添加生物质黑炭对红壤结构稳定性的影响

Effects of Rice Straw-derived Biochar Addition on Soil Structure Stability of an Ultisol

本研究通过室内恒温恒湿控制试验,研究添加黑炭、秸秆在分解过程中对土壤抗破碎性及团聚体稳定性等土壤生物、物理特征的影响。黑炭是在400℃缺氧状态下水稻秸秆焚烧而制成的。实验包括不添加任何物料的对照(CK)、添加黑炭(BC)、黑炭+氮磷钾肥(BC+NPK)、秸秆(Straw)、秸秆+氮磷钾肥(Straw+NPK)等5个处理。研究结果表明,经过55天恒温(25℃)恒湿(田间持水量的40%)培养,黑炭分解速度很慢,通过换算,其周转周期约为1400年,而秸秆周转周期仅为7年,配施氮磷钾能加速黑炭和秸秆的分解。添加黑炭没有提高土壤抗破碎能力和土壤团聚体稳定性(P>0.05),而秸秆则相反(P<0.05)。该研究结果表明生物质黑炭不能像其他有机物料一样提高土壤微生物活性和土壤结构稳定性。

By laboratory experiment under controlled temperature and humidity, the effect of addition of biochar and straw were studied on soil biological and physical properties, such as soil crush resistance and soil aggregate stability. Rice straw-derived bioehars were obtained under 400℃ charring and with 4 h duration. Five different amendment combinations were selected, i.e., control （CK）, 1% biochar （BC）, 1% biochar ＋ NPK （BC＋NPK）, straw, and straw ＋ NPK. The results showed that the decomposition rate of biochar was very slow, and the mean residence time （MRT） of biochar was about 1 400 years by calculation but only 7 years for straw. The decomposition rate could be accelerated by chemical fertilizer, which was proved after 55 d incubation with 25℃ temperature and 40% field moisture capacity. However, Biochar could not improve soil tensile strength and soil aggregate stability （P〉0.05）, which indicated that biomass biochar can＇t improve microbial activity and the stabilization of soil structure as the other organic matters.