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11 pages, 1355 KiB

Open AccessArticle

Distribution Changes of Phosphorus in Soil–Plant Systems of Larch Plantations across the Chronosequence

by Fanpeng Zeng, Xin Chen, Bin Huang and Guangyu Chi

Forests 2018, 9(9), 563; https://doi.org/10.3390/f9090563 - 13 Sep 2018

Cited by 8 | Viewed by 3457

Abstract

Phosphorus (P) is one of the most important factors influencing the growth and quality of larch plantations. A systematic knowledge of the dynamic changes of P in soil–plant systems can provide a theoretical basis for the sustainable development of larch plantations. We determined [...] Read more.

Phosphorus (P) is one of the most important factors influencing the growth and quality of larch plantations. A systematic knowledge of the dynamic changes of P in soil–plant systems can provide a theoretical basis for the sustainable development of larch plantations. We determined the concentration, biomass, and accumulation of P in five tree components (i.e., leaf, branch, bark, stem, and root), and the concentrations of various soil P fractions of larch plantations in 10-, 25-, and 50-year-old stands in northeast China. Our results showed that the N:P ratio and P concentration in leaves increased with stand age, indicating that the growth of larch plantations might be limited by P in the development of stands. The N:P ratio and P concentration in roots, and P resorption efficiency, increased with stand age, indicating the use efficiency of P could be enhanced in older stands. The concentrations of soil-labile P fractions (Resin-P, NaHCO₃-Pi, and NaHCO₃-Po) in 25- and 50-year-old stands were significantly lower than those in 10-year-old stands, indicating the availability of soil P decreases with the development of larch plantations. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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13 pages, 2105 KiB

Open AccessArticle

Joint Control of Net Primary Productivity by Climate and Soil Nitrogen in the Forests of Eastern China

by Zhan Xiaoyun, Guo Minghang and Zhang Tibin

Forests 2018, 9(6), 322; https://doi.org/10.3390/f9060322 - 4 Jun 2018

Cited by 7 | Viewed by 3656

Abstract

The nature and extent of climate and soil nutrient controls in Chinese forests remain poorly resolved. Here, we synthesized the data on carbon–climate–soil in eastern China, and litter N was firstly taken into consideration, to examine the variation of net primary productivity (NPP) [...] Read more.

The nature and extent of climate and soil nutrient controls in Chinese forests remain poorly resolved. Here, we synthesized the data on carbon–climate–soil in eastern China, and litter N was firstly taken into consideration, to examine the variation of net primary productivity (NPP) and its driving forces. Results showed that NPP had significant latitude pattern and varied substantially across climate zones. Bivariate analyses indicated that mean annual temperature (MAT), mean annual precipitation (MAP), soil N content (N_soil), and annual litter N (N_re) were the main controlling factors in spatial pattern of forest NPP. Notably, partial general linear model analysis revealed that MAT, MAP, and N_re jointly explained 84.8% of the spatial variation of NPP. Among the three major factors, N_re explained more variation of forest NPP than the other two factors, and MAT and MAP affected NPP mainly through the change of litter N rather than via themselves, highlighting the importance of litter N in estimating forest NPP. However, to accurately describe the pattern of forest NPP in China, more detailed field measurements and methodologies on NPP and relevant confounding factors should be addressed in future studies. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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14 pages, 1956 KiB

Open AccessArticle

Characterization of Phosphorus in a Toposequence of Subtropical Perhumid Forest Soils Facing a Subalpine Lake

by Yo-Jin Shiau, Chung-Wen Pai, Jeng-Wei Tsai, Wen-Cheng Liu, Rita S. W. Yam, Shih-Chieh Chang, Sen-Lin Tang and Chih-Yu Chiu

Forests 2018, 9(6), 294; https://doi.org/10.3390/f9060294 - 25 May 2018

Cited by 7 | Viewed by 4325

Abstract

The productivity of forests is often considered to be limited by the availability of phosphorus (P). Knowledge of the role of organic and inorganic P in humid subtropical forest soils is lacking. In this study, we used chemical fractionation and ³¹P nuclear [...] Read more.

