Seasonal response of soil enzyme activity to thinning intensity of aerial seeded Pinus tabulaeformis stands

Aerial seeding is one of the most important vegetation restoration patterns in remote hilly areas, and studies concerning soil quality and its management have practical value. In 2000, a study of the effect of thinning intensities at five different treatments levels, 0 (CK), 30% (slight thinning), 48.75% (medium thinning), 53.75% (intense thinning) and 65.6% (super intense thinning) on soil enzyme activity was carried out on 9-year-old aerial seeded Chinese pine (Pinus tabulaeformis Carr.) stands with an initial density of 8000 trees/hm², in the Wang-jiapu Aerail Seeding Center, Yanqing County, Beijing. Five years later, the activities of five kinds of soil enzymes, soil urease, alkaline phosphatase, inertase, catalase and polyphenol oxidase in the first 20 cm of soil layer were compared during four seasons. Relationships among soil enzymes and soil physiochemical properties were also analyzed to examine the possibility of using soil enzymes to evaluate thinning intensities. The results showed that the maximum enzyme activities of catalase and polyphenol oxidase occurred in June, those of soil urease and alkaline phosphatase occurred in October, and soil invetase had its maximum in April. In addition, the five soil enzymes were affected differently by thinning intensities. Soil catalase, urease and invertase showed the highest response to a slight thinning, followed by medium thinning, which is the opposite experienced with polyphenol oxidase and alkaline phosphatase. There are statistically significant and positive relationships between soil enzymes and organic matter and available K. It should be noted that soil water was a limiting factor to soil enzyme activity. Compared with soil physicochemical characteristics, soil enzymes were more sensitive to levels of thinning intensities. Among the enzymes, soil alkaline phosphatase and catalase could be regarded as indicators to assess soil quality. It is concluded that a suitable thinning intensity benefits the development of undergrowth and soil enzymes. Generally, when the stand with initial density of 8000 trees/hm² grows up to nine years old, the most suitable thinning intensity should be about 50%. __________ Translated from Journal of Beijing Forestry University, 2008, 30(2): 82–88 [译自: 北京林业大学学报]     

喀斯特断陷盆地不同植被恢复模式土壤水分动态变化

[目的]以喀斯特断陷盆地小流域中典型植被恢复模式,即桉树(Eucalyptus maideni)林、冲天柏(Cupressus duclouxiana)林、马尾松(Pinus massoniana)林以及天然次生灌丛、高盖度车桑子(Dodonaea viscosa)灌丛和低盖度车桑子灌丛为研究对象,探究断陷盆地不同植被恢复模式土壤水分时空变异规律,为该地区植被生态恢复工作提供参考。[方法]利用自动气象观测系统和土壤水分传感器同步监测2016年5月—2017年4月期间小流域降雨量与各林地土壤水分,采用变异系数与克里金插值分析方法,对6种植被恢复模式林地的土壤水分时空异质性以及持续干旱条件下土壤水分衰减特征进行研究。[结果]表明:(1)同一植被类型不同土层雨季和旱季土壤体积含水量垂直变化趋势相同,且雨季土壤水分含量显著高于旱季(P0.05),均为中等变异(Cv:12.88%28.66%)。(2)同一乔木林雨季和旱季的土壤活跃层与次活跃层垂直分布不同,但同一灌丛雨季和旱季分布相同。(3)6种植被恢复模式土壤体积含水量均在降雨量较充足的8—9月达到最大值,其变化范围介于26.25%44.08%之间,在降雨量明显不足的3—4月达到最小值,土壤体积含水量介于9.48%17.47%之间。(4)3种乔木林0 30 cm土层、3种灌丛0 10 cm土层充分降雨后约10 d土壤水分恢复为降雨前1 d水平,低盖度和高盖度车桑子灌丛10 30 cm土层土壤水分降雨后15 d恢复为降雨前1 d水平,并且接近植物萎蔫系数。[结论]不同植被恢复模式间雨季、旱季和月均土壤体积含水量均表现为桉树林天然次生灌丛冲天柏林马尾松林高盖度车桑子灌丛低盖度车桑子灌丛。喀斯特断陷盆地季节性干旱和临时性干旱问题严峻,乔木林和灌丛经充足降雨,达到田间持水量后,在连续放晴天气下林地土壤水分可供植物10 15 d的消耗。     

