Effects of biochar-based soil conditioners on ameliorating acid soil in vegetable field

Abstract

This study is to explore the effects of different biochar-based soil conditioners on the amelioration of acidic soil in vegetable fields. Using quicklime, fly ash, steel slag, and biochar as raw materials, nine biochar-based soil conditioners were prepared by employing an orthogonal test of four factors and three levels. The dosages of lime, fly ash, and steel slag were 0, 2.5 g·kg-1, and 5.0 g·kg-1, and the dosages of biochar were 0, 25.0 g·kg-1, and 50.0 g·kg-1. A pot experiment was conducted to study the effects of these soil conditioners on soil quality, vegetable yield, and nutrient uptake with four replicates. With the application of different biochar-based soil conditioners, soil pH, soil exchangeable Ca, and soil cation exchange capacity（CEC） significantly（P<0.05） increased by 0.82-1.75 units, 38.52%-122.63%, and 41.10%-78.65%, respectively. Soil microbial abundance was promoted, especially for Lysobacter and Massilia. The uptake of N, P, and K by lettuce increased by 7.94%-64.79%, and lettuce yield increased by 8.03%-16.68%. However, the soil ′ s alkaline hydrolysis nitrogen content decreased significantly. There were no significant effects of treatments on soil urease or catalase activity. The contents of soil organic matter, total N, available P, available K, and exchangeable Mg, and the activities of soil phosphatase and invertase all increased upon the addition of soil conditioners with proper material ratios. Biochar-based soil conditioners were effective at ameliorating acidic soil in vegetable fields. The optimal combination of quicklime, fly ash, steel slag, and biochar involved an input of 5.0, 2.5, 5.0 g·kg-1, and 50.0 g·kg-1, respectively.