The productivity of forests is often considered to be limited by the availability of phosphorus (P). Knowledge of the role of organic and inorganic P in humid subtropical forest soils is lacking. In this study, we used chemical fractionation and ³¹P nuclear magnetic resonance (NMR) spectroscopy to characterize the form of P and its distribution in undisturbed perhumid Taiwan false cypress (Chamaecyparis formosensis Matsum.) forest soils. The toposequence of transects was investigated for the humic layer from summit to footslope and lakeshore. The clay layer combined with a placic-like horizon in the subsoil may affect the distribution of soil P because both total P and organic P (P_o) contents in all studied soils decreased with soil depth. In addition, P_o content was negatively correlated with soil crystalline Fe oxide content, whereas inorganic P (P_i) content was positively correlated with soil crystalline Fe oxide content and slightly increased with soil depth. Thus, P_i may be mostly adsorbed by soil crystalline Fe oxides in the soils. Among all extractable P fractions, the NaOH-P_o fraction appeared to be the major component, followed by NaHCO₃-P_o; the resin-P and HCl-P_i fractions were lowest. In addition, we found no typical trend for P_i and P_o contents in soils with topographical change among the three sites. From the ³¹P-NMR spectra, the dominant P_o form in soils from all study sites was monoesters with similar spectra. The ³¹P-NMR findings were basically consistent with those from chemical extraction. Soil formation processes may be the critical factor affecting the distribution of soil P. High precipitation and year-round high humidity may be important in the differentiation of the P species in this landscape. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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21 pages, 1365 KiB

Open AccessArticle

Soil Chemical Attributes, Biometric Characteristics, and Concentrations of N and P in Leaves and Litter Affected by Fertilization and the Number of Sprouts per the Eucalyptus L’Hér. Strain in the Brazilian Cerrado

by Natasha M. I. Godoi, Sabrina N. dos S. Araújo, Salatiér Buzetti, Rodolfo De N. Gazola, Thiago De S. Celestrino, Alexandre C. da Silva, Thiago A. R. Nogueira and Marcelo C. M. Teixeira Filho

Forests 2018, 9(6), 290; https://doi.org/10.3390/f9060290 - 24 May 2018

Cited by 2 | Viewed by 3442

Abstract

Given the lack of recommendations for the fertilization of Eucalyptus clones in the second production cycle, the effects of fertilizer rates and the number of sprouts per strain in terms of the soil chemical attributes, biometric characteristics, and the concentrations of N and [...] Read more.

Given the lack of recommendations for the fertilization of Eucalyptus clones in the second production cycle, the effects of fertilizer rates and the number of sprouts per strain in terms of the soil chemical attributes, biometric characteristics, and the concentrations of N and P in the leaves and in the litter of Eucalyptus L’Hér. in the Brazilian Cerrado were evaluated. The experimental design was a randomized block with four replicates, arranged in a 2 × 4 factorial scheme: one or two sprouts per strain; four fertilizer rates (0, 50, 100, or 200% of 200 kg ha⁻¹ of the formula 06-30-06 + 1.5% Cu + 1% Zn) applied immediately after sprout definition. The option of one sprout per strain yielded higher contents of organic matter (K, S, B, and Mn) in the 0.20–0.40-m layer, the leaf chlorophyll index, the diameter at breast height, and the height of the Eucalyptus 44 months after the definition of sprouts. However, N and P leaf concentrations and the wood volume did not differ as a function of the sprout numbers. The fertilizer dosage did not influence the wood volume, even in sandy soil with low fertility. Approximately 86% of the wood volume was obtained from the supply of soil and root nutrient reserves and 14% of this productivity is due to fertilization minerals. The adequate fertilization in the first cycle of the Eucalyptus supplies almost the entire nutritional demand of the forest in the second production cycle. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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13 pages, 1316 KiB