森林土壤酶的研究进展

土壤酶在土壤生态系统的物质循环和能量流动方面扮演重要的角色。目前 ,在几乎所有的森林生态系统研究中 ,土壤酶活性的监测似乎成为必不可少的研究内容。森林凋落物分解过程中的酶活性动态 ,植被特征与土壤酶活性的关系 ,土壤微生物与土壤酶的关系 ,植物 -土壤界面的土壤酶 ,森林土壤质量评价指标的土壤酶及人类活动干扰对森林土壤酶活性的影响等是当前森林土壤酶学的研究重点。由于土壤酶的功能和生态重要性 ,森林土壤酶研究可能包括 :(1 )土壤酶系统分异 ;(2 )作为森林土壤质量综合评价指标的土壤酶活性 ;(3)植被动态与土壤酶的关系 ;(4 )退化森林生态系统的土壤酶活性特征 ;(5 )人工林土壤酶活性特征 ;(6 )人类活动对森林土壤酶系统的影响。本文从土壤酶系统分异和生态系统的角度对土壤酶在森林生态系统中的作用和地位进行了综述 ,这对于加深理解森林生态系统中的物质循环、土壤酶的生态重要性以及森林生态系统退化机理有重要作用     

滇东南岩溶山区树种配置的初步研究

3年来在滇东南岩溶山区开展的树种配置试验的初步研究结果表明 :影响岩溶山地林木生长的主要因素是坡度、岩石裸露率、土类、土层厚度和土壤中的石砾含量 ,而坡向、坡位、土壤的吸湿水、旱季土壤含水率、pH值及土壤养分对林木生长的影响不明显。在岩溶地区的造林应采取特殊的措施 ,尽量保护原有植被 ,对于形成复层的林分结构具有非常重要的作用 ,特别是在多石的薄层石灰土类型上 ,人工种植的阔叶树生长较差 ,通过种植针叶树 ,能形成乔灌草结构的复层林分 ,对改善岩溶山区的生态环境效果十分明显。在吸湿水、全氮、水解氮、速效磷、速效钾、pH值、有机质和旱季土壤含水率等 8个土壤性状中 ,吸湿水、速效磷、速效钾 3个性状在年度间的差异非常显著 ,其中吸湿水平均增加 3 6 6 % ,每kg干土中的速效磷和速效钾平均分别增加9 99mg和 4 2 5 9mg ,显示出林木对土壤的改良作用。在多石的石灰土类型上 ,适宜营造墨西哥柏、郭芬柏和冲天柏等针叶树 ,在其中土层较厚的地方可种植银荆 ;在厚层山地红壤类型上 ,适宜营造墨西哥柏、冲天柏、郭芬柏、川滇桤木、滇合欢、银荆、杜仲、酸枣、苦刺等针阔、阔阔混交林以提高其生态和经济效益     

Canonical correlation analysis of soil nutrients, microorganisms and enzyme activities in vegetation restoration areas of degraded and eroded soils in northwestern Hunan Province, China

With the aid of canonical correlation analysis, the relations among soil nutrients, soil microorganisms, and soil enzyme activities were studied in vegetation restoration areas of degraded and eroded soils in the Nverzhai watershed in northwestern Hunan. The main results were as follows: the key factors in soil nutrients, microorganisms, and enzyme activities were N and P elements, number of bacteria, carbon and nitrogen in soil microbial biomass and the activities of urease, polyphenol oxidase, phosphatase, and invertase. The activities of urease and polyphenol oxidase are related to the inversion of N and P elements that had important impact on the accumulation of carbon and nitrogen in soil microbial biomass. Moreover, the activities of urease, polyphenol oxidase, and phosphatase could promote carbon accumulation in microbial biomass; however, invertase activities inhibited the accumulation of microbial biomass nitrogen. On the other hand, urease activities were beneficial to the N element content in soils but unfavorable for P elements. There is a negative relation between polyphenol oxidase activity and N element content. For every canonical variable group, the tendencies of soil nutrients, microorganisms, and enzyme activities to accumulate in different soil layers in different vegetation restoration communities could offer some scientific basis for the diagnosis of the health of the soil and the site type division in the process of vegetation restoration.     

