Yang Cai-di, Lu Sheng-Gao
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Huan Jing Ke Xue. 2020 Sep 8;41(9):4246-4252. doi: 10.13227/j.hjkx.202002213.
To compare the dynamic effects of straw and corresponding biochar on soil acidity, nutrients, and exchangeable capacity in red soil, a pot experiment was performed. The treatments included control (CK), rice straw (R1B0), rice straw biochar prepared at 350℃ (R1B1) and 550℃ (R1B2), rape stalk (R2B0), and rape stalk biochar prepared at 350℃ (R2B1) and 550℃ (R2B2). Straw at 1% and corresponding biochar were added to a strongly acidic red soil. The rice was planted as the experimental crop. Soils were collected at the seedling, tillering, filling and mature stages of rice growth, respectively. The changes in soil pH, exchangeable acidity, organic matter, nutrients (NH-N and NO-N), and exchangeable cations in soils were measured. The results showed that soil pH, NH-N, and NO-N concentrations decreased with the growth period of rice, while the organic matter content and cation exchange capacity (CEC) increased. Direct returning of straw and biochar could increase soil pH, organic matter content, and exchangeable cations content, and reduce the total amount of exchangeable acids. In the mature stage of rice, rice straw and rape stalk biochar at 350℃ increased the soil pH by 0.29 and 0.42, respectively, compared to the control treatment. Similarly, biochar decreased the exchangeable acidity and exchangeable Al content significantly compared to the direct returning treatments of straw. The exchangeable acidity and exchangeable Al contents of soils in R1B2 and R2B1 treatments decreased by 54.8% and 58.9%, respectively, compared to the control treatment. The soil organic matter (SOM) content and CEC in biochar treatments were significantly higher than those in direct returning treatments of straw. Overall, the effects of rape stalk biochar on soil properties were slightly stronger than those of rice straw. The correlation analysis showed that soil exchangeable acids had a significantly negative correlation with organic matter (=-0.912, <0.01), and CEC (=-0.866, <0.05). The CEC in soils was positively related to organic matter (=0.833, <0.05). Direct returning of straw and biochar applications can effectively improve soil acidity and increase nutrient contents. The effects of straw biochar on soils were stronger than the direct returning of straw in decreasing soil acidity, and increasing soil organic matter content and exchangeable capacity in acidic soils.
为比较秸秆及其相应生物炭对红壤土壤酸度、养分和交换容量的动态影响，进行了盆栽试验。处理包括对照（CK）、稻草（R1B0）、350℃制备的稻草生物炭（R1B1）和550℃制备的稻草生物炭（R1B2）、油菜秸秆（R2B0）、350℃制备的油菜秸秆生物炭（R2B1）和550℃制备的油菜秸秆生物炭（R2B2）。将1%的秸秆及其相应生物炭添加到强酸性红壤中。以水稻作为试验作物进行种植。分别在水稻生长的苗期、分蘖期、灌浆期和成熟期采集土壤。测定土壤pH值、交换性酸度、有机质、养分（铵态氮和硝态氮）以及土壤中交换性阳离子的变化。结果表明，土壤pH值、铵态氮和硝态氮浓度随水稻生育期的推进而降低，而有机质含量和阳离子交换量（CEC）增加。秸秆和生物炭直接还田可提高土壤pH值、有机质含量和交换性阳离子含量，并降低交换性酸总量。在水稻成熟期，与对照处理相比，350℃的稻草和油菜秸秆生物炭分别使土壤pH值提高了0.29和0.42。同样，与秸秆直接还田处理相比，生物炭显著降低了交换性酸度和交换性铝含量。与对照处理相比，R1B2和R2B1处理土壤的交换性酸度和交换性铝含量分别降低了54.8%和58.9%。生物炭处理的土壤有机质（SOM）含量和CEC显著高于秸秆直接还田处理。总体而言，油菜秸秆生物炭对土壤性质的影响略强于稻草。相关性分析表明，土壤交换性酸与有机质（r = -0.912，P < 0.01）和CEC（r = -0.866，P < 0.05）呈显著负相关。土壤中的CEC与有机质呈正相关（r = 0.833，P < 0.05）。秸秆直接还田和施用生物炭可有效改善土壤酸度并增加养分含量。在降低土壤酸度、增加酸性土壤有机质含量和交换容量方面，秸秆生物炭对土壤的影响强于秸秆直接还田。
