Spatial Variability of Soil Cation Exchange Capacity in Hilly Tea Plantation Soils Under Different Sampling Scales

Studies on the spatial variability of the soil cation exchange capacity （CEC） were made to provide a theoretical basis for an ecological tea plantation and management of soil fertilizer in the tea plantation. Geostatistics were used to analyze the spatial variability of soil CEC in the tea plantation site on Mengding Mountain in Sichuan Province of China on two sampling scales. It was found that, （1） on the small scale, the soil CEC was intensively spatially correlative, the rate of nugget to sill was 18.84% and the spatially dependent range was 1 818 m, and structural factors were the main factors that affected the spatial variability of the soil CEC; （2） on the microscale, the soil CEC was also consumingly spatially dependent, and the rate of nugget to sill was 16.52%, the spatially dependent range was 311 m, and the main factors affecting the spatial variability were just the same as mentioned earlier. On the small scale, soil CEC had a stronger anisotropic structure on the slope aspect, and a weaker one on the lateral side. According to the ordinary Kriging method, the equivalence of soil CEC distributed along the lateral aspect of the slope from northeast to southwest, and the soil CEC reduced as the elevation went down. On the microscale, the anisotropic structure was different from that measured on the small scale. It had a stronger anisotropic structure on the aspect that was near the aspect of the slope, and a weaker one near the lateral aspect of the slope. The soil CEC distributed along the lateral aspect of the slope and some distributed in the form of plots. From the top to the bottom of the slope, the soil CEC increased initially, and then reduced, and finally increased.

Tea Plantation Frost Damage Early Warning Using a Two-Fold Method for Temperature Prediction

As the source and main producing area of tea in the world, China has formed unique tea culture, and achievedremarkable economic benefits. However, frequent meteorological disasters, particularly low temperature frostdamage in late spring has seriously threatened the growth status of tea trees and caused quality and yield reduction of tea industry. Thus, timely and accurate early warning of frost damage occurrence in specific tea garden isvery important for tea plantation management and economic values. Aiming at the problems existing in currentmeteorological disaster forecasting methods, such as difficulty in obtaining massive meteorological data, largeamount of calculation for predicted models and incomplete information on frost damage occurrence, this paperproposed a two-fold algorithm for short-term and real-time prediction of temperature using field environmentaldata, and temperature trend results from a nearest local weather station for accurate frost damage occurrence leveldetermination, so as to achieve a specific tea garden frost damage occurrence prediction in a microclimate. Timeseries meteorological data collected from a small weather station was used for testing and parameterization of atwo-fold method, and another dataset acquired from Tea Experimental Base of Zhejiang University was furtherused to validate the capability of a two-fold model for frost damage forecasting. Results showed that comparedwith the results of autoregressive integrated moving average (ARIMA) and multiple linear regression (MLR),the proposed two-fold method using a second order Furrier fitting model and a K-Nearest Neighbor model(K = 3) with three days historical temperature data exhibited excellent accuracy for frost damage occurrence prediction on consideration of both model accuracy and computation (98.46% forecasted duration of frost damage,and 95.38% for forecasted temperature at the onset time). For field test in a tea garden, the proposed methodaccurately predicted three times frost damage occurrences, including onset time, duration and occurrence level.These results suggested the newly-proposed two-fold method was suitable for tea plantation frost damage occurrence forecasting.

An Edge-assisted, Object-oriented Random Forest Approach for Refined Extraction of Tea Plantations Using Multi-temporal Sentinel-2 and High-resolution Gaofen-2 Imagery

