不同种类中国杉对土壤养分状况的影响

The effects of different types of Chinese fir stand,including those with varous composition (pure and mixed),in various cropping systems (first and continuous cropping system)and at different ages,on the nutrient status of soils the hilly regions of southern Anhui Province were studied by means of ecological sequential comparison on the basis of similar climate and soil type.The work was carried out in the Xiaoxi Forest Farm of Jingxian County and the Caijiaqiao Forest Farm of Jingde Coundy,where the soil is parayellow soil derived from phyllite and sandstone,The results revealed that with the increase of age,Chinese fir pure stand could accumulate organic matter and nitrogen in the soil but it resulted in decreasing of soil pH and base ions(especially Ca^2 ) compared to its mixed stand with broad-leaf trees such as Chinese sassafras,In order to improve the soil fertility,It would be better to mix Chinese fir with broad-leaf trees when afforestation In the management of Chinese fir pure stand,base compounds and phosphates should be added to the soil for mintaining soil fertility and raising and raising forest productivity.     

土壤中汞的化学形态及其影响因素

An investigation and on 13-year-old(1984-1996) Chinese fir and Tsoong‘s tree mixed forests in Jianou City,Fujian Province,China was carried out to compare the influences of different interplanting types of individual tree-tree,row-row,row-strip(three rows)and pure Chinese fir stands on soil properties.Compared with the pure stands of Chinese fir ,the mixed stands exerted a posivtive effect on soil fertility,with increases in soil organic matter,total N,available P and available K.Moreover,improvements were also observed in soil enzymatic activities ,aggregate structure,structure,stability,status of soil porosity,soil aeration and penetrability in miexd stands.The row-row interplanted stands had the best effect on tree growth and soil properties among these mixed forests.In the southern subtropical region,the spreading of the row-row mixing model of the two tree species would be helpful to preventin ghe soil from fertility deterioratio caused by successive plantation of Chineses fir.     

人工林代替天然林后土壤碳库的变化

Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) and bamboo (Phyllostachys pubescent) plantations substituted for a native forest (Quercus acutissima, Cyclobalanopsis glauca, Cas-tanops~.s sclerophyUa, Platycarya strobilacea, Lithocarpus glaber) were studied on the hills with acid parent rock and soils classified as red soils (Ferrisols) in Huzhou, Zhejiang Province of east China. It was found that total soil organic carbon (TSOC), easily oxidisable carbon (EOC) and water-soluble organic carbon(WSOC) under bamboo plantation were increased, but microbial biomass carbon (MBC) was decreased. On the contrary, Chinese fir induced declines of all fractions of C including TSOC, EOC, WSOC and MBC.The percentages of the active fractions of soil C (EOC and WSOC) were increased in the plantations as compared to the native broad-leaved forest, but proportions of soil organic C as MBC were decreased. It could be concluded that bamboo plantation had a great ability of not only fixing C but also accelerating soil C pool cycle, improving nutrient and microorganism activity; therefore, it is a good ecosystem and could be recommended for wide development. Chinese fir would shrink the soil C pool and deteriorate sou biological fertility, so it did not benefit CO2 fixing and land sustainable utilization.     

Effects of Chinese Fir,Loblolly Pine and Deciduous Oak Forests on Nutrient Status of Soils in Northern Subtropics of China

This paper deals with a study on the effects of Chinese fir,lobolly pine and deciduous oak forests o the nutrient status of soils in northern subtropics of China,adopting the principle of forest ecology in the case of similar climate and soil type.The experimental area was situated in the Xiashu Experimental Centre of Forest,where the soil is yellow-brown soil derved from siliceous slope wash.Sample plots of these 3 stands were established to study the nutrient status in litter ,the amount of nutrient uptake by roots,the quantity of nutrient output by percolating water outside the deep layer of soil,and the seasonal dynamics of available nutrient in surface soil.It was whown that the intensity of nutrient cycling in soil under deciduous oak was the highest,and the effect of oak in improving soil fertility was the best.The result of improving soil fertility by Chinese fir was the most inferior,though the intensity of nutrient cycling under that stand was higher than that under loblolly pine stand.The influence of loblolly pine on the improvement of soil fertility was better than that of Chinese fir,in spite of its lowest intensity of nutrient cycling.     

