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1.
WANG Qing-kui WANG Si-long 《林业研究》2006,17(3):197-200
Conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation is a common management practice in subtropical China. In this study, we compared soil physico-chemical properties, microbial biomass in one natural secondary broad-leaved forest and two C. lanceolata plantation sites to estimate the effects of forest conversion on soil microbial biomass at the Huitong Experimental Station of Forestry Ecology, Chinese Academy of Sciences. Concentrations of soil organic carbon, total nitrogen, NH4^+-N and microbial biomass carbon and nitrogen were much lower under C. lanceolata plantations as compared to natural secondary broad-leaved forest. Soil microbial biomass C in the first and second rotation of C. lanceolata plantations was only 53%, 46% of that in natural secondary broad-leaved forest, and microbial biomass N was 97% and 79%, respectively. The contribution of microbial biomass C to soil organic C was also lower in the plantation sites. However, the contribution of microbial N to total nitrogen and NH4^+-N was greater in the C. lanceolata plantation sites. Therefore, conversion of natural secondary broad-leaved forest to C. lanceolata plantation and continuous planting of C. lanceolata led to the decline in soil microbial biomass and the degradation of forest soil in subtropical China. 相似文献
2.
亚热带地区杉木人工林和阔叶林土壤活性有机质研究(英文) 总被引:1,自引:2,他引:1
土壤活性有机质对土壤养分如氮、磷、硫的生物化学循环具有作用,其含量和质量影响土壤的初级生产力。本试验在中国科学院会同森林生态实验站通过对第一代、第二代杉木纯林和地带性阔叶林土壤活性有机质组分的对比研究,发现杉木纯林土壤活性有机质的含量低于地带性阔叶林。第一代杉木纯林易氧化有机碳、微生物生物量碳、水溶性有机碳和水溶性碳水化合物的含量分别比第二代杉木纯林高35.9%、13.7%、87.8%和50.9%,比地带性阔叶林的低15.8%、47.3%、38.1%和30.2%。在调查的三种林地内,土壤微生物生物量碳和水溶性有机碳含量下降幅度较大,其次为水溶性碳水化合物,而易氧化有机碳的变化最小。同时,杉木纯林土壤养分等理化性质也比地带性阔叶林低。这表明在杉木纯林取代地带性阔叶林以及杉木纯林连栽后林地的土壤肥力降低。图3 表2参26。 相似文献
3.
Vegetation recovery is a key measure to improve ecosystems in the Loess Plateau in China. To understand the evolution of soil
microorganisms in forest plantations in the hilly areas of the Loess Plateau, the soil microbial biomass, microbial respiration
and physical and chemical properties of the soil of Robinia pseudoacacia plantations were studied. In this study, eight forest soils of different age classes were used to study the evolution of
soil microbial biomass, while a farmland and a native forest community of Platycladus orientalis L. were chosen as controls. By measuring soil microbial biomass, metabolic quotient, and physical and chemical properties,
it can be concluded that soil quality was improved steadily after planting. Soil microbial biomass of C, N and P (SMBC, SMBN
and SMBP) increased significantly after 10 to 15 years of afforestation and vegetation recovery. A relatively stable state
of soil microbial biomass was maintained in near-mature or mature plantations. There was an increase of soil microbial biomass
appearing at the end of the mature stage. After 50 years of afforestation and vegetation recovery, compared with those in
farmland, the soil microbial biomass of C, N and P increased by 213%, 201% and 83% respectively, but only accounting for 51%,
55% and 61% of the increase in P. orientalis forest. Microbial soil respiration was enhanced in the early stages, and then weakened in the later stage after restoration,
which was different from the change of soil organic carbon. The metabolic quotient (qCO2) was significantly higher in the soils of the P. orientalis forest than that in farmland at the early restoration stage and then decreased rapidly. After 25 years of afforestation and
vegetation recovery, qCO2 in soils of the R. pseudoacacia forest was lower than that in the farmland soil, and reached a minimum after 50 years, which was close to that of the P. orientalis forest. A significant relationship was found among soil microbial biomass, qCO2 and physical and chemical properties and restoration duration. Therefore, we conclude that it is possible to artificially
improve the ecological environment and soil quality in the hilly area of the Loess Plateau; a long time, even more than 100
years, is needed to reach the climax of the present natural forest.
