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One of the major problems in any crop production system is weed infestation
which causes reduction in both the yield and quality of produce. Although the use of
herbicides provides effective and sustained weed control, it is not a preferred option
because of environmental concerns. This is particularly true in the case of vegetables,
some of which are consumed either partially cooked or raw. The research programme
entitled ‘Non-chemical weed management in chilli (Capsicum annuum L.)’ was
carried out with the objective of evaluation of non-chemical methods of weed
management in chilli.
The experiment was conducted at the Department of Agronomy, College of
Agriculture, Vellanikkara from June 2020 to September 2020. The field was infested
with broad leaf weeds, grasses and sedges. Randomized block design used for laying
out the experiment, with seven treatments and three replications. The treatments
were, T1: stale seed bed for 14 days followed by shallow digging and planting of
chilli, followed by two hand weedings at 30 DAT and 60 DAT, T2: stale seed bed for
14 days followed by shallow digging and planting of chilli, followed by one hand
weeding at 45 DAT, T3: black polythene mulch (30 microns), T4: straw mulch at 7.5
t/ha applied twice, at planting and one month after planting, T5: straw mulch at 7.5
t/ha applied twice, at planting and one month after planting followed by one hand
weeding at 60 DAT, T6: hand weeding at 30 and 60 DAT and T7: unweeded control.
Black polythene mulch (T3) recorded highest weed control efficiency and
lowest weed density, weed dry matter production and weed index, whereas straw
mulch when applied alone (T4) and when followed by one hand weeding (T5) were the
next best treatments with high weed control efficiency and low weed index. The
treatments hand weeding (T6), stale seed bed when followed by two hand weedings
(T1) and one hand weeding (T2) were not effective in controlling weeds. The lowest
weed control efficiency and the highest weed index values were recorded for the
unweeded control (T7) at all stages of observation.
Various weed management practices had significant effect on growth and yield
parameters of chilli. At all stages of observation, the plant height of chilli in polythene
mulching (T3) was found to be the greatest followed by straw mulching when done
alone (T4) and when followed by one hand weeding (T5). Unweeded control (T7) had
the lowest values. Chilli plants in polythene mulching (T3) recorded the highest
number of fruits per plant (218) and fruit yield (22.44 t/ha), followed by straw
mulching both when done alone (T4) (182 nos. and 18.89 t/ha respectively) and when
followed by one hand weeding (T5) (177 nos. and 18.38 t/ha respectively). Hand
weeding (T6) and stale seed bed when followed by two hand weedings (T1) recorded
lower yields than straw mulching. Unweeded control (T7) recorded lowest values for
fruit length, fruit girth, fruit weight, number of fruits per plant and fruit yield.
The soil physico-chemical characteristics pH, EC, organic carbon, and
available N, P and K were influenced by different weed management practices. The
organic carbon content in soil was highest in polythene mulching (T3) at 60 DAT
(1.45 %) and after the final harvest (1.49 %). At both stages of observation, straw
mulching (T4) had highest values of available P (77 and 79 kg/ha respectively) and K
(414 and 408 kg/ha respectively), whereas available N was found higher in black
polythene mulch (T3) at 60 DAT (246 kg/ha) and in stale seed bed followed by one
hand weeding (T2) after the final harvest (239 kg/ha).
Considering the economics of cultivation, black polythene mulching (T3)
recorded highest gross returns (Rs.22.44 lakhs/ha), net returns (Rs. 9.94 lakhs/ha)
and B:C ratio (1.84) and was followed by straw mulching when done alone (T4) and
when followed by a hand weeding (T5). Black polythene mulching was thus
identified as the best non-chemical weed management technique in chilli, having
highest weed control efficiency leading to enhanced growth and yield parameters and
highest net returns and B:C ratio. Straw mulching when done alone or when
followed by one hand weeding were the next best treatments with respect to weed
control efficiency, growth, yield and net returns of chilli.