Open AccessArticle

Changes in Soil Enzyme Activities and Microbial Biomass after Revegetation in the Three Gorges Reservoir, China

by Qingshui Ren, Hong Song, Zhongxun Yuan, Xilu Ni and Changxiao Li

Forests 2018, 9(5), 249; https://doi.org/10.3390/f9050249 - 4 May 2018

Cited by 24 | Viewed by 4598

Abstract

Soil enzymes and microbes are central to the decomposition of plant and microbial detritus, and play important roles in carbon, nitrogen, and phosphorus biogeochemistry cycling at the ecosystem level. In the present study, we characterized the soil enzyme activity and microbial biomass in [...] Read more.

Soil enzymes and microbes are central to the decomposition of plant and microbial detritus, and play important roles in carbon, nitrogen, and phosphorus biogeochemistry cycling at the ecosystem level. In the present study, we characterized the soil enzyme activity and microbial biomass in revegetated (with Taxodium distichum (L.) Rich. and Cynodon dactylon (L.) Pers.) versus unplanted soil in the riparian zone of the Three Gorges Dam Reservoir (TGDR), in order to quantify the effect of revegetation on the edaphic microenvironment after water flooding in situ. After revegetation, the soil physical and chemical properties in revegetated soil showed significant differences to those in unplanted soil. The microbial biomass carbon and phosphorus in soils of T. distichum were significantly higher than those in C. dactylon and unplanted soils, respectively. The microbial biomass nitrogen in revegetated T. distichum and C. dactylon soils was significantly increased by 273% and 203%, respectively. The enzyme activities of T. distichum and C. dactylon soils displayed no significant difference between each other, but exhibited a great increase compared to those of the unplanted soil. Elements ratio (except C/N (S)) did not vary significantly between T. distichum and C. dactylon soils; meanwhile, a strong community-level elemental homeostasis in the revegetated soils was found. The correlation analyses demonstrated that only microbial biomass carbon and phosphorus had a significantly positive relationship with soil enzyme activities. After revegetation, both soil enzyme activities and microbial biomasses were relatively stable in the T. distichum and C. dactylon soils, with the wooded soil being more superior. The higher enzyme activities and microbial biomasses demonstrate the C, N, and P cycling and the maintenance of soil quality in the riparian zone of the TGDR. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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12 pages, 4787 KiB

Open AccessArticle

Soil Nitrogen Responses to Soil Core Transplanting Along an Altitudinal Gradient in an Eastern Tibetan Forest

by Li Zhang, Ao Wang, Fuzhong Wu, Zhenfeng Xu, Bo Tan, Yang Liu, Yulian Yang, Lianghua Chen and Wanqin Yang

Forests 2018, 9(5), 239; https://doi.org/10.3390/f9050239 - 2 May 2018

Cited by 1 | Viewed by 3019

Abstract

To understand the differential effects of altitudinal gradient on soil inorganic nitrogen concentration and associated ammonia-oxidizingbacteria (AOB) and archaea (AOA), intact soil cores from a primary coniferous forest were in situ incubated in an alpine forest at a 3582-m altitude (A1) and transplanted [...] Read more.

To understand the differential effects of altitudinal gradient on soil inorganic nitrogen concentration and associated ammonia-oxidizingbacteria (AOB) and archaea (AOA), intact soil cores from a primary coniferous forest were in situ incubated in an alpine forest at a 3582-m altitude (A1) and transplanted to subalpine forests at a 3298-m altitude (A2) and 3023-m altitude (A3) on the eastern Tibetan Plateau. Transplant cooled the soil temperature of A2 but warmed the A3 soil temperature. Both AOA and AOB were found at the three altitudes. Compared to A1, A2 had greater AOA and AOB abundance, but A3 showed lower AOA abundance in organic soil. The AOA abundance was negatively correlated with ammonium concentration at all three altitudes, but AOB showed the reverse trend. Our results suggested that the soil nitrogen process responded differentially to soil core transplanting at different altitudes. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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10 pages, 1485 KiB