中国土壤学过去30年在一些关键领域的研究进展

Due to continuous decreases in arable land area and continuous population increases,Chinese soil scientists face great challenges in meeting food demands,mitigating adverse environmental impacts,and sustaining or enhancing soil productivity under intensive agriculture.With the aim of promoting the application of soil science knowledge,this paper reviews the achievements of Chinese scientists in soil resource use and management,soil fertility,global change mitigation and soil biology over the last 30 years.During this period,soil resource science has provided essential support for the use and exploitation of Chinese soil resources,and has itself developed through introduction of new theories such as Soil Taxonomy and new technologies such as remote sensing.Soil fertility science has contributed to the alleviation and elimination of impeding physical and chemical factors that constrain availability of essential nutrients and water in soils,the understanding of nutrient cycling in agroecosystems,and the increase in nutrient use efficiency for sustainable crop production.Chinese soil scientists have contributed to the understanding of the cropland’s role in global change,particularly to the understanding of methane and nitrous oxide emission from rice fields and the effect of elevated carbon dioxide and ozone on rice-wheat system.Soil biology research has progressed in biological N fixation,distribution of fauna in Chinese soils,and bioremediation of polluted soils.A new generation of soil scientists has arisen in the last three decades.The gaps between research and application in these soil science fields are also discussed.     

Evaluation of Soil Labile Phosphorus Using a Double—Labeling （^32P and ^33P） Technique

Isotopic exchangeability of phosphorus in four Chinese soils with and without P application was studied by ^32P and ^33P double-labeling technique in relation to routine chemical extractions.The results showed that Bray-I and Bray-Ⅱ reagents could extract most of the fast exchangeable P.Not all of the Olsen-P belonged to fast exchangeable P,but it was about the same quantity of fast exchangeable P in a calcareous soil and a neutral soil without P application.Sequential fractionation of the soil phosphorus showed that most of the added radioisotopes in high P fixation red soils were tightly held by iron and aluminium oxides,which could be totally extracted only by 0.1M NaOH solution.In the neutral and calcareous soils most of the radioisotopes added were loosely held on the surface of soil particles and could be extracted by anion exchange resin.Phosphate application increased the resin-P fraction significantly for all the soils studied.     

Changes in Soil Iron Fractions and Availability in the Loess Belt of Northern China After 28 Years of Continuous Cultivation and Fertilization

Iron(Fe) deficiency in calcareous soils of the Loess Plateau of China is a wide spread issue and primarily affects agricultural production due to the relatively higher soil pH and carbonate content. Understanding the relationships between Fe distribution in soil fractions, Fe availability, and their responses to cropping and fertilization could provide essential information for assessing Fe availability in soils and managing soils to improve Fe availability. A long-term field experiment was established in 1984 in a split-plot design using cropping systems as main plots and fertilizer treatments as subplots on a farmland in the Loess Plateau. The cropping systems included fallow, continuous wheat cropping, continuous alfalfa cropping, continuous maize cropping, and a rotation system that included a legume. Various fertilization treatments using chemical and/or manure fertilizers were included in each cropping system. Soil samples were collected from 0–10 and 20–40 cm depths in 2012. Long-term planting of crops significantly increased the concentrations of available Fe in the soils. The largest increase was observed in the continuous alfalfa cropping system. Long-term cropping significantly increased the concentrations of Fe associated with carbonates and organic matter, but decreased the concentration of Fe associated with minerals in the soils. The effect of fertilization on the distribution of Fe in the soil fractions varied with cropping system and soil depth. The fertilization treatment with manure generally increased the concentrations of Fe associated with the soil fractions.Long-term cropping and fertilization in the highland farmland significantly affected the availability of Fe and the distribution of Fe fractions in the soil.     

种植制度和施肥对半干旱区土壤中锰形态及有效性的影响

Manganese(Mn) deficiencies are common in soils on the Loess Plateau of China. This research provided essential information on improving Mn availability in semiarid soils through agricultural practices. Twelve cropping system and fertilization treatments were designed in a 28-year experiment. The cropping systems included long-term fallow, continuous winter wheat cropping, pea(1 year)-winter wheat(2 years)-millet(1 year) rotation(crop-legume rotation) cropping, and continuous alfalfa cropping. The fertilizer treatments under the cropping systems included no-fertilizer control(CK), application of P fertilizer(P), application of N and P fertilizers(NP), and application of N and P fertilizers and manure(NPM), but the NP treatment was excluded in the continuous alfalfa cropping system. Available Mn and Mn fractions of soil samples(0–20 and 20–40 cm depths) were measured and further analyzed quantitatively using path analyses. Results showed that the crop-legume rotation and continuous alfalfa cropping systems significantly increased available Mn compared with the fallow soil. Compared with the no-fertilizer control, manure application increased available Mn in soil of the continuous wheat cropping system. Across all treatments, the averaged content of mineral-, oxide-, carbonateand organic matter-bound and exchangeable Mn accounted for 42.08%, 38.59%, 10.05%, 4.59%, and 0.09% of the total Mn in soil,respectively. Cropping significantly increased exchangeable Mn in soil and the highest increase was 185.7% in the continuous wheat cropping system at 0–20 cm depth, compared with the fallow soil. Fertilization generally increased exchangeable and carbonate-bound Mn in soil. Carbonate-bound Mn was the main and direct source of available Mn in soil, followed by exchangeable and organic matterbound Mn. These results indicated that crop-legume rotation cropping, continuous alfalfa cropping and application of manure, have the potential to promote Mn availability in soils of rainfed farmlands.     