As a consumed and influential natural plant beverage,tea is widely planted in subtropical and tropical areas all over the world.Affected by(sub)tropical climate characteristics,the underlying surface of the tea distribution area is extremely complex,with a variety of vegetation types.In addition,tea distribution is scattered and fragmentized in most of China.Therefore,it is difficult to obtain accurate tea information based on coarse resolution remote sensing data and existing feature extraction methods.This study proposed a boundary-enhanced,object-oriented random forest method on the basis of high-resolution GF-2 and multi-temporal Sentinel-2 data.This method uses multispectral indexes,textures,vegetable indices,and variation characteristics of time-series NDVI from the multi-temporal Sentinel-2 imageries to obtain abundant features related to the growth of tea plantations.To reduce feature redundancy and computation time,the feature elimination algorithm based on Mean Decrease Accuracy(MDA)was used to generate the optimal feature set.Considering the serious boundary inconsistency problem caused by the complex and fragmented land cover types,high resolution GF-2 image was segmented based on the MultiResolution Segmentation(MRS)algorithm to assist the segmentation of Sentinel-2,which contributes to delineating meaningful objects and enhancing the reliability of the boundary for tea plantations.Finally,the object-oriented random forest method was utilized to extract the tea information based on the optimal feature combination in the Jingmai Mountain,Yunnan Province.The resulting tea plantation map had high accuracy,with a 95.38%overall accuracy and 0.91 kappa coefficient.We conclude that the proposed method is effective for mapping tea plantations in high heterogeneity mountainous areas and has the potential for mapping tea plantations in large areas.

Investigation on Species of Spiders in Tea Plantations in Enshi Region of China

The spider resources in tea plantations in Enshi region have been investigated and 51 species of spiders belonging to 22 families have been identified in the paper. The dominant species are clarified and their directory and distribution status are also listed in the paper.

Study on the Construction Modes of Rural Landscape and Ecological Tea Plantation——With Tea Plantations in Helong Township,Ya'an City as a Study Case

By analyzing the present situation and advantages of tea plantations in Helong Township,Ya'an City,the construction modes of rural landscape and ecological tea plantation were studied from the perspective of landscape ecology.

Spatial Analysis of Pollution-free Land for Tea Plantation and Comprehensive Evaluation of Soil Suitability

To survey the tea resource advantages in Guizhou's mountainous areas and complete rational layout of pollution-free tea planting areas, we take the case of Guiding County in Guizhou Province to establish the comprehensive evaluation indicator system of pollution-free land for tea plantation and comprehensive evaluation model of soil suitability of land for tea plantation according to the Environmental Conditions Standard for Pollution-free Food-Tea Producing Areas by the Ministry of Agriculture (NY 5020-2001), using land use data, remote sensing data, soil data, temperature, precipitation, light, DEM and other critical basic data, combined with the spatial analysis statistical method. The results show that the area of land suitable for planting tea is 1265 km2, accounting for 77.57% of the entire study area; the area of land with soil quality, climatic conditions and terrain conditions to meet the planting standard of pollution-free tea is 1232.51 km2, accounting for 75.57% of the total land area; the area of land most suitable for the planting of pollution-free tea is 128.71 km2, accounting for 7.89% of the total land area. The above studies can provide scientific basis and decision support for the implementation of tea planting industry standards in the specific areas, and provide reference for the comprehensive assessment of tea planting in other areas.

Canopy Cultivation Technology and Benefit Analysis of Tea Tree Canopy in Preserved Tea Plantations

The present study introduced the concept and characteristics of preserved tea plantation,and analyzed application and benefit of stereoscopic trimming and pruning technology in the cultivation of tea tree canopy in preserved tea plantations.The results show that the stereoscopic trimming and pruning technology of tea trees has more advantages in production efficiency than other trimming and pruning techniques in terms of yield and output value,and can better exert the regeneration ability of tea branches.The grade of branching is increased from grade 3-4 before unpruning to grade 9-13(3-4 times higher),the length of internode is increased from 1-2 cm to 3-7 cm(increased 3-4 times),the picking area is increased from 0.9 m×1.1 m to 2.8 m×4.2 m(an increase of nearly 10 times),accordingly achieving the best production and economic benefits required in tea production.

