Degradation in soil fertility is an enormous problem in agricultural intensification system. Availability in phosphate is one of among encountered problems. Peat soils have large areas and great potential for agriculture and plantations, but have many obstacles in their management. One of the issues is the low soil fertility and low availability of nutrients, especially phosphate which exists in many organic forms that are not available to plants. Phosphorous is an essential element after nitrogen, which plays an important role in plant growth and metabolism and the process of soil microbiology. Introduction of phosphate-solubilizing bacteria (PSB) as biofertilizer, is a renewable energy based which can increase the availability of phosphate to plants can overcome this problem and at the same time reducing the use of inorganic P fertilizer. Indigenous PSB, isolated from palm oil plantation could be used as a better and friendly bio-agent to improve soil fertility, specifically for phosphate availability. Eight PSB have been isolated from peat soil in oil palm platation. Morphological, biochemical characterization and molecular identifications showed that the 8 isolates belonged to Flavobacterium and Enterobacter genera, more precisely the species of Burkholderia sp and Novosphingobium nitrogenifigens. Characterization of isolates of the highest PSB activity consisted of the ability to dissolve phosphate in Pikovskaya solid medium, temperature resistance optimization and the ability to produce phosphatase enzyme. Results showed that isolate with the highest potentiality of dissolving phosphate formed 3.5 cm of clear zone diameter and the phosphatase activity at 9 days of incubation 5.992 units (μmol / ml / min). The peak of enzyme's activity was reached at 6 days , which corresponded to 54.782 ppm of phosphorus solubilised. The lowest pH (3.2) was reached at 1 st day of incubation. These isolates showed the ability to grow optimally at temperature range of 25 to 30 0 C. Indigenous PSB could be used as biofertilizer agents which are eco friendly.

Fungi endofit hidup dan berkoloni dalam jaringan tanaman namun tanpa menunjukkan gejala perusakan pada tanaman inang. Sebagai mikroba pengkoloni internal, akan lebih memudahkan dalam bersaing dalam system vascular dengan patogen seperti Ganoderma boninense penyebab busuk pangkal batang tanaman kelapa sawit. Mikroba endofitik bekerja melawan patogen tanaman melalui mekanisme antibiosis, persaingan ruang dan nutrisi untuk pertumbuhannya, dan menginduksi ketahanan tanaman melalui metabolit yang dihasilkan. Tujuan dari penelitian ini adalah mengidentifikasi fungi dari akar tanaman kelapa sawit asal kebun endemik G.boninense di Sumatera Utara berdasarkan karakteristik morfologi dan histologi. Lima sampel diambil secara acak dari masing-masing lokasi. Sebanyak 75 isolat diisolasi dari akar tanaman kelapa sawit sehat yang tumbuh di kebun endemik. Identifikasi morfologis dan mikroskopis fungi endofit dilakukan dengan mengamati struktur reproduksi seksual maupun aseksual menggunakan kamera terhubung dengan mikroskop. Isolat diidentifikasi ke dalam 8 genera yaitu Trichoderma (20), Fusarium (10), Aspergillus (5), Penicillium (5), Gliocladium (4), Phoma (4), Alternaria (4), dan Curvularia (3). Isolat lainnya tidak teridentifikasi secara morfologis maupun histologis, karena tidak berspora.Kata kunci: area endemik, Elaeis guineensis, busuk pangkal, fungi endofit akar, tanaman kelapa sawit

Indonesia is a major producer of palm oil. Consequently, the use of chemical fertilizers has become more extensive. Microalgae represent a potential alternative for enhancing and protecting crops based on their cell elements. This study applies dry biomass or liquid culture formulation of the green microalgae Haematococcus pluvialis to the rhizosphere of oil palm pre-nursery as a biofertilizer. Soil application of microalgae biomass of 0.5 g/l (MA) or liquid culture of 10% (v/v) (BCMA) is carried out to assess its effects on 4-months-old oil palm at the nursery stage. The compatibility test between microalgae and bio fungicide agents in agricultural practices, Trichoderma spp., is also tested on both microalgae formulations. The result shows that both microalgae biomass and liquid culture, alone or combined with Trichoderma spp., give a better growth performance to the oil palm. The application of MA and BCMA result in a maximum increment of plant height, leaves count, and chlorophyll content. Furthermore, the application of BCMA gives better oil palm growth performance, which may probably be influenced by the accessibility of nutrients for microalgae growth. The study reveals that soil application of microalgae as biofertilizers can improve oil palm growth performance.