为探明免耕对稻油轮作系统土壤结构的影响，基于湖南省洞庭湖区4a的耕作试验（2016-2019），采用X射线CT扫描技术和常规土壤物理分析方法，研究了旋耕和免耕对水稻土0～25 cm土层土壤结构的影响。与旋耕相比，免耕处理对0～5 cm土层的土壤容重和土壤有机碳无显著影响，但免耕处理显著提高了0～10 cm土层>2 mm团聚体的含量和团聚体稳定性。不同耕作方式改变了土壤大孔隙度和孔隙大小分布，与旋耕处理相比，免耕处理增加了0～5和5～10 cm土层各个孔径范围内（>25 μm）的大孔隙度，其中0～5 cm土层300～500 μm孔径的大孔隙显著增加了70.5%，5～10 cm土层25～300和300～500 μm孔径的大孔隙分别增加了82.8%和167.2%（P<0.05）。研究表明，稻油轮作系统免耕有利于提高表层土壤团聚体稳定性和大孔隙度，改善水稻土结构状况。
[Objective] Soil structure is an important factor affecting movement of water, gas and nutrients, root growth, and soil biological activities in the soil. Reasonable tillage is an important farming practice to create soil structure favorable to crop growth. No-tillage has already demonstrated to improve soil structure and soil biodiversity in upland fields. However, so far few studies have reported effect of no-tillage on soil structure of paddy fields. This study was conducted to explore effects of no-tillage on the structure of a paddy soil in a rice-rapeseed rotation system.[Method] Based on a 4-year(2016-2019)tillage field experiment in the Dongting Lake area of North Hunan, effects of rotary tillage (RT) and no-tillage (NT) on soil pore structure of the plough layer (0-25 cm) of a paddy soil were investigated using the X-ray CT imaging technique. Soil aggregate stability was also evaluated using the Le Bissonnais fast wetting method.[Result] The soil organic carbon content of the top soil layer (0-5 cm) in the RT and NT treatments was 34.3 g·kg-1 and 34.4 g·kg-1, respectively, which were higher than those of the other soil layers. Compared with the plots under RT, the plots under NT had a slightly lower soil bulk density in the 0-5 cm soil layer (P>0.05), and significantly more>2 mm soil aggregate in the 0-5 cm and 5-10 cm soil layer. Tillage significantly affected soil macroporosity (>25 μm). Compared with the RT treatment, the NT treatment significantly increased soil macroporosity by 78% and 115% in the 0-5 cm and the 5-10 cm soil layer, respectively. Soil pore size distribution was also greatly altered by tillage practices. The NT treatment increased macroporosity of each of the pore size fractions in the 0-5 cm and 5-10 cm soil layers, especially increased the 300-500 μm macropores in the 0-5 cm soil layer and the 25-300 and 300-500 μm macropores in the 5-10 cm soil layer by 70.5%, 82.8% and 167.2%, respectively.[Conclusion] Our findings show that no-tillage in paddy field improves soil aggregate stability and increases macroporosity of the topsoil, which are beneficial to improvement of physical structure of the paddy soil.
刘玲玲,李超,房焕,赵杨,张中彬,彭新华,尹力初,周虎.免耕对稻油轮作系统土壤结构的影响[J].土壤学报,2021,58(2):412-420. DOI:10.11766/trxb201911110460 LIU Lingling, LI Chao, FANG Huan, ZHAO Yang, ZHANG Zhongbin, PENG Xinhua, YIN Lichu, ZHOU Hu. Effect of No-till Farming on Soil Structure in Rice-rapeseed Rotation System[J]. Acta Pedologica Sinica,2021,58(2):412-420.复制