MORPHOLOGICAL RESPONSE OF Parkia speciosa SEEDLINGS EXPOSED TO VARIOUS AMELIORANTS, SHALLOW GROUNDWATER, AND THE EFFECTS ON MICROCLIMATE CONDITIONS

The cultivation of stinky bean (Parkia speciosa Hassk.) in wetlands is significantly affected by shallow water table conditions. Therefore, this research aimed to explore the growth of stinky bean seedlings and microclimate conditions in various substrate mixtures and shallow water table levels. The experiment was conducted at the Jakabaring Research Facility (104°46'44''E, 3°01'35''S), Palembang, South Sumatra, from September to December 2023 using a factorial randomized block design. The first and second factors were an ameliorant mixture in the substrate and shallow water table depth respectively, with each treatment repeated four times. The results showed that optimal leaf growth occurred using biochar ameliorant, but no significant difference was observed among the four types of planting media. Although the conditions of air and substrate temperature and soil moisture varied, the stinky bean seedlings still grew optimally on all four planting media, including biochar, peat, cocopeat, and topsoil under shallow water table conditions. A zero-intercept linear model was considered optimal for predicting leaf area based on midrib length, leaf width, and the interaction indicated by the R² value. Optimal stinky bean leaf growth was observed at shallow water table SWT-12, but plant growth at three variations of SWT-20, SWT-16, and SWT-12 was not significantly different. Fluctuations in the microclimate, including air and substrate temperature, as well as humidity did not significantly affect growth, suggesting that the cultivation of stinky bean plants could be carried out in all shallow water table conditions.