Efektivitas Kombinasi Bakteri Pemacu Tumbuh, Bradyrhizobium dan Sumber Nutrisi Terhadap Pertumbuhan Vegetatif dan ReproduktifKedelai.

Abstract

Dalam intensifikasi pert ani an, penggunaan pupuk an organik yang terus menerus dapat mengakibatkan semakin menurunnya kesuburan tanah. Sehubungan dengan hal ini maka aplikasi pupuk organik ataupun pupuk hayati merupakan alternatif untuk mengurangi ketergantungan terhadap pupuk an organik. Tujuan penelitian ini adalah: (1) mengetahui efektivitas kombinasi bakteri PGPR dan Bradyrhizobium dalam mempengarnhi pola serapan hara, pertumbuhan vegetatif dan reproduktif kedelai di lapang, (2) mempelajari efek pupuk hayati dalam bentuk cair dan padat pada berbagai sumber nutrisi terhadap pertumbuhan dan produksi tanaman. Penelitian ini dilakukan di Kebun Percobaan Cikabayan IPB Bogor.

In intensive agriculture, continuous application of anorganic fertilizer can decrease soil fertility. The purpose of this research was to evaluate : (1) the effectiveness of combination between Bradyrhizobium and PGPR in influencing nutrient uptake, vegetative growth and yield of soybean in the field, and (2) the effect of biofertilizer in liquid form and solid form in combination with various nutrition sources on growth and production. The experiment was carried out using randomized block design with 3 factors. The first factor was Bradyrhizobium application with 2 levels i.e. without Bradyrhizobium (RO), and with Bradyrhizobium (Rl). The second factor was PGPR application with 3 levels i.e. without PGPR (PO), PGPR in liquid form (PI), and PGPR in solid fonn (P2). The third factor was nutrition sources application with 4 levels i.e. without nutrition sources (NO), with 100% recommendation dosage of NPK fertilizer (Nl), 100% recommendation dosage of compost (N2), and 50% dosage of NPK fertilizer + 50% dosage of compost (N3). Every unit had 3 replications, so that the total experiment were 72 units. The result showed that the application between Bradyrlzizobium in combination with PGPR improved nutrition uptake, plant growth and grain yield of soybean. The higher increase of total macro and micro nutrition uptake was recorded from the combined treatment between Bradyrhizobium and solid PGPR (RIP2) which an increase by about 66,20%, and 41,40%, followed by combination between Bradyrhizobium and liquid PGPR (RIPl) by 39,17% and 16,20% as compared to the control. The combination RIP2 increased number of branches, plant dry weight, root dry weight, number of nodule, dry weight of nodule, number of pod, and seed dry weight/plant by approximately 31,33%, 50,87%, 48,17%, 207,68%, 185.66%, 78,7%, 83,69%, respectively compared to the control. The best treatment was resulted by RIP2N2, the combination between Bradyrhizobium, solid PGPR and compost 100% dosage. This treatment had the significant in increasing the number of branches, fresh weight, plant dry weight and root dry weight by 101,64%, 159,30%, 118,42%, 115,36% respectively. This treatment also caused the improvement of number of pod, and seed dry weight/plant by 163,64% and 174,73%. These result showed that the biofertilizer produced from PGPR have synergical effect with Bradyrhizobium to improve nutrient absorption, growth and yield of soybean.