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1. chinaXiv:202103.00125 [pdf]

Quantification of red soil macropores affected by slope erosion and sediment using computed tomography

Si-Yi Zhang; Bin He; Yan Sun; Fan-Ling Kong; Wan-Yi Huang
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

Purpose Soil structures are the main course of the formation and development of collapsing gullies, which are the most severe type of erosion in south China. However, few studies have focused on the relationship between soil macropores, soil erosion, and local topography. This study aimed to quantify and compare soil properties and macropore characteristics in the collapsing gully region, and explore their influences on the formation and development of the associated erosion. Materials and methods Soil core columns at different positions of a typical collapsing gully were excavated, and then scanned to analyze soil macropores. Moreover, soil properties and saturated hydraulic conductivity were investigated in the laboratory and in the field, respectively. Results and discussion The results indicated that the sand content increased from the ridge to the slope and the valley, while silt and clay contents decreased for the same catena. The mean weight diameter of aggregates was largest at the ridge and lowest at the valley. The infiltrate rates were highest at the valley and lowest at the slope. The valley had the greatest macroporosity (1.09±0.33%), and the highest number (5919±703), volumes (24.7±7.5 cm3) and surface (10.4±2.6 m2) of macropores, as well as the highest conectivity (42.3), while the slope had the smallest macroporosity (0.15±0.14%), and the smallest number (1189±747), volumes (3.4±3.2 cm3) and surface (1.7±1.4 m2) of macropores. The mean pore volume of macropores larger than 1 mm3 was largest at the ridge (16.8±7.4), and smallest at the slope (10.6±2.9). The number of macropores and their macroporosity mainly decreased with increasing depth, but were influenced by the soil macrofauna as well as the erosion and sediment processes. Macropores were mainly vertical, which is affected by the roots of plants and is conducive to the vertical infiltration of water. But, there wer many horizontal macropores at the valley because of the sediment process. The equivalent pore diameter of macropores was mainly smaller than 2 mm (accouting for more than 76.3%), and the macropores larger than 5 mm were less than 1%. Conclusions The macropore characteristics at different sites of the collapsing gullies affected the soil water infiltration and hydraulic conductivity, and further affected the processes of water erosion and mass ersion. The highest macroposities at the valley would result strong subsurface flow erosion and the loss of the base of collapsing wall. Macropores at the ridge would increase rain infiltration and promote soil collapsing. Few macropores and low infiltration abilities at the slope would strengthen the overland flow erosion. Thus, macropore characteristics had significant effects on both the formation and development of collapsing gullies.

submitted time 2021-03-17 Hits403Downloads197 Comment 0

2. chinaXiv:202102.00028 [pdf]

Taurine is found in rumen fluid, plasma and urine of beef cattle fed a ration containing sodium sulfate

Zhao, Yuchao ; Zhao, Guangyong
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Animal Husbandry and Veterinary Medicine

Objective: The objectives of the experiment were to study the effects of dietary supplementation with sodium sulfate (Na2SO4) on taurine concentrations of plasma, urine and rumen fluid in steers. Methods: Six Simmental steers (bodyweight 449 ± 19 kg) were used as experimental animals. Three levels of Na2SO4, i.e. 0, 20 and 40 g/d, were added in a basal ration as experimental treatments. The animals and the dietary treatments were randomly allocated in a replicated 3 × 3 Latin square design. Each experimental period included 15 days for adaptation and 5 days for sampling. Rumen fluid, blood and urine were sampled from the steers during each sampling period. Results: Dietary addition with Na2SO4 at 40 g/d increased plasma taurine concentration (P < 0.05) and tended to increase the plasma taurine concentration with increasing Na2SO4 level in a linear manner (P = 0.052). A linear positive regression relationship was found between plasma taurine concentration (?g/mL) and sulfur intake (g/d) (R2 = 0.18, P = 0.046). Taurine was found in rumen fluid and urine. No differences were found in ruminal taurine concentrations or urinary taurine excretions among treatments (P > 0.05). Limitations: We infer that the taurine in rumen fluid should have come from the blood through saliva secretion or/and the rumen microbial synthesis. However, no reports are available on the hypothesis. Further research is needed to investigate the possible origins of ruminal taurine as well as the impacts of taurine on rumen microecosystem and fermentation. Conclusions: Taurine has been found in rumen fluid for the first time in the experiment. Dietary addition with Na2SO4 increased plasma taurine concentrations whereas it did not affect urinary taurine excretions in steers.

submitted time 2021-02-08 Hits497Downloads247 Comment 0

3. chinaXiv:202006.00139 [pdf]


