【摘要】 稻虾轮作模式在湖北江汉平原已发展近30年,对农民增产增收具有重要作用。开展不同年限稻虾轮作对土壤理化性质影响的研究,有助于科学指导该模式下的农田管理。在同一农渠范围内选择相似的稻田,分别采集水稻单作(CK)和稻虾轮作(1、3、7、13、18和23a)的3个土层深度(0～20、20～40和40～60 cm)原状土样,分析其相应的理化指标。结果显示,与中稻单作相比,长期稻虾轮作会显著降低0～20和20～40 cm土层土壤容重并提高非毛管孔隙度、毛管孔隙度和总孔隙度,而40～60 cm土层变化较小;稻虾轮作1 a后土壤pH、全氮和易氧化有机碳含量显著增加,但速效养分和阳离子交换量增幅不明显。与稻虾轮作1 a相比,轮作7～13 a稻田的土壤pH和其他各项指标均显著增加;轮作13 a以上,0～20 cm土层的pH、全氮和速效养分增幅最为明显,但20～60 cm土层的理化性质无明显变化。随着轮作年限的延长,0～20 cm土层的pH和其他各项指标均表现为:23 a>18 a>13a>7a>1a>0(CK),20～40cm和40～60cm土层的pH、全氮、碱解氮、有效磷和速效钾含量也有相似规律,但增幅并不明显。因此,长期稻虾轮作有助于改善耕层土壤结构、增强土壤缓冲能力和提高pH及氮、磷、钾等速效养分含量。更多还原

【Abstract】 【Objective】 In recent years, domestic and foreign scholars have conducted in-depth researches on modes of comprehensive farming of paddy fields, but with focus mostly on mixed cultivation of rice and fish or crab. There are a few studies done on the mode of rice-crawfish rotation, with focus leaning on technology and economy of the mode, rather than on its effects on evolution of the paddy soil per se in the paddy field. Therefore, this study was oriented to explore effects of rice-crawfish rotation relative to cultivation history on physical and chemical properties of the soil, in an attempt to elucidate how the soil evolves in physicochemical properties under long-term rice-crawfish rotation, and provide certain scientific basis for guiding farmland management under such a cultivation model.【Methods】In this study, paddy fields, similar in soil and irrigation/drainage conditions, were selected within the scope of an irrigation/drainage ditch. Soil samples were collected by layer in a paddy field under mono-cropping of mid-rice as CK and paddy fields under rice-crawfish rotation different in cultivation history( 1, 7, 13,18 and 23 years. and labeled as CR1, CR7, CR13, CR18 and CR~23, respectively) for analysis of soil pH,bulk density, porosity, total nitrogen, alkaline nitrogen, available phosphorus, available potassium, cation exchange capacity(CEC), and soil oxidizable organic carbon(ROC).【Results】Results show that longterm rice-crawfish rotation significantly reduced soil bulk density and increased non-capillary porosity,capillary porosity, and total porosity in the 0～20 and 20～40 cm soil layers, but did not have much effect in the 40～60 cm soil. In the paddy field, 1 year old in rotation, soil pH, total nitrogen, and oxidizable organic carbon content increased significantly, but available nutrient and cation exchange capacity did not as much.Compared with the paddy field 1 year old in rotation 1 a, the paddy fields, 7～13 years old in rotation,were significantly higher in soil pH and other indices, and the paddy fields over 13 years old in rotation,soil pH, total nitrogen and content of available nutrients increased the most significantly in the 0～20 cm soil layer, but did not change much in physical and chemical properties in the 20～60 cm soil layer.In terms of significance of the changes in soil pH and other indices in the 0～20 cm soil layer, the paddy fields displayed an order of 23 a> 18 a> 13 a> 7 a> 1 a> 0(CK), and pH, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus and available potassium in the 20～40 cm and 40～60 soil layers had similar trends, though not so significant. 【Conclusion】Therefore, it can be concluded that long-term rice-crawfish rotation helps improve soil structure of the plough layer of the field, and increase soil buffering capacity,soil pH and contents of available nutrients, such as nitrogen, phosphorus, and potassium.更多还原