Abstract:

In order to provide scientific basis for the development of special slow-release fertilizer for cassava and improve the benefit of cassava planting, a field trial was conducted in 2021 with 8 treatments, including no fertilization (CK) and conventional fertilization, and other 6 combinations of two slow released fertilizers (C1, single-film slow released fertilizer with small particle; C2, double-film slow released fertilizer with small particle), and two types of mulching, including plastic film mulching (PF) and ground cloth (GC) mulching. Cassava growth and root yield, nutrient absorption and fertilizer utilization were investigated. The results showed that cassava growth such as plant height and stem diameter were stimulated by fertilization, as well as the biomass accumulation and cassava yield. Compared with conventional fertilization, slow-release fertilizer improved the growth of cassava, the root yield increased by 21.29%-53.00%, the starch yield increased by 25.46%-58.1%, and the nutrient utilization rate increased by 1.9%-27.1%; C1 and C2 combined with mulching film/ cloth had better effect on promoting the growth of cassava, increasing cassava yield and fertilizer utilization rate, increasing the yield of fresh root by 37.41%-52.00% and starch by 39.58%-58.1%; compared with conventional fertilization, slow-release fertilizers C1 and C2 reduced the amount of phosphate fertilizer and greatly improved its utilization rate by 14.0%-47.3% while ensuring the yield of cassava. In conclusion, applying C1 and C2 is an effective way to increase cassava growth and root yield, and fertilizer utilization rate, and it is more helpful when combined with plastic film or cloth mulching. The application of C1 with N 100 kg/hm², P₂O₅ 33.3 kg/hm² and K₂O 100 kg/hm², together with ground cloth covering is the optimum for cassava in this study.

Key words: slow-release fertilizer, plastic film, ground cloth, cassava, yield, fertilizer efficiency