MSc

An experiment was conducted in the summer rice fallows of
the Agricultural Research Station, Mannuthy during 1997 to develop
and test mulch-cum-drip irrigation system for okra (Abelmoschus
esculentus Moench.) and compare this system with drip without mulch or
furrow irrigation system either with or without mulch. The soil was sandy
clay loam, medium in organic carbon and available potassium and high in
available phosphorus. The ten treatments comprised of combinations of
two irrigation systems (Drip irrigation and furrow irrigation) and three
irrigation frequencies (soil moisture tension at 0.04, 0.06 and 0.08 MPa)
either with or without mulch. The experiment was laid out in randomised
block design with three replications. In case of drip irrigation system 41ph
emitters were placed 60 cm apart such that there was one emitter in
between two plants. In mulched plots, after the formation of ridges, the
field was covered with black LDPE sheet before sowing. Holes were
made on this sheet at a spacing of 30 cm and seeds were dibbled
through these holes.
The study proved the beneficial effects of mulching in the vegetable
crop bhindi, irrespective of the levels and methods of irrigations. Biometric
characters like plant height, number of leaves and leaf area index and the
yield attributing characters like number of flowers, number of fruits and total
weight of fruits plant' were favourably influenced by mulching both under
furrow and drip systems of irrigations, irrespective of levels of irrigation.

The maximum fruit yield of 24.88 t ha-1 was produced when the crop was
mulched and furrow irrigated at soil moisture tension of 0.08 MPa. This
accounted for 93.48 per cent Increase in yield over the control crop that
received irrigation by furrow method at 0.06 MPa without mulch.
The crop under mulched situation consumed lesser amount of water
compared to without mulch situations at all the frequencies of irrigations.
This decline of consumptive use of water, was to the tune of 49, 97 and
192 percent respectively at the soil moisture tension of 0.04, 0.06 and
0.08 MPa in case of drip irrigation and 49, 97 and 135 per cent in case of
furrow irrigation. Under drip irrigation the total soil moisture extracted from
0-15 and 15-30 cm layers was 30.68 to 49.56 and 50.43 to 69.31 per cent
respectively in open situation. The respective values under mulched
situation were 39.16 to 45.1 and 54.89 to 60.83 per cent. In case of
furrow irrigation system the respective values were 35.58 to 47.39 and
52.60 to 64.41 under mulched situation and 41.01 and 58.98 per cent in
unmulched situation.
When mulching was adopted under drip irrigation or surface method
of irrigation with the irrigation schedules at the soil moisture tensions of
0.04, 0.06 or 0.08 MPa, the cropping became profitable. Then, the B.C.
ratios varied between 0.91 to 1.58. Maximum benefit cost ratio of 1.58
was derived when the crop was mulched and furrow irrigated at soil
moisture tension of 0.08 MPa.