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Translated from Acta Ecologica Sinica, 2007, 27(3): 909–917 [译自: 生态学报] 相似文献
4.
杉木纯林、混交林土壤微生物特性和土壤养分的比较研究 总被引:6,自引:0,他引:6
本文于2005年5月份,在中国科学院会同森林生态实验站选择了一块15年生的杉木纯林和两块15年生杉阔混交林作为研究对象,调查了林地土壤有机碳、全氮、全磷、硝态氮、有效磷和土壤微生物碳、氮、磷、基础呼吸以及呼吸熵,比较了纯林和混交林土壤微生物特性和土壤养分.结果表明,杉阔混交林的土壤有机碳、全氮、全磷硝态氮和有效磷含量高于杉木纯林;在混交林中,土壤微生物学特性得到改善.在0(10 cm和10(20 cm两层土壤中,杉阔混交林土壤微生物氮含量分别比杉木纯林高69%和61%.在0(10 cm土层,杉阔混交林土壤微生物碳、磷和基础呼吸分别比杉木纯林高11%、14%和4%;在10(20 cm土层,分别高6%、3%和3%.但是,杉阔混交林土壤微生物碳:氮比和呼吸熵较杉木纯林低34%和4%.另外,土壤微生物与土壤养分的相关性高于土壤呼吸、微生物碳:氮比和呼吸熵与土壤养分的相关性.由此可知,在针叶纯林中引入阔叶树后,土壤肥力得以改善,并有利于退化森林土壤的恢复. 相似文献
5.
Responses of labile soil organic carbon and enzyme activity in mineral soils to forest conversion in the subtropics 总被引:1,自引:0,他引:1
Aims
Globally, extensive areas of native forest have been almost replaced by plantations to meet the demands for timber, fuel material and other forest products. This study aimed to evaluate the effects of forest conversion on labile soil organic C (SOC), soil respiration, and enzyme activity, and to quantify their relationship in subtropical forest ecosystems.Methods
Surface mineral soil (0–20 cm) was collected from a Cunninghamia lanceolata Hook. plantation, Pinus massoniana Lamb. plantation, Michelia macclurei Dandy plantation, and an undisturbed native broadleaf forest. Soil microbial biomass C, dissolved organic C, permanganate-oxidizable C, basal respiration, and six enzyme activities were investigated.Results
Soil microbial biomass C was higher by 45.9 % in native broadleaf forest than that in M. macclurei Dandy plantation. The ratio of soil microbial biomass C to total SOC was 27.6 % higher in the M. macclurei Dandy plantation than in the native broadleaf forest. The soil respiration increased by 25.2 % and 21.7 % after conversion from native broadleaf forest to P. massoniana Lamb. and M. macclurei Dandy plantations respectively. The effects of forest conversion on the soil enzyme activities differed among the tree species. Soil microbial biomass C had higher correlation with soil respiration than with the other SOC fractions. Moreover, soil microbial biomass C was positively correlated with urease and negatively correlated with cellulase activity. Soil respiration had higher correlation with soil microbial biomass C, dissolved organic C and permanganate-oxidizable C.Conclusion
Forest conversion affected the soil microbial biomass C, soil respiration, invertase, cellulase, urease, catalase, acid phosphatase, and polyphenol oxidase activities, but their response depended on tree species. Soil respiration was mainly controlled by labile SOC, not by total SOC. 相似文献6.