Open AccessArticle

Interstorm Variability in the Biolability of Tree-Derived Dissolved Organic Matter (Tree-DOM) in Throughfall and Stemflow

by Daniel H. Howard, John T. Van Stan, Ansley Whitetree, Lixin Zhu and Aron Stubbins

Forests 2018, 9(5), 236; https://doi.org/10.3390/f9050236 - 1 May 2018

Cited by 20 | Viewed by 5387

Abstract

Dissolved organic matter (DOM) drives carbon (C) cycling in soils. Current DOM work has paid little attention to interactions between rain and plant canopies (including their epiphytes), where rainfall is enriched with tree-derived DOM (tree-DOM) prior to reaching the soil. Tree-DOM during storms [...] Read more.

Dissolved organic matter (DOM) drives carbon (C) cycling in soils. Current DOM work has paid little attention to interactions between rain and plant canopies (including their epiphytes), where rainfall is enriched with tree-derived DOM (tree-DOM) prior to reaching the soil. Tree-DOM during storms reaches soils as throughfall (drip through canopy gaps and from canopy surfaces) and stemflow (rainwater drained down the trunk). This study (1) assessed the susceptibility of tree-DOM to the consumption by microbes (biolability); (2) evaluated interstorm variability in the proportion and decay kinetics of biolabile tree-DOM (tree-BDOM), and (3) determined whether the presence of arboreal epiphytes affected tree-BDOM. Tree-BDOM from Juniperus virginiana L. was determined by subjecting throughfall and stemflow samples from five storms to 14-day microbial incubations. Tree-DOM was highly biolabile, decreasing in concentration by 36–73% within 1–4 days. Tree-BDOM yield was 3–63 mg-C m⁻² mm⁻¹ rainfall, which could represent 33–47% of annual net ecosystem exchange in Georgia (USA) forests. Amount and decay kinetics of tree-BDOM were not significantly different between throughfall versus stemflow, or epiphyte-covered versus bare canopy. However, epiphyte presence reduced water yields which reduced tree-BDOM yields. Interstorm proportions, rates and yields of tree-BDOM were highly variable, but throughfall and stemflow consistently contained high tree-BDOM proportions (>30%) compared to previously-published litter and soil leachate data (10–30%). The high biolability of tree-DOM indicates that tree-BDOM likely provides C subsidies to microbial communities at the forest floor, in soils and the rhizosphere. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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14 pages, 1709 KiB

Open AccessArticle

Effects of Near Natural Forest Management on Soil Greenhouse Gas Flux in Pinus massoniana (Lamb.) and Cunninghamia lanceolata (Lamb.) Hook. Plantations

by Angang Ming, Yujing Yang, Shirong Liu, Hui Wang, Yuanfa Li, Hua Li, You Nong, Daoxiong Cai, Hongyan Jia, Yi Tao and Dongjing Sun

Forests 2018, 9(5), 229; https://doi.org/10.3390/f9050229 - 26 Apr 2018

Cited by 22 | Viewed by 4425

Abstract

Greenhouse gases are the main cause of global warming, and forest soil plays an important role in greenhouse gas flux. Near natural forest management is one of the most promising options for improving the function of forests as carbon sinks. However, its effects [...] Read more.

