粉垄深度对稻作烟区土壤理化特性及作物周年产量的影响

  背景和目的  为了揭示不同粉垄深度对湖南稻作烟区土壤理化性状及烤烟根系生长和烟稻周年产量的影响。   方法  大田试验于2019年在长沙浏阳永安镇开展，采用单因素随机区组试验设计，设置粉垄深耕20 cm（T1）、30 cm（T2）、40 cm（T3）和直接旋耕12 cm（CK）四个处理，采用50 cm土柱取样器，每个处理取土柱3个。研究了0~50 cm土层土壤理化性状的变化。并分析了不同处理对烤烟根系生长状况、烤后烟叶物理性状和化学成分、经济性状和作物周年产量的影响。  结果  与CK处理相比，T2和T3处理在0~40 cm土层土壤容重显著降低1.49%~8.97%，土壤孔隙度增加0.44%~12.88%，土壤紧实度降低0.37%~24.37%；T2处理在20~30 cm土层土壤碱解氮、有效磷和速效钾含量的提升效果最为显著，较CK处理分别提升了22.82%、58.02%、52.41%；T2处理改善烤烟物理性状及内在化学成分的效果最为显著，各粉垄深耕处理均提高了烤烟的产量和上等烟比例，并且也能提高后茬作物水稻产量，其中T2处理作物产量产值最高。  结论  粉垄耕作30 cm显著改善了稻作烟区土壤物理性质，提高了土壤速效养分在20~40 cm土层中的含量，提升了烟叶的品质和产量，作物周年产值显著提高18029.89元/hm2。 

Effect of ridge depth on soil physicochemical and annual crop yield in rice growing tobacco area

  Background  This study aims to reveal the effect of ridge depths on soil physical and chemical properties, root growth of flue-cured tobacco and annual crop yield in rice-growing tobacco areas of Hunan province.  Methods  A field experiment was carried out in 2019 by adopting a single-factor randomized block experiment design, where four treatments including powder ridge deep ploughing of 20 cm (T1), 30 cm (T2), 40 cm (T3) and direct rotary tillage ridge of 12 cm (CK) were set. The changes of soil physical and chemical properties of 0-50 cm soil layer was studied, and the effects of different treatments on the growth of flue-cured tobacco root system, physical properties and chemical components of flue-cured tobacco leaves, economic properties and annual crop yield were analyzed.  Results  Compared with CK treatment, T2 and T3 treatments significantly reduced soil bulk density, increased soil porosity, and reduced soil compaction in the 0-40 cm soil layer; powder ridge cultivation significantly increased the organic matter content, where T2 led to the most significant improvement in contents of soil alkali-hydrolyzable nitrogen, available phosphorus and available potassium. Moreover, T2 treatment had the most significant effect of regulating the physical properties and internal chemical composition of flue-cured tobacco. All powder ridge deep ploughing treatments increased the yield of flue-cured tobacco and the proportion of high-quality tobacco, and increased the yield of rice as afterreap crop, where T2 treatment led to the highest yield of rice.  Conclusion  Powder ridge tillage of 30 cm significantly improved the physical properties of the soil in the rice-growing tobacco area, changed the content of soil available nutrients in the 20-40 cm soil layer, improved the quality and yield of tobacco leaves, and significantly increased the annual yield of crops.