Next Article in Journal
Comparing Regression and Classification Models to Estimate Leaf Spot Disease in Peanut (Arachis hypogaea L.) for Implementation in Breeding Selection
Previous Article in Journal
Influence of EMR–Phosphogypsum–Biochar Mixtures on Sudan Grass: Growth Dynamics and Heavy Metal Immobilization
Previous Article in Special Issue
Yield, Protein Content and Water-Related Physiologies of Spring Wheat Affected by Fertilizer System and Weather Conditions
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Agronomy
Volume 14
Issue 5
10.3390/agronomy14050946
agronomy-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Active Soil Organic Carbon Pools Decrease with Increased Time since Land-Use Transition from Rice Paddy Cultivation to Areca Nut Plantations under the Long-Term Application of Inorganic Fertilizer

by
Yunxing Wan
1,
Qilin Zhu
1,
Lijun Liu
2,
Shuirong Tang
1,
Yanzheng Wu
2,
Xiaoqian Dan
2,
Lei Meng
1,
Qiuxiang He
2,*,
Ahmed S. Elrys
2 and
Jinbo Zhang
1
1
School of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, China
2
School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
*
Author to whom correspondence should be addressed.
Agronomy 2024, 14(5), 946; https://doi.org/10.3390/agronomy14050946
Submission received: 29 March 2024 / Revised: 26 April 2024 / Accepted: 29 April 2024 / Published: 30 April 2024
(This article belongs to the Special Issue Exploring the Potential for Crop Productivity by Applying Novel Agrochemicals, including Fertilizers, Biochar, Biostimulants, and Plant Nutrition Regulators)
Browse Figures
Versions Notes

Abstract

:
Many croplands in the tropics of China have been converted over the last decades into areca nut plantations due to their high economic returns. This land-use transition was accompanied by changes in agricultural practices such as soil moisture regimes and fertilizer inputs, which may affect soil organic carbon (SOC) and its fractions, especially in tropical soils with low fertility and high nitrogen loss. Yet, how the time since land-use transition from rice paddy cultivation to areca nut plantations affects soil carbon dynamics and their underlying mechanisms in the tropics of China remains elusive. Here, areca nut plantation soils with different ages (2, 5, 10, 14, and 17 years) and paddy fields in the tropical region of China were investigated. The study result indicates that the contents of dissolved organic carbon (DOC), particulate organic carbon (POC), easily oxidized organic carbon (EOC), light organic carbon (LFOC), and microbial biomass carbon (MBC) decreased significantly with increased time since land-use transition from rice paddy cultivation to areca nut plantations. Similarly, the ratios of DOC/SOC, MBC/SOC, POC/SOC, LFOC/SOC, and EOC/SOC decreased significantly with increased time since land-use transition. Compared with the paddy soil, the carbon pool management index decreased by 36.6–76.7% under the areca nut plantations, concluding that increasing the time since land-use transition from rice paddy cultivation to areca nut plantations with high application rates of chemical fertilizers resulted in reduced soil active carbon fractions and SOC supply capacity. Therefore, agricultural practices such as the use of organic fertilizers should be applied to improve the soil’s ability to supply organic carbon in managed plantation ecosystems in the tropics of China.

1. Introduction

The areca nut, a perennial evergreen woody plant of the Palmaceae, is one of the most important commercial crops in the tropics and has substantial economic value [1]. In recent years, areca nut has become the second largest commercial crop in the tropics of China, with an area of approximately 102,500 ha, making it the primary economic source in this region [2]. Over the last decades, many croplands in the tropics of China have been converted into areca nut plantations due to their high economic returns [3]. For example, many paddy fields were converted into areca nut plantations in Hainan province, which was accompanied by changes in agricultural practices (e.g., soil moisture and fertilizer inputs) [4]. To increase profit, excess fertilizers and water were used in areca nut plantations than paddy fields; however, nitrogen (N) fertilization may cause soil degradation, nitrogen leaching, and low water and nitrogen use efficiency, especially under high temperature and moisture conditions, ultimately negatively affecting the crop yield [5]. Long-term planting of areca nut not only reduces the yield but also adversely impacts the transformation of soil nutrients [5]. Increasing soil carbon (C) storage, which is an important index to measure soil quality, is beneficial to increasing renewable water resources, promoting crop yield, improving biodiversity, and strengthening element cycling [6]. Maintaining and improving soil C content is crucial for the sustainability of areca nut plantations [1]. Thus, exploring the impact of land-use transition from rice paddy cultivation to areca nut plantations on C stocks and its potential mechanisms in tropical soils is important for agricultural management to improve areca nut production and soil C sequestration.
Soil organic carbon (SOC) is generally divided into stable and active C pools [7]. Stable C fractions, whose turnover time can be thousands of years, are not affected by land use or human interference [8]. Active organic C, however, is highly susceptible to mineralization and decomposition [8]. Although soil reactive C fractions (e.g., soil particulate organic C (POC), light fraction organic C (LFOC), dissolved organic C (DOC), and easily oxidizable organic C (EOC) account for a low proportion of total SOC; they are more sensitive to land-use change and can better reflect soil C pools balance and soil fertility [2]. Previous studies have generally focused on how the conversion of croplands to natural ecosystems leads to an increase in SOC storage [9]. For instance, converting croplands to forests resulted in an increase of 18–19% in SOC storage globally [10]. In contrast, previous studies reported that the conversion of paddy fields to dry land significantly reduced SOC and its fractions [11]. Concomitantly, increased soil moisture may improve conditions for microorganisms, resulting in enhanced decomposition of soil organic matter [12]. Yet, it is still unclear how the content of SOC and its fractions change over time after converting paddy fields into areca nut plantations in the tropical region of China.
The fertilizer application rate of paddy fields is generally low, and paddy fields have higher soil C content due to long-term flooding [4]. However, in order to achieve high yield and efficiency, the fertilization inputs of areca nut plantations must be higher than those of paddy fields [4]. Differences in management practices (e.g., soil moisture and fertilizer inputs) between paddy and areca nuts resulted in significant differences in soil properties [13]. The higher long-term application of inorganic N has resulted in a severe loss of soil nutrients and a significant reduction in organic C in areca nut cultivation. Previous studies have reported that long-term N, phosphorus (P), and potassium (K) fertilization decreased the SOC content of organic pools [14]. In addition, soil C sequestration capacity decreases with reducing soil moisture content [15]. Previous studies have reported that the contents of DOC and EOC were significantly increased due to the high water content in paddy fields [16], mainly due to reduced soil organic matter decomposition [17]. However, the low water supply in areca nut plantations is not conducive to soil C sequestration [18]. Yet, it remains unknown how and why the time since land-use transition from rice paddy cultivation to areca nut plantations affects soil SOC and active C fractions. We hypothesized that active soil organic C pools decrease with increased time since land-use transition from rice paddy cultivation to areca nut plantations due to long-term fertilization.
To address the above hypothesis, soil samples from areca nuts plantations, which were converted from tropical paddy fields, with different plantation ages (2, 4, 5, 10, 14, and 17 years) were collected. The current study aims to evaluate how and why SOC and its fractions change over time after converting tropical paddy soils to areca nut plantations.

