Pengaruh Remediasi Biochar dan Bioslurry Tanah Tercemar Terhadap Kadar Timbal Terlarut dan Bioavailabilitasnya pada Sawi Hijau (Brassica rapa)

Abstract

Remediasi tanah dengan metode amobilisasi dapat dilakukan untuk mengaktifkan lahan pertanian tercemar timbal secara efektif dengan biaya rendah. Pada penelitian ini biochar dan bioslurry digunakan untuk amandemen tanah tercemar dan diuji keefektifannya mengurangi kadar Pb terlarut dan Pb yang diserap tanaman sawi hijau (B. rapa) di rumah kaca. Selanjutnya budidaya sawi di lapangan dilakukan untuk mengetahui dampak amandemen terhadap pertumbuhan dan kadar Pb-sawi serta kemungkinan kontaminasi Pb pada tanah sekitar. Sampel tanah tercemar diambil dari Desa Cinangka, Bogor sedangkanbioslurry dan sisa kegiatan pertanian/peternakan diperoleh dari Desa Jeruk Sawit di sekitar Kota Surakarta. Amandemen tanah ber-Pb 4.296 ppm dengan kombinasi biochar dan bioslurry (0; 2,5; 5,0; 10%) mampu mengurangi kelarutan Pb s.d 87,7% sekaligus mengurangi risiko ekologisnya dari tingkat moderat ke tingkat rendah. Pada uji rumah kaca, kombinasi biochar dan bioslurry menurunkan kadar Pb-daun sawi mencapai maksimal 63,11% dari 44,00 menjadi 16,23 ppm. Pertumbuhan tanaman sawi meningkat pada penambahan bioslurry tetapi penambahan biochar pada kadar 5 dan 10% menekan pertumbuhan yang kemungkinan karena pH yang terlalu tinggi untuk sawi. Uji lapangan selama satu kali masa tanam dengan kadar biochar dan bioslurry (5%/5%) mengakibatkan pertumbuhan sawi yang 20x lebih baik dibanding hasil budidaya rumah kaca, menurunkan Pb-daun dari 34,92 menjadi 21,71 ppm, serta mampu mencegah migrasi Pb ke sekitar media tanam.

ABSTRAK

Immobilization method of soil remediation can be conducted to activate lead contaminated agricultural land effectively at low cost. In this study, biochar and bioslurry were used to amend polluted soil and tested their effectiveness in reducing the levels of dissolved Pb and Pb absorbed by the green mustard (B. rapa) in the greenhouse. Furthermore, mustard cultivation in the field was carried out to determine the impact of the amendment on the growth and Pb levels of green mustard and the possibility of Pb contamination in the surrounding soil. Polluted soil samples were taken from Cinangka Village, Bogor, while bioslurry and the byproduct of agricultural/animal husbandry were obtained from Jeruk Sawit Village around Surakarta City. Polluted soil containing 4296 ppm Pb amended with a combination of biochar and bioslurry (0; 2.5; 5.0; 10%) were able to reduce Pb solubility up to 87.7% while reducing the ecological risk from moderate to low level. In the greenhouse test, the combination of biochar and bioslurry reduced the Pb level in mustard leaves to a maximum of 63.11% from 44.00 to 16.23 ppm. The growth of mustard plants increased with the addition of bioslurry but the addition of biochar at levels of 5 and 10% suppressed growth which was probably due to the pH being too high for green mustard. Field trial during one planting period with biochar and bioslurry level (5%/5%) resulted in 20x better growth of green mustard than greenhouse cultivation, reduced leaf-Pb from 34.92 to 21.71 ppm, and was able to prevent Pb migration around the planting medium.