MSc

The study entitled ‘Production potential of fodder cowpea – amaranthus
sequential cropping system in Onattukara’ was carried out during 2021-2023 at College
of Agriculture, Vellayani, Thiruvananthapuram and Instructional farm attached to
Onattukara Regional Agricultural Research Station, Kayamkulam, Kerala. The
objectives were to assess the yield enhancement in fodder cowpea through foliar
nutrition of boron and zinc, and to find the residual effect of fodder cowpea on
sequentially cropped amaranthus in the sandy loam soils of Onattukara. The field
experiment was done during December 2022 to March 2023 at Onattukara Regional
Agricultural Research Station, Kayamkulam. The experiment was done in two parts
where in the first part (December 2022 – February 2023), the experiment was laid out
in randomized block design (RBD). The eight treatments replicated thrice were t1 (100%
RDF), t2 (75% RDF), t3 (t1 + zinc @ 0.25% as foliar spray at 20 DAS), t4 (t1 + boron @
0.25% as foliar spray at 20 DAS), t5 (t1 + boron @ 0.125% + zinc @ 0.125% as foliar
spray at 20 DAS), t6 (t2 + zinc @ 0.25% as foliar spray @ 20 DAS), t7 (t2 + boron @
0.25% as foliar spray @ 20 DAS) and t8 (t2 + boron @ 0.125% + zinc @ 0.125% as
foliar spray at 20 DAS). Fodder cowpea sequentially cropped with amaranthus was the
second part of the experiment (February 2023 to March 2023) and was done in splitplot design with eight main plot treatments (residual effect of treatments for previous
crop of fodder cowpea) and two sub plots (nutrition for amaranthus- n1 - 100% RDF
and n2 - 50% RDF). The crops were managed in raised beds in the lowland with a
spacing of 30 cm x 15 cm as per KAU Package of practices.
The results of this study revealed that in treatment t3, fodder cowpea which
received 100 per cent RDF along with foliar spray of zinc (0.25%) at 20 DAS in fodder
cowpea, produced significantly higher values for growth characters like plant height,
number of leaves per plant and LAI at 30 DAS and at harvest. The green fodder yield
per plant (106.72 g), green fodder yield per hectare (23.74 t), dry fodder yield per plant
(10.12 g) and dry fodder yield per hectare (2.25 t) were significantly increased by the
treatment t3. Among quality parameters, the leaf: stem ratio was also significantly
improved by t3 treatment (1.26).
The treatment t3 significantly improved the N, P and K uptake (48.55 kg ha-1
,
8.41 kg ha-1
and 57.34 kg ha-1
) of fodder cowpea and remained comparable with t5.
Among the soil parameters, organic carbon was significantly influenced by t3 (0.89%)
and the values were comparable with t5 (0.87%) and t1 (0.82%). The available N was
significantly influenced by the treatment t1 (167.25 kg ha-1
) and was comparable with
t3 (163.07 kg ha-1
), t4 (154.71 kg ha-1
) and t5 (154.71 kg ha-1
). The available P was
significantly influenced by the treatment t1 (68.95 kg ha-1
) and was comparable with t5
(67.35 kg ha-1
), t3 (65.52 kg ha-1
) and t4 (63.13 kg ha-1
).
For the sequential crop of amaranthus, the results revealed that the growth
attributes viz. plant height and number of leaves per plant were significantly influenced
by the main plot treatments (residual effect of treatments for previous crop of fodder
cowpea) and sub plot treatments (nutrition for amaranthus). The treatment t3 resulted in
taller plants at harvest (45.67cm) and was comparable with t5 (44.67 cm) and
t1 (44.28 cm). The treatment t4 produced more leaves per plant at 20 DAT (29.95) and
was comparable with the treatments t1 (29.56), t6 (29.39), t3 (29.33), t5 (29.28) and t2
(28.11). At harvest, the number of leaves per plant were significantly higher for the
treatment t3 (52.28) and was comparable with the t5 (51.22). With respect to nutrition,
n1 produced taller plants (39.91 cm) with more number of leaves (54.14) at harvest. The
yield of amaranthus was significantly influenced by the treatments. Higher yield per
plant (222.22 g) and yield per hectare (31.11 t) was observed in t3 and was comparable
with t1 (209.73 g and 29.35 t respectively) and t4 (202.78 g and 28.38 t respectively).
The treatment n1 produced higher yield per plant and yield per hectare. The interaction
effect was not significant.
Treatments had no significant influence on N and P uptake in amaranthus. The
treatment t3 (60.35 kg ha-1
) recorded higher K uptake and remained comparable with
the treatments t1 (57.19 kg ha-1
), t4 (54.33 kg ha-1
) and t5 (52.97 kg ha-1
). The treatment,
n1 recorded higher N, P and K uptake. Among the interaction effects, higher P uptake
was recorded for t8n1 (14.51 kg ha-1
). In terms of soil properties, higher organic carbon
was recorded for the treatment t3 (0.89%) which was on a par with t5 (0.88%), t4
(0.86%), t1 (0.85%), t6 (0.82%) and t2 (0.81%). The treatment n1 recorded higher organic
carbon content (0.85 %) for nutrition in amaranthus. The treatment t1 (127.53 kg ha-1
)
recorded higher available N and was found to be on a par with t3 (123.35 kg ha-1
), t4
(123.35 kg ha-1
) and t2 (121.26 kg ha-1
). Available P was found higher for the treatment
t1 (82.88 kg ha-1
) and was on a par with t5 (82.13 kg ha-1
), t4 (81.48 kg ha-1
) and t3 (81.20
kg ha-1
). Higher available K was recorded for the treatment t7 (239.12 kg ha-1
) and was
found on a par with t8 (232.96 kg ha-1
), t2 (226.17 kg ha-1
), t6 (222.88 kg ha-1
) and t4
(218.17 kg ha-1
). Among nutrition, the treatment n1 recorded significantly higher
available N, P and K (118.12 kg ha-1
, 79.26 kg ha-1
and 232.29 kg ha-1
respectively).
Higher net income and benefit cost ratio were observed for the treatment
t3 (₹ 595577 ha-1
and 3.33 respectively) and was found to be on par with
t1 (₹ 549669 ha-1
and 3.19 respectively). The n1 treatment recorded higher net income
(₹ 593331 ha-1
) and benefit cost ratio (3.06).
The results of the study revealed that in a fodder cowpea-amaranthus sequential
cropping system at Onattukara, the yield of fodder cowpea could be enhanced by
application of 100 per cent RDF along with a foliar spray of zinc sulphate heptahydrate
@ 0.25 per cent at 20 DAS. For sequentially cropped amaranthus, 100 per cent RDF
was required to achieve higher productivity and profitability in the sandy loam soils of
Onattukara.