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1.
Kyotaro Noguchi Qingmin Han Masatake G. Araki Tatsuro Kawasaki Shinji Kaneko Masamichi Takahashi Yukihiro Chiba 《Journal of Forest Research》2011,16(4):284-291
Fine roots play a key role in carbon and nutrient dynamics in forested ecosystems. Fine-root dynamics can be significantly
affected by forest management practices such as thinning, but research on this topic is limited. This study examined dynamics
of fine roots <1 mm in diameter in a 10-year-old stand of hinoki cypress (Chamaecyparis obtusa) for 3 years following thinning (65% in basal area). Fine-root production and mortality rates were estimated using a minirhizotron
technique in combination with soil coring. In both thinned and un-thinned control plots, fine-root elongation occurred from
early spring to winter (March to December) and fluctuated seasonally. In the thinned and the control plots, the annual fine-root
production rates were estimated to be 101 and 120 g m−2 year−1, respectively, whereas the estimated annual fine-root mortality rates were 77 and 69 g m−2 year−1, respectively. At 3 years after thinning, live fine-root biomass was significantly smaller in the thinned plot (143 g m−2) than in the control plot (218 g m−2), whereas dead fine-root biomass was not (147 and 103 g m−2, respectively). Morphological and physiological indices of fine roots such as diameter, specific root length, and root tissue
density of the live fine roots was similar in both plots. These results suggested that thinning tended to decrease biomass
and production of fine roots, but the effects on characteristics of fine roots would be less evident. 相似文献
2.
The cutting seedlings ofLiriodendron chinense xtulipifera were treated with the different concentrations of auxin (treatment1: IBA of 50 g·kg−1+NAA of 300 g·kg−1; treatment2; IBA of 100 g·kg−1+NAA of 300 g·kg−1). The biomass nutrient element contents for different organs (root, stem, leaf) of cutting seedling ofLiriodendron chinense xtulipifera were measured by the dry method, Kjeldahl method and Atomic Absorption Spectroscopy method. The result showed that the biomass
of root, stem, and leaf of the cutting seedling treated with auxin was all remarkably increased. The contents of element C
in root, stem and leaf had no significant difference between the control and auxin treatments, while the contents of N, P,
K and Ca in stem were much lower than that in leaf and root. Variance analysis showed that for the same organ with different
concentration treatment of auxin, the four nutrient elements (N, P, K, and Ca) had no significant difference in contents,
while there existed significant or very significant difference in contents of the four nutrient elements in different organs
with the same concentration auxin treatment. The N, P, K and Ca contents were very low in cutting seedlings; as a result,
additional fertilizer should be applied to the seedlings when they were planted in the field.
Foundation item: This paper was supported by Jiangsu Province Science Foundation (BE96350).
Biography: ZHANG Xiao-ping, (1972-), female, Ph. Doctor in Nanjing Forestry University. Nanjing 210037, P. R. China.
Responsible editor: Zhu Hong 相似文献
3.
Satish Chandra Garkoti 《Journal of Forest Research》2011,16(2):136-143
Fine root biomass, rates of dry matter production and nutrients dynamics were estimated for 1 year in three high elevation
forests of the Indian central Himalaya. Fine root biomass and productivity were higher in closed canopied cappadocian maple
forest (9.92 Mg ha−1 and 6.34 Mg ha−1 year−1, respectively), followed by Himalayan birch forest (6.35 Mg ha−1 and 4.44 Mg ha−1 year−1) and Bell rhododendron forest (6.23 Mg ha−1 and 2.94 Mg ha−1 year−1). Both fine root biomass and productivity declined with an increase in elevation. Across the sites, fine root biomass was
maximal in fall and minimal in summer. In all sites, maximum nutrient concentration in fine roots was in the rainy season
and minimum in winter. Fine root biomass per unit basal area was positively related with elevation, Bell rhododendron forest
having the largest fine root biomass per unit of basal area (0.53 Mg m−2) and cappadocian maple the least (0.18 Mg m−2). The production efficiency of fine roots per unit of leaf biomass also increased with elevation and ranged from 1.13 g g−1 leaf mass year−1 in cappadocian maple forest to 1.28 g g−1 leaf mass year−1 in Bell rhododendron forest. Present fine root turnover estimates showed a decline towards higher elevations (0.72 year−1 in cappadocian maple and 0.58 year−1 in Bell rhododendron forest) and are higher than global estimates (0.52). 相似文献
4.