茶树种植对中国东部黄棕壤酸化的影响

Soil acidification is an important process in land degradation around the world as well as in China. Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China. Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period. Soil pH of composite samples from cultivated layers decreased by 1.37, 1.62 and 1.85, respectively, after 13, 34 and 54 years of tea plantation, as compared to the surface soil obtained from the unused land. Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages. The acidification rate for the period of 0-13 years was as high as 4.40 kmol H⁺ ha^-1 year^-1 for the cultivated layer samples. Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity. Soil acidification also caused the decrease of soil cation exchange capacity, especially for the 54-year-old tea garden. Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al, which was responsible for the Al toxicity to plants.     

我国东南部地区红壤表土养分的淋溶及再分布

The leaching and redistribution of nutrients in the surface layer of 4 types of red soils in Southeast China were studied with a lysimeter experiment under field conditions. Results showed that the leaching concentrated in the rainy season (from April to June). Generally, the leaching of soil nutrients from the surface layer of red soils was in the order of Ca > Mg > K > NO₃-N. In fertilization treatment, the total amount of soil nutrients leached out of the surface layer in a red soil derived from granite was the highest in all soils. The uptake by grass decreased the leaching of fertilizer ions in surface layer, particularly for NO₃-N. Soil total N and exchangeable K, Ca and Mg in the surface layer decreased with leaching and grass uptake during the 2 years without new fertilization of urea, Ca(H₂PO₄)₂, KCl, CaCO₃ and MgCO₃. Ca moved from the application layer (0~5 cm) of fertilizer and accumulated in the 10~30 cm depth in the soils studied except that derived from Quaternary red clay. The deficiency of soil exchangeable K will become a serious degradation process facing the Southeast China.     

马尾松纯林改造成针阔混交林后土壤化学性质的变化

在25 a生的马尾松林下分别套种火力楠、闽粤栲、苦槠、格氏栲、青栲和拉氏栲等阔叶树种的1 a生幼苗,16年后形成郁闭的针阔混交异龄林。土壤化学分析结果显示,在马尾松林下套种阔叶树(除青栲外)明显增加了林下表层土壤(0~20 cm)的有机质含量。各林分下土壤全K、全M g、全C a、全N和全P的平均含量分别为11.41,6.64,4.33,1.45,0.46 g/kg,表明土壤K、M g、C a的含量比较丰富,而N和P则相对缺乏,营造混交林在一定程度上增加了土壤N、P含量。所有混交林深层土壤(20~60 cm)的有效N、P含量均大于马尾松纯林,而有效K的含量则相反。混交林下0~20 cm,20~40 cm和40~60 cm土壤的平均pH值分别为4.40,4.61和4.68,而马尾松纯林下各土层的pH值则依次为4.39,4.41及4.42,说明在马尾松林下套种阔叶树在一定程度上降低了20 cm以下土层的活性酸度。套种阔叶树(除苦槠外)后由于降低了土壤交换性酸度,增加了土壤盐基离子浓度,从而明显提高了土壤盐基饱和度。     

