• ISSN 1008-505X
  • CN 11-3996/S
魏彬萌, 王益权. 渭北果园土壤物理退化特征及其机理研究[J]. 植物营养与肥料学报, 2015, 21(3): 694-701. DOI: 10.11674/zwyf.2015.0316
引用本文: 魏彬萌, 王益权. 渭北果园土壤物理退化特征及其机理研究[J]. 植物营养与肥料学报, 2015, 21(3): 694-701. DOI: 10.11674/zwyf.2015.0316
WEI Bin-meng, WANG Yi-quan. Physical degradation characteristics and mechanism of orchard soil in Weibei Region[J]. Journal of Plant Nutrition and Fertilizers, 2015, 21(3): 694-701. DOI: 10.11674/zwyf.2015.0316
Citation: WEI Bin-meng, WANG Yi-quan. Physical degradation characteristics and mechanism of orchard soil in Weibei Region[J]. Journal of Plant Nutrition and Fertilizers, 2015, 21(3): 694-701. DOI: 10.11674/zwyf.2015.0316

渭北果园土壤物理退化特征及其机理研究

Physical degradation characteristics and mechanism of orchard soil in Weibei Region

  • 摘要: 【目的】 针对我国渭北苹果主产区出现的随植果年限增加,果园土壤质量严重退化,树势衰弱、树体过早衰老、抗性降低、腐烂病及早期落叶病频繁发生,果品产量与品质下降等问题, 开展了渭北苹果园土壤物理质量退化特征、退化机理及危害程度等问题的研究,以期查明制约果业可持续发展的因素,为果园土壤科学管理提供依据。【方法】 在渭北黄土塬区选取了10 a、10~20 a、20 a 3个园龄段果园各4个,并以土壤条件相同的农田作对照,在果树冠层投影范围内距树干2/3处采取土样,测定土壤剖面不同层次容重、紧实度、孔隙度、饱和导水率、粘粒含量等物理性指标。【结果】 渭北果园土壤容重和紧实度随园龄和土层深度的增加而增大,尤其在表层(20 cm)以下,土壤容重已经达到了1.45~1.61 g/cm3,紧实度达到933~2433 kPa,严重超出果树健康生长的阈值。土壤孔隙度仅在020 cm土层能够保持在50%以上,属于良好状态,而2060 cm土层维持在40%~46%,已处于紧实和严重紧实状态。土壤饱和导水率在果园表层和紧实层均表现出随植果园龄的增大而减小的趋势,尤其是10~20 a和>20 a的果园亚表层土壤饱和导水率低至46.88 cm/d 和20.89 cm/d,制约着降水入渗和土壤蓄墒。3个园龄段果园土壤剖面上粘粒含量随土层深度呈递增趋势,且在030 cm土层随园龄的增加而明显减少,而在30 cm以下则随园龄的增加而呈递增趋势。进一步分析发现,粘粒含量与土壤容重、紧实度以及孔隙度之间呈极显著的相关关系。以压实密度(PD)为指标,对渭北果园土壤压实程度进行评估,发现渭北果园20 cm土层以下的土壤压实密度都在1.40 g/cm3以上,均达到了中度压实的程度,严重影响果树根系的健康生长及对养分的吸收。【结论】 渭北果园20 cm以下的亚表层土壤孔隙密实、容重和紧实度增大, 土壤饱和导水率递减是其土壤物理性质退化的主要特征,表层土壤粘粒的深层移动与淀积是土壤物理退化的主要过程和机理,果园土壤翻耕扰动少、对物理退化干预少是其土壤物理退化程度逐渐加剧的外在原因,土壤团聚体稳定性差是土壤物理状态退化的根本原因。

     

    Abstract: 【Objective】 Apple production contributes to the economy in Shaanxi province greatly. But soil quality of the orchard land has degradated greatly after years of fruit production. That may has led to many issues such as trees weakening, fast aging and reduced resilience. Specifically the apple tree valsa canker and leaf defoliation diseases occur more frequently, and fruit yield and quality decreases greatly. The objective of this study was to investigate the characteristics, mechanism and degree of soil physical degradation in different aged orchards, to provide scientific basis for orchard soil management and eventually to improve the yield and quality of apple production. 【Methods】 Four replicates of 10-, 10-20-and 20-year old orchards were selected for the study. Soil samples within two-thirds of the radius of the tree canopy projection to the trunk were taken. Soil samples were used to measure physical properties such as soil bulk density, compaction, porosity, saturated hydraulic conductivity, and clay content. Comparison was conducted between the orchard and adjacent similar farmland soils. 【Results】 Soil bulk density and compaction increased with orchard age and soil depth. Especially at 20 cm soil layer, soil bulk density reached 1.45-1.61 g/cm3, compaction reached 933-2433 kPa. Porosity of the soil profile in 0-20 cm soil layer remained 50%, and the soil structure was in good condition. However, soil porosity reached 40%-46% in the 20-60 cm soil layer, which was in a state of compaction and severe compaction. Soil saturated hydraulic conductivity decreased even in the surface layer as the orchard aged. In the 10-20 and 20-year-old orchards, soil saturated hydraulic conductivity in the subsurface declined to 46.88 and 20.89 cm/d, reducing the infiltration of the rainfall and the capacity of soil water storage. Soil clay content increased with the depth of soil profile. Clay content at the 0-30 cm depth decreased with increasing orchard age but increased below the 30 cm layer. Further analysis found that the clay content was significantly correlated with soil bulk density, compactness, and porosity. Using packing density as index to evaluate the degree of compaction in orchard soil, the result showed that the soil packing density of orchards was above 1.40 g/cm3 underneath 20 cm depth in Weibei region. The orchard soils in this area have reached the moderate degree of compaction.【Conclusions】 The main characteristics of soil physical degradation of orchards in Weibei Region were reduced soil porosity, increased soil bulk density and compaction, and decreased soil saturated hydraulic conductivity. The main processes and mechanism of orchard soil degradation are clay translocation and accumulation of clay at deep soil. Reduced plow and aeration on soils is the main external cause to anabatic dominanted soil degradation. This is reflected with less soil aggregates.

     

/

返回文章
返回