Quicklime sterilization of planting holes and topsoil enhances Sacha inchi yield and suppresses root rot in tropical conditions

Zhang, Jialin

INDUSTRIAL CROPS AND PRODUCTS

2026

241

Fu, QT; Liu, CA

Sacha inchi (Plukenetia volubilis L.), a perennial oilseed crop native to the Andean tropics, is increasingly cultivated in China for its omega-rich seeds. However, the increasing incidence of root rot, primarily caused by Fusarium oxysporum, poses a significant threat to its productivity and industry viability. The study aimed to evaluate the effects of different cultivation practices-including soil amendment, intercropping, and mulching-on soil health, root disease incidence, and the yield of Sacha inchi under tropical field conditions. A three-year randomized block field experiment (2020-2023) was conducted to test five treatments: S1 (monoculture control), S2 (intercropping with soybean), S3 (quicklime sterilization of planting holes and topsoil;), S4 (sulfur fertilization), and S5 (plastic film mulching). Among all treatments, quicklime application (S3) produced the most significant improvements. It reduced abundance of Fusarium, and root rot incidence (44.44 %) compared to the control (77.78 %) and enhanced soil pH, increased exchangeable calcium (Ca) and magnesium (Mg), and reduced exchangeable aluminum (Al). Yield under S3 (6065.4 kg ha-1) was 48.99 % higher than the control (S1), and notably higher than all other treatments. However, S3 also reduced soil-available copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe). Overall, our results demonstrate quicklime application to planting holes and topsoil is a practical strategy to manage root rot and boost Sacha inchi productivity in tropical cropping systems, thereby ensuring the sustainable development of the Sacha inchi industry.