吉林省东部低山丘陵区4种林分类型林地的土壤肥力分析

根据吉林省东部低山丘陵区汪清林业局金仓林场中4种主要林分类型(长白落叶松天然林、长白落叶松人工林、天然针阔混交林和天然阔叶混交林)的土壤肥力调查数据,分析和比较了4种林分类型林地的土壤物理和化学性质,并采用主成分分析评价了其土壤肥力状况。(1)随土壤深度增加,土壤容重和土壤pH值增大,而土壤含水量、阳离子交换量和养分含量减少,但其在不同林分下的变化程度不同;(2)林分类型对部分土壤化学性质(如土壤CEC、有机质、全氮和速效钾)影响显著。其中,天然针阔混交林的土壤含水量、土壤pH值、阳离子交换量、有机质含量及全氮、磷、钾含量均为最高;(3)采用主成分分析法对不同林分类型的林地土壤肥力状况进行了评价,结果发现土壤肥力状况为:天然针阔混交林>长白落叶松天然林>长白落叶松人工林>天然阔叶混交林。建议在经营现有的林分时,考虑近自然育林,及时进行林下补植更新,并营造针阔混交林,以改善该区林地土壤的肥力状况。     

Carbon Mineralization of Soils from Native Evergreen Broadleaf Forest and Three Plantations in Mid‐subtropic China

Mineralization of soil organic carbon (C) plays a key role in supplying nutrient elements essential to plant growth. Changes of C mineralization of mixed stands of Chinese fir and Michelia macclurei (a broadleaf tree), pure M. macclurei stands, and pure Chinese fir (Cunninghamia lanceolata) stands established in 1983 after clear‐felling of a first‐generation Chinese fir forest were analyzed in Huitong, Hunan Province, China, and compared with those of a stand of native secondary evergreen broadleaf forest (NBF). The results showed that NBF soil had the greatest C mineralization. Mixture of Chinese fir and M. macclurei had no effect on total soil organic C in comparison with pure Chinese fir plantation, but significantly increased C mineralization from soils was detected in this study. This positive influence on C mineralization could be explained by the increase of soil labile C pools and soil microbial biomass and activity. From the analysis of C mineralization, soil microbial properties, and labile organic C, mixtures of broadleaf and Chinese fir can be considered to be an effective sustainable management model for a Chinese fir plantation. Given strong correlations with microbiological and biochemical characteristics of soils and an easier process of determination, hot water extraction, hot water–extractable C (HWC) could be used as an integrated measure of forest soil quality in mid‐subtropics.     

南方茶园土壤酸化特征及交换性酸在水稳性团聚体中的分布

通过采集浙江省杭州西湖龙井茶园土壤,研究茶园土壤剖面的酸度特征、养分变化以及交换性酸在水稳性团聚体中的分布特征,以了解南方茶园土壤的酸化过程。结果表明:茶园表层土壤(0-20cm)酸化严重,最低的pHH2O值达到4.0,并且有明显的深层化趋势;表土的有机质和速效磷含量较高,速效磷含量最高可达138.2mg/kg;表土团聚体分级表明茶园土壤有良好的团聚体结构,具有良好的水稳性;除了交换性H+在0.5～0.25mm和0.25～0.106mm水稳性团聚体之间没有明显差别外,交换性酸总量、交换性H+和交换性Al 3+含量均随着水稳性团聚体粒径的减小而降低;水稳性大团聚体中交换性Al 3+相对交换性H+占有明显的优势,而在0.106～0.05mm水稳性微团聚体中交换性H+占有明显的优势。交换性酸总量、交换性H+和交换性铝主要分布于>2mm和2～0.5mm水稳性团聚体中,同时在不同粒级团聚体中的分布随粒径的减小而降低。     

杉木取代阔叶林后林下水源涵养功能差异评价

为研究杉木人工林取代常绿落叶阔叶混交林后土壤水源涵养能力的变化,采用室内浸水法和环刀法分别研究杉木纯林和常绿落叶阔叶混交林的枯落物与土壤的持水特性。结果表明:(1)枯落物平均蓄积量表现为常绿落叶阔叶混交林(3.42 t/hm^2)>杉木纯林(3.12 t/hm^2),枯落物平均厚度表现为杉木纯林(9.17 cm)>常绿落叶阔叶混交林(5.42 cm)。(2)最大持水量表现为常绿落叶阔叶混交林(6.23 t/hm^2)>杉木纯林(5.57 t/hm^2),最大持水率也表现出相同的规律,即常绿落叶阔叶混交林(184.40%)>杉木纯林(179.50%);有效拦蓄量表现为常绿落叶阔叶混交林(4.48 t/hm^2)>杉木纯林(4.13 t/hm^2),最大拦蓄量表现为常绿落叶阔叶混交林(5.41 t/hm^2)>杉木纯林(4.97 t/hm^2)。(3)枯落物层的吸水量与浸水时间符合对数函数Q=aln(t)+b,而吸水速率与浸水时间符合指数函数V=at^b,常绿落叶阔叶混交林的蓄水能力强于杉木纯林。(4)土壤水分最大吸持贮水量表现为常绿落叶阔叶混交林(43.58 mm)>杉木纯林(41.88 mm),可以看出常绿落叶阔叶混交林内的土壤可以更好地为植被提供良好的水分供其生长;土壤水分最大滞留贮存量表现为常绿落叶阔叶混交林(8.20 mm)<杉木纯林(10.22 mm),即杉木纯林内的土壤具有更好的涵养水源能力。从枯落物最大持水量、有效拦蓄量以及土壤毛管孔隙度、非毛管孔隙度等多个因素的计算综合推断可知,杉木人工林水源涵养能力优于常绿落叶阔叶混交林。     