C and N stocks under three plantation forest ecosystems of Chinese fir, Michelia macclurei and their mixture 总被引:1,自引:0,他引:1
Chinese fir (Cunninghamia lanceolata), a type of subtropical fast-growing conifer tree, is widely distributed in South China. Its plantation area covers more
than 7 × 106 hm2, accounting for 24% of the total area of plantation forests in the country. In recent decades, the system of successive plantation
of Chinese fir has been widely used in southern China due to anticipated high economic return. However, recent studies have
documented that the practice of this system has led to dramatic decreases in soil fertility and forest environment as well
as in productivity.
Some forest ecologists and managers recognize the ecological role performed by broadleaf trees growing in mixtures with conifers,
and a great deal of studies on mixture effects have been conducted, particularly on mixture species of temperate and boreal
forests, but these research results were not completely consistent. Possibilities include dependence of the mixture effects
in large part to specific site conditions, the interactions among species in mixtures and biological characteristics of species.
Although some researchers also studied the effects of mixtures of Chinese fir and broadleaf tree species on soil fertility,
forest environment and tree growth status, little information is available about the effects of Chinese fir and its mixtures
with broadleaves on carbon and nitrogen stocks.
The experimental site is situated at the Huitong Experimental Station of Forest Ecology, Chinese Academy of Sciences, Hunan
Province (26°40′–27°09′ N, 109°26′–110°08′ E). It is located at the transition zone from the Yunnan-Guizhou Plateau to the
low mountains and hills of the southern bank of the Yangtze River at an altitude of 300–1,100 m above mean sea level. At the
same time, the site is also a member of the Chinese Ecosystem Research Network (CERN), sponsored by the Chinese Academy of
Sciences (CAS). This region has a humid mid-subtropical monsoon climate with a mean annual precipitation of 1,200–1,400 mm,
most of the rain falling between April and August, and a mean temperature of 16.5°C with a mean minimum of 4.9°C in January
and a mean maximum of 26.6°C in July. The experimental field has red-yellow soil.
After a clear-cutting of the first generation Chinese fir (Cunninghamia lanceolata) plantation forest in 1982, three different plantation forest ecosystems, viz. mixture of Michelia macclurei and Chinese fir (MCM), pure Michelia macclurei stand (PMS) and pure Chinese fir stand (PCS), were established in the spring of 1983. A comparative study on C and N stocks
under these three plantation forest ecosystems was conducted in 2004. Results showed that carbon stocks were greater under
the mixtures than under the pure Chinese fir forest and the pure broad-leaved forest, and the broadleaves and the mixtures
showed higher values in nitrogen stocks compared with the pure Chinese fir forest. The spatial distribution of carbon and
nitrogen stocks was basically consistent, the value being greater in soil layer, followed by tree layer, roots, understory
and litter layer. The carbon and nitrogen stocks in soil layer were both highly correlated with the biomass in understory
and litter layer, indicating that understory and forest litterfall exerted a profound effect on soil carbon and nitrogen stocks
under plantation ecosystems. However, correlations among soil carbon, nitrogen stocks and below ground biomass of stand have
not been observed in this study.
Translated from Acta Ecologica Sinica, 2005, 25(12): 3,146–3,154 [译自: 生态学报] 相似文献
7.
Hui Wang Jiangming Mo Xiankai Lu Jinghua Xue Jiong Li Yunting Fang 《Frontiers of Forestry in China》2009,4(1):21-27
2003
Wallenstein M D.McNulty S.Fernandez I J.Boggs J Schlesinger W H
Nitrogen fertilization decreases forest soil fungal and bacterial biomass in three long-term experiments [其它论文]
2006
Wang X F.Li S Y.Bai K J.Kuang T Y
Influence of doubled CO2 on plant growth and soil microbial biomass C and N
1998(12)
Xue J H.Mo J M.Li J.Li D J
The short-term response of soil microorganism number to simulated nitrogen deposition
2007(02)
Yao W H.Yu Z Y
The nutrient content of throughfall inside the artificial forests on downland
1995
Yi Z G.Yi W M.Zhou L X.Wang X M
Soil microbial biomass of the main forests in Dinghushan Biosphere Reserve
2005(05)
Zhou G Y.Yan J H
The influence of region atmospheric precipitation characteristics and its element inputs on the existence and development of Dinghushan forest ecosystems [其它论文]
-Acta Ecologica Sinica2001
8.