李典鹏; 姚美思; 孙 涛
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

明确不同生态系统土壤碳排放规律及其影响因素对准确评估全球碳循环具有重要意义。为揭示干旱区典型盐湖沿岸土壤呼吸(Rs)、土壤呼吸温度敏感系数(Q10)变化特征及其影响因素,以新疆干旱区达坂城盐湖和巴里坤湖沿岸土壤为研究对象,在2015—2016年5~10月利用LI–8100土壤碳通量自动测量系统对盐湖沿岸土壤呼吸速率进行测定,分析了土壤呼吸季节性变化特征及其影响因子。结果表明,干旱区盐湖土壤呼吸变幅较大(0.07~11.59 μmol?m-2?s-1),平均值为2.45 μmol?m-2?s-1,7月土壤呼吸速率最高为4.69 μmol?m-2?s-1,10月最低(1.01 μmol?m-2?s-1);土壤CO2累积排放量为9.30 g?m-2?d-1,7月累积排放量最大为17.82 g?m-2?d-1。Q10呈“降低—增加—降低”趋势,6月最低(2.25)9月最高(3.52),平均值为2.79。干旱区盐湖沿岸土壤呼吸受土壤有机碳(SOC)、5 cm土壤温度(ST5)、土壤含水量(SM)和土壤盐分(Salt)的共同影响,单因素模型模拟可解释土壤呼吸速率变化的41.7%~75.7%(R2=0.417~0.757,P<0.05),多因子综合模型拟合结果最佳Rs=0.001×SOC+0.039 ×SM-0.534×Salt-0.116×ST5+5.06(R2=0.804,P=0.05),且均表明盐分是影响干旱区盐湖沿岸土壤呼吸速率的主要因子。因此,在考虑陆地生态系统碳收支和碳循环时不能忽略干旱区盐湖沿岸土壤碳过程,以及盐分对盐湖生态系统碳排放的影响。

submitted time 2020-06-12 From cooperative journals:《干旱区地理》 Hits3010Downloads693 Comment 0

4. chinaXiv:202002.00074 [pdf]

Molecular karyotypes of loquat (Eriobotrya japonica) aneuploids can be detected by using SSR markers combined with quantitative PCR irrespective of heterozygosity

Wen, Guo; Dang, Jiangbo; Xie, Zhongyi; Wang, Jinying; Jiang, Pengfei; Guo, Qigao; Liang, Guolu
Comment:This article has been published online in Plant Methods (
Subjects: Biology >> Botany
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Horticulture

Background: Aneuploidy, a condition caused by an imbalance between the relative dosages of chromosomes, generally produces a novel phenotype specific to the molecular karyotype. Few techniques are currently available for detecting the molecular karyotypes of aneuploids in plants. Methods: By PCR amplification of 209 pairs of SSR primers, 17 pairs of SSR primers with no polymorphism and stable amplification in 23 different ploidy loquat were screened out. Seventeen SSR markers combined with qPCR for detection of aneuploid loquat H39 (2n=2x+5=39) karyotype variation. To verify the method for detection of aneuploid karyotype variation, 9 hybrid offspring of Q24 × ‘Huabai No. 1’ and 16 open-pollination progeny of the triploid loquat A313 and A322 were obtained, and we detected their chromosome numbers using conventional cytological methods. The SSR-qPCR method was used to detect the molecular karyotypes of aneuploids in the 9 hybrid offspring of Q24 × ‘Huabai No. 1’ and 16 open-pollination progeny of the triploid loquat A313 and A322. Results: Based on this imbalance in chromosome dosage, a new approach (referred to as ‘SSR-qPCR’) combining simple sequence repeat (SSR) markers and quantitative real-time PCR (qPCR) has been developed and utilized to detect some common aneuploids irrespective of heterozygosity. We screened 17 specific SSR markers covering all loquat linkage groups and redesigned 6 pairs of primers for SSR markers that can detect loquat chromosome aneuploidies. The SSR-qPCR detection results obtained for hybrid progeny and open-pollination progeny of triploid loquat showed diagnostic accuracies of 88.9% and 62.5%, respectively, compared with the chromosome preparation results. Limitations: Loquat genome sequences have not been published, available SSR markers are currently limited. Conclusion: SSR-qPCR can detect loquat aneuploids and be used to construct the entire molecular karyotypes of aneuploid individuals. Therefore, this method offers a novel alternative for the detection of chromosome aneuploidies.

submitted time 2020-03-03 Hits15129Downloads1612 Comment 0

5. chinaXiv:202001.00083 [pdf]


左宋林; 宫新栋; 王飞; 魏玲玲
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Forestry


submitted time 2020-01-13 Hits8894Downloads1166 Comment 0

6. chinaXiv:201906.00046 [pdf]

Multi-scale spatial relationships between soil total nitrogen and influencing factors in a basin landscape based on multivariate empirical mode decomposition