Teak (Tectona grandis L.f.) is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5–8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System (DRIS). Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or Al, Ca with Mg, and Fe with Al provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study. 相似文献
5.
The responses of fine root mass, length, production and turnover to the increase in soil N availability are not well understood
in forest ecosystems. In this study, sequential soil core and ingrowth core methods were employed to examine the responses
of fine root (≤1 mm) standing biomass, root length density (RLD), specific root length (SRL), biomass production and turnover
rate to soil N fertilization (10 g N m−2 year−1) in Larix gmelinii (larch) and Fraxinus mandshurica (ash) plantations. N fertilization significantly reduced fine root standing biomass from 130.7 to 103.4 g m−2 in ash, but had no significant influence in larch (81.5 g m−2 in the control and 81.9 g m−2 in the fertilized plots). Similarly, N fertilization reduced mean RLD from 6,857 to 5,822 m m−2 in ash, but did not influence RLD in larch (1,875 m m−2 in the control and 1,858 m m−2 in the fertilized plots). In both species, N fertilization did not alter SRL. Additionally, N fertilization did not significantly
alter root production and turnover rate estimated from sequential soil cores, but did reduce root production and turnover
rate estimated from the ingrowth core method. These results suggested that N fertilization had a substantial influence on
fine root standing biomass, RLD, biomass production and turnover rate, but the direction and magnitude of the influence depended
on species and methods. 相似文献
6.
Differences in sensitivity to soil conditions across tree species and developmental stage are important to predicting forest response to environmental change. This study was conducted to compare elemental concentrations in leaves, stems, and roots of (1) sugar maple (Acer saccharum Marsh.) seedlings vs. mature trees and (2) mature sugar maple vs. mature American beech (Fagus grandifolia Ehrh.) in two sites that differ in soil base saturation and pH. Both sites are located in Huntington Forest, NY, USA; one site (hereafter ‘H’) has higher soil pH and Ca, Mg, and Mn concentrations than the other site (hereafter ‘L’). Sugar maple growth at H (14.8 cm2 year−1 per tree) was much greater than at L (8.6 cm2 year−1 per tree), but the growth of beech was not different between the two sites. Leaves, roots, and stem wood of mature beech trees and sugar maple seedlings and mature trees were sampled for nutrient analysis. Foliar Ca, K, and Al concentrations were positively correlated with soil elements, but Mn concentrations were negatively correlated. Sugar maple differed more than beech between sites in foliar K and Mn concentrations. Root Mg and P concentrations reflected soil chemistry differences, in contrast to foliar concentrations of Mg and P, which were indistinguishable between the sites. In sugar maple, seedlings differed more than in mature trees in nutrient concentrations in roots, especially for Mg and Mn. Although beech was not as responsive to nutrient availability as sugar maple in foliar and root nutrient concentrations, Ca and Mg concentrations in beech wood were higher in H (52% higher for Ca and 68% higher for Mg), while sugar maple did not differ between sites. Sugar maple regeneration failure on acidic soils in the same region is consistent with our finding that sugar maple seedlings were very sensitive to nutrient availability. This sensitivity could ultimately contribute to the replacement of sugar maple by American beech in regions of low pH and base cations if base cation leaching by anthropogenic deposition and tree harvesting continues. 相似文献
7.