Effects of different vegetation restoration models on soil microbial biomass in eroded hilly Loess Plateau, China 总被引:2,自引:0,他引:2
Vegetation restoration is a key measure to improve the eco-environment in Loess Plateau, China. In order to find the effect
of soil microbial biomass under different vegetation restoration models in this region, six trial sites located in Zhifanggou
watershed were selected in this study. Results showed that soil microbial biomass, microbial respiration and physical and
chemical properties increased apparently. After 30 years of vegetation restoration, soil microbial biomass C, N, P (SMBC,
SMBN, SMBP) and microbial respiration, increased by 109.01%–144.22%, 34.17%–117.09%, 31.79%–79.94% and 26.78%–87.59% respectively,
as compared with the farmland. However, metabolic quotient declined dramatically by 57.45%–77.49%. Effects of different models
of vegetation restoration are different on improving the properties of soil. In general, mixed stands of Pinus tabulaeformis-Amorpha fruticosa and Robinia pseudoacacia-A. fruticosa had the most remarkable effect, followed by R. pseudoacacia and Caragana korshinkii, fallow land and P. tabulaeformis was the lowest. Restoration of mixed forest had greater effective than pure forest in eroded Hilly Loess Plateau. The significant
relationships were observed among SMBC, SMBP, microbial respiration, and physical and chemical properties of soil. It was
concluded that microbial biomass can be used as indicators of soil quality.
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Translated from Journal of Natural Resources, 2007, 22(1): 20–27 [译自: 自然资源学报] 相似文献
9.
Lei Hu Zeyu Xiang Genxu Wang Rashad Rafique Wei Liu 《Scandinavian Journal of Forest Research》2016,31(3):242-253
The effects of the interaction between tree species composition and altitude on soil microbial properties are poorly understood. In this study, soil samples (0–20?cm) were collected in August 2011 from Betula platyphylla and Picea crassifolia forests along two different altitudinal gradients. Soil microbial activity and biomass were measured using Biolog-ECO plates and phospholipid fatty acid analysis. Both of the forest soils were characterized by a significantly lower soil pH (p?.05) and higher soil organic matter (SOM) and nutrient levels (total nitrogen, available nitrogen and phosphorus) at higher altitudes compared with lower altitudes. Soil microbial activity was significantly lower in the birch forests (p?.05), but changed little in the spruce forests with increasing altitude. Soil microbial biomass decreased in the two forest soils across altitude gradients. With each 100-m drop in altitude, the soil microbial biomass exhibited a sharper decline in the spruce forests than in the birch forests. SOM had significant negative effects on soil microbial biomass, but no effects on soil microbial activity. Soil pH was significantly negative correlated with soil microbial biomass and activity. The tree species composition exhibited more negative effects on soil microbial biomass in the spruce forests, while altitude had a greater effect in the birch forests. 相似文献
10.
11.
Soil properties under an exotic plantation (Pinus caribaea) and an indigenous plantation (Podocarpus imbricatus) were compared with adjacent secondary forests and abandoned land in the tropical forest areas of Jianfengling National Nature
Reserve in Hainan province, southern China. The surface soil (0–0.2 m) under Pi. caribaea has higher bulk density, lower soil organic carbon, total N, total K, available N, microbial biomass carbon, and smaller
soil microbial communities (as indicated by soil Biolog profiles) than under Po. imbricatus. Both land use types showed negative cumulative soil deterioration index (DI) compared to secondary forests. However, compared
to abandoned land (DI = –262), the soil quality of Po. imbricatus showed improvement (DI = –194) while that of Pi. caribaea showed deterioration (DI = –358). These results demonstrated that these exotic pine plantations can significantly and negatively
influence soil properties. By contrast, our results showed that adoption of indigenous species in plantations, or natural
regeneration, can improve soil quality. 相似文献
12.