Greenhouse gases are the main cause of global warming, and forest soil plays an important role in greenhouse gas flux. Near natural forest management is one of the most promising options for improving the function of forests as carbon sinks. However, its effects on greenhouse gas emissions are not yet clear. It is therefore necessary to characterise the effects of near natural forest management on greenhouse gas emissions and soil carbon management in plantation ecosystems. We analysed the influence of near natural management on the flux of three major greenhouse gases (carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)) in Pinus massoniana Lamb. and Cunninghamia lanceolata (Lamb.) Hook. plantations. The average emission rates of CO₂ and N₂O in the near natural plantations were higher than those in the corresponding unimproved pure plantations of P. massoniana and C. lanceolata, and the average absorption rate of CH₄ in the pure plantations was lower than that in the near natural plantations. The differences in the CO₂ emission rates between plantations could be explained by differences in the C:N ratio of the fine roots. The differences in the N₂O emission rates could be attributed to differences in soil available N content and the C:N ratio of leaf litter, while the differences in CH₄ uptake rate could be explained by differences in the C:N ratio of leaf litter only. Near natural forest management negatively affected the soil greenhouse gas emissions in P. massoniana and C. lanceolata plantations. The potential impact of greenhouse gas flux should be considered when selecting tree species for enrichment planting. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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18 pages, 1964 KiB

Open AccessArticle

Discriminating between Seasonal and Chemical Variation in Extracellular Enzyme Activities within Two Italian Beech Forests by Means of Multilevel Models

by Antonietta Fioretto, Michele Innangi, Anna De Marco, Cristina Menta, Stefania Papa, Antonella Pellegrino and Amalia Virzo De Santo

Forests 2018, 9(4), 219; https://doi.org/10.3390/f9040219 - 19 Apr 2018

Cited by 12 | Viewed by 3727

Abstract

Enzymes play a key-role in organic matter dynamics and strong scientific attention has been given to them lately, especially to their response to climate and substrate chemical composition. Accordingly, in this study, we investigated the effects of chemical composition and seasons on extracellular [...] Read more.

Enzymes play a key-role in organic matter dynamics and strong scientific attention has been given to them lately, especially to their response to climate and substrate chemical composition. Accordingly, in this study, we investigated the effects of chemical composition and seasons on extracellular enzyme activities (laccase, peroxidase, cellulase, chitinase, acid phosphomonoesterase, and dehydrogenase) by means of multilevel models within two Italian mountain beech forests. We used chemical variables as the fixed part in the model, season as random variation and layers (decomposition continuum for leaf litter and 0–5, 5–15, 15–30, and 30–40 cm for soil) as nested factors within the two forests. Our results showed that seasonal changes explained a higher amount of variance in enzyme activities compared to substrate chemistry in leaf litter, whereas chemical variation had a stronger impact on soil. Moreover, the effect of seasonality and chemistry was in general larger than the differences between forest sites, soils, and litter layers. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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14 pages, 6937 KiB

Open AccessArticle

Tropical Tree Species Effects on Soil pH and Biotic Factors and the Consequences for Macroaggregate Dynamics

by Ann E. Russell, Stephanie N. Kivlin and Christine V. Hawkes

Forests 2018, 9(4), 184; https://doi.org/10.3390/f9040184 - 4 Apr 2018

Cited by 15 | Viewed by 5430

Abstract

Physicochemical and biotic factors influence the binding and dispersivity of soil particles, and thus control soil macroaggregate formation and stability. Although soil pH influences dispersivity, it is usually relatively constant within a site, and thus not considered a driver of aggregation dynamics. However, [...] Read more.

Physicochemical and biotic factors influence the binding and dispersivity of soil particles, and thus control soil macroaggregate formation and stability. Although soil pH influences dispersivity, it is usually relatively constant within a site, and thus not considered a driver of aggregation dynamics. However, land-use change that results in shifts in tree-species composition can result in alteration of soil pH, owing to species-specific traits, e.g., support of nitrogen fixation and Al accumulation. In a long-term, randomized complete block experiment in which climate, soil type, and previous land-use history were similar, we evaluated effects of individual native tropical tree species on water-stable macroaggregate size distributions in an Oxisol. We conducted this study at La Selva Biological Station in Costa Rica, in six vegetation types: 25-year-old plantations of four tree species grown in monodominant stands; an unplanted Control; and an adjacent mature forest. Tree species significantly influenced aggregate proportions in smaller size classes (0.25–1.0 mm), which were correlated with fine-root growth and litterfall. Tree species altered soil pH differentially. Across all vegetation types, the proportion of smaller macroaggregates declined significantly as soil pH increased (p ≤ 0.0184). This suggests that alteration of pH influences dispersivity, and thus macroaggregate dynamics, thereby playing a role in soil C, N, and P cycling. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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12 pages, 17348 KiB

