Diversity and species composition of weeds in rice cultivation, Tarakan Island.

Weed management is through physical/mechanical, biological, and chemical control. In addition, the study of species composition is utilized for the control of weeds. The study was conducted to describe the diversity and composition of weeds in rice cultivation, Tarakan Island. The research was collected the Mamburungan, East Mamburungan, and Tanjung Pasir areas. Weeds were collected samples by the quadratic method with a size of 50 x 50 cm. There were 20 points/squared per location that took 3 (three) times. Weed composition has described the value of SDR (sum dominance ratio), and the diversity was species richness index (R), Shanon-Wiener diversity index (H), evenness index (E), and similarity index. In total, 16 species of weeds were collected from sites. Monochoria vaginalis species had the highest SDR values in Mamburungan (32.7), and East Mamburungan (35.9), while species Fimbristylis littoralis in Tanjung Pasir (32.0). The diversity and evenness indeks were calculated in Mamburungan Timur (R=1.04, H'=1.34, E=0.61), Mamburungan (R=1.49; H'=1.64; E=0.64), and Tanjung Pasir (R=0.81; H'=1.36; E=0.70). The Mamburungan and Tanjung Pasir locations have the highest similarity index (70%). Then, the Mamburungan have the lowest index, which is 55%. The characteristics of the site have an effect on diversity and composition which are influencing the strategic control of weed in rice cultivation in Tarakan Island. [ABSTRACT FROM AUTHOR]