Evaluation of the Effectiveness of the Urea Deep Placement (UDP) Technology on Upland Maize Production.

Field trials were conducted in three communities in northern Ghana to evaluate effectiveness of the urea deep placement (UDP) technology for upland maize production. The UDP technology was compared with the standard farmer practice on the three maize varieties of differing maturity periods (early-, medium- and late-maturing varieties). Urea supergranules (USG) was applied at two time periods (4 and 6 weeks after planting (WAP)) to evaluate the effects of application time on the USG effectiveness. The response of the maize varieties to the USG application differed, with the medium and late maturing varieties responding better, in terms of increased yields, than the early maturing variety. Irrespective of the maize variety, applying USG at 6 WAP was not effective, and resulted in lower yields than the standard farmer practice. For medium and late maturing maize varieties, USG application significantly increased maize yields from 2.8 tons/ha in the standard farmer practice, to ~4 tons/ha, when it was applied at 4 WAP. This shows over 25% increase in yield with less fertilizer use (~15 % less fertilizer). For the early maturing maize variety, application of USG did not show any significant effects on maize yields, possibly due to the time of application of the USG. Thus, time of USG application is critical to the effectiveness of the UDP technology for upland maize production. Therefore, for medium and late maturing maize varieties, the USG must be applied to the maize plants by the fourth week after planting. Further studies will re-evaluate the optimal USG application time for early maturing maize varieties.