The Use of Humic Acid-Coated Biochar (Bicomat) and Plant Spacing on Paddy Plant Production and the Reduction of Heavy Metal Content

Abstract

This study aimed to find out the use of Bicomat doses and spacing to increase crop production and heavy metal reduction. It was carried out in paddy fields in Karangploso Subdistrict of Malang District from April to July 2022. The study used a Randomized Group Design (RGD), 2 factors and 3 repetitions. The first factor was the dose of Bicomat (B) consisting of B0 = Control (without Bicomat), B1 = Bicomat 10 t ha -1 , B2 = Bicomat 20 t ha -1 , and B3 = Bicomat 30 t ha -1 ; the second factor was the planting distance (P) comprising 3 planting distances of paddy plants: P1 = 20 × 20 cm, P2 = 20 × 30 cm, and P3 = 20 × 40 cm. The observed parameters included the plant height, number of leaves, stem diameter, number of saplings, paddy grain weight per plot, and weight of 1000 paddy grains. While the analyzed heavy metal were Pb and Cu. The results showed that the use of BCH doses increased the growth of paddy plants on all observed parameters. The use of a dose of Bicomat of 10-20 t ha -1 increased the weight of grain and the weight of 1000 grains of paddy. The use of doses of 10 t and 20 t with a planting distance of 20 × 40 cm showed significant growth. The average weight of dry grain obtained at the doses of 10 and 20 t of ha -1 and a planting spacing of 20 × 40 cm amounted to 7.93 and 7.53 kg of plot-1. While in the weight parameter of 1000 grains of paddy, the results averaged out at 32.67 and 34.33 g. The reduction of Pb and Cu metal obtained were 26.23%-58.77% and 56.12%-89.96%, respectively.