Bareroot Changbai larch (Larix olgensis Henry.) seedlings were reared with inorganic fertilizer (nitrogen (N):phosphorus (P) = 1:1, W/W) applied at a rate of 100
(F100) or 200 kg N ha−1 (F200) with (+) or without (−) chicken manure as a soil amendment (O) in north-eastern China. An unfertilized control treatment
was included. Inorganic and organic fertilizer treatments tended to increase soil ammonium, nitrate, available P, total P,
organic carbon content and electrical conductivity, and biomass and N concentration in seedlings. Organic amendment improved
first order lateral root number, tap root length, fine root morphology (length, surface area, volume) in seedlings, while
the F100 treatment increased N accumulation in needles and stems compared to the F200 treatment, on average. Most fertilizer
treatments tended to increase P content in combined stems and roots, but F200 − O and F100 + O treatments diluted P in needles.
Organic amendment combined with inorganic fertilizer at a rate of 100 kg N and P ha−1 is recommended to improve seedling growth and N reserves in woody tissues. 相似文献
8.
In order to quantify the importance of ectomycorrhizal fungi on nutrient uptake from the coarse-soil fraction of a haplic Cambisol (alumic), a microcosm study that allowed for nutrient budgets was designed. Ectomycorrhizal- and fungicide-treated spruce seedlings were grown on isolated and cleaned gneiss fragments (6.3 mm > Ø > 2 mm) from 90 cm soil depth. The substrate was the only source of Ca, K and Mg. Ectomycorrhizal seedlings showed no signs of nutrient deficiencies and biomass increased significantly compared to initial seedling biomass. Ectomycorrhizal seedlings seemed well adapted to survive on the coarse-soil substrate and acquired Ca, K and Mg from the coarse-soil substrate. Gneiss fragments of the ectomycorrhizal treatment were covered by fine roots and ectomycorrhizal hyphae, as observed microscopically. Fungicide-treated seedlings?? root development was retarded, and shoot biomass only increased from stored nutrient reserves of the seedlings. The suppression of EcM colonization by the fungicide Topas® apparently caused a root growth inhibiting effect. Furthermore, the extinction of mycorrhiza initiated an increased nitrification and acidification and a consequent nutrient cation release triggered by nitrate in the drainage. 相似文献
9.
Bilas Singh 《Journal of Sustainable Forestry》2013,32(6):480-495
We assessed interactive effects of varying levels of applied phosphorus fertilizer and water stress on growth, productivity, and mineral accumulation in container-grown Dalbergia sissoo L. seedlings. Height, collar diameter, leaf size and area, root volume and total biomass were reduced, and dry matter allocation to root was increased with increasing levels of soil water stress. The reduction was >32% in growth, >50% in leaf, and >77% in biomass when seedlings were grown with <50% of soil field capacity. Phosphorus application at the level of 10 mg kg?1 soil enhanced stems and leaf biomass and nutrient accumulation at all irrigation levels, and thus tolerance to drought. Phosphorus responses to growth and biomass production increased with irrigation levels. Thus, 20 mg P kg?1 soil is beneficial at sufficient soil water availability and a lower dose (i.e., 10 mg P kg?1) is recommended under high soil water stress conditions to benefit growth and productivity of D. sissoo. 相似文献
10.
