Mikroba pelarut P anorganik pada tanah masam Haplohumult Kadubitung Lebak, Jawa Barat.

BAHASA: Di daerah perakaran terdapat mikroba pelarut P-anorganik yang umumnya terdiri dari kelompok bakteri, kapang, ragi dan sedikit aktinomisetes. Penelitian untuk mengetahui jenis dan jumlah mikroba pelarut P-anorganik dalam tanah masam serta kemampuannya melarutkan P-anorganik dilakukan dengan menggunakan suspensi tanah masam Haplohumult dari Lebak yang telah diberi kompos dan pupuk P serta media tumbuh Pikovskaya. Didapatkan bahwa takaran pupuk P mapun kompos tidak berpengaruh terhadap populasi mikroba pelarut P-anorganik, karena terjadi persaingan dengan mikroba lain yang terdapat dalam tanah dan adanya bentuk-bentuk P-anorganik. Dari suspensi contoh tanah ditemukan 4 jenis bakteri yaitu 3 spesies Pseudomonas dan 1 spesies Corynebacterium serta 3 jenis kapang yaitu Aspergillus tamarri, Aspergillus niger dan Penicellium sp. dengan populasi antara 2,0 x 10 pangkat 4 - 14,5 x 10 pangkat 4 per gram tanah. Tiap jenis mikroba mempunyai sifat khusus dan kemampuan melarutkan P-anorganik yang berbeda-beda. Setelah 2, 4, 9 dan 14 hari inokulasi, mikroba-mikroba ditemukan dapat melarutkan Ca3(PO4)2 masing-masing antara 43-97, 72-84, 69-95 dan 51-94 ppm P. Jumlah tersebut cukup tinggi untuk tanah masam.

English. Various P-inorganic solvent microbes are found in rhizopheres. They consist of bacteria, fungi, yeast and some actinomycetes. A series of experiment were done in laboratory to study the kind and population of each kind of those microbes, and the total amount of inorganic-P that could be dissolved by them. Acid soil samples of Hapluhumult at Lebak were taken from field experimental plots in which 4 levels of compost and 3 levels of TSP were applied 3 months before. These soil samples were used for the experiment. By isolating soil samples diluted suspension into Pikovskaya media, no significant effect of both compost as well as TSP to microbes population was obtained. There were 4 genus of bacteria consisted of 3 species of Pseudomonas and 1 species of Corynebacterium, and also 3 species of fungi consisted of Aspergillus tamarri, Aspergillus niger and Penicellium sp. were found in soil samples suspension. The total amount of these microbes ranging from 2,0 x 14 at the power of 4 until 14,5 x 10 at the power of 4 per gram of soil. Each kind microbe has its own characters and ability to dissolve inorganic-P. The total amount of inorganic-P that could be dissolved by each kind of microbe during 2, 4, 9 and 14 days after isolation were 43-97, 72-84, 64-95 and 51-94 ppm P respectively. Those amount are high enough for acid soil.