Qiufang Xu

Review of Carbon Fixation in Bamboo Forests in China

Bamboo is widespread in the subtropics and tropics of Asia, Africa, and Latin America. The total area of bamboo forests of various species is 22.0u2009×u2009106xa0ha, accounting for about 1.0% of the total global area of forest. Although the total forest areas in many countries have decreased drastically, bamboo forests have increased at a rate of 3% annually. China has the richest resources of bamboo in the world, with over 500 species in 39 genera. Carbon storage of vegetation, soils, and litter in bamboo forest system in China was 0.2511u2009×u20091015, 0.8516u2009×u20091015, and 0.0361u2009×u20091015xa0gxa0C, respectively, giving a total of 1.1388u2009×u20091015xa0gxa0C. This paper reviews carbon storage of vegetation, soils, and litter in bamboo forest system and compares the carbon fixation abilities of bamboo forest ecosystems with those of other tree species in subtropical China.

Dissolved soil organic carbon and nitrogen were affected by conversion of native forests to plantations in subtropical China

To better understand the impact of converting native forests to intensively managed plantations on soil carbon (C) and nitrogen (N) dynamics in subtropical China, we examined the seasonal patterns of water-soluble organic C (WSOC) and N (WSON) concentrations in soils in Chinese chestnut (Castanea mollissima Blume) (CF) and bamboo (Phyllostachys praecox C.D. Chu & C.S. Chou) plantation forests (BF) and adjacent native evergreen broadleaf forests (NF) in Ling-long Mountain, Zhejiang Province, China. The plantations were disturbed through surface soil removal and were fertilized and/or mulched, from which economic products (such as nuts and bamboo shoots) were annually harvested. We found that WSOC and WSON had large seasonal variations and were lower in the warmer than in the colder season. Average WSOC concentrations followed the order of BF (58.6) > NF (35.1) > CF (18.1 mg C kg-1), a pattern mainly caused by mulching in BF in winter and the removal of surface soil in CF. Soil total C and N followed the or...

Response of microbial community structure and function to short-term biochar amendment in an intensively managed bamboo (Phyllostachys praecox) plantation soil: Effect of particle size and addition rate

Biochar incorporated into soil has been known to affect soil nutrient availability and act as a habitat for microorganisms, both of which could be related to its particle size. However, little is known about the effect of particle size on soil microbial community structure and function. To investigate short-term soil microbial responses to biochar addition having varying particle sizes and addition rates, we established a laboratory incubation study. Biochar produced via pyrolysis of bamboo was ground into three particle sizes (diameter size<0.05mm (fine), 0.05-1.0mm (medium) and 1.0-2.0mm (coarse)) and amended at rates of 0% (control), 3% and 9% (w/w) in an intensively managed bamboo (Phyllostachys praecox) plantation soil. The results showed that the fine particle biochar resulted in significantly higher soil pH, electrical conductivity (EC), available potassium (K) concentrations than the medium and coarse particle sizes. The fine-sized biochar also induced significantly higher total microbial phospholipid fatty acids (PLFAs) concentrations by 60.28% and 88.94% than the medium and coarse particles regardless of addition rate, respectively. Redundancy analysis suggested that the microbial community structures were largely dependent of particle size, and that improved soil properties were key factors shaping them. The cumulative CO2 emissions from biochar-amended soils were 2-56% lower than the control and sharply decreased with increasing addition rates and particle sizes. Activities of α-glucosidase, β-glucosidase, β-xylosidase, N-acetyl-β-glucosaminidase, peroxidase and dehydrogenase decreased by ranging from 7% to 47% in biochar-amended soils over the control, indicating that biochar addition reduced enzyme activities involved carbon cycling capacity. Our results suggest that biochar addition can affect microbial population abundances, community structure and enzyme activities, that these effects are particle size and rate dependent. The fine particle biochar may additionally produce a better habitat for microorganisms compared to the other particle sizes.

Comparative Study of Carbon Storage in Different Forest Stands in Subtropical China

Selection and development of tree species with high fixing CO2 capacity is an increasing problem worldwide. A comparative study on carbon fixation ability of three forest stands was conducted at Linlong Mountain, Li’nan County, Zhejiang Province, China. The results showed that total carbon storage in the ecosystems of Moso bamboo, Chinese fir, and Masson pine stands were 104.83, 95.66, and 96.49xa0tu2009C/ha, respectively. The spatial distribution of carbon storage in the three ecosystems decreased in the order: soil > tree story > the vegetation under the forests. Carbon storage in the soils under Moso bamboo, Chinese fir, and Masson pine stands accounted for 65.3, 61.4, and 55.6% of the total CSs, respectively. The Moso bamboo forest ecosystem fixed 1.69 and 1.63 times as much C (9.64xa0tu2009C/ha/year) as the Chinese fir and Masson pine forest ecosystems, respectively.

