Weed Population Dynamics under Organic, Bio-dynamic, Conventional Bt and Non-Bt Cotton (Gossypium hirsutum)

Aim: In order to compare the weed seed bank and population dynamics under organic, biodynamic, Bt-conventional, and non-Bt conventional management systems of cotton (Gossypium hirsutum), a field experiment was carried out.

Study Design: Randomized Block Design (RBD)

Place and Duration of Study: bioRe-FiBL research trails, bioRe Association, Kasrawad, Khurgone, Madhya Pradesh during the kharif season of 2020-21.

Methodology: Five distinct crop management techniques were used in the field experiment, each duplicated four times, and the experiment was set up using a randomized block design. The treatments were distributed at random to different plots. The five management treatments were Absolute Control (no fertilizers), Conventional management of non-Bt cotton, Conventional management of Bt cotton, Bio-dynamic and Organic management of cotton. For the duration of the experiment, four 1 m × 1 m (1 m2) quadrats were randomly placed on each experimental plot's four sides, and different biometric observations were recorded from each quadrant according to its treatment. For the purpose of collecting the necessary observations, two of these quadrants were regularly weeded every 20 days, while the other two were left unweeded for the duration of the experiment.

Results: The dominant weed species includes Panicum dichotomiflorum, Cyperus rotundus, Paspalum dilatatum, Euphorbia hirta, Acalypha indica and Digeria arvensis. Poaceae was the dominant family in terms of composition. There was very less variation in the weed flora between the treatments. Significantly higher weed seed bank, weed species, weed density and weed dry weight were observed in Organic and Biodynamic cotton than in the Conventional cotton. Weed control efficiency was found to be maximum in the Conventional cotton compared to the Organic and Biodynamic cotton.

Conclusion: From the experiment, it can be concluded that the Conventional cotton especially Conventional management Bt Cotton was found to be most efficient among all the treatments. However, the Organic cotton was observed with high number of overall plant species and best in conserving the plant species biodiversity.