megalab system. Before sending samples to other laboratories contact us to check whether the Megalab service is available.
Author: John Brooks, Global
Published: June 2000