2. Materials and Methods

2.1. Soil Samples Site

The study site was located in Beishan village (19°6′ N, 110°32′ E) in the southeast of Hainan province, China, where paddy and areca nut plantations were mainly cultivated. It has a tropical monsoon climate, with an average annual rainfall of 2000 mm and an average annual temperature of 24.3 °C. The soils in this area are Ultisols, according to the FAO classification. In this study, rice fields were converted to areca nut plantations, and all areca nut plantations with different conversion ages received the same management practices. The content of nutrients for different fertilization treatments is presented in Table 1.
In June 2023, soil samples were collected from farms that converted from rice fields to areca nut plantations 2, 4, 5, 10, 14, and 17 years ago (hereinafter referred to as A2, A5, A10, A14, and A17, respectively). Soil samples from adjacent paddy fields were collected and used as a control. Three replicates for each areca nut plantation and the paddy soil were selected. At each site, five plots (approximately 1 × 1 m) were selected and randomly sampled over 20 cm. Litters were removed from the soil prior to sampling, then a sample of the topsoil (0–20 cm) was taken using a soil auger with a diameter of 5 cm, and then all samples were mixed to form a composite sample. Litter, roots, and other impurities present in the composite sample were removed, and the soil was then sieved (2 mm mesh).

2.2. Soil Properties Analysis

The soil’s physical and chemical properties were analyzed according to the Soil and Agricultural Chemistry Analysis [19]. The pH of the soil sample was measured using a pH meter at a soil/water ratio of 1:2.5 (w/w). The SOC was determined using the potassium dichromate–sulfuric acid external heating method. The soil total nitrogen (TN) was determined using the semi-micro-Kjeldahl method. The soil-available potassium (AK) was determined using a flame photometer, while the soil-available phosphorus (AP) was determined using the molybdenum blue colorimetry method.

2.3. Determination of Soil Active Organic C

Soil microbial biomass C (MBC) and N (MBN) were determined by the chloroform fumigation method [20]. Soil-dissolved organic C (DOC) was determined using the method described by Zsolnay [21] by a Shimadzu automatic SOC analyzer. Determination of light fraction organic C (LFOC) was performed by the density gradient method described by Gregorich [22]. Easily oxidizable soil organic C (EOC) was determined using the KMnO4 oxidation method [23]. Particulate organic C (POC) was determined by the particle size method described by Camberdella and Elliott [24].

2.4. Calculation of the Soil Carbon Pool Management Index

The soil C pool management index (CPMI) was calculated as follows [25]:
CPMI = CPI × LI × 100
where CPI is the C pool index and LI is the C pool activity index, and they are computed as follows:
CPI = SOCs × SOCr−1
where SOCs and SOCr are the SOC content of a given treatment and the reference soil, respectively. In this experiment, the paddy field was used as the reference soil.
LI = Ls × Lr−1
where Ls and Lr−1 represent the C pool activity of the treatment and reference soil (the paddy field), respectively.
L = EOC × NLC−1
where L is the carbon pool activity. EOC is the content of easily oxidizable organic C, while NLC refers to nonlabile C, which is the content of inactive organic C, calculated as the difference between SOC and EOC.

2.5. Statistical Analysis

The experimental data were collated using Excel 2021. The one-way analysis of variance and multiple comparisons (p < 0.05) were performed using IBM SPSS 25.0 statistical software. Correlation analysis was performed using bivariate correlation analyses and curve-fitting methods. Structural equation models (SEMs) were constructed using AMOS software (version 25) to examine the effects of land utilization type on soil properties and C components.

3. Results

3.1. Soil Physicochemical and Biological Properties

Our study showed that SOC concentration was significantly higher in the rice cultivations (20.87 g C kg−1; Table 2) than in the areca nut plantations (11.92–17.05 g C kg−1). Soil pH, TN, AK, MBC, and MBN were also significantly higher in the rice cultivations than in the areca nut plantations, but the opposite was true for AP and NH4+ concentrations (Table 2). The soil C/N ratio tended to increase in response to land-use change from rice cultivations to areca nut plantations, especially at A14 and A17. The results also showed that MBC and MBN significantly decreased with increased time since land-use transition from rice paddy cultivations to areca nut plantations (Table 2).