Open AccessArticle

Regional Scale Determinants of Nutrient Content of Soil in a Cold-Temperate Forest

by Shusheng Yuan, Tongtong Tang, Minchao Wang, Hao Chen, Aihua Zhang and Jinghua Yu

Forests 2018, 9(4), 177; https://doi.org/10.3390/f9040177 - 30 Mar 2018

Cited by 5 | Viewed by 3466

Abstract

The effect of climatic factors on soil nutrients is significant. Identifying whether soil nutrients respond to local climate and how the forest types modulate this responsiveness is critical for forest management. Therefore, six soil nutrients from five main forest types found for a [...] Read more.

The effect of climatic factors on soil nutrients is significant. Identifying whether soil nutrients respond to local climate and how the forest types modulate this responsiveness is critical for forest management. Therefore, six soil nutrients from five main forest types found for a range of sites within the Daxing’an Mountains, China, were investigated. Climatic factors were obtained from the WorldClim dataset. Pearson correlations and stepwise regressions were employed to elucidate and model the response of the six soil nutrients to the four different climatic factors in this study. On the whole, climate was correlated with all the nutrients. Further, from stepwise regressions, climatic factors could affect soil nutrients in distinct forests. Our findings suggest that climatic factors are instrumental in affecting soil nutrients in different forest types. Identifying the relationships between soil nutrients, climatic factors and forest types, as suggested in this research, can provide theoretical foundations to further comprehend nutrient cycling in the forest ecosystem. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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17 pages, 3064 KiB

Open AccessArticle

Seasonal Effects on Microbial Community Structure and Nitrogen Dynamics in Temperate Forest Soil

by Tomohiro Yokobe, Fujio Hyodo and Naoko Tokuchi

Forests 2018, 9(3), 153; https://doi.org/10.3390/f9030153 - 19 Mar 2018

Cited by 43 | Viewed by 6341

Abstract

The soil microbial community and nitrogen (N) dynamics change seasonally due to several factors. The microbial community structure (MCS) can regulate N dynamics. However, there is insufficient information on seasonal changes in MCS and the relationship between MCS and N dynamics. We investigated [...] Read more.

The soil microbial community and nitrogen (N) dynamics change seasonally due to several factors. The microbial community structure (MCS) can regulate N dynamics. However, there is insufficient information on seasonal changes in MCS and the relationship between MCS and N dynamics. We investigated MCS and N dynamics in forest soils with two different fertilities throughout a year. MCS, measured with phospholipid fatty acid (PLFA) analysis, showed a consistent seasonal trend, regardless of the fertility. Microbial indices (particularly the Saturated-/monounsaturated-PLFA ratio; Sat/mono) indicated a major PLFA shift among seasons, with temperature likely the most important factor. The fungal-/bacterial-PLFA ratio in the dormant season (December–April) was approximately 1.3 times greater than in the growing season (June–November). The trend in N dynamics showed that in summer (June–August), the gross N mineralization potential was greater than immobilization, whereas in winter (December–April), immobilization was dominant. The net mineralization potential in the growing season was approximately 1.6 times higher than in the dormant season. Moreover, a relationship was found between Sat/mono and N transformation potentials. We highlight the microbial sensitivity to seasonal dynamics which can be associated with temperature, as well as carbon and N dynamics. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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16 pages, 1410 KiB

