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Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To understand the effects of clones and planting spacing on carbon storage in poplar plantations, the impacts of four planting spacings（6 m×6 m, 4.5 m×8.0 m, 5 m×5 m, and 3 m×8 m） for NL-895 and 6 m×6 m spacing for two clones（NL-95, and NL-797） on carbon storage in the plantations were investigated using the direct harvesting of forest biomass method. A significant difference in single tree biomass was evident among the investigated plantations（P＜0.05). The highest biomass(400.96 kg·tree-1) occurred in the 6 m×6 m stand of NL-895. No significant variation was observed in biomass production per area among the four planting spacings for NL-895. The stand biomass production was significantly greater in clones NL-895 and NL-95 than in NL-797 at a planting spacing of 6 m×6 m（P＜0.05). The carbon content in the poplar components ranged from 39.79% to 47.76% in the order stem＞ branch＞ root＞ leaf. The variation tendency of poplar carbon storage was similar to the biomass production of the plantations. The highest and lowest tree carbon storage was observed in the NL-895 plantation with a planting spacing of 6 m×6 m and 3 m×8 m, respectively. Soil carbon storage in the top 1 m accounted for approximately 71.7% of the total carbon storage. However, no obvious variation in soil carbon storage was detected among plantations. The total carbon storage among the plantations differed significantly with the four planting spacings in NL-895（P＜0.05). By contrast, no significant difference was observed among the plantations with the three poplar clones at 6 m×6 m spacing. Overall, the highest carbon storage of 192.46 t·hm-2 was obtained in the 6 m×6 m plantation of NL-895; this level was 1.17-, 1.31-, and 1.38-times the levels in the plantations with 4.5 m×8.0 m, 5 m×5 m, and 3 m×8 m spacings, respectively. The collective findings indicate that using the clone NL-895 as the planting material and establishing a plantation with an even planting spacing of 6 m×6 m are optimal management patterns for carbon sequestration forests at similar sites in Jiangsu Province. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to understand the effects of different grass cultivation on the orchard soil environment and fruit quality of sweet orange pomelo» by taking the clean cultivation as the control group, six treatments of Vulpiamyuros, Brassica campestris, Lolium multiflorum, Astragalus sinicus, Medicago falcata and Vicia saliva were set up in the field to conduct the experiment of grass cultivation. Then, the soil and fruit samples were collected and analyzed. The results showed that compared with the clean cultivation, the pH value of soil in orchards increased by 12. 2 % and 8. 1% after planting Brassica campestris and Vicia saliva, and the difference reached significant level (P<0.05). The contents of soil available nitrogen, available phosphorus and rapid available potassium in the six treatments of grass cultivation increased by 32. 2%--50. 7%, 31. 3% -- 50. 0% and 35. 9% -- 49. 4% (P0. 05). In summary, the grass cultivation improved the environment of soil in orchards and could be promoted and applied in the production of sweet orange pomelo. [ABSTRACT FROM AUTHOR]

We measured dinitrogen monoxide (N2O) emissions and soil carbon accumulation in the soil of a sandy field using swine manure. The continuous use of swine manure resulted in higher N2O emissions compared to the use of chemical fertilizers alone. These emissions endured for six years when swine manure was used only in the first year. The accumulated N2O emissions correlated with the amount of surplus nitrogen accumulated.Soil carbon content decreased without compost or compost applied only in the first year, but when used every year, the decrease was small and maintained at the initial value.When compost was used every year, there was little reduction in soil carbon, but high N2O emissions. Therefore, the greenhouse gas suppression effect was lower than when compost was not applied. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND Research on fractions of soil carbon can not only be helpful to realize the migration and transformation of carbon, but also provide the scientific basis for reducing global carbon emissions. There is lack of systematic research on organic carbon fractions, especially the chronic and inert fractions. OBJECTIVES To lay the foundation for future research through the summary of previous research on composition, distribution and roles of different carbon fractions. METHODS It proposes development directions for future works through a summary of previous research. RESULTS The main occurrence form of inorganic carbon was carbonate. The soil organic carbon pool covered the activated carbon pool (turnover time:0.1-4.5 year), chronic carbon pool (turnover time:5-50 year) and inert carbon pool (turnover time:50-3000 year). Previous studies showed that the activated carbon pool, which contained dissolved organic carbon, labile organic carbon and microbial biomass carbon, could reflect the small change of physical and chemical properties of soil sensitivity. Chronic carbon, as the important indicator of the conversion of organic matters in soil, contained light fraction organic carbon and particulate organic carbon. Heavy fraction organic carbon and mineral-associated organic carbon belonged to the inert carbon pool, which was one of the important mechanisms of organic carbon sequestration in soil. Carbonate in soil was always analyzed by gasometric method or titrimetry, while the organic carbon tended to be measured by the volumetric method, colorimetric method or gravimetric method. CONCLUSIONS Study on soil inorganic carbon and inert organic carbon should be strengthened. As far as the analysis methods, 'ramped combustion method' should be researched further. The in-situ measurement method of soil carbon (including organic carbon and inorganic carbon) also needs to be developed. Reference materials of soil carbon fractions with different soil type and different concentration are also necessary.