3.2. Active SOC Pools

We found that land-use transition from rice paddy cultivations to areca nut plantations significantly increased all studied active SOC pools (DOC, EOC, POC, and LFOC) in the short term (e.g., A2) but decreased them in the long term (e.g., A5–A17) (Figure 1). Active SOC pools in the second year of transition from rice cultivation to areca increase and after that decrease in time. At the same time, SOC decreased in the second year in all the studied years (Table 3).

3.3. Relationship between SOC and Its Fractions and Environmental Factors

Our study revealed that SOC increased significantly with increasing the time since land-use transition (p < 0.01; Figure 2a). However, DOC and DOC/SOC, MBC and MBC/SOC, POC and POC/SOC, LFOC and LFOC/SOC, and EOC and EOC/SOC decreased significantly with increased time since land-use transition (p < 0.01; Figure 2b–k). Soil NH4+ concentration had a significant and positive relationship with DOC and MBC (p < 0.01; Figure 2o,p). Soil MBC content increased significantly with increased DOC, POC, and soil pH (p < 0.01; Figure 2l–n). Soil DOC had a significant and positive relationship with EOC, POC, and, soil pH (p < 0.01; Figure 2q–s). Soil EOC was positively correlated to LFOC (p < 0.01; Figure 2t). We also found that SOC had a significant and positive correlation with NLC and CPI (p < 0.001; Figure 3). The EOC, LFOC, DOC, POC, and MBC were positively correlated to LI and CPMI (p < 0.001; Figure 3). The structural equation model (SEM) showed that land-use transition indirectly reduced LFOC, POC, and MBC, as well as EOC, by decreasing TN and soil pH and increasing the soil’s C/N ratio.

3.4. Areca Nut Plantations Reduced Soil Organic C Supply Capacity

The NLC and CPI were significantly decreased after the paddy field was converted into areca nut plantations (Table 4). Compared with paddy fields, the NLC and CPI were significantly decreased by 30–45% and 18–43%, respectively, in response to land-use transition. Similarly, the CPMI was significantly decreased in response to land-use transition (Table 4). Compared with paddy fields, the CPMI was significantly decreased by 36.6%, 76.7%, 73.3%, 68.3%, and 52.9% at A2, A5, A10, A14, and A17, respectively.

4. Discussion

This study showed that the conversion of paddy fields to areca nut plantations significantly reduced SOC content. Although the long-term land-use transition (e.g., A14 and A17) significantly increased SOC content relative to the short-term transition (e.g., A2–A10), significant reductions in active C fractions with increased time since land-use transition were observed. The decrease in TN and soil pH and the increase in soil C/N ratio were the main reasons for the reduction in active SOC pools and SOC supply capacity in response to land-use change. These findings are significant for implementing appropriate agricultural management to improve and maintain SOC stocks in areca nut plantations.
We mainly focused on the mechanism of SOC supply capacity degradation under land-use change. Combining soil physicochemical properties with soil C fractions can more intuitively show the main factors influencing the SOC supply capacity under land-use change (Figure 4). The results of this study confirm that the SOC and MBC were significantly reduced by the conversion of paddy fields to areca nut plantations (Table 1). Short soil flooding time increases soil aeration and the number of aerophilic microorganisms, which ultimately may accelerate the decomposition of soil organic matter after the conversion of rice fields to areca nut plantations [26]. In addition, the conversion of rice fields to areca nut plantations resulted in a decrease in root exudation, plant residue, and soil animal and microbial activities, decreasing SOC and MBC [27]. This study also showed that the DOC (A5–A17) decreased significantly with the conversion of paddy fields to areca nut plantations (Figure 1). The reason may be that about 50–70% of DOC is adsorbed by iron and aluminum oxides and hydroxides, resulting in increased DOC in paddy fields [28]. The POC is an energy source and unstable organic C reservoir for microorganisms [29]. The results of this study show that POC decreased significantly (A5–A17) after the conversion of paddy fields to areca forests (Figure 1). Our results show a significant and positive correlation between soil pH and POC (Figure 3 and Figure 4). The decrease in microbial activity caused by long-term flooding and the decrease in soil pH caused by long-term fertilization leads to a decrease in soil POC content [30]. Previous studies have also reported that LFOC is affected by organic matter input and decomposition rate [31]. The EOC is directly involved in the nutrient supply of plants and microorganisms, which is the most available component of SOC [32]. The results show that soil TN and POC were significantly positively correlated with LFOC and EOC, respectively (Figure 3 and Figure 4). Moreover, the conversion of paddy fields to areca nut plantations significantly decreased the LFOC and EOC (A5–A17) (Figure 1). This may be due to the high temperature and rapid decomposition of large amounts of straw and roots in paddy fields increasing the content of TN and POC, which resulted in the accumulation of LFOC and EOC [33]. On the other hand, most areca plantations are roughly managed, with less tree litter and sparse understorey vegetation, resulting in a reduction in the LFOC and EOC [34]. The DOC, EOC, POC, and LFOC in A2 were significantly higher than in paddy fields (Figure 1). The reason is that in the short term, the residue of straw and root system in paddy fields will supplement the SOC content, resulting in an increase in the contents of DOC, EOC, POC, and LFOC [35].
Soil DOC, MBC, LFOC, and EOC were significantly positively correlated with pH (Figure 3). Soil POC and MBC are directly affected by pH (Figure 4). In this study, soil POC and MBC decreased with the increased age of areca nut plantations (Figure 1). In addition, The POC/SOC and MBC/SOC ratios showed the same trends as the POC and MBC concentrations, which showed that the long-term planting of areca nut resulted in a decrease in soil POC and MBC concentrations. This may be related to soil acidification due to long-term fertilization, which affects soil structure and its microbial activity [36]. Soil POC and MBC were influenced by soil structure and soil permeability [9]. Previous studies have reported that POC accumulates under the physical protection of the stable structure of soil aggregates [37]. Good air permeability can promote soil fertility, which increases microbial activity [38]. The proliferation of soil microbes significantly increases the MBC content of the soil [39]. Our study also revealed that soil POC and MBC decreased significantly with the increased age of areca nut plantations. This may be due to the fact that areca nut plantation management is no-till, with poor soil aggregate structure and permeability [40].
In agricultural production, CPMI is one of the most commonly used soil management indicators, which helps to reveal the response of organic C to changes in soil management practices and serves as a comprehensive measure of the quantity and quality of organic C. The higher the CPMI of the soil, the higher the SOC content, and the greater the nutrient storage in the organic matter [41]. The conversion of paddy fields to areca nut plantations not only reduced SOC and EOC (A5–A17) but also significantly reduced CPMI contents (Table 3). The CPMI decreased significantly with the increase in the planting age of areca plantations. It showed an increasing trend at A10 but was significantly lower than that of the paddy fields. Rice cultivation is conducive to maintaining and improving the soil C pool management index, which is related to the relatively slow decomposition and transformation of organic C due to the lack of oxygen under flood conditions [42]. From the calculation formula of the soil C pool management index, it can be seen that the decrease in SOC and EOC will lead to a decrease in the soil C pool management index. Therefore, the management of long-term areca nut plantations should have some measures, such as increasing the application of organic fertilizer, to increase soil organic matter.

