生物炭连续施用对油菜产量及旱地红壤溶解性有机碳光谱特征的影响

林小兵; 王馨悦; 黄尚书; 何绍浪; 刘艳琴; 张昆; 王斌强; 黄欠如; 成艳红

doi:10.19336/j.cnki.trtb.2021111902

生物炭连续施用对油菜产量及旱地红壤溶解性有机碳光谱特征的影响

Effects of Continuous Biochar Application on Rapeseed Yield and Spectral Characteristics of Dissolved Organic Carbon in Upland Red Soil

摘要

摘要:
目的揭示生物炭连续添加对旱地红壤溶解性有机碳的影响。
方法通过定位试验，探讨了低剂量（0.75 ~ 1.5 t hm⁻²）生物炭连续施用7年后油菜产量、土壤理化性质和溶解性有机碳荧光光谱组分及参数变化特征。
结果与对照（CK）相比，生物炭施用降低了土壤交换性Al³⁺含量（0.69 ~ 0.87 cmol kg⁻¹），提高了土壤pH（0.13 ~ 0.21个单位）、有机质含量（11.7% ~ 18.1%）和可溶性碳含量（127.5% ~ 127.8%）；油菜单株角果数提高了39.8% ~ 45.2%，油菜产量增加了3.5% ~ 20.3%，其产量随着生物炭添加量呈递增趋势。连续施用生物炭有利于增加溶解性有机碳中类酪氨酸和类富里酸的比例，且显著降低了微生物代谢产物的比例。与CK相比，连续施用生物炭后土壤溶解性有机碳荧光指数降低了4.4% ~ 10.6%，新鲜度指数降低了17.4% ~ 18.4%，自生源指数降低了0.26（22.6%），而腐殖化指数增加了1.2% ~ 5.1%。相关分析表明溶解性有机碳与pH呈显著正相关，而与交换性Al³⁺呈显著负相关；微生物代谢产物与pH呈显著负相关，而与交换性Al³⁺呈显著正相关；土壤类酪氨酸与交换性Al³⁺呈显著负相关。冗余分析表明土壤pH和交换性H⁺是影响溶解性有机碳及其光谱特征变化的主要指标。
结论红壤旱地低剂量生物炭连续施用可以增加油菜产量，改良红壤酸度，增加土壤溶解性有机碳含量，且更利于溶解性有机碳中类富里酸物质的增加，增加溶解性有机碳的腐殖化系数，提高其稳定性。

Abstract:
Objective The paper aims to make sure the effects of continuous biochar application on dissolved organic carbon (DOC) in upland red soil.
Method The soil physicochemical properties, rapeseed yield, DOC fluorescence spectrum components, and parameters were detected after 7 years of low-dose (750-1500 kg hm⁻²) biochar application.
Result Biochar application reduced soil exchange Al³⁺ (0.69-0.87 cmol kg⁻¹), but decreased the soil pH (0.13-0.21), organic matter (11.7%-18.1%), and soluble carbon contents (127.5%-127.8%) compared with control. The pods’ number and the yield were increased 39.8%-45.1% and 3.5%-20.3%, respectively. And the trend was increased with the amount of biochar application. Continuous biochar application increased the proportion of tyrosine and fulvic acid-like in DOC, but reduced the proportion of microbial metabolites. Biochar application decreased fluorescence index (4.4%-10.6%), freshness index (17.4%-18.4%) and biogenic index 0.26 (22.6%), and increased the humification index (1.2%-5.1%) in soil DOC. Correlation analysis indicated that soil DOC was positively correlated with soil pH, and negatively correlated with exchange Al³⁺. Microbial metabolites were negatively correlated with pH, and positively correlated with exchange Al³⁺. Soil tyrosine was negatively correlated with exchange Al³⁺. Redundancy analysis showed that soil pH and exchangeable H⁺ were the main indicators affecting the changes of soil DOC and its spectral characteristics.
Conclusion Continuous low-volume biochar application in red soil dryland can increase rapeseed yield, improve the acidity of red soil, increase DOC content, fulvic acid-like substances, and humification coefficient to improve stability in DOC soil.

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