Insights into seasonal variation of litter decomposition and related soil degradative enzyme activities in subtropical forest in China

We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in s...     

不同放牧强度对辽西沙地生物结皮理化性质及土壤酶活性变化的影响

通过对辽西地区不同放牧强度样地上藻结皮、藓结皮2类生物结皮理化性质、土壤酶活性的变化情况进行的调查研究,结果表明:不同程度放牧样地恢复区内藓结皮的有机质含量、结皮厚度、全氮、全磷、全钾、微生物碳、微生物氮、土壤含水量等均高于藻结皮,土壤中脲酶、蛋白质酶活性整体也是藓结皮优于藻结皮;中度、轻度放牧样地恢复区2种结皮土壤脲酶、蛋白质酶活性均高于重度放牧样地;随着土层的加深,酶活性逐渐降低。适度的放牧有助于改善土壤理化性质和提高土壤酶活性。     

Comparative study of the stoichiometric characteristics of karst and non-karst forests in Guizhou,China

Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.     

杉木林采伐迹地连栽和撂荒对林地土壤养分与酶活性的影响

研究湖南会同连栽第2代杉木人工纯林和撂荒对第1代杉木人工林采伐迹地土壤养分与酶活性的影响.结果表明:0～30 cm和30～60 cm土层中,撂荒地土壤有机质、养分含量普遍高于连栽杉木人工林地,且腐殖质碳、有效磷含量的差异均达到极显著水平(P＜0.01),全磷含量在0～30 cm土层中的差异达到显著水平(P＜0.05).0～30 cm土层中,撂荒地过氧化氢酶活性极显著高于连栽杉木人工林地(P＜0.01),磷酸酶、脲酶、蔗糖酶活性均显著高于连栽杉木人工林地(P＜0.05),30～60 cm土层中,撂荒地过氧化氢酶、蔗糖酶活性也显著高于杉木人工林地(P＜0.05),磷酸酶和脲酶活性也高于连栽杉木人工林地,但差异不显著(P＞0.05).林地土壤过氧化氢酶、磷酸酶、脲酶、蔗糖酶活性与土壤有机质、养分含量之间均呈较好的正相关,而且与水解氮、速效磷、腐殖质碳的相关性高于其与有机质的相关性.主成分分析表明,土壤酶活性在林地土壤质量体系中扮演着重要角色,其中脲酶、蔗糖酶和磷酸酶可作为林地土壤质量评价的指标.撂荒具有更好地恢复土壤养分含量和酶活性的能力,对维持杉木人工林地持续生产力有着重要作用.     

江汉平原杨树林下土壤肥力因子的关联性研究

通过对土壤酶活性、土壤微生物数量和土壤养分的分析,研究江汉平原上游10个县(市)杨树林下土壤肥力因子之间时空变化及其相互关系。结果表明:无论是林下相对于林外,还是生长季相对于落叶季,细菌数量与磷酸酶活性、真菌数量与蛋白酶活性总是正相关;而在杨树的生长季节,土壤AA含量与各类微生物数量均呈正相关;土壤NO3--N、有效Ca含量与各类微生物数量均呈负相关;Mg/K与真菌数量显著正相关;土壤NO3--N含量与有效B含量呈极显著正相关;有效Ca含量与有效Mg含量呈显著正相关,与Mg/K呈极显著正相关。     

Soil microarthropod populations under natural and planted fallows in southwestern Nigeria

Microarthropods, such as soil mites (Acari) and springtails (Collembola), with body width between 0.08 mm and 0.5 mm play important roles in soil fertility maintenance through their regulatory activities in decomposition and nutrient turnover. Observations were made at IITA, Ibadan, southwestern Nigeria to evaluate the effects of natural regrowth of vegetation — mainly the shrub Chromolaena odorata — and three planted woody fallow species (Acacia leptocarpa, Senna siamea, and Leucaena leucocephala) on soil microarthropods in a degraded Alfisol. Populations of soil microarthropods were higher in the rainy season than the dry season, and populations were greater under natural fallow than for continuous cropping with maize (Zea mays) and cassava (Manihot esculenta). Populations of soil microarthropods were comparable under leucaena and natural fallow, but populations in the rainy season were 38% higher under senna than natural fallow and 36% higher under acacia than natural fallow. Regression analysis indicated that soil microarthropod population under fallow species was positively correlated with the lignin contents of leaf litter.This revised version was published online in November 2005 with corrections to the Cover Date.     

