轮作模式对滩涂土壤有机碳及团聚体的影响

摘要

Three years of field experiment was conducted to study 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 rice-wheat rotation mode was more beneficial for the soil desalinization in 1 m soil depth. Under the treatment of no-fertilizer application and equivalent nitrogen application, SOC in 0–10 cm of rice-wheat rotation mode were increased by about 83% and 75% compared with those 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 two rotation systems, especially in 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 those of maize-wheat rotation mode, respectively. The study indicated that rice-wheat rotation mode played a more effective role than maize-wheat rotation mode in soil desalinization, SOC accumulation and the improvement of soil instruction in the coastal saline soils.%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%，pH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。