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Research on fractions of soil carbon can not only be helpful to realize the migration and transformation of carbon, but also provide the scientific basis for reducing global carbon emissions. There is lack of systematic research on organic carbon fractions, especially the chronic and inert fractions. OBJECTIVES: To lay the foundation for future research through the summary of previous research on composition, distribution and roles of different carbon fractions. METHODS: It proposes development directions for future works through a summary of previous research. RESULTS: The main occurrence form of inorganic carbon was carbonate. The soil organic carbon pool covered the activated carbon pool (turnover time: 0. 1 -4. 5 year) , chronic carbon pool (turnover time: 5-50 year) and inert carbon pool (turnover time: 50 - 3000 year). Previous studies showed that the activated carbon pool, which contained dissolved organic carbon, labile organic carbon and microbial biomass carbon, could reflect the small change of physical and chemical properties of soil sensitivity. Chronic carbon, as the important indicator of the conversion of organic matters in soil, contained light fraction organic carbon and particulate organic carbon. Heavy fraction organic carbon and mineral-associated organic carbon belonged to the inert carbon pool , which was one of the important mechanisms of organic carbon sequestration in soil. Carbonate in soil was always analyzed by gasometric method or titrimetry , while the organic carbon tended to be measured by the volumetric method , colorimetric method or gravimetric method. CONCLUSIONS: Study on soil inorganic carbon and inert organic carbon should be strengthened. As far as the analysis methods , ‘ ramped combustion method ’ should be researched further. The in-situ measurement method of soil carbon (including organic carbon and inorganic carbon) also needs to be developed. Reference materials of soil carbon fractions with different soil type and different concentration are also necessary. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the source of soil carbon(C) includes not only the input of crop C(rhizodeposit- and residue-C) to soil organic C(SOC) but also the contribution of soil autotrophic microorganisms to SOC and the fixation of soil inorganic C(SIC) from the soil inorganic chemical pathway and microbial biomineralization pathway. The level of SOC in croplands is mainly controlled by the balance between the input of crop C and the loss of SOC via decomposition. In the short term, the input of crop C usually promotes the SOC decomposition, showing a positive(rhizosphere) priming effect. We analyzed the literature on the rhizosphere priming effect of major crops and the priming effect of straw additions and found that they were on average 75% and 67%, respectively. The residual straw C in the soil could completely compensate for the SOC loss caused by the priming effect of straw returning. In croplands, rhizodeposit- and residue-C often coexisted, which resulted in at least three C sources(rhizodeposit-, straw-, and soil-C) for soil C input and output. Finally, we proposed a new method to distinguish the contribution of multiple C sources to the CO 2 emission and the SOC input in rhizosphere soils, as well as the contribution of inorganic chemistry and microbial pathways to the SIC input in calcareous soils. This review is helpful to improve the understanding of the input and output pathways of SOC and SIC in croplands and to improve the accuracy of soil C assessment in croplands.

