Tanah merupakan sumber daya penting bagi kehidupan yang ada di muka bumi.  Tanah menyediakan air, udara dan nutrisi yang dibutuhkan bagi makhluk hidup seperti mikroorganisme tanah dan tanaman.  Tujuan dari penelitian adalah : mengisolasi dan karakterisasi bakteri pelarut fosfat, dan menguji patogenitas isolat bakteri pelarut fosfat pada tanaman tembakau. Penelitian dilakukan di Laboratorium Biologi Tanah, Departemen Ilmu Tanah dan Sumber Daya Lingkungan, Institut Pertanian Bogor, pada bulan Oktober 2017 sampai Januari 2018. hasil isolasi bakteri pada tanah lahan percobaan kampus Institut Pertanian Bogor diperoleh empat isolat potensial yang mempunyai kemampuan tinggi dalam melarutkan fosfat dengan membentuk zona bening (halozone). Hasil pengujian patogenitas pada daun tembakau setelah 48 jam menunjukkan tingkat patogenitas yang berbeda dari masing-masing isolat potensial.  Hasil uji patogenitas pada tanaman tembakau diperoleh dua isolat potensial dari empat isolat terpilih yang kompeten digunakan sebagai pupuk hayati yaitu isolat BPF P (dari tanaman padi) dan BPF J (dari tanaman jagung).

Different land use at the study site such as forest, dry land and rice fields originating from the same soil type, affects the presence of various phosphorus (P) fractions in the soil profile. The purpose of this study was to study the chemical characteristics of Al, Fe, Mn, exchangeable and inorganic P fractions of the soil on the Ultisol soil profile using forest, dry land and rice fields in Jasinga. Soil samples were taken on three horizons (Ao or Ap, AB and B) at profiles of forest soil and dry land, while in paddy fields taken at a depth of 0–20 cm, 20–40 cm and 40–60 cm from the ground surface. The chemical properties of the soil analyzed were soil pH, C-organic, exchangeable-Al, exchangeable-Fe, exchangeable-Mn and P fractionation. The results showed that the soil in the study site had a cleavage texture with a pH range of very acidic to slightly acidic. The highest exchangeable-Al levels were found in forest land at 433 ppm, the highest exchangeable-Fe was in rice fields at 0.019 ppm and the highest exchangeable-Mn was in dry land use at 0.063 ppm. The significant correlation of the (Ca, Mg)-P fraction with soil pH of selected chemical properties on dry land showed that this fraction would increase with increasing pH and vice versa would decrease with increasing exchangeable-Al and exchangeable-Mn.