Physiological studies of sweet corn under chemical weed management
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Date
2019
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Orissa University of Agriculture and Technology, Bhubaneswar
Abstract
The present investigation entitled “Physiological studies of sweet corn under chemical weed management” was carried out during rabi season of 2018-19 at Central Farm OUAT, Bhubaneswar with five treatments and control(weedy check) .The treatments consisted of atrazine @1kg/ha, pendimethalin 0.75kg/ha ,tembotrione @0.1kg/ha and topramezone @0.025 kg/ha. The treatments laid out with three replications with a plot size of 20m2 . The herbicides were sprayed by using a knapsack sprayer with flat fan nozzle using 500 l /ha.The Maize variety ‘Sugar-75’ was grown as test crop. The results of the experiment indicated that the morphological characters like plant height, number of leaves, dry matter accumulation, leaf area were increased in all stages of crop growth with two hand weedings (20 and 40 DAS) and were comparable with post-emergence application of tembotrione (0.1 kg/ha )and topramezone (0.025kg/ha). The weed floral composition of the experiment site were Echinochloacolonum, Digitariasanguinalis, Elucineindica among grasses, Cyperusrotundus ,Cynodondactylon among sedges and Aegeratumconizoides,Cleome viscose among broad leaved weeds. Weed parameters like weed density (28.0 number m-2), weed dry matter (21.4 g m-2) were lowest in two hand weeding which was followed by tembotrioneapplication.The highest value growth parameters such as LAI(3.38), CGR(31.53 g m-2 day-1), NAR (7.75g m-2 day-1), RGR (0.09g g-1 day-1) were recorded in two hand weeding and increased in response to herbicide application over control and LAI, NAR, CGR were positively correlated with the cob yield. The beneficial microbial population like bacteria, fungi and actinomycetes were decreased with the application of pre-emergence herbicides (atrazine and pendimethalin) at initial period of crop growth. However at later stages, the population build up to (31.7x 105/g of soil) and (19.7x106/g of soil) for bacteria and actinomycetes respectively and was well comparable with weedy check. Highest yield was contributed by two hand weedings (11.62 t/ha) and followed by tembotrione (11.13 t/ha) which increased to a tune of 53.7% and 47.2% respectively over control.The higher cobs weight(345.33 g) were obtained from twice hand weedings followed by tembotrione and it was significantly superior over control. Similar trend was found with regards to yield attributing characters like kernels cob-1(410),cob length (20.5cm) and diameter(11.17cm), test weight(24.53g) and harvest index (39.61%). Application of tembotrione recorded higher benefit cost ratio (3:2) and lower cost of cultivation (Rs59,500) than two hand weedings. In view of present findings it can be concluded that post-emergence application of tembotrione @0.1kg/ha increased the yield and the supporting physiological parameters of the crop by effectively controlling the weeds at critical period of crop weed competition over the control.
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Th-5676
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