Weed Species Composition and Distribution in Rice Fields in Comparison Between Off‐ and Main‐Season of 2014/2015 in KADA Granary Area of Malaysia

ABSTRACT

This study aimed to identify weed composition, distribution, and dominance under water‐scarce conditions in 45 fields across three locations in the KADA granary area of Malaysia during the main‐ and off‐season of 2014/2015. The survey employed a quantitative method using 0.5 m × 0.5 m quadrats, with 20 samples per rice field laid out systematically in an inverted W pattern. Resultantly, the survey revealed variations in weed composition and prevalence between rice planting seasons, driven by varying moisture stress levels that favored specific weed survival traits under fluctuating water availability. A total of 30 weed species were identified from 14 different families, comprising 6 grasses, 6 sedges, and 18 broadleaved weeds. Based on the relative abundance and ranking of the weeds in the surveyed rice fields, Fimbristylis miliacea (84.2%), followed by Leptochloa chinensis (41.6%), Scirpus grossus (30.1%), and Ischaemum rugosum (23.6%) were the most prevalent and abundant species in the off‐season 2014. Conversely, the 2014/2015 main‐season was highly dominated by Echinochloa crus‐galli (62.8%), followed by L. chinensis (37.3%), Limnocharis flava (25.1%), and F. miliacea (22.3%). Sorenson's index values (92.9%–100.0%) during the 2014 off‐season indicate high weed species similarity across districts, while lower values (59.6%–76.6%) in the 2014/2015 main‐season suggest slight variations in weed composition between districts. These findings provide critical baseline data for developing targeted weed control strategies to enhance rice yield and promote sustainable agricultural practices.