Juan A. Oliet Rosa Planelles Francisco Artero Rosario Valverde Douglass F. Jacobs Maria L. Segura 《New Forests》2009,37(3):313-331
In Mediterranean arid regions, relatively small planting stock has traditionally been used in an attempt to reduce drought
susceptibility, though few studies have examined influences of initial seedling morphology and nutrition on long-term plantation
establishment. We fertilized Pinus halepensis Mill. seedlings in the nursery with controlled release fertilizer (CRF) varying in formulations and rates; 9-13-18 and 17-10-10
(N-P-K) formulations at 3, 5 and 7 g l−1 substrate plus an unfertilized control and we evaluated growth and survival 7 years after planting in arid conditions in
Almería province, southeast Spain. Interactions between initial height and fertilizer treatments occurred during the first
3 years; initial size advantages of specific fertilizer treatments (7 g l−1 of 9-13-18 and 17-10-10 at 3 g l−1) persisted after 7 years. The largest and most nutrient-rich seedlings from 9-13-18 at 7 g l−1 (41.0 cm tall, 4.4 mg of P per g of root tissue at time of planting) exhibited the highest survival after 7 years (79%),
while survival declined to 42% for non-fertilized plants (12.9 cm tall and 0.6 mg of P per g of root tissue). Initial seedling
morphological parameters were most consistently correlated with field performance. Root P concentration was the nutrient variable
most closely related to survival. Our data emphasizes importance of longer-term experiments to accurately assess influences
of nursery treatments on field responses, particularly in arid areas. We suggest that larger seedlings with greater nutrient
reserves than are currently being used should be incorporated into Mediterranean plantations. 相似文献
11.
Kyotaro Noguchi Tadashi Sakata Takeo Mizoguchi Masamichi Takahashi 《Journal of Forest Research》2005,10(6):435-441
Fine roots are a key component of forested ecosystems, but available information is still limited. This study examined the
production and mortality of fine roots less than 1 mm in diameter in a Japanese cedar (Cryptomeria japonica D. Don) plantation located on the Kanto Plain in central Japan. We used a minirhizotron technique in combination with soil
coring, and collected data for 1 year (May 2002–May 2003). Fine root production and mortality were determined from changes
in the lengths of individual fine roots on minirhizotron tubes. Both fine root production and mortality rates were greater
in the upper soil than in lower soil levels. Both rates were seasonal, with higher values in summer than in winter; this trend
was more pronounced in upper soil levels. These results suggest that environmental conditions, such as temperature or soil
properties, affect the production and mortality rates of fine roots. Fine root production and mortality occurred simultaneously,
and their rates were similar, which may have led to unclear seasonal changes in fine root standing crop estimates. Soil coring
indicated that the fine root biomass of this stand was about 120 g m−2, of which 40% was from Japanese cedar. The estimated rates of dry matter production and mortality of total fine roots, including
understory plants, were both approximately 300 g m−2 year−1. 相似文献
12.
孟加拉东南部土壤中的砷含量很高,不仅威胁人的健康,而且对土壤也有破坏作用。云南石梓(Gmelina arborea)在孟加拉是个快速生长的树种,也是含砷土壤中的潜力树种。研究评价了含砷试验土中丛枝菌根真菌对云南石梓(Gmelina arborea)生长的影响。播种前,四种不同浓度的砷(10mg·kg-1、25mg·kg-1、50mg·kg-1和100mg·kg-1)被加入到试验土中。记录生长参数,如,植物的根、苗鲜重、干重、冠幅径、根长和苗高、根瘤菌和孢子菌群落。菌根植株较非菌根植株生长好。与其它含砷量高的土壤中植株的生长情况相比,在含砷量为10-mg·kg-1的土壤中,菌根植株和菌根生长效果最佳,菌根植株生物量最高。随着砷浓度的增加,种苗生长,根瘤菌和孢子菌群落均明显降低p0.05)。与非菌根植株比较,菌根植株高生长增加了40%,生物量增加了2.4倍。研究表明,根瘤菌接种可以减少有害土壤中的云南石梓(Gmelina arborea)的初生长的影响。 相似文献
13.