Influence of Tea Plantations, Forest and Mixed Farming on Stream Flow and Sediment Loads, Case of Sondu Miriu River Basin, Kenya

The changing patterns of land cover and land use in the tropical river basin over time are critical. The hydrological phenomena at basin and sub basin scale are affected positively or negatively by dynamics of the land cover and land use patterns. Hence identifying causes and driving factors aid in taking appropriate measures to avert the impacts. This study determined the influences of sub basins dominated by tea plantations, forests and agricultural land uses in terms of streamflow and sediment flux variability in Sondu Miriu River Basin in Kenya, East Africa. Field-based investigations were conducted through sampling of flow velocities, turbidity and TSSC obtained from existing River Gauging Stations established within the three sub basins. The sub basin dominated by mixed farming land cover exhibits high turbidity approximately 620 NTU and high levels of total suspended sediment concentration (TSSC) of the order of 630 mg/l in wet seasons. The turbidity levels and TSSC were low in sub basins dominated by forest and tea plantations with approximately mean value of 17 - 29 NTU and 0.019 g/l. The sediment loads in sub basin dominated by mixed farming in the pre planting season in January to February were about 900 tonnes/day higher than that in crop growing season. In sub basins dominated by forest cover and tea plantations, sediment loads were low ranging between 2 - 7 tonnes/day. The relationship between stream flows and area under tea plantations, forests and mixed farming ranged between R2 of 0.025 and 0.16. Tea plantations and forests influence the stream flows and sediment yields in long term duration while in mixed farming variations were observed seasonally. The strong relationships between rainfall and stream flows at the sub basins ranging between R2 of 0.84 and 0.97 revealed the significance of rainfall in hydrologic response of the Sondu Miriu River Basin.

Insight into the sorption and desorption pattern of pyrrolizidine alkaloids and their N-oxides in acidic tea(Camellia sinensis)plantation soils

Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are crucial due to the horizontal transfer of these natural products from PA-producing plants to soil and subsequently absorbed by plant roots.This study firstly investigated the sorption/desorption behaviors of PAs/PANOs in tea plantation soils with distinct characteristics.Sorption amounts for seneciphylline(Sp)and seneciphylline-N-oxide(SpNO)in three acidic soils ranged from 2.9 to 5.9μg/g and 1.7 to 2.8μg/g,respectively.Desorption percentages for Sp and SpNO were from 22.2%to 30.5%and 36.1%to 43.9%.In the mixed PAs/PANOs systems,stronger sorption of PAs over PANOs was occurred in tested soils.Additionally,the Freundlich models more precisely described the sorption/desorption isotherms.Cation exchange capacity,sand content and total nitrogen were identified as major influencing factors by linear regression models.Overall,the soils exhibiting higher sorption capacities for compounds with greater hydrophobicity.PANOs were more likely to migrate within soils and be absorbed by tea plants.It contributes to the understanding of environmental fate of PAs/PANOs in tea plantations and provides basic data and clues for the development of PAs/PANOs reduction technology.

Exploiting push-pull strategy to combat the tea green leafhopper based on volatiles of Lavandula angustifolia and Flemingia macrophylla

Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.

Ecological risk assessment of heavy metals in tea plantation soil around Tai Lake region in Suzhou,China

Tea plant[Camellia sinensis(L.)O.Kuntze]is one of the important foliar cash crops in China,and its root system absorbs heavy metal(HM)elements enriched in the soil and transports them to the over ground part.In order to ensure the safety of the soil ecological environment and tea raw materials in the tea production area,the HM contents of soil and tea plant leaves in Suzhou tea plantations were detected,the relationship between HMs and soil physicochemical properties was analyzed,and the ecological risk of HMs in tea plantation soils was evaluated by using relevant detection techniques and evaluation models.The results showed that the average pH of tea plantation soils around Tai Lake in Suzhou was within the range suitable for the growth of tea plants.The pH,soil organic matter,total nitrogen,available phosphorus and available potassium of tea plantation soil satisfying the requirements of high quality,high efficiency and high yield(‘3H’)tea plantation accounted for 47.06%,26.47%,8.82%,79.41%and 67.65%,respectively.Site 2 fully met the requirements of‘3H’tea plantation.In addition,the contents of cadmium(Cd)and mercury(Hg)were extremely variable,and the average contents exceeded the background value of soil in Jiangsu Province,but the HM contents of tea leaves all met the pollution-free standard,and the HM contents of tea leaves around Tai Lake in Suzhou were generally at a safe level.The composite ecological risk index ranged from 0.05 to 0.60,and 32 of the 34 sample sites(except site 21 and site 23)are the most suitable agricultural land for tea plantations.