5. Conclusions

The effects of the time since land-use transition from rice paddy cultivation to areca nut plantations on soil organic carbon and its fractions were studied through an incubation study. The easily oxidized organic carbon, light organic carbon, particulate organic carbon, microbial biomass carbon, and dissolved organic carbon decreased with the increased age of areca nut plantations. The decreases in soil pH and soil total nitrogen were the main factors leading to the decrease in soil organic carbon and its fractions. Long-term areca nut plantations decreased the soil C pool management index, which was mainly related to the decrease in soil organic matter and pH. Therefore, agricultural practices such as lime and organic fertilization can be applied to improve soil’s ability to supply organic C. The study of soil organic carbon fractions is essential for achieving sustainable agricultural development.

Author Contributions

Conceptualization, Y.W. (Yunxing Wan), Q.Z., L.M. and Q.H.; investigation, Y.W. (Yunxing Wan), X.D., S.T. and Y.W. (Yanzheng Wu); formal analysis, Y.W. (Yunxing Wan), L.L., Y.W. (Yanzheng Wu), J.Z. and A.S.E.; software, L.L., X.D. and Q.H.; supervision, S.T. and J.Z.; writing—original draft, Y.W. (Yunxing Wan), L.L., X.D., Y.W. (Yanzheng Wu) and S.T.; writing—review and editing, Y.W. (Yunxing Wan), Q.Z., L.M., Q.H., J.Z. and A.S.E. All authors have read and agreed to the published version of the manuscript.

Funding

Financial support for this work was provided by the National Natural Science Foundation of China (42067008) and the High-Level Talent Project of the Natural Science Foundation of Hainan province (320RC493).