森林土壤化学性质与土壤酶活性典型相关分析

通过对岷江上游连香树、马尾松、桦树、云杉4类森林土壤土壤酶活性和土壤化学性质的研究,运用典范相关分析,证实过氧化氢酶与土壤有机碳的转化关系密切,土壤脲酶与土壤全N关系密切.     

矿渣肥对华西雨屏区白夹竹林土壤化学性质及酶活性的影响研究

华西雨屏区是我国西部地区以阴湿为主要特征的特殊气候地理单元,区域内竹林资源丰富,但由于降雨量大,林地土壤酸化现象较为严重。矿渣肥具有高效化、复混化、缓释化的特点,同时也是酸性土壤改良剂。文章以华西雨屏区主要经济竹种白夹竹为对象,研究氮、磷、钾有效养分含量为45%(N:P2O5:K2O=21:0.67:0.48)的矿渣肥(KZFA)在4种施肥水平上对林地土壤化学性质及土壤酶活性的影响。施肥3年后研究结果表明:1)KZFA施用量为1.225 t/hm2时,对白夹竹林地土壤酸碱性、有机质含量和氮素、磷素、钾素的综合改良效果最好;2)施肥对脲酶活性的影响最大,施肥量、碱解氮(夏季)、速效磷、速效钾含量均与脲酶活性呈显著正相关;3)土壤化学性质的变化对过氧化氢酶、过氧化物酶、磷酸酶、蔗糖酶活性的影响存在明显的季节性差异,各指标间的相关性普遍为冬季大于夏季,但均未达显著水平。     

四川马边植被垂直分布带谱土壤放线菌特征

本文主要对四川省马边县具有垂直分布带谱的山地土壤放线菌数量特征采取微生物平板培养法和计数法进行研究。结果表明:随着土层深度的增加土壤放线菌数量明显下降;不同林分类型土壤放线菌数量差异明显;土壤放线菌的数量随海拔高度的升高先增多后减少;同时,不同植被的林地放线菌总数量在雨季和旱季变化较大,以雨季最大而旱季最小的趋势,且差异显著。     

Temporal changes in soil biochemical properties with seasons under rainfed land use systems in Shiwalik foothills of northwest India

The soil biochemical properties are sensitive to change in land use systems and seasons. The variations in soil management practices and soil moisture content affect the sustainability of the systems. To study the sustainability in lower Shiwalik, a total of 144 soil samples (0–0.15 m) were undertaken to monitor the changes in the soil biochemical properties under rainfed land use systems, i.e., agri-horticulture, agroforestry, cultivated and barren system and seasons, i.e., summer, rainy and winter. Among soil biochemical properties, soil microbial biomass carbon, soil microbial quotient, dehydrogenase activities, basal soil respiration, fluorescein diacetate and urease activities ranged from 77 to 122 μg g^?1, 0.023 to 0.027, 18.3 to 30.6 μg TPF g ^?1 h^?1, 13.2 to 22.7 μg CO₂-C g^?1 day^?1, 1.3 to 2.2 μg g^?1 and 5.83 to 6.38 μg NH₄-Ng^?1 h^?1, respectively. Among 15 soil properties, principal component analysis specified that four major soil properties, i.e., basal soil respiration, metabolic quotient, electrical conductivity and clay content contributed 73% of the soil quality index with contribution of 44, 13, 9 and 7%, respectively. Among seasons, the values for soil biochemical properties were higher in rainy season as compared to winter and summer season. In systems, agri-horticulture followed by agroforestry was the best systems in terms of sustainability in Shiwalik foothills of northwest India.