Juan A. Oliet María Tejada K. Francis Salifu Aleyda Collazos Douglass F. Jacobs 《European Journal of Forest Research》2009,128(3):253-263
Holm oak (Quercus ilex L.) seedlings were exponentially (E) nutrient loaded using incremental increases in fertilizer addition or conventionally
(C) fertilized using a constant fertilizer rate during nursery culture. The fertility treatments (mg N plant−1) were control (0), 25E, 100E, and 100C. Subsequently, 1-year-old plants were transplanted under simulated soil fertility
gradients in a greenhouse to evaluate effects of nutrient loading and post-transplant fertility on seedling performance. Post-transplant
fertility consisted of fertilizing plants at two rates (0 vs. 200 mg N plant−1). A water-soluble fertilizer 20-20-20 was supplied in both nursery and post-transplant experiments. Nutrient loading increased
plant N content by 73% in 100E and by 75% in 100C relative to controls, although no significant differences were detected
between constant and exponential fertilization regimes at the 100 mg N plant−1 rate. When transplanted, nutrient loading promoted post-transplant root growth relative to shoot, implicating potential to
confer competitive advantage to loaded holm oak seedlings after trans-planting. In contrast, post-transplant fertility increased
new shoot dry mass by 140% as well as N, P and K content relative to controls. Results suggest that holm oak seedlings can
be successfully nutrient loaded in the nursery at higher fertility rates, improving its potential to extend new roots, but
alternative fertilization regimes and schedules that better fit nutrient availability to the growth rhythm and conservative
strategy of this species must be tested. 相似文献
14.
Effects of aluminum on growth and nutrient status of Douglas-fir seedlings grown in culture solution
Keltjens WG 《Tree physiology》1990,6(2):165-175
Effects of Al on growth, nutrient uptake and proton efflux were studied in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings grown for about nine months in culture solutions with a pH between 3.4 and 3.6 and with both calcium and magnesium (Ca + Mg) at a concentration of 0.1, 0.5 or 2.5 mM. In the absence of Al, plant dry matter production and root development increased with increasing concentrations of (Ca + Mg) in the culture solution. At the low and intermediate (Ca + Mg) concentrations, optimal root and shoot development were observed at an Al concentration of 4 mg l(-1). At the highest (Ca + Mg) concentration, Al up to 4 mg l(-1) did not affect growth, but at higher concentrations, it significantly reduced both shoot and root growth. As the concentration of (Ca + Mg) in the nutrient solution increased, the concentrations of Ca and Mg increased in shoots and roots also. The concentrations of Ca and Mg in the roots were unaffected by the presence of Al, whereas in the shoots they were either unaffected, or increased, by Al. Concentrations of Al in, or on, roots, or in shoots, did not change in response to changing concentrations of Ca + Mg in the nutrient medium. In general, concentrations of P and K in shoots and roots were higher in seedlings grown in nutrient solutions containing Al. Stimulation of growth by moderate concentrations of Al, which was observed at suboptimal (Ca + Mg) concentrations, was associated with a low NH(4) preference and a low root proton efflux. The Al-induced increase in internal K concentration and reduction in NH(4) preference may be explained by a lower efflux of K and NO(3), respectively. 相似文献
15.
The root parameters of forest trees can be indicators of a changing environment. We summarize the results of root studies
with regard to the effects of acidifying pollutants, especially soil acidification and aluminum toxicity, on various root
parameters of Japanese forest trees under experimentally controlled conditions. All root parameters such as biomass, morphology,
nutritional status, and physiology can be regarded as indicators, because, under laboratory conditions, root responses occur
prior to the responses in the aboveground parts. However, considering the conditions of forest sites, the nutritional status
and physiological changes are better indicators of soil acidification and Al stress than the biomass and morphological response.
The currently available data suggest that the most important indicator is the Ca/Al molar ratio in roots of Japanese tree
species. In order to predict and detect the initial effects of soil acidification, we postulate that the specific root response
to the Ca/Al molar ratio of tree roots should be considered as a parameter for use in long-term forest monitoring sites. 相似文献
16.
