Shifts in weed composition driven by paddy cultivation technology in the medium lands of Garut Regency, Indonesia

Weed infestations in paddy fields significantly reduce rice yields, with shifts in weed diversity influenced by cultivation practices and herbicide use. Studying these shifts is essential to developing effective weed management strategies and ensuring sustainable rice production in changing agricultural environments. The purpose of research is to study the shifting of weed diversity due to the technology application of paddy cultivation by using survey method and experiment. The research was carried out in June until October. A field survey was conducted before the experiment in 4 subdistricts by taking weed samples as many as 20 points using a square frame with the size of 50 cm × 50 cm. The experiment is carried out by applying 2 cultivation technologies, those are: conventional and No-Tillage system. And then, the weddings are no weeding treatment (f0), one-time-weeding of 20 DAP-aged (f1), and 40 DAP– aged (f2). Identification of weed result is analyzed to the diversity index (H’) based on Shannon-Wiener, evenness index (E’), weed abundance and SDR value. The research result shows the shifting of weed composition at cultivation technology application and weeding. On the field before the experiment, the predominant weed is Pistia stratiostes (SDR value of 19.29) with a medium-grouped diversity level (H’ 2,44). After The experiment of diversity level (H’), weed of conventional system and No Tillage is low category. In the application of conventional technology, which is not weeded, the dominant weed is Cynodon dactylon (SDR 21.06), whereas, on the field, which is weeded, the dominant weed is Pistia stratiotes with the value of SDR (f1 25.93 and f2 20.62). In the No Tillage system, the weed dominating is Alternanthera philoxeroides with the value of SDR (f015.31, f1 23.27 and f2 12.97). The distribution pattern of the dominant weed grows in groups (SD/mean greater than 1). The other weed growing in groups at the no tillage system is Marsilea quadrifolia.