李小飞 孙永明 叶川 张昆 黄尚书 余跑兰 武琳 李昊

摘要：【目的】探尋既能有效防止土壤结构发生恶化又能充分营造水、肥、气等茶树良好生长环境的合理耕作深度，为指导茶农科学耕作提供参考。【方法】采用田间试验，以免耕为对照（CK），设耕10 cm、耕20 cm和耕30 cm等3个处理，研究不同耕作深度对茶园土壤容重、水含量、孔隙度、土壤三相比和土壤养分含量的影响。【结果】与CK相比，耕作后0～30 cm土层土壤容重有不同程度下降，其中耕30 cm处理0～30 cm土层的土壤容重均显著降低（P<0.05，下同）。耕作显著增加了土壤水含量，其中耕20 cm处理对0～10和10～20 cm土层土壤水含量的提升效果最佳，耕30 cm处理对20～30 cm土层土壤水含量的提升效果最佳。耕作可增加非毛管孔隙度，减少毛管孔隙度，但总孔隙度依然增加，其中，耕作对0～10 cm土层土壤孔隙状况影响显著，而在10～20 cm土层仅耕20 cm处理对土壤孔隙度状况影响显著，在20～30 cm土层仅耕30 cm处理对土壤非毛管孔隙度、总孔隙度影响显著。耕作后0～10 cm土层气相和液相比例显著增加，固相比例显著下降，其中以耕20 cm处理效果最佳，而在20～30 cm土层，对土壤三相比协调效果最佳为耕30 cm处理。耕作后0～10 cm土层有机质含量下降，20～30 cm土层有机质含量在耕20 cm和耕30 cm处理下显著升高；耕作后0～30 cm土层的速效养分含量有不同程度的增加。主成分分析结果表明，总孔隙度、固相比例是反映不同耕作深度对茶园土壤物理性质影响的关键因子，而有效磷则是养分肥力指标的关键因子。【结论】不同耕作深度均能降低茶园土壤容重，增加土壤水含量、改善土壤孔隙度状况和协调土壤三相比，其中以20 cm耕作深度对茶园土壤的综合改善效果最佳。

关键词： 耕作深度；茶园；土壤理化性状

中图分类号： S341 文献标志码：A 文章编号：2095-1191（2018）05-0877-07

Abstract：【Objective】A reasonable depth of cultivation which would not only effectively prevent the deterioration of soil structure but also could fully create a well-developed environment such as water， fertilizer and air for tea plants was studied to provide technical ways for guiding tea farmers in scientific farming. 【Method】In this study， fild experiment was conducted. No tillage was as control（CK）. Three tillage depths including， 10 cm tillage， 20 cm tillage and 30 cm tillage were set to study the effects of various tillage depths on soil bulk density， water content， porosity， three-phase ratio and nutrient. 【Result】Compared to CK， soil bulk density of 0-30 cm layer decreased to various extents after tillage， and that in 30 cm tillage treatment significantly reduced（P<0.05， the same below）. Tillage significantly increased soil water content， and 20 cm tillage had the best effects on 0-10 and 10-20 cm soil layer， 30 cm tillage had the optimal effects on 20-30 cm soil layer.In addition， tillage also increased non-capillary porosity， but reduced capillary porosity. Overall the total porosity still increased. Tillage had significant effects on soil porosity at the depth of 0-10 cm. The soil porosity was significantly affected by 20 cm tillage at the depth of 10-20 cm， while 30 cm tillage had significant effects on the noncapi-llary and total porosity at the depth of 20-30 cm. After tillage， the gas phase and liquid phase ratios at the depth of 0-10 cm increased significantly， while the solid phase ratio decreased significantly， and 20 cm tillage had the optimal effects. While 30 cm-tillage had the best coordination effects on three-phase ratio at the depth of 20-30 cm. After tillage， the content of organic matter at the soil depth of 0-10 cm decreased， while the content of organic matter at 20-30 cm increased significantly under 20 cm and 30 cm tillage. The content of readily available nutrient at the soil depth of 0-30 cm increased to different degrees after tillage. An analysis of principal components showed that the total porosity and solid phase ratio were the key factors that affected the soil physical properties of the tea plantation， while the available phosphorus was the key factor in nutrient fertility index. 【Conclusion】To sum up， different tillage depths can reduce soil bulk density， increase soil water content， improve soil porosity and coordinate three-phase ratio of soil， and 20 cm tillage has the best effects on comprehensive improvement of tea plantation soil.

Key words： tillage depth； tea plantation； soil physical and chemical properties

0 引言

【研究意义】茶园土壤耕作可增强土壤中的气体交换能力，促进底土熟化，同时具有清除杂草、杀虫灭菌的作用（王叶红，2006）。但是，茶园耕作也存在弊端，一是会增加土壤的透气性，容易导致土壤有机质加速分解，二是容易引起茶树根的损伤，不利于茶树健康生长。我国南方丘陵红壤茶园土壤存在“酸、黏、板、蚀”的突出问题，当下茶农不合理的耕作容易造成土壤结构破坏，影响茶树健康生长。因此，恰当处理好耕作的利弊关系，做到扬长避短进行茶园合理耕作，对茶园土壤改良、提升土壤地力及茶叶增产增收等具有重要意义。【前人研究进展】目前已有许多关于不同耕作深度和耕作方式对土壤理化性质及作物产量影响的报道。深耕可增加土壤通透性，缓解土壤紧实状况，提高水分利用率，实现作物的增产增收（Borghei et al.，2008）。梁金凤等（2010）研究表明，耕作深度对土壤物理性状和作物根系生长影响明显，耕作越深，影响越大。……