Abstract:
The study “Optimization of fertigation level and depth of lateral under subsurface drip
irrigation for amaranthus” was taken up with the objective to optimize the fertigation level and
the depth of laterals under subsurface drip irrigation for amaranthus and workout the cost
economics. The effect of different fertigation levels and depth of laterals under plastic mulch on
the performance of Amaranthus (Amaranthus hypochondriacu, variety: kannara local) were
studied. The observations on number of leaves, stem girth root length and yield were taken. The
number of leaves, root length and yield showed significant difference between the treatments.
The yield showed significant difference with different levels of fertigation and depth of laterals.
Maximum yield of 8.51t/ha was observed for the treatment T2. The yield for treatments T1 was
7.41 t/ha and T3 was 7.2 t/ha. Even though, maximum yield was obtained in T2, as per the
statistical analysis, difference in yield was not that much significant between T2 and T1 and T2
and T3. The treatment T3 is of 10 cm lateral depth with 80 per cent fertigation level. The study
suggested that treatment T3 is better due to the fact that it gives higher crop yields with
substantial saving in fertilizer usage. The benefit cost ratio treatment T2, 100% of fertigation
requirement with lateral depth at 10 cm was 2.6. The benefit cost ratio for T1 was 2.2 and T3
was 2.18. The benefit cost ratio for control was minimum i.e., 1.39. Comparing with the benefit
cost ratio between T2, T1 and T3, it was found that there was not much difference in ratios.
Hence the treatment T3 i.e., 80% fertigation level with 10 cm lateral depth that shows
comparatively better yield with benefit cost ratio of 2.18. The study shows that maximum
fertilizer use efficiency was observed in case of T3 i.e., 80% fertigation level with inline laterals
at 10 cm depth, compared to other treatments. Hence, subsurface drip irrigation of 10 cm lateral
depth with 80 per cent fertigation level under plastic mulching for amaranthus is a good option as
compared to 20 and 30 cm lateral depth with 80, 100 and 120% of fertigation levels.
