Abstract:
Objective The aim was to investigate the impact of various soil amendments on pH modification and nutrient enhancement in acid purplish soils. The result will contribute to the scientific understanding of acid purplish soil management.
Method A field experiment was conducted. Different soil amendments were applied, and the treatments included CK: no amendment; F: conventional fertilizer; SF: lime + fertilizer; OM: organic fertilizer + fertilizer; BF: biochar + fertilizer; JZ: distillery residue ash + fertilizer. The pH, exchangeable acid, nutrients, cation exchange capacity (CEC) and exchangeable cations were determined in the amendment soils.
Result ① Compared with CK treatment, all the soil amendments significantly increased soil pH (P < 0.05). JZ treatment has the best effect, leading to an increase of 3.3 units. Additionally, the SF and JZ treatments showed significantly lower soil exchangeable acid content than other treatments (P < 0.05), with decreases of 99.41% and 99.31%, compared to the CK treatment. ② Several amendments significantly increased the SOM contents (P < 0.05), with increases ranging from 35.26% to 97.66%. The OM treatment showed the largest increase of 9.61 g kg−1. ③ In the JZ treatment, TN (total nitrogen) content increased by 49.32% compared to the CK treatment, AP (available phosphorus) content increased by 49.05%, and both total potassium (TK) and AK (available potassium) contents increased by 13.41% and 15.56% compared to the F treatment. ④ The JZ treatment exhibited the highest CEC at 12.89 cmol kg−1, marking a 31.93% increase compared to the CK treatment. The exchangeable cations in all treatments followed the order Ca2 + >K + >Mg2 + >Na + . The effects of different treatments on exchangeable cations varied. Soil exchangeable Na + , K + , and Ca2 + contents in distillery residue ash treatment were significantly higher than other treatments (P < 0.05), increasing by 223.86%, 417.58% and 67.09%, respectively.
Conclusion According to the experimental results, distillery residue ash can effectively increase soil pH, improve acidification of acid purplish soils, enhance soil buffer capacity and nutrient availability. The application of distillery residue ash is a promising amendment for acid purplish soil improvement.