In sodic soils, excessive amounts of salts have an adverse effect on soil biological activity and stability of soil organic
matter. The study analyzes the role of silvopastoral systems to improve soil organic matter and microbial activity with a
view for effective management of soil fertility. The silvopastoral systems for the present study (located at Saraswati Reserved
Forest, Kurukshetra; 29°4′ to 30°15′ N and 75°15′ to 77°16prime; E) are characterized by tree species of Acacia nilotica, Dalbergia sissoo and Prosopis juliflora along with grass species of Desmostachya bipinnata and Sporobolus marginatus. Soil microbial biomass carbon was measured using the fumigation extraction technique and nitrogen mineralization rates using
aerobic incubation method. The microbial biomass carbon in the soils of D. bipinnata and S. marginatus treatments were low. In silvopastoral systems, microbial biomass carbon increased due to increase in the carbon content in
the soil – plant system. A significant relationship was found between microbial biomass carbon and plant biomass carbon (r = 0.83) as well as the flux of carbon in net primary productivity (r = 0.92). Nitrogen mineralization rates were found greater in silvopastoral systems compared to 'grass-only' system. Soil
organic matter was linearly related to microbial biomass carbon, soil N and nitrogen mineralization rates (r = 0.95 to 0.98, p < 0.01). On the basis of improvement in soil organic matter, enlarged soil microbial biomass pool and greater soil N availability
in the tree + grass systems, agroforestry could be adopted for improving the fertility of highly sodic soil.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
在我国南方,天然次生阔叶林转变为杉木人工林是一种常见的管理措施。为研究森林利用方式转变对土壤微生物量的影响,我们在中国科学院会同森林生态实验站比较了天然次生阔叶林、第一代和第二代杉木人工林土壤理化性质和微生物量。杉木人工林土壤有机碳、全氮、铵态氮和微生物量碳氮含量明显低于天然次生阔叶林。第一代、二代杉木人工林土壤微生物量碳仅为天然次生阔叶林的53%和46%,微生物氮为97%和79%。杉木人工林土壤微生物量碳占有机碳的比例也低于天然次生阔叶林土壤,但微生物量氮则相反,为杉木人工林高于天然次生阔叶林。因此可以得出,天然次生阔叶林转变为杉木人工林以及杉木林连栽引起了土壤生物学特性和土壤质量降低。图2表3参36。 相似文献
14.
In order to clarify the effects of a mixture of deciduous broad-leaved trees on soil fertility, we investigated litter biomass
accumulation, mineral soil chemical and physical characteristics, characteristics of nitrogen mineralization, and the mutual
relationships between them in Japanese cypress (Chamaecyparis obtusa) stands mixed with deciduous broad-leaved trees at different ratios (mixture ratio; MR = 0, 16, 33, 43, 100% by basal area)
in the northern Kanto region of Japan. Litter biomass in the forest floor and mineral soil was 19.1 Mg ha−1 in MR 0% and decreased approximately 60 % in MR 33%, MR 43% and MR100%. The permeability at 0–5 cm soil depth in MR100% was
twice as much as that in MR 0%. Increases in soil permeability were likely due to larger soil pores in the higher MR with
much accumulated deciduous broad-leaves. At 0–5 cm soil depth, the differences in carbon concentration among the plots were
not clear. On the other hand, carbon concentrations at 5–10 cm depth increased from 90 g kg−1 to 147 g kg−1 with increases in MR from 0% to 100%. Concentrations of exchangeable bases increased two to four times with increases in
MR from 0 to 100% at 0–10 cm depth. Soil pH (H2O) generally increased with increases in MR at each depth. The rates of net nitrogen mineralization at 0–5 cm depthin vitro increased from 25 to 87 mg kg−1 2 weeks−1 with increases in MR from 0 to 100%. However, increases in nitrification with increases in MR were not clear compared with
nitrogen mineralization. These results indicated that a mixture of deciduous broad-leaved trees in a Japanese cypress stand
was effective in preventing soil fertility decline.
