Abstract:
A field experiment was conducted to investigate the effect of intra-row spacing and
nitrogen fertilizer rate on yield and yield components of cabbage. The study was conducted
from December 2010 to May 2011 at Holeta Agricultural Research Center. Three intrarow spacing (20, 30 and 40 cm) and four nitrogen fertilizer levels (0, 50,100 and 150
kg/ha) were used. The experiment was laid out in Randomized Complete Block Design
(RCBD) in 3x4 factorial arrangements with three replications. Copenhagen market variety
of cabbage was used for this experiment. Results indicated that head weight and
unmarketable yield were very highly significantly (P<0.001) affected by the interaction
effect of intra-row spacing and nitrogen fertilizer rates. The highest head weight (1.52
kg/plant) and lowest unmarketable yield (0.83 t/ha) were obtained at the interaction of 40
cm intra-row spacing with 150 kg/ha nitrogen fertilizer rates. Days to maturity, leaf
number, leaf area, plant spread, head height, head diameter, whole plant fresh weigh , dry
matter, harvest index and nitrogen left after harvest were very highly significantly
(P<0.001) affected by nitrogen fertilizer rate and intra-row spacing. Wider plant spread
(51.8 cm), larger leaf number (13.7), wider leaf area (463 cm2
), longer head height (16.7
cm), wider head diameter (16.6 cm) were recorded at higher (150 kg/ha) nitrogen fertilizer
rate. Higher marketable yield (78.2 t/ha), higher total yield (80 t/ha), higher harvest index
(0.8) and higher nitrogen left after harvest (0.22%) were also recorded at higher nitrogen
fertilizer rate (150 kg/ha), but lower dry matter percentage (7.78%) was recorded at this
rate. Intra-row spacing of 40 cm was found to be superior for plant spread, head
diameter, head height, leaf number, leaf area, whole plant fresh weight and nitrogen left
after harvest. For higher gross yield 20 cm intra-row spacing was superior. Higher
profitable yield (78 t/ha) or birr 230,530.00 per hectare was obtained at the combination
of 150 kg/ha nitrogen fertilizer rate with 20cm intra row spacing. Correlation analysis
indicated that marketable yield was significantly correlated with outer leaf number
(r=0.71***), head height (r=0.73 ***), head diameter (r=0.87***), whole plant fresh
weight (r=0.8***), head weight(r=0.67) and harvest index (r=0.7***). Results of current
investigation revealed that 20 cm intra-row spacing and 150 kg/ha nitrogen fertilizer rates
can be used for higher marketable yield and profitability. Farmers at Holeta could
therefore be advised to use this combination for high profitable cabbage yield. However,
further investigations may be suggested to be carried out on different soil type, at different
seasons, year and location so as comes up with precise and comprehensive
recommendation.
