First yield results of Nutrients Omission Trials (NOT) reveal significant responses to fertilizer. First data on the 34 NOT trails have been analyzed and it is now available. The average root yield increase with NPK recorded from the first yield results is 4 t/ha but varying between 0-15t/ha.
The results from 23 trials in Tanzania and 11 in Nigeria show substantial responses to fertilizer following trends similar to those observed in other crops like Maize.
The NOT trial activities observed;
- Non-responsive fields with low control yields (less than 10t/ha)
- Strong responses in fields with medium control yields (10-20 t/ha) and less frequently
- High yielding fields of more than 20t/ha with low response to fertilizer
These results seem to indicate that Nitrogen (N) is the most deficient nutrient followed by potassium (K). No yield increase was observed when only Phosphorous (P) and Potassium was added. Application of Potassium results in site specific responses only.
Harvest for the for NOT trials is ongoing. There will be more analysis on the trail results is expected to provide extensive and conclusive data.