EFFECTS OF YARA FERTILIZERS ON THE PERFORMANCE OF RICE (Oryza sativa L) AS INFUENCED BY NPK APPLICATION TIMING IN GUINEA SAVANNAH ZONE OF GHANA

Abstract

There are different Yara fertilizer formulations used by farmers to improve soil fertility for increased rice performance and productivity. There is however very little information on the appropriate Yara NPK and N-source fertilizer formulations and time of application that can support increased rice grain yield. As a result, a field experiment was conducted under rain-fed conditions at Nyankpala near Tamale in 2017 rainyseason to evaluate the effect of Yara NPK fertilizer type (actyva, unik 15 and No fertilization) and N-source (amidas, urea and No N-source) on rice performance under different application regimes at 2 and4WAP.TheGbewaaricevarietywasusedfortheexperiment.Thestudywas a factorial experiment laid out in randomized complete block design (RCBD) in three replications. Actyva and unik 15 fertilizers were applied at the rate of 125 kg/ha at 2 or 4WAP and top-dressed either with amidas at 125 kg/ha or urea at 125 at panicle initiation. Unik 15 recorded significantly highest grain yield of 5305 kg/ha representing 56.51% increase over No NPK fertilization. Unik 15 gave the highest number of effective tillers per hill of 15.1 representing 17.8 % increase over no NPK treatment. Actyva recorded the highest number of tillers per hill, panicle length, number of grains per panicle, number of filled grains per panicle and straw yield. Urea top-dressing gave the highest chlorophyll content, number of filled grains per panicle and dry shoot biomass at harvest. The interaction between actyva and amidas gave the highest number of grains per panicleof140.2.Top-dressingwithureaafterunik15applicationat 2WAPgave the highest straw yield and harvest index. The high grain yield recorded by unik 15 could be due to its N in the form of balanced combination of ammonium and nitrate which ensured sufficient nitrogen under anaerobic condition. This could also be attributed to its 5 % more phosphorus over actyva.