Hu Xin, Ma Weiqin, Pasang Lhamo, Li Jiansheng, Chen Haoming
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Gels. 2024 Mar 25;10(4):222. doi: 10.3390/gels10040222.
Soil amendments play a crucial role in modern agriculture, as they effectively enhance the planting environment. This study innovatively proposes the use of gel as a crosslinking agent to embed biochar and hydroxyapatite (HAP), thereby preparing a novel soil amendment. Furthermore, this study investigates the soil improvement effects of this amendment as well as its influence on plant growth. This study employed a hydrothermal method to combine corn stalk (CB) or sludge (SB) biochar with HAP at different ratios (0-20%). Subsequently, sodium alginate gel (SA) was utilized to encapsulate the biochar and minerals, successfully forming a ternary composite gel material (corn stalk biochar/sludge biochar-sodium alginate gel-hydroxyapatite: CB/SB-SA-HAP). Finally, the practical effectiveness of this amendment was verified through potted soil experiments. The results indicate that the CB/SB-SA-HAP composite materials exhibited a micrometre-scale spherical structure with well-developed micropores and possess the functional groups of CB/SB, SA, and HAP, along with unique mineral properties. Through pot experiments, it was verified that the composite material effectively enhances multiple soil properties. After 21 days of cultivation, the soil pH values stabilized within the neutral range (pH = 7 ± 0.3) across all treatment groups. Except for the CB0 (CB:HAP = 1:0) and CB2.0 (CB:HAP = 1:2) treatments, the remaining treatments significantly reduced the soil EC values by 3.27% to 47.92%. All treatments significantly increased the contents of alkali-hydrolysable nitrogen (AHN) (34.8957.91%), available phosphorus (AP) (35.9356.55%), and available potassium (AK) (36.41~56.80%) in the soil. In comparison, although the SB treatment was more effective in regulating the pH and electrical conductivity (EC) of saline-alkali soil than the CB treatment, it was less effective in promoting plant growth in the short term. Through correlation analysis and redundancy analysis, a significant positive correlation was found between soil pH and ryegrass germination rate and plant height, particularly with the most pronounced impact on soil pH observed in the CB1.0 and SB0 (SB:HAP = 1:0) treatments. This study underscores the potential of CB/SB-SA-HAP composite materials in soil improvement and plant growth promotion, providing valuable insights for soil remediation, enhancement, and plant cultivation advancements in the agricultural sector.
土壤改良剂在现代农业中发挥着至关重要的作用，因为它们能有效改善种植环境。本研究创新性地提出使用凝胶作为交联剂来包埋生物炭和羟基磷灰石（HAP），从而制备一种新型土壤改良剂。此外，本研究还考察了这种改良剂对土壤的改良效果及其对植物生长的影响。本研究采用水热法将玉米秸秆（CB）或污泥（SB）生物炭与不同比例（0 - 20%）的HAP相结合。随后，利用海藻酸钠凝胶（SA）包裹生物炭和矿物质，成功形成一种三元复合凝胶材料（玉米秸秆生物炭/污泥生物炭 - 海藻酸钠凝胶 - 羟基磷灰石：CB/SB - SA - HAP）。最后，通过盆栽土壤实验验证了这种改良剂的实际效果。结果表明，CB/SB - SA - HAP复合材料呈现出微米级的球形结构，具有发育良好的微孔，并拥有CB/SB、SA和HAP的官能团以及独特的矿物特性。通过盆栽实验验证了该复合材料能有效改善多种土壤性质。培养21天后，所有处理组的土壤pH值稳定在中性范围内（pH = 7 ± 0.3）。除了CB0（CB:HAP = 1:0）和CB2.0（CB:HAP = 1:2）处理外，其余处理显著降低了土壤电导率（EC）值3.27%至47.92%。所有处理均显著提高了土壤中碱解氮（AHN）（34.89%57.91%）、有效磷（AP）（35.93%56.55%）和有效钾（AK）（36.41%~56.80%）的含量。相比之下，虽然SB处理在调节盐碱土的pH值和电导率（EC）方面比CB处理更有效，但在短期内对促进植物生长的效果较差。通过相关性分析和冗余分析发现，土壤pH值与黑麦草发芽率和株高之间存在显著正相关，特别是在CB1.0和SB0（SB:HAP = 1:0）处理中对土壤pH值的影响最为明显。本研究强调了CB/SB - SA - HAP复合材料在土壤改良和促进植物生长方面的潜力，为农业领域的土壤修复、改良及植物栽培进步提供了有价值的见解。
