轮作模式对滩涂土壤有机碳及团聚体的影响

通过3年的田间试验,对比研究了在不施肥及施等量氮肥处理下,水旱轮作、旱旱轮作方式对苏北滩涂轻度盐渍化农田土壤脱盐、土壤有机碳、土壤团聚体的影响。结果表明:相同盐分背景条件下,水旱轮作、旱旱轮作两种利用方式下土壤盐分平均分别下降30%和10%,p H分别下降3%和0,水旱轮作更有利于滨海滩涂轻度盐渍化土壤的快速脱盐及降碱。两种轮作模式下土壤有机碳及大团聚体(2.0 mm)含量均随耕作年限而增长,且在不施肥和施肥的情况下,水旱轮作0~10 cm土层的土壤有机碳增长分别高于旱旱轮作约83%和75%;而大团聚体含量相比旱旱轮作分别高出11%和26%。水旱轮作模式对滨海滩涂盐渍化土壤的脱盐、增碳以及结构改良上均显著好于旱旱轮作模式。

Effects of Rotation Systems on Soil Organic Carbon and Aggregates in Light Salinized Farmland in North Jiangsu Province

Three years of field experiment studied the effects of Rice-wheat rotation and Maize-wheat rotation on soil desalination, soil organic carbon (SOC) and aggregates of light salinized farmland in the coastal flat of North Jiangsu Province. The results showed that the Rice-wheat rotation mode was more beneficial for the soil desalinization in 1m soil depth. Under the treatment of no-fertilizer application and equivalent nitrogen application, the increase of SOC in 0~10 cm of Rice-wheat rotation mode were about 83% and 75% higher than that of Maize-wheat rotation mode, respectively. The macro-aggregates (>2.0 mm) and the mean wheat diameter were both increased with the cultivated years in the both rotation systems, especially in the Rice-wheat rotation land, the macro-aggregates under the treatment of no-fertilizer application and equivalent nitrogen application were about 11% and 26% higher than that of Maize-wheat rotation mode, respectively. The study indicates that the Rice-wheat rotation mode plays a more effective role than Maize-wheat rotation mode in the soil desalinization, the SOC accumulation and the improvement of soil instruction in the coastal saline soils.