落叶松水浸液对胡桃楸幼苗生长的影响 总被引:3,自引:0,他引:3
YANG Li-xue 《林业研究》2005,16(4):285-288
A study was conducted to detect the effect of water extracts from different parts such as root, bark, branch and leaf, of adult larch, Larix gmelini, trees on growth of Manchurian walnut, Juglans mandshudca, seedlings and the allelopathy between the two tree species. Four concentrations (100 g. kg i, 50 g. kg^-1, 25 g. kg^-1 and 12.5 g. kg^-1) were prepared for each kind of extracts. Result showed that the water extracts with low and moderate concentrations accelerated the growth of collar diameter and increased biomass and root/shoot ratio of walnut seedlings. The water extracts from branches and barks with low and moderate concentrations accelerated the height growth of the seedlings, while those from leaves and roots slightly decreased the height growth of seedlings. The fact that application of water extracts of larch improved the growth of Manchurian walnut attributes possibly to the allelopathy between the two tree species. 相似文献
17.
Manuel Madeira António Fabião Marta Carneiro 《European Journal of Forest Research》2012,131(3):583-596
Effects of harrowing and fertilisation on tree growth, understory vegetation, forest floor litter and soil properties were
studied in a field experiment installed in a 5-year-old first rotation eucalypt plantation. The treatments were harrowing
(H), fertilisation (F), harrowing and fertilisation (HF) and a control without any treatments (C), with four replicates. Tree
growth, root mass, tree nutrition status, understory vegetation, mass of forest floor litter and soil physical and chemical
properties were monitored till the end of the rotation (stand was 14-year old). Effects of treatments on tree growth, root
mass and timber production were not significant. Root nutrient concentration differed between treatments only few months after
the beginning of the experiment, while differences regarding specific root length and area were observed during the first
year. Harrowing (H and HF) led to significantly smaller biomass of understory vegetation (<13.4 g m−2) than other treatments (33−61 g m−2) during the first 3 years, but at the end of the experiment differences were less important. Forest floor litter mass after
3 years and at the end of the experiment were similar among treatments. Soil bulk density significantly decreased by harrowing
(H and HF treatments), but 16 months after treatments were similar. Although soil chemical properties were not significantly
affected by treatments, a decrease in base cations occurred during the rotation period. Fertiliser application is a questionable
practice under the economic point of view, whereas harrowing can reduce the fuel load only during a short period, without
negative effects on productivity and soil quality. 相似文献
18.
We determined if callose formation in 1-cm-long root apices of European chestnut (Castanea sativa Mill.) seedlings is affected by naturally occurring high concentrations of aluminum (Al) under laboratory conditions and by low base saturation (BS) of soils under forest field conditions. Under controlled conditions in the laboratory, seedlings were treated with simulated soil solutions in the presence or absence (control) of Al. One day after exposing seedlings to a simulated soil solution containing 168 microM Al, callose formation in the root apices had increased significantly. After 7 days, callose concentration in root apices was significantly correlated with the concentration of free Al3+ ions recovered in the simulated soil solution and with the concentration of Al in fine roots. At four field sites in southern Switzerland, seedlings were grown for five months in either A-horizon soil with a BS above 17% or in a B-horizon soil with a BS below 5%. Callose concentrations were significantly higher in root apices in the B horizon than in the A horizon. Callose concentrations in root apices were negatively correlated with Ca/Al molar ratio in fine roots. We conclude that callose in the root apices of European chestnut could be a useful physiological parameter for assessing Al toxicity under both laboratory and field conditions. 相似文献
19.
