Field experiment
The characteristics of the soil at the field experiment site were
the same as those described for the soil used in the pot experiment,
as the soil for the latter was taken from the same area as the site
for the field experiment. Field preparation involved three plowings.
A basal application of lime was made at a rate of 625 kg/ha.
For high rate fertilizer treatment, N-P-K fertilizers (15-15-15) at
rates of 28.13 kg/ha, 12.34 kg P/ha and 23.38 kg K/ha, respectively,
were applied prior to planting, whereas in low rate fertilizer treatment,
N-P-K fertilizers were applied at half the rate of the high rate
treatment.Individual plot size was 1 m
×
5 m, with transplanted seedlings
being spaced at 50 cm
×50 cm. Irrigation was provided manually,
by applying water to the hills of tomato plants until 7 days after
transplanting (DAT), with furrow irrigation then being used. Weeds
were controlled manually during the growing season. Nitrogen and
calcium fertilizer (15-0-0) as calcium nitrate (Ca(NO3)2) at rates of
1.5 kg N/ha and 2.25 kg Ca/ha, were applied at 14 days after transplanting
(DAT). Commercial N-P-K fertilizers (15-15-15) at rates
of 28.13 kg N/ha, 12.34 kg P/ha and 23.38 kg K/ha were applied at
21 DAT and N-P-K fertilizers (13-13-21) at rates of 24.38 kg N/ha,
10.75 kg P/ha and 32.69 kg K/ha at 40 DAT. For low rate chemical fertilizer
treatment, N-P-K and calcium nitrate fertilizers were applied
at half those rates.