This study was supported by a grant from the Showa Shell Sekiyu Fundation for Promotion of Environmental Research. A part
of this study was presented at the 7th International Congress of Ecology (1998). 相似文献
15.
In order to study the effect of tree crop intercropping on a young plantation of Populus tomentosa in the plains along the Yellow River, field experiments were conducted by observing the growth of the plantation, the nutrient
content in leaves, the nutrient and water content in the soil, and the output of crops. The relationship between forest growth
and nutrient content in the tree leaves and the soil were analyzed. Results show that tree crop intercropping in young plantations
can not only improve soil water content, but also enhance the contents of organic matter and the available nitrogen, phosphorus
and potassium in soil resulting in the vigorous growth of the individual trees. Diameter at breast height (DBH) was positively
related to the contents of organic matter in the soil, and the contents of N, P and K in the tree leaves had correlation coefficients
of 0.967, 0.955, 0.988 and 0.972, respectively. Whole tree leaf area, crown width, number of branches and the mean length
of branches in the intercropped plantation (intercropped with watermelon and vegetables, peanut and winter wheat, and soybean)
were, respectively, 1.70–3.0 times, 2.22–2.47 times, 1.0–1.41 times and 1.70–2.32 times of those of CK (without intercropping).
Diameter at breast height (DBH) and tree height in the intercropped plantation were 50.5%–136.7% and 27%–59.5% higher than
those of the CK, respectively. The study also showed that intercropping with watermelon and vegetables proved to have the
highest economic return among the treatments adopted. Tree crop intercropping in young plantations is an effective measure
to increase forest growth and economic benefit.
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Translated from Journal of Beijing Forestry University, 2006, 28(3): 81–85 [译自: 北京林业大学学报] 相似文献
16.
In 1988 an experiment was established to stimulate the effect of windthrow on low-and high-productivity forest types in coastal British Columbia. It was hypothesized that site productivity may be improved by mixing the upper 1 m of the organic matter and mineral soil. Results of this study indicated that soil mixing (1) slightly increased soil pH and temperature on both forest types after 2 and 5 years, (2) decreased all soil nutrient availability indices on the high productivity type after 2 years, but resulted in no difference from the control after 5 years, and (3) decreased microbial activity and cellulose loss rate and most soil nutrient availability indices on the low-productivity type after 2 and 5 years. Soil mixing greatly reduced Gaultheria shallon above-ground biomass on both low- and high productivity forest types, whereas biomass of Epilobium angustifolium and other plant species increased slightly on the high-productivity type after 2 and 5 vears. Tsuga heterophylla was taller on high-productivity type and on mixed plots in both types after 2 and 5 years. Thuja plicata was taller on the high-productivity type after 5 years only. The increased conifer growth measured on the mixed low-productivity type was attributed to higher levels of available nutrients due to reduced G. shallon competition. 相似文献
17.
[目的]研究5种不同密度林分土壤剖面养分含量的变化规律。[方法]以广西大青山37年生杉木密度试验林为研究对象,测定了A(1 667株·hm-2)、B(3 333株·hm-2)、C(5 000株·hm-2)、D(6 667株·hm-2)、E(10 000株·hm-2)5种密度下0 100 cm土层土壤养分含量。利用单因素方差分析和多重比较判断不同密度和不同土层土壤养分含量的差异。[结果]表明:(1)杉木人工成熟林大多数土层土壤有机质、全氮、碱解氮、全磷、有效性铁含量在A、B等低密度林分中最高,并且在0 30 cm的土壤中,随密度的增加表现出总体下降的变化趋势,而土壤pH值与全钾、速效钾随密度的增加而上升,交换性钙与交换性镁含量受密度影响不明显;(2)土壤有机质、全氮、碱解氮、有效磷、速效钾、交换性钙、交换性镁和有效性铁含量均随土层深度的增加而明显下降,0 30 cm表层土壤的降幅较大,密度对不同土壤深度养分含量的变化具有一定影响。[结论]初植密度对杉木人工成熟林土壤养分含量影响明显,低初植密度更有利于杉木人工林土壤肥力的长期维持,南亚热带杉木林密度对土壤养分的影响深度可达60 cm。 相似文献
18.