Dynamics and Distribution of Nutrition Elements in Bamboos

ABSTRACT Mao bamboo (Phyllostachys pubescens) with a high production and wide utilization has been planted in large scale in southern China, but little information about bamboo nutrition is available. The objective of this study was to reveal the dynamics of nutrition with growing time and the distribution of nutrition in different organs. It was found that the nutrition concentration of the whole plant generally declined with time during the period of 1–6 weeks owing to a dilution effect with the result of quickly increasing the biomass. The leaf concentration of nitrogen (N), phosphorus (P), and potassium (K) changed regularly with high concentrations observed at age 1, 2, 4, and 6, and lower at age 3 and 5. While the concentration of N, P, and K in the branch and stem generally declined with the weeks, a rapid decrease occurred from weeks 1 to 2. The concentrations of calcium (Ca) and magnesium (Mg) in bamboo leaf, branch, and stem appeared to be opposite to those of N, P, and K in corresponding plant parts. The elemental concentrations were greater (P < 0.05) in the leaves than in the branches and stems, while the storage of nutrition was greater (P < 0.05) in stem than in leaves and branch. A relative large total storage of nutrition, except P and Mg, were found in bamboo under an intensive management (IM) stand than those under extensive management (EM) stand. The total storage of different nutritions in the above-ground parts was in the order: K (243.0–285.6 kg ha−1) > N (154.5–207.8 kg ha−1) > P (10.4–12.2 kg ha−1). The nutrition stored in the bamboo plant would be removed away from the soil in every other year by the means of harvest of the bamboo trunk which is the largest nutrition pool of the bamboo plant. Therefore, supplementary nutrients, especially N and K, are strongly recommended in order to keep the productivity of bamboo.

Soil Organic Carbon Accumulation in Intensively Managed Phyllostachys praecox Stands

Area of bamboo forest (Phyllostachys praecox) has rapidly increased in southern China during the last 20xa0years due to its high economic value. Aims of this study were to analyse the temporal and spatial variations of soil organic matter (SOM) in heavily winter mulched bamboo stands and to estimate potential for carbon sequestration. Total of 60 soil profiles with 0–15xa0years of bamboo plantation were sampled from three towns in Lin’an County. Results showed that with increased plantation years, SOM decreased slightly at the beginning (1–5xa0years), and then rose up steadily. Based on the average of the three locations, the highest SOM content of 75.82xa0g/kg was the surface layer (0–10xa0cm) of the 15xa0years. As plantation year increased, the variation of SOM in the surface layer (0–10xa0cm) was represented by a parabolic shape, and in the second layer (10–20xa0cm), it was a similar mode, but less vigorous. Soil organic carbon (SOC) storage significantly increased during 5 to 15xa0years after it reached full production, and the calculated annual SOC increment in 0–40xa0cm soil profile was about 6.3xa0tu2009C/ha/year. Therefore, extended Phyllostachys praecox forests can be considered as one option for countering CO2 emissions and regional climate change.

Bamboo invasion of broadleaf forests altered soil fungal community closely linked to changes in soil organic C chemical composition and mineral N production

AimsSoil fungi play an important role in decomposing soil organic matter and facilitating nutrient uptake by plants, however, the relationship between fungal community and soil biogeochemical cycling during plant invasion is poorly understood. The objective of this study was to investigate the effects of Moso bamboo (Phyllostachys edulis) invasion into broadleaf forests on the soil organic C (SOC) chemical composition, fungal community and mineral N production.MethodsWe collected soil samples in evergreen broadleaf forests, mixed bamboo-broadleaf forests and bamboo forests. Soil fungal community and SOC chemical composition were determined.ResultsBamboo invasion decreased alkyl C but increased O-alkyl C contents. Soil fungal abundance (18S rRNA) was decreased, while their alpha diversity was increased by bamboo invasion. Additionally, bamboo invasion enhanced net N mineralization rate but reduced gross nitrification rate. The fungal community composition strongly correlated with alkyl C content, and alkyl C content explained 32% of the variation in the fungal abundance. Fungal community composition correlated with gross nitrification rate, with 43% of the variation in gross nitrification rate attributable to soil fungal abundance.ConclusionsChanges in soil fungal community caused by bamboo invasion into broadleaf forests were closely linked to changed soil organic C chemical composition and decelerated nitrate production.