     

森林土壤化学性质与土壤酶活性典型相关分析

通过对岷江上游四种(连香树、马尾松、桦树、云杉)森林土壤酶活性和土壤化学性质的研究,运用典范相关分析了土壤酶活性和土壤化学性质这两组典型变量之间的关系,结果表明:过氧化氢酶与土壤有机碳的转化关系密切,土壤脲酶与土壤全N关系密切,为维护地力提高森林生产力提供有关土壤生物化学活性方面的科学依据。     

筇竹不同林分类型土壤酶活性的垂直分布特征

在云南省大关县木杆镇选择4种筇竹林分类型：天然筇竹—阔叶树混交林、天然筇竹—山茶混交林、天然筇竹—人工黄皮树混交林、人工筇竹—黄皮树混交林等，研究不同筇竹林分类型、不同土层深度(0~20、20~40和40~60 cm)的土壤过氧化氢酶、蔗糖酶、酸性磷酸酶和脲酶活性。结果表明：1)天然筇竹—阔叶树混交林的土壤过氧化氢酶、酸性磷酸酶和脲酶活性高于其他3种林分类型，人工筇竹—黄皮树混交林的土壤蔗糖酶活性高于其他3种林分类型，说明人工施肥处理对提高蔗糖酶活性有一定的作用；2)除天然筇竹—阔叶树混交林的蔗糖酶外，4种林分类型的土壤酶活性在土层0~20 cm达到最大值，并且随着土壤土层深度的增加而降低；3)除天然筇竹—人工黄皮树混交林的蔗糖酶和脲酶与过氧化氢酶、人工筇竹—黄皮树混交林和天然筇竹—山茶混交林的酸性磷酸酶与过氧化氢酶、天然筇竹—阔叶树混交林的酸性磷酸酶与蔗糖酶无显著相关外，其他酶活性之间均存在显著或极显著相关(P＜0.05或P＜0.01)。研究表明林分类型和土层深度是影响土壤酶活性的重要因素。     

我国西南喀斯特森林生态系统生态化学计量学研究

喀斯特森林生态系统作为喀斯特生态系统的重要组成部分,其生态化学计量特征是喀斯特生态系统研究的热点。对比其他森林生态系统,我国西南喀斯特森林生态系统的植物具有较高的C含量和较低的N、P含量,植物生长一般会受到N、P的限制;凋落物和土壤N、P含量较高,不同植被类型土壤P含量有很大差异;随着植被正向演替的进行,土壤N含量和凋落物N、P含量有逐渐增加的趋势;喀斯特森林生态系统化学计量特征主要受到植物个体差异、气候、地形和人类活动的影响。文中系统总结了我国西南喀斯特森林生态系统的研究概况、生态化学计量特征、影响因素及研究方向,并针对我国西南喀斯特森林生态系统生态化学计量学研究亟待解决的科学问题从4个方面进行了研究展望。     

Germination and early growth of sown Quercus robur L. in relation to soil preparation, sowing depths and prevention against predation

A field experiment was established in the autumn of 1992 in order to study predation of acorns, germination and early growth of oak seedlings. The experiment was established on a clearcut and an adjacent oak shelterwood in southern Sweden. In the experiment, a total of 6 840 acorns were sown. The sowing was carried out with different vegetation control and soil preparation treatments and with different planting depths.The germination percentage was highest for acorns sown at five cm depth and lowest for acorns sown on top of the soil, and lower for acorns sown in areas where the humus layer had been removed than in areas where the humus layer was retained. There was no difference in the percentage germination after two growing seasons between acorns sown inside the shelterwood and acorns sown on the clearcut. The height of the seedlings was lowest when the humus was removed while the number of leaves per seedling was lowest for seedlings in untreated areas after two growing seasons. Furthermore, seedlings in untreated areas showed the lowest relative height growth rate during the second growing season. In spite of higher biomass of ground vegetation in undisturbed areas compared to treated areas, no effect of the soil and vegetation control treatments could be found on soil water potentials. The soil temperature and photosynthetic active radiation at seedling level were higher in areas where soil preparation and vegetation control had been performed. However, it was concluded that neither low soil water availability nor low light levels could be the only cause of lower relative height growth rate during the second growing season for seedlings in undisturbed areas.