杉木人工林皆伐对林地径流水化学特征的影响

杉木人工林皆伐前后径流水化学特征研究结果表明，杉木人工林皆伐后引起林地土壤养分大量流失，皆伐后2年内土壤N素、P素、盐基离子（K^ ,Na^ ,Ca^2 ,Mg^2 ）的可溶性盐分的流失增量分别为20.54kg/hm^2、0.817kg/hm^2、42.67kg/hm^2和774.44kg/hm^2，表晨杉木人工林具有一定的调节、富集和保持土壤养分的能力。     

Decline of soil fertility during forest conversion of secondary forest to Chinese fir plantations in subtropical China

The effects of forest conversion on soil fertility are still not well understood in subtropical zones. This issue was addressed by comparing chemical properties of soil in a secondary forest and a Chinese fir (Cunninghamia lanceolata Hooker) plantation at the Huitong Experimental Station of Forest Ecology. Total N, available P, ‐N, cation exchange capacity (CEC) and exchangeable Al³⁺ and H⁺ of soil were significantly lower in the pure Chinese fir plantation (PCP) than in the secondary forest while soil organic carbon (SOC), total K and exchangeable Na⁺ had a tendency to decrease in the PCP. In contrast, soil pH and percentage base saturation (PBS) significantly increased due to forest conversion, and available K, ‐N and exchangeable Ca²⁺, Mg²⁺ and K⁺ tended to increase in the PCP. Some underlying processes responsible for the differences in soil fertility between the secondary forest and the Chinese fir plantation were low litterfall and root input to soil and site preparation in coniferous plantations. There was no significant difference in the effect of slope position on chemical properties of soil in the PCP and the secondary forest. Results indicated that the conversion of secondary forests to coniferous plantations leads to a decline in soil fertility. Copyright © 2010 John Wiley & Sons, Ltd.     

杉木人工林和阔叶杂木林土壤养分平衡因素差异的初步研究

杉木(Cunninghamia lancelata)是我国南方重要造林树种,人工林分布面积很大。在多年的林业实践中,发现杉木人工林,特别是速生的林分在连续栽植之后,一代不如一代,地力逐渐衰退。因此,连栽二、三代之后,就使其轮荒恢复杂木林。而阔叶杂木林则有恢复土壤肥力的作用,因而杉木一般以在常绿阔叶林或阔叶杂木林砍伐后第一次植杉的土壤上生长为最好^[1]1)。     

不同林分类型土壤水分物理性质及其海拔效应——以浙江省凤阳山为例

以浙江省凤阳山常绿阔叶林和针阔混交林为例,通过野外调查和室内测定土壤容重、土壤孔隙度及土壤含水量等,研究了中亚热带主要林分类型的土壤水分物理性质及其海拔影响.结果表明,在0-60 cm土层中,随着深度的增加土壤容重逐渐增大,土壤总孔隙度、毛管孔隙度、最大持水量、毛管持水量、最小持水量逐渐减小.在海拔300～I 355 m高程范围随着海拔升高土壤容重平均值逐渐减小,土壤总孔隙度、毛管孔隙度、最大持水量、毛管持水量、最小持水量、土壤贮水量平均值均增大;土壤排水能力平均值为:海拔900 m＞海拔600 m＞海拔1 355 m＞海拔300 m.同一海拔4种林分类型土壤容重平均值:人工杉木林＞针阔混交林＞人工柳杉林＞常绿阔叶混交林;土壤总孔隙度、土壤最大持水量、毛管持水量、最小持水量、土壤贮水量平均值均表现为人工柳杉林优于其他3种林分类型;土壤排水能力平均值表现为:常绿阔叶混交林＞人工杉木林＞人工柳杉林＞针阔混交林.综合分析,同一海拔常绿阔叶林水源涵养及保持水土能力要高于人工柳杉林.