Shift in abundance and structure of soil ammonia-oxidizing bacteria and archaea communities associated with four typical forest vegetations in subtropical region

PurposeNitrogen (N) is one of the most important elements that can limit plant growth in forest ecosystems. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are considered as the key drivers of global N biogeochemical cycling. Soil ammonia-oxidizing microbial communities associated with subtropical vegetation remain poorly characterized. The aim of this study was to determine how AOA and AOB abundance and community structure shift in response to four typical forest vegetations in subtropical region.Materials and methodsBroad-leaved forest (BF), Chinese fir forest (CF), Pinus massoniana forest (PF), and moso bamboo forest (MB) were widely distributed in the subtropical area of southern China and represented typical vegetation types. Four types of forest stands of more than 30xa0years grew adjacent to each other on the same soil type, slope, and elevation, were chosen for this experiment. The abundance and community structure of AOA and AOB were characterized by using real-time PCR and denaturing gradient gel electrophoresis (DGGE). The impact of soil properties on communities of AOA and AOB was tested by canonical correspondence analysis (CCA).Results and discussionThe results indicated that AOB dominated in numbers over AOA in both BF and MB soils, while the AOA/AOB ratio shifted with different forest stands. The highest archaeal and bacterial amoA gene copy numbers were detected in CF and BF soils, respectively. The AOA abundance showed a negative correlation with soil pH and organic C but a positive correlation with NO3−−N concentration. The structures of AOA communities changed with vegetation types, but vegetation types alone would not suffice for shaping AOB community structure among four forest soils. CCA results revealed that NO3−−N concentration and soil pH were the most important environmental gradients on the distribution of AOA community except vegetation type, while NO3−−N concentration, soil pH, and organic C significantly affected the distribution of the AOB communities.ConclusionsThese results revealed the differences in the abundance and structure of AOA and AOB community associated with different tree species, and AOA was more sensitive to vegetation and soil chemical properties than AOB. N bioavailability could be directly linked to AOA and AOB community, and these results are useful for management activities, including forest tree species selection in areas managed to minimize N export to aquatic systems.

Bamboo forest expansion increases soil organic carbon through its effect on soil arbuscular mycorrhizal fungal community and abundance

AimsMoso bamboo (Phyllostachys pubescens) is a fast-growing species that can invade neighboring forests through its vigorous rhizome system, leading to large shifts of plant diversity and soil properties. A primary concern is the response of arbuscular mycorrhizal fungal (AMF) communities and related soil C sequestration to bamboo forest expansion.MethodsWe used a long-term soil chronosequence from primary broadleaved forest to moso bamboo forest to examine the changes in AMF abundance and communities, as well as their role in soil C storage.ResultsAMF communities showed strong niche differentiation, and were highly structured by forest type (r2xa0=xa00.648, Pxa0=xa00.001), and marginally correlated to soil pH and organic C. Bamboo forest expansion increased soil AMF biomass as indicated by neutral lipid fatty acids (NLFA) 16:1ω5 abundance, easily extracted glomalin-related soil protein (EE-GRSP), and water-stable macroaggregates. We observed that soil AMF biomass contributed substantially to both soil macroaggregates and EE-GRSP, which were tightly correlated with soil organic C. The influence of bamboo forest expansion on soil C sequestration was mainly due to its indirect effect on AMF biomass.ConclusionsBamboo forest expansion significantly changed soil AMF communities and increased AMF biomass, which in turn contributed to enhanced soil aggregation and C storage.

NUTRITIONAL DIAGNOSIS AND CORRECTION OF SHOOT DIEBACK OF RED BAYBERRY (MYRICA RUBRA SIEB. ET ZUCA)

Shoot dieback characterized by leaflet, rosette shoots, and dieback of shoot tips is one of the most important problems in red bayberry production in south China. However, the causes of shoot dieback have not been determined. The results of leaf analysis and correction experiment showed that leaf boron (B) concentrations were highly correlated with leaf area (P < 0.01), spring shoot length (P < 0.01), and spring shoot numbers sprouting from one old shoot (P < 0.05). Foliar application of B at 2.0 g L–1 of borax was more effective on correcting shoot dieback than foliar application of Zn at 2.0 g L–1 of zinc sulfate and of molybdenum (Mo) at 2.0 g L–1 of ammonium molybdate. Boron application increased fruit yields by 1.23–2.15 times compared with the control. Shoot dieback resulted mainly from B deficiency in the red bayberry trees.