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Southern Agriculture is the property of Journal of Southern Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vegetation rehabilitation is one of the main means in managing soil and water loss, being able to effectively promote the development of eroded soil, improve the soil fertility level, enhance the soil microbial activities, and in further, affect the soil carbon and nitrogen cycles. Therefore, vegetation rehabilitation plays definite roles in the accumulation of soil organic carbon and nitrogen pools and the mitigation of greenhouse gases emission from soil. This paper summarized the effects of vegetation rehabilitation on the soil carbon and nitrogen cycles and the synergetic effects between soil quality and vegetation rehabilitation, and put forward the further research directions, which could provide the reference for the evaluation of the roles of vegetation rehabilitation in response to global climate change, and the practical guidance for the improvement of soil fertility and the recovery and sustainable development of degraded ecosystems. [ABSTRACT FROM AUTHOR]

Taking the rhizosphere and non-rhizosphere soils of five typical plants Agropyron cristatum, Artemisia frigida, Pseudoraphis bungeana, Thymus mongolicus, and Artemisia sacrorum in a mountainous area of southern Ningxia as test objects, this paper studied their C and N forms contents. The C and N forms contents in the rhizosphere and non-rhizosphere soils differed with plant species. In the rhizosphere soil of A. sacrorum, the C content was the highest, with the total soil organic C (TOC), light fraction organic C (LFOC), and heavy fraction organic C contents being 22. 94, 1. 95, and 20. 88 g · kg-1, respectively. In the rhizosphere soil of P. bungeana, the N content was the highest, with the total N (TN), mineralizable N (MN), and available N contents being 2. 05 g · kg-1, 23. 73 mg · kg-1, and 11. 99 mg · kg-1, respectively. In the rhizosphere soil of A. frigida, the LFOC/ TOC and MN/ TN ratios were the highest, which benefited the C and N transformed into more active forms. Light fraction organic C and mineralizable N could be used as the sensitive indicators of plant habitat change. For the five plant species, the contents of different C and N forms in the rhizosphere soil were generally higher than those in the non-rhizosphere soil. [ABSTRACT FROM AUTHOR]

As an important ecological barrier for the North China Plain, research on the spatial variations of soil nutrients in the southern foot of the Taihang Mountains is of great significance for the forestry ecological construction in this rocky mountainous area. With the typical slopes (the artificial forestland and the natural wild slope) of the southern foot of the Taihang Mountains as the research objects, we used the grid method to arrange sampling points, and combined classical statistics, geostatistics and constrained sorting methods to analyze the spatial variations of soil nutrients. The results showed that: 1) soil total carbon (TC) contents were 6.80-57.05 g·kg -1 , and the total nitrogen (TN) contents were 0.74-3.93 g·kg -1 . The coefficients of variation of both soil TC and TN were 25.0%-52.8%, belonging to the moderate degree of variation, which were caused by the combination of random and structural factors. The spatial aggregation of soil nutrients decreased with increasing lag distances. 2) The contents of soil nutrients had increasing trends from the top to the bottom of the slopes, with high nutrient values appearing at the bottom of the slopes. 3) The soil bulk density, gravel content, vegetation coverage, and soil water content were the main factors affecting the spatial variability of soil TC and TN on the southern foot of the Taihang Mountains. 4) Soil water content was the main factor affecting soil nutrients at the natural wild slope, but not at the artificial forestland.

To investigate the effects of plastic film mulching and nitrogen fertilizer application on CH 4 emissions from a vegetable field, static opaque and gas chromatography methods were applied, and in situ field observations of a chili-radish rotation system, from May 2014 to April 2016, were carried out in the Key Field Station for Monitoring of Eco-Environment of Purple Soil of the Ministry of Agriculture of China in the farm of Southwest University in Chongqing. Eight treatments were set up in the field experiment:control routine (no N application and no plastic film mulching) (NN0), control mulching (FN0), low N routine (NN1), low N mulching (FN1), conventional N routine (NN2), conventional N mulching (FN2), high N routine (NN3), and high N mulching (FN3). The characteristics and influencing factors of CH 4 emissions and the changes of soil carbon and nitrogen composition from all treatments were studied. The results showed that there was no significant difference in the CH 4 emissions from the vegetable fields between the mulching methods. From May 2014 to April 2016, the annual average cumulative absorption of CH 4 in nitrogen-free, low-nitrogen, medium-nitrogen, and high-nitrogen vegetable fields under film-mulching cultivation was 28.96, 51.90, 43.43, and 34.41 mg·m -2 , respectively. The average annual cumulative uptake of CH 4 under conventional planting was 40.76, 63.56, 62.77, and 21.92 mg·m -2 , respectively. Different nitrogen application gradients had no significant effect on CH 4 emissions from vegetable fields. There was a significant positive correlation between CH 4 uptake and soil temperature, and a significant negative correlation between CH 4 and soil water content. Plastic film coverage accelerated the mineralization of soil carbon in the pepper season, but there was no significant effect in the radish season.