Veiko Uri Krista Lõhmus Ivika Ostonen Hardi Tullus Renal Lastik Merit Vildo 《European Journal of Forest Research》2007,126(4):495-506
The above-ground biomass and production, below-ground biomass, nutrient (NPK) accumulation, fine roots and foliar characteristics
of a 8-year-old silver birch (Betula pendula) natural stand, growing on abandoned agricultural land in Estonia, were investigated. Total above-ground biomass and current
annual production after eight growing seasons was 31.2 and 11.9 t DM ha−1, respectively. The production of stems accounted for 62.4% and below-ground biomass accounted for 19.2% of the total biomass
of the stand. Carbon sequestration in tree biomass reaches roughly 17.5 t C ha−1 during the first 8 years. The biomass of the fine roots (d < 2 mm) was 1.7 ± 0.2 t DM ha−1 and 76.2% of it was located in the 20 cm topsoil layer. The leaf area index (LAI) of the birch stand was estimated as 3.7 m2 m−2 and specific leaf area (SLA) 15.0 ± 0.1 m2 kg−1. The impact of the crown layer on SLA was significant as the leaves are markedly thicker in the upper part of the crown compared
with the lower part. The short-root specific area (SRA) in the 30 cm topsoil was 182.9 ± 9.5 m2 kg−1, specific root length (SRL), root tissue density (RTD) and the number of short-root tips (>95% ectomycorrhizal) per dry mass
unit of short roots were 145.3 ± 8.6 m g−1, 58.6 ± 3.0 kg m−3 and 103.7 ± 5.5 tips mg−1, respectively. In August the amount of nitrogen, phosphorus and potassium, accumulated in above ground biomass, was 192.6,
25.0 and 56.6 kg ha−1, respectively. The annual flux of N and P retranslocation from the leaves to the other tree parts was 57.2 and 3.7 kg ha−1 yr−1 (55 and 27%), respectively, of which 29.1 kg ha−1 N and 2.8 kg ha−1 P were accumulated in the above-ground part of the stand. 相似文献
20.
Growth and physiological performance of multipurpose tree species can be severely constrained by low phosphorus (P) availability
in highly weathered soils. Limitations to plant growth are accentuated by seasonal dry periods. The overall objective of this
study was to examine P fertilization and irrigation effects on survival, growth, biomass partitioning, foliar nutrients, intrinsic
water-use efficiency (WUE) indexed by δ13C, Rhizobium nodulation, and carbohydrate content as an indicator of resprouting potential, of mimosa (Albizia julibrissin Durz.), a N2-fixing tree species being tested for browse in agroforestry practices in south-central USA. In a field experiment carried
out during two growing seasons near Booneville, Arkansas, USA, mimosa had a strong growth response to irrigation. The trial
was arranged in a split plot design with three replications with irrigation as main plot treatment and P as sub-plot treatment.
Mean total plant aboveground biomass at the end of the second growing season was 9.8 and 44.1 g plant−1 for the rainfed treatment without and with 300 mm of irrigation water, respectively. Placed P fertilization increased mean
total aboveground biomass from 19 g plant−1 for the 0-P treatment to 69 g plant−1 for the treatment with 90 kg P ha−1 year−1. Similarly, irrigation consistently increased stem basal diameter, total height, survival, root, stem, foliar and total aboveground
biomass, and number of nodules per plant. Phosphorus fertilization increased basal diameter, and root and stem biomass in
both irrigation treatments, survival and nodulation in the rainfed treatment, and foliar and total aboveground biomass in
the rainfed +300 mm irrigation treatment. There was a decrease of foliar δ13C suggesting that WUE decreased with P fertilization. In a pot experiment, seedlings were subjected to a factorial combination
of two irrigation treatments and six P levels in a randomized complete block design. Irrigation increased basal diameter,
root, stem, foliar and total biomass, leaf area and nodulation, whereas P fertilization (i.e., levels from 0 to 3.68 g P kg−1 soil) had similar effect in all the above variables except foliar biomass. Foliar P concentration to obtain 90% of the maximum
total plant biomass (critical level) was estimated at 0.157%. Total nonstructural and water soluble carbohydrate, and starch
concentrations increased non-linearly with irrigation and P addition suggesting impaired re-growth potential after defoliation
of seedlings with reduced water supply and at low soil P availability. Results of this study indicated strong limitations
for growth and regrowth potential of mimosa on a highly weathered soil with very low P availability and seasonal water content
shortages. Placed (i.e., near the plant base) application of P appeared to be a good strategy to fertilize perennial woody
plants. 相似文献