模拟降水条件下生物炭对酸性红壤理化性质的影响

摘要

【目的】明确降水条件下生物炭对红壤理化性质的影响。【方法】采用室内模拟降水的方法，将以花生壳为原料在400℃热解制备的生物炭施入红壤，在气温25—30℃、单次降水量20 mm条件下进行连续试验约20 d，分析生物炭对施肥和未施肥红壤的速效钾（SAK）、速效磷（SAP）、铵态氮（SAN）、硝态氮（SAN）、有机碳（SOC）、活性铝（SAA）以及 pH值在降水前后的变化。共设8个试验处理：未施肥+未施 C（CK）、未施肥+1%生物炭（C1）、未施肥+2%生物炭（C2）、未施肥+3%生物炭（C3）；施肥+未施 C（F）、施肥+1%生物炭（FC1）、施肥+2%生物炭（FC2）、施肥+3%生物炭（FC3）。施肥土壤施用KH2PO40.14 g·kg-1、KNO30.51 g·kg-1、NH4NO30.80 g·kg-1和Ca(NO3)20.95 g·kg-1。【结果】施用生物炭的红壤，其速效钾、速效磷、硝态氮、铵态氮、活性铝、有机质和pH等指标在降水后均有较大变化，且不同生物炭用量对红壤理化性质的影响存在较大差异。施用3%生物炭时，土壤理化性质在降水前后变化最为显著，C3处理的pH值比CK处理提高了0.60个单位，速效钾的下降幅度比CK少9.5%，速效磷、硝态氮的下降幅度分别比CK高出33.2%和40.5%，有机碳和铵态氮则没有明显变化，活性铝下降了91.1%。而降水后FC3处理的pH值比F处理提高了1.09个单位，速效钾的下降幅度比对照少10.3%，速效磷和硝态氮的下降幅度分别比F处理高23.4%和21.9%，有机碳和铵态氮的增幅分别比F处理高23.6%和5.4%，活性铝下降了94.8%。【结论】在降水条件下，生物炭有利于酸性红壤保持适宜的速效钾含量，提高土壤pH值和有机碳含量，以及能大幅降低土壤活性铝浓度，且对施肥后酸性红壤理化性质的影响更明显。%[Objective] Purposes of this study are to determine if biochar has effects on red soil under precipitation conditions, and the difference between no-fertilization soil and fertilization soil.[Method]A rainfall simulation experiment was carried out with different biochar levels (biochar/soil: 0%, 1%, 2% and 3%) on red soil, and some characters such as soil available phosphorus (SAP), available potassium (SAK), nitrate nitrogen (SNN), ammonium nitrogen (SAN), organic carbon (SOC) and active aluminum (SAA) were determined.[Result]Under precipitation conditions, the variation of SAN, SOC, SAA and pH in red soil was observably. When 3% biochar was added, the change of soil characters was most significantly. Compared with the no-fertilization control (CK), soil pH raised by 0.60, SAA decreased by 91.1%, the descent range of SAK decreased by 9.5%, the descent ranges of SAP and SNN, respectively, increased by 33.2%, 40.5% in no-fertilization soil with 3% biochar application. Compared with the fertilization control (F), soil pH raised by 1.09, SAA decreased by 94.8%, the descent range of SAK decreased by10.3%, the descent ranges of SAP and SNN, respectively, increased by 23.4% and 21.9%, SOC and SAN, respectively, increased by 23.6% and 5.4% in fertilization soil with 3% biochar application rate.[Conclusion]Under precipitation conditions, biochar was propitious to maintain SAP, improved soil pH and SOC, and decreased SAA, especially in red soil with fertilizer application.