International Journal of Agriculture, Forestry and Plantation, Vol. 3 (June) ISSN 2462-1757 2016 95 EFFECT OF SOILLESS MEDIA ON GROWTH AND SOME PHYSIOLOGICAL TRAITS OF RUBBER (Hevea brasiliensis) SEEDLINGS Monsuru Adekunle Salisu Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia. salisuadekunle@gmail.com Wan Noordin Daud Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia. wnoordin@upm.edu.my Ridzwan A. Halim Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia. ridzwan@upm.edu.my Zulkefly Sulaiman Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, zulkefly@upm.edu.my ABSTRACT This study evaluates the effect of newly prepared soilless media on rubber (Hevea brasiliensis) as alternative growth media to some of the poor soils in the tropics (including those used in rubber nursery in Malaysia). The materials used as media were selected based on their good physiochemical properties and local accessibility. Three different media and soil, which was designated the control treatment, were used. The soilless media significantly influenced the growth and biomass production of the rubber seedlings. The highest rate of seedling growth was recorded in the medium of 10% burned rice husk (BRH), 30% peat moss and 15% vermiculite (coded as M1). The effect was equally noticeable in root morphology, especially with regard to root length, surface area and the number of tips. The pH and EC were 6.5 and 2.3 dS m -1 , respectively. Higher concentrations of N and P were apparent in this medium while the Mg concentration was only significantly higher in soil (the control). Meanwhile, the urea-N used in the medium was lower than that used in the other media. However, the same amounts of rock phosphate (CIRP) were used in the respective media, and significant root growth was recorded. The least amount (5% N) used in the best medium (M1) could be maintained to reduce the use of fertilizer. These results show that the soilless mix that includes BRH with less urea-N as fortification would greatly increase plant growth. This is because it releases more essential plant nutrients due to the favorable pH when compared to the acidic soils used in many plantations in the tropics. The result shows that the soilless media used in this study could be adopted for rubber nursery seedlings. Key words: Soilless, Hevea brasiliens, physiology, seedlings, rubber Introduction Soils used for rubber in the tropical Asia countries has been categorized as low organic C content and highly weathered as a result of overutilization in the last 100 years ( Dharmakeerthi et al., 2012). This has been attributed to the poor growth of rubber (Hevea brasiliensis) especially at nursery stage which sometimes leads to plant death or long term irreparable root and shoot damage. Both the soil medium as well as the type of container (polybag) used may contribute to the poor performance of rubber seedlings. Many soils used for plantation crops in the tropics including Malaysia, are acidic and requires a lot of fertilizer for adequate support of plant growth (Shamshudeen, 2010). As a result, soilless growing system especially for young plants has been widely considered as an alternative growing medium to soil (Van Os and Postma, 2000) while root trainers are being considered as replacement for polybags. Soilless may serve as an alternative planting medium because it reduces incidence associated with soil borne diseases and pests which leads to reduced use of soil fumigant. It improves water use efficiency and fertilizer use due to its high water-holding and cation exchange capacity (Cantliffe et al., 2007). Soilless medium or substrate with good physical and chemical properties gives farmers planting opportunity where soil conditions are certified to be detrimental to crop cultivation (Rodriguez et al., 2006). The natural rubber industry at present adopts a new approach such as the use of soilless media in nursery planting and the use of root