Determinant of optimum plant density, nitrogen and phosphorus fertilization for different wheat genotypes
Keywords:
Variety, planting density, economic analysis, fertilizer.Abstract
Optimum seeding rate and nitrogen (N) and phosphorus (P) fertilization are the most important production
factors for higher grain yield. Indiscriminate use of seeding rates and N and P fertilization does not only
increase production costs but usually decrease wheat grain yield. Study on the interaction effect of planting
density and N and P-fertilizer levels on bread wheat varieties was conducted in 2014 cropping season on
vertisols of Ofla and Emba-Alaje districts of southern Tigray, Ethiopia with the objective of determining the
optimum plant density and optimum N and P fertilization for different Wheat genotypes. The experiment
contained split-split plot design on which three recently released bread Wheat varieties (Mekelle 3, Mekelle 4
and Danda’a) were assigned as a main plot, Four level of N/P205 combination (46/46, 92/69, 115/92 and
138/115 kg N/P205 ha
-1
) arranged in a sub plot and four levels of planting density (150, 300, 400 and 500
plant/m
2
) assigned as sub-sub plot factor and replicated three times. The analysis of variance indicate that
variety, fertilizer, planting density, variety x fertilizer, variety x planting density, fertilizer x planting density,
and variety x fertilizer x planting density interaction, have significant (P<0.05) effect on grain yield of bread
Wheat varieties. Nitrogen and phosphorus fertilizers and variety showed significance (P<0.05) effect on
biomass yield, seeds per spike, effective tiller number and plant height. Grain yield, plant height, effective
tiller number/m2 and biomass yield of bread wheat variety increase linearly with planting density and N/P205
fertilizer rate. More grain (6.93 and 5.21 t/ha) for Emba-Alaje and Ofla, respectively was recorded from the
interaction effects of 138/115 kg of N/P205 ha-1 with 300 plant/m2 planting density for variety Mekelle-3.
However, 115/92 kg of N/P205 ha -1 with planting density of 500 plants/m2 reached higher economical return
(MRR=3166.12).
