Perbaikan Sifat Tanah dan Hasil Kedelai (Glycine max) dengan Pemberian Amelioran Biochar dan Pupuk Kandang di Lahan Sawah Tadah Hujan
Abstract
Abstrak. Lahan sawah tadah hujan menjadi salah satu alternatif dalam budidaya kedelai, namun hasil kedelai pada lahan sawah tadah hujan relatif rendah, salah satu penyebabnya diperkirakan adalah rendahnya kesuburan tanah. Perbaikan produktivitas tanah dan tanaman dapat dilakukan dengan pemberian bahan amelioran, antara lain arang biomassa (biochar) dan pupuk kandang (Pukan). Penelitian ini bertujuan untuk mengetahui pengaruh pemberian amelioran biochar dan Pukan terhadap sifat fisikokimia tanah dan hasil kedelai di lahan sawah tadah hujan. Penelitian dilaksanakan di Kabupaten Tulungagung, Jawa Timur pada dua musim tanam, tahun 2018 dan 2019 dengan perlakuan berupa: pupuk dosis petani (P1); pupuk dosis rekomendasi (P2); P1 + Pukan 10 t ha-1 (P3); P1 + biochar 10 t ha-1 (P4); dan P1 + Pukan 5 t ha-1 + biochar 5 t ha-1 (P5). Hasil penelitian menunjukkan bahwa penambahan biochar 10 t ha-1 dapat menurunkan bobot isi tanah, meningkatkan kandungan air tersedia, meningkatkan pH tanah, dan meningkatkan kandungan K dapat ditukar. Penambahan Pukan tidak memberikan pengaruh nyata terhadap sifat tanah, namun meningkatkan hasil kedelai. Penambahan biochar dan Pukan (P3, P4, P5) memberikan hasil biji dan brangkasan kedelai lebih tinggi 18-21% dibandingkan budidaya cara petani (P1). Hasil penelitian ini menegaskan kembali pentingnya penggunaan biochar dan Pukan dalam pengembangan komoditas kedelai di lahan sawah tadah hujan.
Abstract. Rainfed paddy field is one of the alternative lands for soybean cultivation, but soybean yield is relatively low, seemingly due to low soil fertility. Soil and plant productivity could be improved by amelioration such as by using biochar and manure. This study aims to investigate the effetcs of biochar and manure on soil physicocemical characteristics and the yield of soybean in rainfed paddy field. This study was carried out in Tulungagung District, East Java Province, in two consecutive growing seasons of 2018 and 2019 with five treatments as follow: farmers’ fertilizer dosage (P1); recommended fertilizer dosage (P2); P1 + manure 10 t ha-1 (P3), P1 + biochar 10 t ha-1 (P4); and P1 + manure 5 t ha-1 + biochar 5 t ha-1 (P5). The results showed that the application of 10 t ha-1 biochar in association with farmer’s practice decreased soil bulk density, increased soil available water, increased pH, and increased exchangeable K. Manure application did not significantly improve soil properties, but increased soybean yield. Biochar and manure application (P3, P4, P5) increased grain and biomass yields of soybean 18-21% higher than those of farmers’ practice without soil ameliorant (P1). This study reemphasizes the importance of biochar and manure for soybeans production in rainfed paddy field.