Open AccessFeature PaperArticle

Charcoal Increases Microbial Activity in Eastern Sierra Nevada Forest Soils

by Zachary W. Carter, Benjamin W. Sullivan, Robert G. Qualls, Robert R. Blank, Casey A. Schmidt and Paul S.J. Verburg

Forests 2018, 9(2), 93; https://doi.org/10.3390/f9020093 - 16 Feb 2018

Cited by 7 | Viewed by 4283

Abstract

Fire is an important component of forests in the western United States. Not only are forests subjected to wildfires, but fire is also an important management tool to reduce fuels loads. Charcoal, a product of fire, can have major impacts on carbon (C) [...] Read more.

Fire is an important component of forests in the western United States. Not only are forests subjected to wildfires, but fire is also an important management tool to reduce fuels loads. Charcoal, a product of fire, can have major impacts on carbon (C) and nitrogen (N) cycling in forest soils, but it is unclear how these effects vary by dominant vegetation. In this study, soils collected from Jeffrey pine (JP) or lodgepole pine (LP) dominated areas and amended with charcoal derived from JP or LP were incubated to assess the importance of charcoal on microbial respiration and potential nitrification. In addition, polyphenol sorption was measured in unamended and charcoal-amended soils. In general, microbial respiration was highest at the 1% and 2.5% charcoal additions, but charcoal amendment had limited effects on potential nitrification rates throughout the incubation. Microbial respiration rates decreased but potential nitrification rates increased over time across most treatments. Increased microbial respiration may have been caused by priming of native organic matter rather than the decomposition of charcoal itself. Charcoal had a larger stimulatory effect on microbial respiration in LP soils than JP soils. Charcoal type had little effect on microbial processes, but polyphenol sorption was higher on LP-derived than JP-derived charcoal at higher amendment levels despite surface area being similar for both charcoal types. The results from our study suggest that the presence of charcoal can increase microbial activity in soils, but the exact mechanisms are still unclear. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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2057 KiB

Open AccessArticle

Soil Degradation and the Decline of Available Nitrogen and Phosphorus in Soils of the Main Forest Types in the Qinling Mountains of China

by Xiaofeng Zheng, Jie Yuan, Tong Zhang, Fan Hao, Shibu Jose and Shuoxin Zhang

Forests 2017, 8(11), 460; https://doi.org/10.3390/f8110460 - 21 Nov 2017

Cited by 15 | Viewed by 4706

Abstract

Soil degradation has been reported worldwide. To better understand this degradation, we selected Pinus armandii and Quercus aliena var. acuteserrata forests, and a mixed forest of Q. aliena var. acuteserrata and P. armandii in the Qinling Mountains in China for our permanent plots [...] Read more.

Soil degradation has been reported worldwide. To better understand this degradation, we selected Pinus armandii and Quercus aliena var. acuteserrata forests, and a mixed forest of Q. aliena var. acuteserrata and P. armandii in the Qinling Mountains in China for our permanent plots and conducted three investigations over a 20-year period. We determined the amounts of available nitrogen (N) and phosphorus (P) in the soil to track the trajectory of soil quality and compared these with stand characteristics, topographic and climatic attributes to analyze the strength of each factor in influencing the available N and P in the soil. We found that the soil experienced a severe drop in quality, and that degradation is continuing. Temperature is the most critical factor controlling the soil available N, and species composition is the main factor regulating the soil available P. Given the huge gap in content and the increasing rate of nutrients loss, this reduction in soil quality will likely negatively affect ecosystem sustainability. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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2983 KiB

Open AccessArticle

Soil Organic Matter Accumulation and Carbon Fractions along a Moisture Gradient of Forest Soils

by Ewa Błońska and Jarosław Lasota

Forests 2017, 8(11), 448; https://doi.org/10.3390/f8110448 - 17 Nov 2017

Cited by 30 | Viewed by 7263

Abstract

The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a [...] Read more.