Yumei Zhou Shijie Han Junqiang Zheng Lihua Xin Haisen Zhang 《Frontiers of Forestry in China》2008,3(2):131-138
The two main components of soil respiration, i.e., root/rhizosphere and microbial respiration, respond differently to elevated
atmospheric CO2 concentrations both in mechanism and sensitivity because they have different substrates derived from plant and soil organic
matter, respectively. To model the carbon cycle and predict the carbon source/sink of forest ecosystems, we must first understand
the relative contributions of root/rhizosphere and microbial respiration to total soil respiration under elevated CO2 concentrations. Root/rhizosphere and soil microbial respiration have been shown to increase, decrease and remain unchanged
under elevated CO2 concentrations. A significantly positive relationship between root biomass and root/rhizosphere respiration has been found.
Fine roots respond more strongly to elevated CO2 concentrations than coarse roots. Evidence suggests that soil microbial respiration is highly variable and uncertain under
elevated CO2 concentrations. Microbial biomass and activity are related or unrelated to rates of microbial respiration. Because substrate
availability drives microbial metabolism in soils, it is likely that much of the variability in microbial respiration results
from differences in the response of root growth to elevated CO2 concentrations and subsequent changes in substrate production. Biotic and abiotic factors affecting soil respiration were
found to affect both root/rhizosphere and microbial respiration.
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Translated from Journal of Plant Ecology, 2007, 31(3): 386–393 [译自: 植物生态学报] 相似文献
19.
Coffee (Coffea canephora var robusta) is grown in Southwestern Togo under shade of native Albizia adianthifolia as a low input cropping system. However, there is no information on carbon and nutrient cycling in these shaded coffee systems.
Hence, a study was conducted in a mature coffee plantation in Southwestern Togo to determine carbon and nutrient stocks in
shaded versus open-grown coffee systems. Biomass of Albizia trees was predicted by allometry, whereas biomass of coffee bushes was estimated through destructive sampling. Above- and
belowground biomass estimates were respectively, 140 Mg ha−1 and 32 Mg ha−1 in the coffee–Albizia association, and 29.7 Mg ha−1 and 18.7 Mg ha−1 in the open-grown system. Albizia trees contributed 87% of total aboveground biomass and 55% of total root biomass in the shaded coffee system. Individual
coffee bushes consistently had higher biomass in the open-grown than in the shaded coffee system. Total C stock was 81 Mg ha−1 in the shaded coffee system and only 22.9 Mg ha−1 for coffee grown in the open. Apart from P and Mg, considerable amounts of major nutrients were stored in the shade tree
biomass in non-easily recyclable fractions. Plant tissues in the shaded coffee system had higher N concentration, suggesting
possible N fixation. Given the potential for competition between the shade trees and coffee for nutrients, particularly in
low soil fertility conditions, it is suggested that the shade trees be periodically pruned in order to increase organic matter
addition and nutrient return to the soil.
An erratum to this article can be found at 相似文献
20.
Trunk circumferences and canopy diameters of Prosopis glandulosa, P. chilensis and P. alba, and soil nitrogen under and between the trees were measured in a seven-year-old plantation at the University of California,
Riverside. P. glandulosa had the smallest biomass of the three species. However, the nitrogen concentration of the soil under P. glandulosa was higher than under the other two species. Presumably more nitrogen is cycled through the leaves of this species rather
than invested in wood production, where it would be sequestered. The soil nitrogen accumulation under P. glandulosa was significantly higher (total and subsurface) than that measured in soil taken between trees. The soil nitrogen content
under P. chilensis and P. alba was not significantly different than that between the trees. These results indicate that the choice of woody legume in an
agroforestry system will depend on its intended use. The most efficient nutrient cycling is not necessarily associated with
the best biomass production. 相似文献