Data Availability Statement

Data is contained within the article.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Salehi, B.; Konovalov, D.A.; Fru, P.; Kapewangolo, P.; Peron, G.; Ksenija, M.S.; Cardoso, S.M.; Pereira, O.R.; Nigam, M.; Nicola, S.; et al. Areca catechu—From farm to food and biomedical applications. Phytother. Res. 2020, 34, 2140–2158. [Google Scholar] [CrossRef]
  2. Yuan, J.; Zhang, H.; Zhao, H.; Ren, H.; Zhai, H. Study on Dissociation and Chemical Structural Characteristics of Areca Nut Husk. Molecules 2023, 28, 1513. [Google Scholar] [CrossRef]
  3. Lu, H.; Bai, Y.; Ren, H.; Campbell, D.E. Integrated emergy, energy and economic evaluation of rice and vegetable production systems in alluvial paddy fields: Implications for agricultural policy in China. J. Environ. Manag. 2010, 91, 2727–2735. [Google Scholar] [CrossRef]
  4. Zhu, Q.; Liu, L.; Li, K.; Wen, C.; Li, M.; Fan, C.; Zhu, T.; Shen, Q.; Wu, Y.; Tang, S.; et al. Decrease in soil inorganic nitrogen supply capacity under long-term areca nut plantations in the tropics. Land Degrad. Dev. 2022, 33, 3926–3937. [Google Scholar] [CrossRef]
  5. Dai, Z.; Fei, L.; Huang, D.; Zeng, J.; Chen, L.; Cai, Y. Coupling effects of irrigation and nitrogen levels on yield, water and nitrogen use efficiency of surge-root irrigated jujube in a semiarid region. Agric. Water Manag. 2019, 213, 146–154. [Google Scholar] [CrossRef]
  6. Choudhury, B.U.; Ansari, M.A.; Chakraborty, M.; Meetei, T.T. Effect of land-use change along altitudinal gradients on soil micronutrients in the mountain ecosystem of Indian (Eastern) Himalaya. Sci. Rep. 2021, 11, 14279. [Google Scholar] [CrossRef]
  7. Bhat, R.; Sujatha, S. Soil fertility and nutrient uptake by arecanut (Areca catechu L.) as affected by level and frequency of fertigation in a laterite soil. Agric. Water Manag. 2009, 96, 445–456. [Google Scholar] [CrossRef]
  8. Stockmann, U.; Adams, M.A.; Crawford, J.W.; Field, D.J.; Henakaarchchi, N.; Jenkins, M.; Minasny, B.; McBratney, A.B.; de Courcelles, V.d.R.; Singh, K.; et al. The knowns, known unknowns and unknowns of sequestration of soil organic carbon. Agric. Ecosyst. Environ. 2013, 164, 80–99. [Google Scholar] [CrossRef]
  9. Six, J.; Conant, R.T.; Paul, E.A.; Paustian, K. Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils. Plant Soil 2002, 241, 155–176. [Google Scholar] [CrossRef]
  10. Zhang, Y.; Liao, X.; Wang, Z.; Wei, X.; Jia, X.; Shao, M. Synchronous sequestration of organic carbon and nitrogen in mineral soils after conversion agricultural land to forest. Agric. Ecosyst. Environ. 2020, 295, 106866. [Google Scholar] [CrossRef]
  11. Saha, S.K.; Ramachandran Nair, P.K.; Nair, V.D.; Kumar, B.M. Carbon storage in relation to soil size-fractions under tropical tree-based land-use systems. Plant Soil 2010, 328, 433–446. [Google Scholar] [CrossRef]
  12. Trost, B.; Ellmer, F.; Baumecker, M.; Meyer-Aurich, A.; Prochnow, A.; Drastig, K. Effects of irrigation and nitrogen fertilizer on yield, carbon inputs from above ground harvest residues and soil organic carbon contents of a sandy soil in Germany. Soil Use Manag. 2014, 30, 209–218. [Google Scholar] [CrossRef]
  13. Zhang, X.; Xiao, G.; Bol, R.; Wang, L.; Zhuge, Y.; Wu, W.; Li, H.; Meng, F. Influences of irrigation and fertilization on soil N cycle and losses from wheat–maize cropping system in northern China. Environ. Pollut. 2021, 278, 116852. [Google Scholar] [CrossRef]
  14. Dou, X.; He, P.; Cheng, X.; Zhou, W. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses. Sci. Rep. 2016, 6, 19061. [Google Scholar] [CrossRef] [PubMed]
  15. Jiang, Z.; Yang, S.; Ding, J.; Sun, X.; Chen, X.; Liu, X.; Xu, J. Modeling Climate Change Effects on Rice Yield and Soil Carbon under Variable Water and Nutrient Management. Sustainability 2021, 13, 568. [Google Scholar] [CrossRef]
  16. Li, Z.; Zhao, B.; Zhang, J. Effects of maize residue quality and soil water content on soil labile organic carbon fractions and microbial properties. Pedosphere 2016, 26, 829–838. [Google Scholar] [CrossRef]
  17. Duan, H.; Wang, L.; Zhang, Y.; Fu, X.; Tsang, Y.; Wu, J.; Le, Y. Variable decomposition of two plant litters and their effects on the carbon sequestration ability of wetland soil in the Yangtze River estuary. Geoderma 2018, 319, 230–238. [Google Scholar] [CrossRef]
  18. Shi, A.; Yan, N.; Marschner, P. Cumulative respiration in two drying and rewetting cycles depends on the number and distribution of moist days. Geoderma 2015, 243–244, 168–174. [Google Scholar] [CrossRef]
  19. Bao, S.D. Soil and Agricultural Chemistry Analysis; China Agricultural Press: Beijing, China, 2000. [Google Scholar]
  20. Vance, E.D.; Brookes, P.C.; Jenkinson, D.S. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem. 1987, 19, 703–707. [Google Scholar] [CrossRef]
  21. Zsolnay, Á. Dissolved organic matter: Artefacts, definitions, and functions. Geoderma 2003, 113, 187–209. [Google Scholar] [CrossRef]
  22. Gregorich, E.G.; Janzen, H.H. Storage of soil carbon in the light fraction and macroorganic matter. In Structure and Organic Matter Storage in Agricultural Soils; CRC Press: Boca Raton, FL, USA, 2020; pp. 167–190. [Google Scholar]
