氮肥及黄腐酸对盐渍土有机碳和团聚体特征的调控作用

为了探明不同氮肥水平下黄腐酸对盐碱障碍土壤的改良及培肥效应,本研究以滨海滩涂新垦轻中度盐碱障碍土壤为研究对象开展田间试验,采用水稻-小麦轮作种植模式,通过测定土壤电导率、pH、有机碳和土壤团聚体含量及其稳定性,研究黄腐酸与不同氮肥水平对土壤盐分消减调控和土壤地力提升效应。结果表明:黄腐酸能有效降低耕层土壤盐分,在氮水平300 kg/hm²条件下黄腐酸处理对耕层0～20 cm土壤电导率与p H降低效果最好;黄腐酸可以有效改善土壤结构及稳定性,小麦季与水稻季,在氮水平300kg/hm²条件下黄腐酸处理土壤>2mm水稳性大团聚体含量相较于不施肥对照分别增加18.6%和13.8%,土壤团聚体平均重量直径与当地常规施肥相比增加38%;围垦初期,氮水平处理相较于黄腐酸处理对耕层土壤有机碳含量的影响更大,氮水平300kg/hm²处理相较于低氮(225kg/hm²)与高氮(325kg/hm²)处理,两季土壤总有机碳积累量分别增加31.0%和120.0%。综合考虑土壤改良效应,黄腐酸处理土...

Regulation of Nitrogen and Fulvic Acid on Soil Organic Carbon and Aggregates in Saline Soil

In order to find out the improvement effect of fulvic acid on soil with saline-alkaline disturbance and fertilizer effect under different nitrogenous fertilizer levels. The soil was selected as the research object to carry out the field experiment. The rice-wheat cropping pattern was used. The effects of fulvic acid and different nitrogen levels on soil salinity control and soil fertility enhancement were studied by measuring soil electric conductivity, pH value, organic carbon and aggregate content and stability. The results showed that fulvic acid could effectively reduce the soil salt content in topsoil. When the nitrogen level was 300 kg/hm₂, the effect of fulvic acid on decreasing soil electric conductivity and pH value of 0~20 cm layer in top soil were the best. The fulvic acid could effectively improve the soil structure, soil water-stable macro-aggregates (>2 mm) increased by 18.6% and 13.8%, respectively, which compared with control treatment under the nitrogen level of 300 kg/hm₂ in the wheat and rice seasons. The aggregates mean weight diameter increased by 38% compared with the conventional fertilization. In the initial stage of reclamation, the nitrogen level had a greater impact on the organic carbon content of topsoil than that of fulvic acid, When the nitrogen level was 300 kg, compared with low nitrogen (225 kg /hm₂) and high nitrogen (325 kg /hm₂) treatment, the total organic carbon accumulation in two seasons increased by 31.0% and 120.0% respectively. Considering the effects of soil improvement, soil salinity decreased, the content of water-stable macro-aggregates increased and its stability increased, and the content of organic carbon increased. Therefore, fulvic acid combined with the appropriate amount of nitrogen is moderate and moderate saline-alkali soil optimization fertilization measures.