Distribution, abundance, and soil seed bank of parthenium weed (Parthenium hysterophorus L.) in Kuala Muda, Kedah, Malaysia and its growth performance under different soil types and soil moistures

Parthenium weed (Parthenium hysterophorus L.) is an alien species in Malaysia and was firstly detected in 2013. Among the states in Malaysia, Kedah is worst infested by this weed. It is harmful to human and animal’s health, reduces crop production and leads to losses in biodiversity. Research on distribution, abundance, soil seed bank, and growth performance of this weed species is essential. Thus, this study was conducted to (ⅰ) determine the distribution and abundance of parthenium weed in the infested area in Kuala Muda, Kedah, (ⅱ) assess the status of parthenium weed seed banks in selected villages, and (ⅲ) investigate the growth performance of parthenium weed on different soil types and soil moistures. Three experiments including two field surveys (in March and September 2015), whereby the soil seed bank study four different soil depths from four selected villages and pot experiment to assess the effects of three different soil types (loamy, sandy, and clay) under six different soil moistures (15%, 30%, 45%, 60%, 75%, and control) on parthenium weed growth performance in greenhouse condition were conducted. Results revealed that 16 villages under Kuala Muda were infested by the parthenium weed with the medium (M: 5-25%) degrees of infestation. When the comparison was made between these two surveys, the percentage coverage by the parthenium weed was found to increase from trace (T: <1%) and low (L: 1-5%) to medium (M) in the second survey. In Kg. Semeling, the degree of infestation changed from M to H (High: 25-100%). The relative density (RD) and abundance (A) of the weed also increased in the second survey by 24.3% and 20.8%, respectively in all 16 villages. The highest RD was noted in the Kg. Semeling (27.3%), followed by Kg. Kongsi 6 (23.2%) and the lowest RD was found in Kg. Banggol (5.3%). The highest of parthenium (A) was recorded in Kg. Kongsi 6 (27.0/m2), followed by Kg. Semeling (26.5/m2) and the lowest was noted in Kg. Banggol (5.5/m2). The size of seed banks was not significantly(P>0.05) affected by the interaction between villages and soil depths. The number of seeds at top layer (0-5 cm) was the highest with 2784/m2. The second layer (5-10 cm), third layer (10-15 cm), and the fourth layer (15-20 cm) contained the seeds at the rates of 990/m2, 315/m2 and 7/m2, respectively. The highest seed accumulation was recorded in Kg. Kongsi 6 (1729/m2) followed by Kg. Sg. Tok Rawang (1120/m2) and the lowest accumulation was noticed in Kg. Zainal Abidin (249/m2). The growth performance of parthenium weed was significantly affected by the interaction between soil types and soil moistures. It was found that, parthenium weed grew well on loamy soil with soil moisture ranging from 15% to 45%, while the growth of parthenium was reduced on clay soil under all soil moistures applied. The dry weight accumulation was xxi the highest under the loamy soil with soil moisture of 45% (9.21 g/plant) followed by control (8.93 g/plant), 30% (7.19 g/plant) and 15% (5.59 g/plant). The results from this recent study indicating the dangerous signpost of parthenium hazard in Kuala Muda, Kedah Malaysia. The existence and the growth of parthenium weed shall need to be monitored and the concerned authority needs to adopt appropriate control methods for its sustainable management.