  23. Gu, C.; Liu, Y.; Mohamed, I.; Zhang, R.; Wang, X.; Nie, X.; Jiang, M.; Brooks, M.; Chen, F.; Li, Z. Dynamic changes of soil surface organic carbon under different mulching practices in citrus orchards on sloping land. PLoS ONE 2016, 11, e0168384. [Google Scholar] [CrossRef]
  24. Cambardella, C.A.; Elliott, E.T. Particulate Soil Organic-Matter Changes across a Grassland Cultivation Sequence. Soil Sci. Soc. Am. J. 1992, 56, 777–783. [Google Scholar] [CrossRef]
  25. Huang, B.; Zhang, L.; Cao, Y.; Yang, Y.; Ping, W.; Li, Z.; Lin, Y. Effects of land-use type on soil organic carbon and carbon pool management index through arbuscular mycorrhizal fungi pathways. Glob. Ecol. Conserv. 2023, 43, e02432. [Google Scholar] [CrossRef]
  26. Zhang, Y.F.; Zhao, S.W.; Li, X.X.; Luo, Z.D.; Wang, Z.L. The influence of aggregate stability and characteristics of SOC functional groups in anthropogenic-alluvial soil under different land use patterns. J. Soil Water Conserv. 2015, 29, 169–174. [Google Scholar]
  27. Liao, H.; Long, J.; Li, J. Conversion of cropland to Chinese prickly ash orchard affects soil organic carbon dynamics in a karst region of southwest China. Nutr. Cycl. Agroecosystems 2016, 104, 15–23. [Google Scholar] [CrossRef]
  28. Kindler, R.; Siemens, J.A.N.; Kaiser, K.; Walmsley, D.C.; Bernhofer, C.; Buchmann, N.; Cellier, P.; Eugster, W.; Gleixner, G.; Grũnwald, T.; et al. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance. Glob. Chang. Biol. 2011, 17, 1167–1185. [Google Scholar] [CrossRef]
  29. Liao, L.; Wang, J.; Lei, S.; Zhang, L.; Ye, Z.; Liu, G.; Zhang, C. Differential effects of nitrogen addition on the organic carbon fractions of rhizosphere and bulk soil based on a pot experiment. J. Soils Sediments 2023, 23, 103–117. [Google Scholar] [CrossRef]
  30. Liu, F.; Qin, S.; Fang, K.; Chen, L.; Peng, Y.; Smith, P.; Yang, Y. Divergent changes in particulate and mineral-associated organic carbon upon permafrost thaw. Nat. Commun. 2022, 13, 5073. [Google Scholar] [CrossRef] [PubMed]
  31. Yang, X.; Meng, J.; Lan, Y.; Chen, W.; Yang, T.; Yuan, J.; Liu, S.; Han, J. Effects of maize stover and its biochar on soil CO2 emissions and labile organic carbon fractions in Northeast China. Agric. Ecosyst. Environ. 2017, 240, 24–31. [Google Scholar] [CrossRef]
  32. Han, X.; Liu, X.; Li, Z.; Li, J.; Yuan, Y.; Li, H.; Zhang, L.; Liu, S.; Wang, L.; You, C.; et al. Characteristics of Soil Organic Carbon Fractions and Stability along a Chronosequence of Cryptomeria japonica var. sinensis Plantation in the Rainy Area of Western China. Forests 2022, 13, 1663. [Google Scholar] [CrossRef]
  33. Wang, Y.; Gao, S.; Li, C.; Zhang, J.; Wang, L. Effects of temperature on soil organic carbon fractions contents, aggregate stability and structural characteristics of humic substances in a Mollisol. J. Soils Sediments 2016, 16, 1849–1857. [Google Scholar] [CrossRef]
  34. Baude, M.; Meyer, B.C.; Schindewolf, M. Land use change in an agricultural landscape causing degradation of soil based ecosystem services. Sci. Total. Environ. 2019, 659, 1526–1536. [Google Scholar] [CrossRef] [PubMed]
  35. Yuan, G.; Huan, W.; Song, H.; Lu, D.; Chen, X.; Wang, H.; Zhou, J. Effects of straw incorporation and potassium fertilizer on crop yields, soil organic carbon, and active carbon in the rice–wheat system. Soil Tillage Res. 2021, 209, 104958. [Google Scholar] [CrossRef]
  36. Chen, X.; Liu, J.; Deng, Q.; Yan, J.; Zhang, D. Effects of elevated CO2 and nitrogen addition on soil organic carbon fractions in a subtropical forest. Plant Soil 2012, 357, 25–34. [Google Scholar] [CrossRef]
  37. Wang, L.; Gao, C.; Yang, K.; Sheng, Y.; Xu, J.; Zhao, Y.; Lou, J.; Sun, R.; Zhu, L. Effects of biochar aging in the soil on its mechanical property and performance for soil CO2 and N2O emissions. Sci. Total Environ. 2021, 782, 146824. [Google Scholar] [CrossRef] [PubMed]
  38. McLatchey, G.P.; Reddy, K.R. Regulation of Organic Matter Decomposition and Nutrient Release in a Wetland Soil. J. Environ. Qual. 1998, 27, 1268–1274. [Google Scholar] [CrossRef]
  39. He, H.; Peng, M.; Lu, W.; Ru, S.; Hou, Z.; Li, J. Organic fertilizer substitution promotes soil organic carbon sequestration by regulating permanganate oxidizable carbon fractions transformation in oasis wheat fields. Catena 2023, 221, 106784. [Google Scholar] [CrossRef]
  40. Cavalieri, K.M.V.; da Silva, A.P.; Tormena, C.A.; Leão, T.P.; Dexter, A.R.; Håkansson, I. Long-term effects of no-tillage on dynamic soil physical properties in a Rhodic Ferrasol in Paraná, Brazil. Soil Tillage Res. 2009, 103, 158–164. [Google Scholar] [CrossRef]
  41. Lin, S.; Wang, W.; Vancov, T.; Lai, D.Y.F.; Wang, C.; Wiesmeier, M.; Jin, Q.; Liu, X.; Fang, Y. Soil carbon, nutrients and their stoichiometry decrement in relation to paddy field degradation: Investigation in a subtropical region. Catena 2022, 217, 106484. [Google Scholar] [CrossRef]
  42. García-Campos, E.; Zorita, F.; Leirós, M.C.; Gil-Sotres, F.; Trasar-Cepeda, C. Evaluation of C Stocks in Afforested High Quality Agricultural Land. Forests 2022, 13, 2055. [Google Scholar] [CrossRef]
Agronomy 14 00946 g001
