Effect of density of salvinia molesta on the growth and development of rice

The experiment was conducted in Agro Park, Universiti Malaysia Kelantan, Jeli Campus to study the impact of different weed densities of Salvinia molesta on the rice growth and development. Five densities (0, 2, 4, 8, and 12) of weeds per pots were introduced to the two transplanted rice seedlings in a pot of size 25cmx30cm. The effect of weed densities on the rice height, number of tiller per plant, leaf area per plant, and dry weight per plant were studied. The effects of rice plants on the growth of weeds were also studied. The weeds densities had a non-significant effect on rice height, number of tiller per plant, leaf area per plant, and dry weight per plant. From the experiment, the percentage reduction of plant height of the rice with two, four, eight, and twelve weed densities were 8.4%, 14.78%, 10.53% and 19.08% respectively when compared to control pot. The percentage reduction of number of tiller of rice with two, four, eight and twelve weed densities were 15.3%, 18.5%, 19.4% and 29.0% respectively. The percentage reduction of leaf area of rice with two, four, eight and twelve weeds density were 17.7%, 15.15%, 20.12% and 28.98%. Rice lost the dry weight by 12.9%, 18.5%, 31.3% and 30.7% respectively due to competition from two, four, eight, and twelve weeds. When all these reduction were considered together all together and calculated the average percent inhibition, it was noticed that S. molesta inhibited the growth of rice by 13.6%, 16.7%, 20.3% and 27.0% due to competition from two, four, eight, and twelve weeds respectively. Therefore, eight Salvinia molesta per pot (163 weeds/ m²) is detrimental to rice growth.