Assessment of soil degradation and chemical compositions in Rwandan tea-growing areas

This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda,Africa.Soil degradation accelerated by erosion is caused not only by topography but also by human activities.This soil degradation involves both the physical loss and reduction in the amount of topsoil associated with nutrient decline.Soil samples were collected from eleven tropical zones in Rwanda and from variable depth within each collecting site.Of these,Samples from three locations in each zone were analyzed in the laboratory,with the result that the pH of all soil samples is shown to be less than 5（pH〈5） with a general average of 4.4.The elements such as iron（Fe）, copper（Cu）,manganese（Mn）,and zinc（Zn） are present in high concentration levels.In contrast calcium （Ca） and sodium（Na） are present at low-level concentrations and carbon（C） was found in minimal concentrations.In addition,elements derived from fertilizers,such as nitrogen（N）,phosphorous（P）,and potassium（K） which is also from minerals such as feldspar,are also present in low-level concentrations. The results indicate that the soil in certain Rwandan tea plantations is acidic and that this level of pH may help explain,in addition to natural factors,the deficiency of some elements such as Ca,Mg,P and N.The use of chemical fertilizers,land use system and the location of fields relative to household plots are also considered to help explain why tea plantation soils are typically degraded.

Some Biogeochemical Characteristics of Tea Soils

Characteristics of the element abundance, material cycling, element budget in tea soils were discussed based on investigations of six tea plantations and the adjacent waste lands in the Three Gorges region.The plantations have different soil-forming parent materials, but similar landforms, and the same tea variety and close ages. The results showed that tea growing could increased the contents of organic matter,total and available N, P, Al and Mn; the elements enriched by tea trees were in the following descending Sequence: P > Ca> K > Mn > Mg > Zn > Al > Fe; elements returned through litter of tea were in the sequence of Ca> Mn > P > Zn > Mg > K > Al > Fe; in the nutrient budget of the soil-tea system, P and K were in deficit,whereas Al, Ca, Fe and Mn in surplus.

Hyperparasitism of Homona coffearia Nietn. (Lepidoptera: Tortricidae), the Tea Tortrix of Sri Lanka: Implications for Biological Control

Tea tortrix, Homona coffearia Nietner (Lepidoptera: Tortricidae), is a seasonal pest of tea in Sri Lanka. Though it is active in dry weather, it is observed that populations do occur in wet weather causing serious damage to tea. The parasite, Macrocentrus homonae Nixon (Hymenoptera: Braconidae), controls the tortrix populations, but the efficiency of Macrocentrus has been reduced on account of hyperparasites in recent times. Level of hyperparasitism was studied in some tea tortrix prone areas in the up country region to study how this affected the tortrix populations during wet weather. The hyperparasitism varied during the study period of which average values observed ranged from 35% to 52% in the plantations studied. A negative linear relationship was observed between the average number of parasite cocoons in a cocoon mass and the percentage hyperparasitism. Three generations of tortrix were evident during the study period of May to November 2005. It is observed that tortrix populations do occur in dry and wet weather, and that hyperparasitism has been identified as the major cause affecting the efficient control of tortrix by the parasite. Possibilities of tea tortrix control in wet weather are discussed.