Figure 1. Effects of different land uses on the content of organic C fractions. The 2, 5, 10, 14, and 17 represent the cultivation durations of the areca nut plantations. DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, and MBC: soil microbial carbon. Different lowercase letters in the figure represent significant differences between treatments (p < 0.05). In the results of two-factor ANOVA, U represents different utilization methods and A represents time treatment. U × A represents the interaction effect of different utilization modes and time processing; NS: no significant difference; **: p < 0.01. (a–d) indicates the subgraph number in the caption.
Figure 1. Effects of different land uses on the content of organic C fractions. The 2, 5, 10, 14, and 17 represent the cultivation durations of the areca nut plantations. DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, and MBC: soil microbial carbon. Different lowercase letters in the figure represent significant differences between treatments (p < 0.05). In the results of two-factor ANOVA, U represents different utilization methods and A represents time treatment. U × A represents the interaction effect of different utilization modes and time processing; NS: no significant difference; **: p < 0.01. (a–d) indicates the subgraph number in the caption.
Agronomy 14 00946 g001
Agronomy 14 00946 g002
Figure 2. Correlation between planting years of areca nut and organic C and its fractions. Plant age represents the cultivation durations of the areca nut plantations. TOC: soil organic carbon, NH4+: soil ammonium-nitrogen, DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, and MBC: soil microbial carbon. (a–t) indicates the subgraph number in the caption.
Figure 2. Correlation between planting years of areca nut and organic C and its fractions. Plant age represents the cultivation durations of the areca nut plantations. TOC: soil organic carbon, NH4+: soil ammonium-nitrogen, DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, and MBC: soil microbial carbon. (a–t) indicates the subgraph number in the caption.
Agronomy 14 00946 g002
Agronomy 14 00946 g003
Figure 3. Correlation analysis of soil organic C and its fractions to soil properties. * Significant correlation at 0.05; ** Significant correlation at 0.01; *** Significant correlation at 0.001. SOC: soil organic carbon, DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, MBC: soil microbial carbon, NLC: nonlabile carbon, LI: carbon pool activity index, CPI: carbon pool index, CPMI: carbon pool management index, TN: soil total nitrogen, C/N: carbon to nitrogen ratio, NH4+: soil ammonium–nitrogen, NO3−: soil nitrate–nitrogen, CEC: soil cation exchange capacity, WHC: water-holding capacity, AP: soil available phosphorus, AK: soil available potassium.
Figure 3. Correlation analysis of soil organic C and its fractions to soil properties. * Significant correlation at 0.05; ** Significant correlation at 0.01; *** Significant correlation at 0.001. SOC: soil organic carbon, DOC: dissolved organic carbon, EOC: easily oxidizable organic carbon, POC: particulate organic carbon, LFOC: light fraction organic carbon, MBC: soil microbial carbon, NLC: nonlabile carbon, LI: carbon pool activity index, CPI: carbon pool index, CPMI: carbon pool management index, TN: soil total nitrogen, C/N: carbon to nitrogen ratio, NH4+: soil ammonium–nitrogen, NO3−: soil nitrate–nitrogen, CEC: soil cation exchange capacity, WHC: water-holding capacity, AP: soil available phosphorus, AK: soil available potassium.
Agronomy 14 00946 g003
Agronomy 14 00946 g004
Figure 4. Direct and indirect effects of soil properties and soil C fractions on soil C pool under land-use change. TN: soil total nitrogen, SOC: soil organic carbon, C/N: carbon to nitrogen ratio, POC: particulate organic carbon, LFOC: light fraction organic carbon, MBC: soil microbial carbon, and EOC: easily oxidizable organic carbon. Line width indicates normalized path coefficient strength. Black arrows and red arrows indicate positive and negative significant relationships. χ2/df, chi−square/degrees of freedom; p, probability level; GFI, goodness−of−fit index; RMSEA, root mean squared error of approximation. Significance levels of each predictor are p < 0.01. * Significant correlation at 0.05; ** Significant correlation at 0.01; (a,b) indicates the subgraph number in the caption.
Figure 4. Direct and indirect effects of soil properties and soil C fractions on soil C pool under land-use change. TN: soil total nitrogen, SOC: soil organic carbon, C/N: carbon to nitrogen ratio, POC: particulate organic carbon, LFOC: light fraction organic carbon, MBC: soil microbial carbon, and EOC: easily oxidizable organic carbon. Line width indicates normalized path coefficient strength. Black arrows and red arrows indicate positive and negative significant relationships. χ2/df, chi−square/degrees of freedom; p, probability level; GFI, goodness−of−fit index; RMSEA, root mean squared error of approximation. Significance levels of each predictor are p < 0.01. * Significant correlation at 0.05; ** Significant correlation at 0.01; (a,b) indicates the subgraph number in the caption.
Agronomy 14 00946 g004
Table 1. Fertilizer inputs (kg ha−1y−1) of the treatments in soil tested.
Table 1. Fertilizer inputs (kg ha−1y−1) of the treatments in soil tested.
