Pengaruh Kombinasi Pupuk Kandang, Biochar, dan Inokulasi Rhizobium terhadap Serapan Nitrogen Kedelai pada Entisol, Bugel, Kulon Progo

Jhihan Kartika Eka Paksi, Tantriani, S.P., M.Agr., Ph.D. ; Prof. Dr. Ir. Benito Heru Purwanto, M.P., M.Agr.

2026 | Skripsi | ILMU TANAH

Tanah Entisol merupakan tanah muda yang memiliki kemampuan rendah dalam mempertahankan nitrogen sehingga efisiensi pemupukan nitrogen pada tanaman kedelai menjadi rendah. Kondisi tersebut menyebabkan sebagian nitrogen yang diberikan belum dapat dimanfaatkan secara optimal oleh tanaman. Oleh karena itu, diperlukan upaya untuk meningkatkan efisiensi pemanfaatan nitrogen melalui kombinasi pupuk kandang, biochar, dan inokulasi Rhizobium. Penelitian ini bertujuan untuk mengetahui pengaruh kombinasi pupuk kandang, biochar, dan inokulasi Rhizobium terhadap pertumbuhan, serapan nitrogen kedelai (Glycine max L.), dan sifat kimia tanah Entisol Bugel.

Penelitian dilaksanakan menggunakan rancangan faktorial yang terdiri atas faktor rasio pupuk kandang dan biochar serta faktor inokulasi Rhizobium. Parameter yang diamati meliputi tinggi tanaman, jumlah daun, jumlah bintil akar efektif, bobot segar dan kering tajuk, bobot segar dan kering akar, kadar nitrogen tanaman, serapan nitrogen tanaman, serta sifat kimia tanah setelah panen. Data dianalisis menggunakan analisis ragam (ANOVA) pada taraf 5%, dilanjutkan dengan uji Duncan Multiple Range Test (DMRT) apabila terdapat pengaruh nyata. Hubungan antara sifat kimia tanah dan serapan nitrogen dianalisis menggunakan korelasi Pearson.

Hasil penelitian menunjukkan bahwa faktor rasio pupuk kandang dan biochar memberikan pengaruh nyata hingga sangat nyata terhadap sebagian besar parameter pertumbuhan tanaman, kadar nitrogen, serapan nitrogen, dan sifat kimia tanah. Faktor Rhizobium memberikan pengaruh terhadap parameter pertumbuhan tanaman. Interaksi antara rasio pupuk kandang–biochar dan Rhizobium memberikan pengaruh sangat nyata terhadap kadar N tajuk dan serapan N tajuk. Berdasarkan hasil penelitian dapat disimpulkan bahwa kombinasi pupuk kandang dan biochar lebih berperan dalam meningkatkan serapan nitrogen tanaman kedelai dibandingkan inokulasi Rhizobium pada tanah Entisol Bugel. Perlakuan PB3R1 merupakan kombinasi terbaik dalam meningkatkan kadar dan serapan nitrogen tanaman kedelai.

Entisol is a young soil characterized by a low capacity to retain nitrogen, resulting in low nitrogen fertilization efficiency in soybean cultivation. Under these conditions, a considerable portion of the applied nitrogen cannot be utilized optimally by the plants. Therefore, efforts are needed to improve nitrogen use efficiency through the combined application of chicken manure, biochar, and Rhizobium inoculation. This study aimed to determine the effects of different ratios of chicken manure and biochar combined with Rhizobium inoculation on soybean (Glycine max L.) growth, nitrogen uptake, and the chemical properties of Entisol from Bugel.

The experiment was arranged in a factorial design consisting of two factors: the ratio of chicken manure to biochar and Rhizobium inoculation. The observed parameters included plant height, number of leaves, number of effective root nodules, shoot and root fresh weight, shoot and root dry weight, plant nitrogen content, plant nitrogen uptake, and post-harvest soil chemical properties. Data were analyzed using analysis of variance (ANOVA) at the 5% significance level, followed by Duncan's Multiple Range Test (DMRT) when significant differences were detected. The relationship between soil chemical properties and nitrogen uptake was evaluated using Pearson correlation analysis.

The results showed that the ratio of chicken manure to biochar had significant to highly significant effects on most growth parameters, plant nitrogen content, nitrogen uptake, and soil chemical properties. Rhizobium inoculation significantly affected plant growth parameters. A highly significant interaction between the chicken manure–biochar ratio and Rhizobium inoculation was observed for shoot nitrogen content and shoot nitrogen uptake. It can be concluded that the combination of chicken manure and biochar played a more important role in enhancing soybean nitrogen uptake than Rhizobium inoculation in Bugel Entisol. The PB3R1 treatment was identified as the best combination for improving soybean nitrogen content and nitrogen uptake.

Kata Kunci : bochar, Entisol, kedelai, pupuk kandang ayam, Rhizobium, serapan nitrogen.