Enhancing Sorghum (Sorghum bicolor) Productivity Through Soil Amelioration in Ultisol

Food is essential to life. As the population grows, the need for food increases consequently. On the other hand, fertile land conversion from agricultural use to others causes the land for food crop scarcer. Land for agricultural expansion uses marginal land, including Ultisols. Ultisols are acidic and contain low content of essential elements for plant growth, such as nitrogen, phosphorus, and potassium. Thus, it is necessary to utilize environmental tolerant/adaptive crop like sorghum (Sorghum bicolor) and use zeolite and bio-slurry organic fertilizer to improve soil fertility. The study aimed to determine the optimum concentration of bio-slurry in conjunction with zeolite to promote sorghum growth and yield in Ultisols. This research was carried out in Kandang Limun Village, Muara Bangkahulu District, Bengkulu City, Indonesia. A completely randomized design (CRD) with two factors and three replications was utilized for the study. The first factor was the dosage of bio-slurry fertilizer consisting of six levels, namely: 0 ton/ha, 4 ton/ha, 8 ton/ha, 12 ton/ha, 16 ton/ha, and 20 ton/ha (absolute dry weight). The second factor was the zeolite dosage, consisting of three levels, namely: 0 ton/ha, 3 ton/ha, and 6 ton/ha. There is a combination effect of bio-slurry and zeolite on panicle length and number of leaves. Bio-slurry at a dose of 13.2 ton/ha without zeolite produced the most leaves (15 pieces), while the combination of 13.2 ton/ha of bio-slurry and 3 ton/ha of zeolite produced the most extended panicle length (20.6 cm). Bio-slurry treatment at a dose of 15.88 ton/ha yielded the highest shoot dry weight of sorghum. The highest leaf area, the dry weight of seeds per panicle, and the dry weight of 100 seeds were the highest at a dose of 15.87 ton/ha, 18.26 ton/ha, and 15.29 ton/ha, respectively. The application of bio-slurry and zeolite is promising to improve the productivity of sorghum cultivated in Ultisols.