不同有机物料对苏打碱化土有机碳库和化学性质的影响

以内蒙古河套灌区苏打碱化土为研究对象开展田间试验,设置常规施肥(CK)、生物炭+常规施肥(BC)、牛粪+常规施肥(CD)、玉米秸秆+常规施肥(SW)和羊粪+常规施肥(GM)5个处理,研究不同有机物料添加对碱化土壤有机碳(SOC)库和化学性质的影响。分别于2019年和2020年收获季采集0—30 cm耕层土壤,分析不同有机物料添加下SOC及其活性碳组分和主要盐碱指标的变化特征及其相关关系。结果表明:与CK相比,2019年和2020年各有机物料添加处理下SOC平均增幅分别为22.7%和17.2%,土壤有机碳储量(SOCs)平均增幅分别为22.9%和18.2%;4种有机物料均提高了碱化土壤活性有机碳组分含量,其中,CD和GM处理下各活性碳组分含量增幅较其他处理更高;2019年各有机物料添加处理下碳库管理指数(CPMI)较CK提高53.8%~108.3%,2020年提高71.3%~144.1%(P＜0.05),CD和GM对CPMI的提升作用更明显。土壤化学性质方面,2020年各有机物添加处理下pH均显著下降,BC和CD处理下碱化度(ESP)分别显著下降36.9%和29.3%,CD处理下蔗糖酶活性提高36.7%(P＜0.05)。主成分分析(PCA)表明,影响苏打碱化土SOC含量变化的主要因素为活性有机碳组分和ESP。牛粪和羊粪施用对苏打碱化土有机碳库质量提升作用较好,生物炭施用对盐碱化指标改良效果最明显。

Effect of Different Organic Amendments on Soil Organic Carbon Pool and Chemical Properties in Soda Alkaline Soil

A field experiment was conducted in soda alkaline soil in the Hetao Irritated Area of Inner Mongolia to study the effect of different organic amendments on soil organic carbon (SOC) pool and chemical properties. Five treatments were designed as follows:traditional chemicals fertilizer only (CK), CK+biochar (BC), CK+cow dung (CD), CK+corn straw (SW), CK+goat manual (GM). Soil samples (0-30 cm depth) were collected after maize was harvested in 2019 and 2020, respectively, and the changes of SOC pool, labile organic carbon fractions, main saline and alkaline indexes and the relationship between them were analyzed. The results showed that compared with CK, the average increase of SOC in all organic amendment treatments were 22.7% and 17.2% in 2019 and 2020, respectively. The average increase in organic carbon stock (SOCs) were 22.9% and 18.2%, respectively. Labile organic carbon content increased in organic amendment treatments, among which the increase of CD and GM were higher than those in other treatments. CPMI increased by 53.8%~108.3% in organic amendment treatments compared with CK in 2019, and increased by 71.3%~144.1% in 2020 (P<0.05), and the promotive effect of CD and GM treatments was more obvious. As to the chemical properties, pH decreased apparently in four organic amendment treatments in 2020, exchangeable sodium percentage (ESP) decreased by 36.9% and 29.3% in BC and CD treatments, respectively (P < 0.05). Principal component analysis (PCA) showed that labile organic carbon fractions and ESP were the main factors which affected SOC content in soda alkaline soil. Cow dung and sheep manure had better effect on improving the quality of the organic carbon pool, and biochar had the most obvious effect on improving the chemical properties of soda alkaline soil.