基于空间差异的有机茶园环境适宜性评价的土壤采样方法

Soil sampling methods for evaluation of environmental suitability in organic tea garden based on spatial difference

为完善和规范有机认证技术体系,基于有机产品标准和有机认证的环境要求,开展了茶叶有机种植基地土壤环境评价的采样方法研究。针对有机茶园土壤性质的空间差异特征,分析不同采样深度、采样密度和采样点布设等对茶园土壤pH、重金属等指标评价结果的影响。结果表明:供试有机茶园不同深度土层的土壤pH值和有机质含量差异显著(P<0.05)。茶树根系集中分布的20~30 cm土层pH值较低,有机质含量较高。采集0~30 cm的土壤进行检测能更加客观地反映茶园土壤环境适宜性;供试茶园土壤重金属的空间变异系数大小排序为Pb>Hg>Cu>Cr>As,其中重金属Pb、Hg等存在外源性输入,在土壤表层0~10 cm聚集;通过不同采样密度获得的土壤环境指标检测结果差异显著(P<0.05),建议对较大规模的茶场进行分区采样,并增加送检样本数量。

In order to promote the development of organic agriculture, improve and standardize the organic certification technology system, a study on soil sampling methods for organic tea garden was carried out. Spatial differences of soil properties, such as organic matter content,heavy metal content and pH were analyzed under varying sampling methods, including depth, sample point layout and sample numbers among five organic tea gardens. The results show that among different depths of soil profile, both organic matter content and pH changed sig-nificantly（P〈0.05）. The pH was lower and organic matter content was higher in 20～30 cm soil layer where most tea roots exist. Recom-mended sampling depth of tea garden is 30 cm, as it reflects environmental suitability of tea garden soils more objectively. The order of spatial variation coefficient of heavy metals in the tea gardens was as follows：Pb 〉Hg〉 Cu 〉Cr 〉As. Hg and Pb were from external sources and clustered in 0～10 cm soil layer, accounting 49.52% and 61.56% respectively. At the range of different altitudes, soil of slope crest possess higher organic matter content and lower pH value. Soil indexes changed significantly（P〈0.05）by different sampling densities.It is recommended to use area sampling and increase sample numbers in order to solve the problem caused by spatial difference in tea garden soils.