Abstract:
Inorganic fertilizer application is among the major factors help to improve crop
productivity. Use of fertilizersfor major cereal crops, including wheat, was started in
Ethiopia before forty years; even though the recommendation still remained more
general. The current scenario of fertilizer requirement is moving towards soil and crop
specific recommendations. This study was conducted to evaluate the feasibility of
previous and current NP blanket recommendations for wheat production on Andosol. It
was carried out in Cheleleka Donga kebele ofOmo Nada district in Jimma zone, Oromia
Regional State, south western Ethiopia during the crop season of 2019 on farmers’
field. N and P rates recommended at various times were used as a base for treatment
setting. Accordingly, two rate of N (64 and 73 kgN/ha), three rates of P2O5 (37.7, and 69
kg /ha) and three rates of K2O (0, 18 and 36kg/ha)were used.The experiment was laid
downin a randomized complete block (RCB) design with a 2*3*3 factorial treatment
arrangement in four replications.The soil analysis result showed that it is strongly acidic,
deficient in available phosphorus, optimum in total nitrogen and organic carbon and
high in available potassium. The differences among fertilizer treatments were not
significant for plant height(PH), leaf area index(LAI) and biomass yield (BMY). Spike
length was significantly influenced (P < 0.05) by nitrogen rate. Spikelet per spike was
significantly affected by the interaction of Pand K. Number of seeds per spike was
significantly influenced (P < 0.05) by the interaction of N and K. Thousand seed (kernel)
weight was significantly affected (P < 0.05) by K rate. Grain yield was only significantly
affected(P < 0.05) by P rate and the maximum value (4574 kg/ha)was obtained when
69kg/ha P2O5 was applied, followed by 46 kg/ha P2O5 with grain yield of 4323kg/ha ,
with the respective yield advantage of 12.74% and 6.56% over the minimum rate (37.7 kg
P2O5/ha). The maximum net benefit was recorded for plots which received 69kg/ha P2O5
with MRR of 258%. In general, Phosphorus was found to be the major limiting nutrient
and, hence, improving its availability through improving soil pH and applying enough
amount of fertilizer would enhance wheat production in the area.