施肥类型对茶园土壤酸度的影响研究

【目的】茶园土壤酸化是当前茶叶生产中面临的重要问题。研究施肥类型对茶园土壤酸度的影响,为茶园土壤酸化阻控和改良提供理论依据。【方法】对比福建省周宁县17个定位监测茶园2013年和2021年土壤酸度变化,并根据相应茶企施肥档案资料,将茶园施肥类型划分为无机型(纯化肥施用)、有机无机型(有机肥和化肥配合施用)、有机型(纯有机肥施用)等3种类型,分析不同施肥类型对茶园土壤酸度的影响。【结果】2013—2021年,无机型肥料管理模式茶园0~20 cm、20~40 cm土层土壤pH平均值分别降低0.26和0.24个单位,年均降低0.033和0.030个pH单位,土壤酸化程度加剧。有机无机型茶园土壤pH分别提高0.19和0.20个单位,年均提高0.024和0.025个pH单位;有机型茶园土壤pH分别提高0.39和0.23个单位,年均提高0.048和0.028个pH单位,土壤酸化得到缓解和改良。茶园土壤pH变化速率与化肥施用量呈极显著的正相关关系,而与有机肥施用量呈极显著的负相关关系,施氮量增加加速茶园土壤酸化,增施有机肥可以减缓和改良土壤酸化。茶园土壤pH变化速率与初始土壤基本理化性状相关关系不显著。【结论】施肥类型是影响茶园土壤酸度变化的主要因素。在茶叶生产中,可通过控制化肥施用量,增加有机肥施用量来阻控和改良茶园土壤酸化。

我国茶园土壤酸化现状、问题及调控途径

土壤酸化问题正在成为限制茶园土壤健康和茶叶优质高产的重要因素,然而,当前对茶园土壤酸化的现状、机制及调控途径尚缺乏系统性总结,制约了茶产业高质量发展。对我国茶园土壤酸化现状进行重点分析,系统阐述茶园土壤酸化的内部机制和外部因素,解析了土壤酸化对茶树生长、土壤元素转化和生态系统过程的影响。针对茶园酸化土壤改良目标,提出酸化土壤的有效调控途径,旨在为茶园土壤健康管理和茶产业绿色可持续发展提供依据。

田间老化生物质炭对茶园土壤氮素形态和细菌群落的影响

【目的】研究田间老化生物质炭对酸性茶园土壤氮素形态和细菌群落结构的影响,探讨土壤氮素形态与微生物群落结构及多样性之间的关系,从而为评估生物质炭在茶园生态系统的长期效应提供科学数据。【方法】2010年在福建省农业科学院茶叶研究所试验基地,试验设置5个生物质炭施用量:0、8、16、32和64 t·hm^(-2),依次记为CK、B1、B2、B3和B4处理。2022年(第12 a)春茶采收后,采集0~20 cm土层土壤,探究不同生物质炭用量对土壤氮素形态及细菌群落结构的影响,并分析其影响因素。【结果】与CK相比,施用生物质炭处理12a后土壤有机碳、全氮、硝态氮、铵态氮、有效钾、pH、砂粒含量分别增加了7.95%~21.40%、11.69%~25.54%、53.45%~115.84%、1.13%~38.86%、28.49%~114.13%、5.51%~12.46%和21.11%~67.88%;碱解氮、有效磷、黏粒和粉粒含量分别下降了11.97%~17.25%(B1处理除外)、15.18%~50.36%、15.64%~38.21%和8.57%~30.63%。生物质炭处理可提高土壤细菌Alpha多样性,增加了变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadota)和粘球菌门(Myxococcota)的丰度,减少绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)和浮霉菌门(Planctomycetes)的丰度。非度量多维尺度和线性判别分析结果显示,B0和B4之间有比较明显的分离,B4处理下产生了19种显著差异的微生物类群。相关分析和冗余分析结果表明,土壤有效磷、速效钾、硝态氮、黏粒是驱动土壤细菌群落结构变化的关键环境因子。【结论】生物质炭施用12a后,仍然能够增加土壤碳氮和速效养分养分含量,改善土壤质地结构,从而提高了土壤细菌群落多样性,64 t·hm~(-2)生物质炭用量可长期提高土壤供氮能力。