The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a regular grid of points (100 × 300 m). Each plot was represented by one soil profile located at the plot’s center. Sample plots were located in the area with Gleysols, Cambisols and Podzols with the water table from 0 to 100 cm. In each soil sample, particle size, total carbon and nitrogen content, acidity, base cations content and fractions of soil organic matter were determined. The organic carbon stock (SOCs) was calculated based on its total content at particular genetic soil horizons. A Carbon Distribution Index (CDI) was calculated from the ratio of the carbon accumulation in organic horizons and the amount of organic carbon accumulation in the mineral horizons, up to 60 cm. In the soils under study, in the temperate zone, moisture is an important factor in the accumulation of organic carbon in the soil. The highest accumulation of carbon was observed in soils of swampy variant, while the lowest was in the soils of moist variant. Large accumulation of C in the soils with water table 80–100 cm results from the thick organic horizons that are characterized by lower organic matter decomposition and higher acidity. The proportion of carbon accumulation in the organic horizons to the total accumulation in the mineral horizons expresses the distribution of carbon accumulated in the soil profile, and is a measure of quality of the organic matter accumulated. Studies have confirmed the importance of moisture content in the formation of the fractional organic matter. With greater soil moisture, the ratio of humic to fulvic acids (HA/FA) decreases, which may suggest an increase in carbon mobility in soils. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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Review

Jump to: Research

18 pages, 1953 KiB

Open AccessFeature PaperReview

Enrichment Planting and Soil Amendments Enhance Carbon Sequestration and Reduce Greenhouse Gas Emissions in Agroforestry Systems: A Review

by Bharat M. Shrestha, Scott X. Chang, Edward W. Bork and Cameron N. Carlyle

Forests 2018, 9(6), 369; https://doi.org/10.3390/f9060369 - 20 Jun 2018

Cited by 27 | Viewed by 7506

Abstract

Agroforestry practices that intentionally integrate trees with crops and/or livestock in an agricultural production system could enhance carbon (C) sequestration and reduce greenhouse gas (GHG) emissions from terrestrial ecosystems, thereby mitigating global climate change. Beneficial management practices such as enrichment planting and the [...] Read more.

Agroforestry practices that intentionally integrate trees with crops and/or livestock in an agricultural production system could enhance carbon (C) sequestration and reduce greenhouse gas (GHG) emissions from terrestrial ecosystems, thereby mitigating global climate change. Beneficial management practices such as enrichment planting and the application of soil amendments can affect C sequestration and GHG emissions in agroforestry systems; however, such effects are not well understood. A literature review was conducted to synthesize information on the prospects for enhancing C sequestration and reducing GHG emissions through enrichment (i.e., in-fill) tree planting, a common practice in improving stand density within existing forests, and the application of organic amendments to soils. Our review indicates that in agroforests only a few studies have examined the effect of enrichment planting, which has been reported to increase C storage in plant biomass. The effect of adding organic amendments such as biochar, compost and manure to soil on enhancing C sequestration and reducing GHG emissions is well documented, but primarily in conventional crop production systems. Within croplands, application of biochar derived from various feedstocks, has been shown to increase soil organic C content, reduce CO₂ and N₂O emissions, and increase CH₄ uptake, as compared to no application of biochar. Depending on the feedstock used to produce biochar, biochar application can reduce N₂O emission by 3% to 84% as compared to no addition of biochars. On the other hand, application of compost emits less CO₂ and N₂O as compared to the application of manure, while the application of pelleted manure leads to more N₂O emission compared to the application of raw manure. In summary, enrichment planting and application of organic soil amendments such as compost and biochar will be better options than the application of raw manure for enhancing C sequestration and reducing GHG emissions. However, there is a shortage of data to support these practices in the field, and thus further research on the effect of these two areas of management intervention on C cycling will be imperative to developing best management practices to enhance C sequestration and minimize GHG emissions from agroforestry systems. Full article

(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)

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