The chemical properties of Podsolic Red-Yellow soil have pH is very acidic to slightly acidic, low to moderate percentage of C-organic, low to moderate P, and low status of K, Ca, Mg, Na, and other saturation of bases. Also, the physical characteristics of the Red-Yellow Podsolic soil show a distinctive characteristic, as bulk density soil index of 1.30 - 1.50 g.cm-3, with low water absorption. The chemical and physical properties are bad enough to make Red-Yellow Podsolic soil have a low ability to provide macronutrients needed by plants. Organic matter is proven to be able to control nutrient availability in mineral soils. The potentials for organic material that has been completely decomposed is crumb rubber solid waste. The use of crumb rubber solid waste material as organic material is expected to be able to influence the availability of macronutrients and improve the physical characteristics of the Podsolic Red-Yellow soil. This study aims to find differences in the availability of NH4+ NO3-, H2PO4-, K-exchangeable, C-organic and to compare the treatments that produce the best index of soil bulk density, increase the percentage of water content, and determine the soil temperature of Red-Yellow Podsolic with the application of crumb rubber solid waste with difference level, statistical test with through the index of mean difference Tukey’s test on level α 5%. In this research it was concluded that the application of crumb rubber solid waste could increase soil pH, provide levels of NH4+, NO3-, H2PO4, K-exchangeable, C-organic and reduce soil bulk density index, increase water content and soil temperature compared to not using crumb rubber solid waste. PCr3 treatment showed the highest yield at pH, NH4+, H2PO4, C-organic and increased water content, but it was not significantly different than PCr2 treatment, whereas PCr2 was significantly different from PCr3 in providing NO3-, K-exchangeable.

Penelitian ini dilakukan di lapangan untuk mengetahui produksi biomassa dan kandungan unsur hara dari tanaman turi mini (Sesbania rostrata) sebagai pupuk hijau menggunakan jarak tanam dan umur panen yang berbeda. Penelitian dilaksanakan di Dusun Bontouse, Kelurahan Pincengpute, Kecamatan Tanasitolo, Kabupaten Wajo, Provinsi Sulawesi Selatan, Indonesia dari Desember 2018 hingga Juli 2019. Penelitian ini dirancang dengan menggunakan rancangan acak kelompok (RAK) pola faktorial dua faktor. Faktor pertama jarak tanam (J) 3 taraf : 5 cm x 20 cm (J1), 10 cm x 20 cm (J2), 15 cm x 20 cm (J3) dan faktor kedua umur panen pupuk hijau (U) dengan 4 taraf : 15 hari (U1), 30 hari (U2), 45 hari (U3), 60 hari (U4). Setiap unit perlakuan dibuat bedengan 3 m x 2 m dan masing-masing unit perlakuan diulang 3 kali. Hasil penelitian menunjukkan bahwa rata-rata produksi biomassa kering tanaman turi mini terberat 569 g m-2 atau 5,69 ton ha-1 pada jarak tanam 5 cm × 20 cm (j1) dan berbeda nyata dengan jarak tanam 10 cm × 20 cm (j2) serta jarak tanam 15 cm × 20 cm (j3). Untuk umur panen tanaman 60 hari (u4) diperoleh rata-rata biomassa kering terberat 1.133 g m-2 atau 11,33 ton ha-1 dan berbeda nyata dengan umur panen tanaman 15 hari (u1), 30 hari (u2) dan 45 hari (u3). Sedang kandungan unsur hara Sesbania rostrata dengan penggunaan berbagai jarak tanam tidak berbeda nyata; jarak 10 cm × 20 cm (j1) kandungan nitrogen (N) (4,56 %), produksi posfor (P) tertinggi (0,24 %). Untuk umur panen 45 hari (u3) menghasilkan rata-rata kandungan nitrogen tertinggi (5,1 %), rata-rata kandungan posfor tertinggi (0,26 %), dan umur panen 15 hari (U1) rata-rata kandungan kalium tertinggi (6,54 %).

Nutrient availability is very significant in supporting plant growth. The low content of organic fertilizers and existing minerals appear as the primary limiting factors for soybean cultivation on acid soils. Therefore, the purpose of this research is to determine the effect of organic fertilizers and Plant Growth Promoting Rhizobacteria (PGPR) on plant growth and yield. A completely randomized block design (CRBD) factorial with three replications was employed, where the first variable involved the chicken and cow composts as well as Tithonia green fertilizer. Meanwhile, the second referred to PGPR at 0, 5, 10 and 15 ml.L^-1. The results showed no interaction between the application of organic fertilizers and PGPR on soybean growth as well as the yield. Furthermore, the cow manure treatment of 10 t.ha^-1 reportedly increased the total dry weight and sample growth rate by 0.44 and 0.86%, respectively, compared to the chicken manure at similar composition. Also, 10 ml.L^-1 of PGPR was known to improve the pod quantity per plant and harvest index by 0.58 and 2.66% harvest index, correspondingly, than without PGPR.