山地茶园模块化全向动态四点调平装置设计与试验

本文针对目前山地茶园机械转场稳定性差的问题和作业姿态调整的需求,基于四点中心不动调平法原理,设计了一种搭载于底盘上,匹配多种作业机具的全向动态调平装置;开展调平装置关键部件参数设计和力学分析,建立了各支腿受力的数学模型,并仿真验证了模型的准确性。搭建样机并对整机的稳定性进行了分析,然后在丘陵山地综合性能测试平台上进行了转场及斜坡作业试验。试验结果表明:在转场试验中,底盘俯仰角和侧倾角幅值分别为17.9°、16.5°,平台俯仰角和侧倾角分别为6.4°、4.3°,平台俯仰角和侧倾角均值都小于1.8°;在斜坡4种作业工况下,底盘倾斜度均值分别为14.1°、15.2°、15.5°、14.1°,平台倾斜度均值分别为1.8°、1.6°、1.7°、1.6°,且平台的倾斜度标准差均小于底盘倾斜度标准差。研究表明该全向动态四点调平装置精度和稳定性满足山地茶园机具转场和坡地作业的需求。

不同管理方式对古茶园土壤理化性状及酶活性的影响

以云南省普洱市澜沧县惠民乡景迈山大平掌古茶园为试验对象,设置不同管理方式(大量疏枝、免耕,少量疏枝、浅耕,不疏枝、浅耕,不疏枝、免耕),分别采集0~20 cm和20~40 cm土层土壤样,分别测定p H值、有机质、全氮、全磷、全钾、速效钾、有效磷、氨态氮、硝态氮含量及脲酶、蔗糖酶、过氧化氢酶、酸性磷酸酶、蛋白酶的活性。结果表明,少量疏枝、免耕管理方式可有效提高土壤有效磷(13.55 mg/kg)、速效钾(171.44 mg/kg)、全钾(13.27g/kg)等养分的含量,更有利于古茶树的生长和发育;不疏枝、浅耕管理方式对提高古茶园土壤脲酶与蛋白酶的活性效果最佳,更利于提高古茶园的土壤肥力。古茶园的土壤理化性质与土壤的酶活性变化直接相关,其中土壤酸性磷酸酶和蛋白酶更适宜评价古茶园多数土壤性质的变化。

贵州典型茶园土壤酸化及其养分变化特征

茶树长期宿根连作使得茶园土壤酸化严重、养分失衡,导致茶叶产量和品质下降,制约中国茶产业的可持续发展。对贵州省茶叶主产区17个乡镇21个茶园土壤剖面及相邻林地进行调查取样,分析茶园土壤剖面酸度和养分特征。结果表明:茶园土壤0~20、20~40、40~60 cm 3个土层土壤平均pH为4.28、4.44、4.63,土壤酸化明显,呈现出强酸性至极强酸性的特征;其中,0~20 cm土层土壤酸化最为严重,其土壤pH<4.5的样品比例高达71.4%,比相邻林地高出23.8%。茶园土壤养分自表层向下逐步降低;与林地比较,表层茶园土壤有机质下降,而全氮、碱解氮明显增加;当pH<4.5后,除有效铁外,表层土壤其他养分均易流失。与林地比较,茶园土壤交换性酸、交换性铝、交换性氢含量增加,在0~20 cm土层中含量较高,分别达10.25、9.44、0.81 cmol/kg;而阳离子交换量和交换性钙、镁含量则呈下降趋势。相关性分析表明,茶园土壤pH与全氮、碱解氮、有效磷、有效铁、交换性酸和交换性铝存在显著或极显著的负相关关系,而与盐基饱和度、交换性钙镁离子含量存在极显著正相关关系;当pH低于5.2时,尤其是低于4.5后,土壤pH主要受到交换性酸的影响;而高于5.2后,pH主要受到盐基饱和度的影响,且主要取决于钙镁离子含量的高低。