statistically different from all other treatments. Fruit size significantly differed
among the treatments. The longest fruit was observed in treatment N120 P40 K80 S30
followed by that from N120 P40 K80 S20 in both the years and these were
significantly different from all other treatments. The shortest fruit was obtained
in control plot. The maximum diameter was found in the treatment N120 P40 K80
S30 and it was statistically similar with the treatments N120 P40 K80 S20, N120 P60 K80
S20 and N120 P40 K40 S20 in 2010. During 2011, treatments N120P40K80S30 and N120
P40 K80 S20 gave statistically similar fruit diameter, which was significantly
different from rest of the treatments. The minimum diameter of bitter gourd was
recorded in control treatment. Application of chemical fertilizer also increased
the single fruit weight, which was the highest with N120 P40 K80 S30 treatment and
it was statistically identical with treatment N120 P40 K80 S40. These two treatments
were significantly different from all other treatments in both the years. The
lowest fruit weight was noted in control plot.
The fruit yield/ha of bitter gourd was significantly influenced by different
treatment combinations (Table 1). Fertilizer application in general increased fruit
yield from 6.47 to 19.90 t/ha in 2010 and 8.50 to 20.15 t/ha in 2011. The highest
yield (19.90 t/ha in 2010 and 20.15 t/ha in 2011) was obtained from N120 P40 K80
S30 treatment and it was significantly different from all other treatments. Sanap et
al. (2010) reported that application of 250 kg N, 50 kg P2O5 and 100 kg K2O/ha
significantly increased the yield of bitter gourd in India. Islam and Irabangon
(1994) also observed that application of 240-120-60-kg NPK/ha markedly
improved the number of fruiting and yield of bitter gourd. Rajan and Markose
(2005) reported that the maximum fruit set and yield were obtained with 90:
25:50 kg NPK/ha. The maximum yield/ha produced by N120 P40 K80 S30 treatment
was mainly due to cumulative effects of number of fruits/plant, fruit size, and
fruit weight. The experimental soil was highly deficient in different nutrients.
So, the application of different nutrients to the soil resulted in the highest uptake
by plants which ultimately helped increase production of assimilates that causes
higher fruit size and yield. Plants grown without added fertilizer (native nutrient)
produced the lowest yield (6.47 t/ha in 2010 and 8.50 t/ha in 2011).
The yield increase over control due to single effect of NPK and S are
shown in Table 2. Nitrogen application up to 120 kg/ha increased yield
significantly and thereafter decreased. Application of 120 kg N/ha increased
yield of bitter gourd by 86% in 2010 and 54% in 2011 over the control. Yield
of bitter gourd also increased significantly due to application of P up to 40
kg/ha and further increase in P decreased the yield. Fertilization with K also
followed the same response on yield (Table 2). The yield varied from 14.07 to
18.56 t/ha in 2010 and 13.65 to 17.85 t/ha in 2011 due to different levels of K
application. Yield of bitter gourd also increased with the increase rate of S up