Land UseUreaSuper-PhosphatePotassium OxideRice Straw
(kg ha−1 y−1)(kg ha−1 y−1)(kg ha−1 y−1)(kg ha−1 y−1)
Paddy180–20080–100150–2001000–2000
A2350–400220–260200–250without
A5350–400220–260200–250without
A10350–400220–260200–250without
A14350–400220–260200–250without
A17350–400220–260200–250without
The A2, A5, A10, A14, and A17 represent the cultivation durations of the areca nut plantations.
Table 2. Soil basic properties of studied soils under different land uses.
Table 2. Soil basic properties of studied soils under different land uses.
ParameterPaddyA2A5A10A14A17
SOC (g C kg−1)20.87 ± 0.41 a11.92 ± 0.65 d13.14 ± 0.33 cd12.16 ± 0.38 d14.63 ± 0.87 c17.05 ± 1.49 b
TN (g N kg−1)1.92 ± 0.05 a1.26 ± 0.17 c1.22 ± 0.02 c1.15 ± 0.05 c1.31 ± 0.07 c1.51 ± 0.11 b
C/N10.86 ± 0.08 ab9.60 ± 1.42 b10.75 ± 0.08 ab10.6 ± 0.36 ab11.20 ± 0.07 a11.26 ± 0.19 a
NH4+ (mg kg−1)15.46 ± 1.00 a8.71 ± 1.59 b7.31 ± 0.40 bc6.65 ± 0.81 c5.81 ± 0.13 c5.99 ± 0.53 c
NO3− (mg kg−1)3.93 ± 0.4 c8.86 ± 0.35 bc12.27 ± 2.54 ab16.49 ± 3.79 a11.33 ± 3.13 ab5.34 ± 0.23 c
pH5.8 ± 0.01 a5.48 ± 0.16 b5.04 ± 0.01 c4.68 ± 0.16 c4.84 ± 0.14 c5.34 ± 0.23 c
CEC (mmol kg−1)4.03 ± 2.61 a3.99 ± 2.50 a4.75 ± 1.31 a3.88 ±7.71 a4.03 ± 5.04 a4.39 ± 6.41 a
AP (mg kg−1)34.78 ± 7.67 c119.20 ± 11.8 a116.89 ± 9.86 a127.37 ± 6.67 a79.13 ± 4.92 b87.50 ± 6.11 b
AK (mg kg−1)392.30 ± 0.00 a146.39 ± 2.43 d146.13 ± 6.28 d260.03 ± 14.4 b134.34 ± 28.4 d180.89 ± 8.88 c
MBC (mg kg−1)242.31 ± 10.1 a191.94 ± 9.17 b135.27 ± 13.7 c112.61 ± 0.94 d85.84 ± 4.15 e83.62 ± 4.89 e
MBN (mg kg−1)35.11 ± 4.11 a23.76 ± 4.37 d19.93 ± 4.94 bc14.36 ± 0.83 cd11.97 ± 0.55 d11.22 ± 0.94 d
The A2, A5, A10, A14, and A17 represent the cultivation durations of the areca nut plantations. SOC: soil organic carbon, TN: soil total nitrogen, C/N: carbon to nitrogen ratio, NH4+: soil ammonium–nitrogen, NO3−: soil nitrate–nitrogen, CEC: soil cation exchange capacity, AP: soil available phosphorus, AK: soil available potassium, MBC: soil microbial carbon, and MBN: soil microbial nitrogen. Values are mean ± standard error (n = 3). Different letters indicate significant differences in different soils (p < 0.05).
Table 3. The ratio of active fractions to SOC under different land uses.
Table 3. The ratio of active fractions to SOC under different land uses.
ParameterPOC/SOCEOC/SOCDOC/SOCLFOC/SOCMBC/SOC
Paddy12.73 ± 0.14 b1.60 ± 0.34 b1.02 ± 0.02 d4.80 ± 0.84 bc1.16 ± 0.04 b
A227.18 ± 1.20 a5.49 ± 0.75 a2.03 ± 0.13 a17.88 ± 1.85 a1.62 ± 0.15 a
A511.55 ± 1.80 b1.45 ± 0.17 b1.56 ± 0.04 b3.35 ± 1.04 c1.03 ± 0.10 bc
A109.37 ± 0.62 c2.09 ± 0.28 b1.63 ± 0.02 b5.57 ± 0.89 b0.93 ± 0.04 c
A146.29 ± 0.07 d1.42 ± 0.25 b1.21 ± 0.12 cd3.28 ± 0.56 c0.59 ± 0.04 d
A176.12 ± 0.82 d1.41 ± 0.42 b1.41 ± 0.08 c5.85 ± 1.18 b0.50 ± 0.09 d
The A2, A5, A10, A14, and A17 represent the cultivation durations of the areca nut plantations. The same lowercase letters suggest no significant difference between different planting years of areca nut and rice at 0.05 level.
Table 4. Effects of land-use change on soil organic C supply capacity.
Table 4. Effects of land-use change on soil organic C supply capacity.
ParameterNLC (g C kg−1)LLICPICPMI
Paddy20.54 ± 0.48 a6.85 ± 1.62 a1.00 ± 0.00 a1.00 ± 0.00 a100.00 ± 0.00 a
A211.27 ± 0.85 d7.30 ± 0.19 a1.10 ± 0.25 a0.57 ± 0.03 d63.39 ± 16.8 b
A512.95 ± 0.42 cd2.46 ± 0.16 c0.37 ± 0.08 b0.63 ± 0.01 bc23.33 ± 5.11 d
A1011.91 ± 0.49 d3.01 ± 0.21 bc0.46 ± 0.12 b0.58 ± 0.03 d26.70 ± 7.18 d
A1414.42 ± 1.08 c2.97 ± 0.31 bc0.45 ± 0.09 b0.70 ± 0.07 c31.73 ± 9.62 cd
A1714.42 ± 1.85 b3.95 ± 0.75 b0.58 ± 0.09 b0.82 ± 0.07 b47.13 ± 3.50 c
The A2, A5, A10, A14, and A17 represent the cultivation durations of the areca nut plantations, NLC: nonlabile carbon, L: carbon pool activity index, LI: carbon pool activity index, CPI: carbon pool index, and CPMI: carbon pool management index. The same lowercase letters suggest no significant difference between different planting years of areca nut and rice at 0.05 level.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Wan, Y.; Zhu, Q.; Liu, L.; Tang, S.; Wu, Y.; Dan, X.; Meng, L.; He, Q.; Elrys, A.S.; Zhang, J. Active Soil Organic Carbon Pools Decrease with Increased Time since Land-Use Transition from Rice Paddy Cultivation to Areca Nut Plantations under the Long-Term Application of Inorganic Fertilizer. Agronomy 2024, 14, 946. https://doi.org/10.3390/agronomy14050946

AMA Style

Wan Y, Zhu Q, Liu L, Tang S, Wu Y, Dan X, Meng L, He Q, Elrys AS, Zhang J. Active Soil Organic Carbon Pools Decrease with Increased Time since Land-Use Transition from Rice Paddy Cultivation to Areca Nut Plantations under the Long-Term Application of Inorganic Fertilizer. Agronomy. 2024; 14(5):946. https://doi.org/10.3390/agronomy14050946

Chicago/Turabian Style

Wan, Yunxing, Qilin Zhu, Lijun Liu, Shuirong Tang, Yanzheng Wu, Xiaoqian Dan, Lei Meng, Qiuxiang He, Ahmed S. Elrys, and Jinbo Zhang. 2024. "Active Soil Organic Carbon Pools Decrease with Increased Time since Land-Use Transition from Rice Paddy Cultivation to Areca Nut Plantations under the Long-Term Application of Inorganic Fertilizer" Agronomy 14, no. 5: 946. https://doi.org/10.3390/agronomy14050946

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop