Pemanfaatan Biopori Serasah Daun Kering Untuk Memperbaiki Kesuburan Tanah Pada Pertanaman Kemiri Sunan (Reutealis trisperma (Blanco) Airy Shaw) - Santoso, Budi; Cholid, Mohammad (Buletin Tanaman Tembakau, Serat & Minyak Industri, 2021)
Pengembangan kemiri sunan diarahkan pada lahan kering marginal, yang umumnya memiliki keterbatasan dalam menyediakan hara dan air bagi tanaman.   Tingkat kesuburan lahan marginal dapat diperbaiki dengan teknologi biopori. Kondisi lahan marginal memiliki kandungan bahan organik rendah, sementara serasah daun kering kemiri sunan yang rontok melimpah pada saat menjelang musim kemarau. Daun kering kemiri sunan berpeluang dimanfaatkan sebagai pengisi biopori untuk meningkatkan bahan organik tanah, dan  kapasitas memegang air. Tujuan penelitian untuk mengukur sumbangan bahan organik daun kering kemiri sunan melalui proses biopori terhadap perbaikan kesuburan tanah entisols. Penelitian dilakukan pada tahun 2017-2018 di Asembagus, ketinggian 5,5 m dpl, dan curah hujan sekitar 1.500 mm per tahun.  Perlakuan  disusun dalam Racangan  Acak Kelompok (RAK), dengan 5 ulangan.  Susunan perlakuan adalah a) Tanpa biopori dan daun kering (0); b) Biopori 20 cm, diisi 410 g daun kering; c) Biopori 30 cm, diisi 615 g daun kering; d) Biopori 40 cm diisi daun 820 g daun kering; dan e) Biopori 50 cm diisi 1.025 g daun kering. Tabung biopori (Æ13 cm) ditanam di bawah tajuk pohon kemiri sunan (umur 3 tahun), sebanyak 2 buah  tabung, di sebelah kanan dan kiri.  Parameter yang diamati meliputi tinggi tanaman, lingkar batang, jumlah cabang, lebar kanopi, Carbon, Nitrogen, C/N ratio dan bahan organik tanah. Setelah 90 hari aplilkasi hasil penelitian menunjukan bahwa perlakuan biopori dengan pemberian daun kering kemiri sunan belum berpengaruh terhadap parameter vegetatif  kemiri sunan tetapi berpengaruh nyata terhadap C-organik, N-total, C/N-ratio.  Dari penelitian ini belum dapat diukur secara kuantitatif sumbangan bahan organik daun kering kemiri sunan dalam memperbaiki kesuburan tanah entisolAbstractToxic candlenut growing is directed at marginal dry land which generally has limitations in nutrients and water. Fertility can be improved with biopore technology. The  dry leaves of toxic candlenut have the opportunity to be used as biopore litter to increase soil organic matter, water holding capacity and soil fertility. The aim of the research was to  study the contribution of  dry leaf of  toxic candlenut through the biopore process to improve soil fertility of Entisols soil. The research was conducted in 2017-2018 at Asembagus with altitude of 5.5 m asl, and a rainfall of around 1500 mm per year. The treatments were arranged using a Randomized Block Design with 5 replicates i.e. a) Without  biopore without  dry leaves; b) 20 cm  biopore length, filled with 410 g of  dry leaves; c). 30 cm  biopore length, filled with 615 g of  dry leaves; d) 40 cm  biopore length, filled with 820 g of  dry leaves and e) 50 cm  biopore length, filled with 1025 g of  dry leaves.  Biopore tubes planted under the canopy of the 3 years old candlenut tree, in right and left of trunk. The parameters observed included plant height, stem diameter, number of branches, canopy width,  soil Carbon, Nitrogen, C/N ratio and organic matter. The results showed that biopore treatment with  dry toxic candlenut leaves had not affected on vegetative parameters, but had a significant effect on organic C, N-total, C/N-ratio and organic matter which would improve the soil fertility,   However, the contribution of the candlenut leaves to improve the fertility of entisol soil has not been quantitively measured.