ZHU Hongfen
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The relationships between soil total nitrogen (STN) and influencing factors are scale-dependent. The objective of this study was to identify the multi-scale spatial relationships of STN with selected environmental factors (elevation, slope and topographic wetness index), intrinsic soil factors (soil bulk density, sand content, silt content, and clay content) and combined environmental factors (including the first two principal components (PC1 and PC2) of the Vis-NIR soil spectra) along three sampling transects located at the upstream, midstream and downstream of Taiyuan Basin on the Chinese Loess Plateau. We separated the multivariate data series of STN and influencing factors at each transect into six intrinsic mode functions (IMFs) and one residue by multivariate empirical mode decomposition (MEMD). Meanwhile, we obtained the predicted equations of STN based on MEMD by stepwise multiple linear regression (SMLR). The results indicated that the dominant scales of explained variance in STN were at scale 995 m for transect 1, at scales 956 and 8852 m for transect 2, and at scales 972, 5716 and 12,317 m for transect 3. Multi-scale correlation coefficients between STN and influencing factors were less significant in transect 3 than in transects 1 and 2. The goodness of fit root mean square error (RMSE), normalized root mean square error (NRMSE), and coefficient of determination (R2) indicated that the prediction of STN at the sampling scale by summing all of the predicted IMFs and residue was more accurate than that by SMLR directly. Therefore, the multi-scale method of MEMD has a good potential in characterizing the multi-scale spatial relationships between STN and influencing factors at the basin landscape scale.

submitted time 2019-06-20 From cooperative journals:《Journal of Arid Land》 Hits11592Downloads1248 Comment 0

7. chinaXiv:201903.00234 [pdf]

Effects of spring fire and slope on the aboveground biomass, and organic C and N dynamics in a semi-arid grassland of northern China

ZHAO Xiang; HU Shuya
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

The aboveground primary production is a major source of carbon (C) and nitrogen (N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass (AGB) and the soil C and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern China to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic C and total N contents in different plant functional groups (C3 grasses, C4 grasses, forbs, Artemisia frigida plants, total grasses and total plants). The dynamics of AGB and the contents of organic C and N in the plants were examined in the burned and unburned plots on different slope positions (upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of C3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of C4 grasses and A. frigida plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of C3 grasses and total grasses in July, and the AGB of forbs and C4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic C and N contents in the plants. The lower and upper slopes differed with respect to the organic C and N contents of C3 grasses, C4 grasses, total grasses, forbs, A. frigida plants and total plants in different growing months. Slope position and spring fire significantly interacted to affect the AGB and organic C and N contents of C4 grasses and A. frigida plants. We observed the AGB and organic C and N contents in the plants in a temporal synchronized pattern. Spring fire affected the functional AGB on different slope positions, likely by altering the organic C and N contents and, therefore, it is an important process for C and N cycling in the semi-arid natural grasslands. The findings of this study would facilitate the simulation of ecosystem C and N cycling in the semi-arid grasslands in northern China.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits11586Downloads1366 Comment 0

8. chinaXiv:201903.00236 [pdf]

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

WANG Bisheng; GAO Lili; WEI Xueqin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon (SOC) content and aggregate distribution in a deep soil (>20-cm depth) in a dryland environment, this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon (OC) and SOC physical fractions. Conservation tillage (reduced tillage with residue incorporated (RT) and no-tillage with residue mulch (NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal (CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased (by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that: (1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and (2) the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

submitted time 2019-03-28 From cooperative journals:《Journal of Arid Land》 Hits11984Downloads1455 Comment 0

9. chinaXiv:201811.00103 [pdf]

Changes in soil microbial community response to precipitation events in a semi-arid steppe of the Xilin River Basin, China

ZHANG Hui; LIU Wenjun; KANG Xiaoming; CUI Xiaoyong; WANG Yanfen; ZHAO Haitao; QIAN Xiaoqing; HAO Yanbin
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science

In the context of climate change, precipitation is predicted to become more intense at the global scale. Such change may alter soil microbial communities and the microbially mediated carbon and nitrogen dynamics. In this study, we experimentally repackaged precipitation patterns during the growing season (from June to September) of 2012 in a semi-arid temperate steppe of the Xilin River Basin in Inner Mongolia of China, based on the 60-year growing season precipitation data. Specifically, we manipulated a total amount of 240 mm precipitation to experimental plots by taking the following treatments: (1) P6 (6 extreme precipitation events, near the 1st percentile); (2) P10 (10 extreme precipitation events, near the 5th percentile); (3) P16 (16 moderate precipitation events, near the 50th percentile); and (4) P24 (24 events, 60-year average precipitation, near the 50th percentile). At the end of the growing season, we analyzed soil microbial community structure and biomass, bacterial abundance, fungal abundance and bacterial composition, by using phospholipid fatty acid (PLFA), real-time quantitative polymerase chain reaction (RT-qPCR) and 16S rRNA gene clone library methods. The extreme precipitation events did not change soil microbial community structure (represented by the ratio of PLFA concentration in fungi to PLFA concentration in bacteria, and the ratio of PLFA concentration in gram-positive bacterial biomass to PLFA concentration in gram-negative bacterial biomass). However, the extreme precipitation events significantly increased soil microbial activity (represented by soil microbial biomass nitrogen and soil bacterial 16S rRNA gene copy numbers). Soil fungal community showed no significant response to precipitation events. According to the redundancy analysis, both soil microbial biomass nitrogen and soil ammonium nitrogen (NH4-N) were found to be significant in shaping soil microbial community. Acidobacteria, Actinobacteria and Proteobacteria were the dominant phyla in soil bacterial composition, and responded differently to the extreme precipitation events. Based on the results, we concluded that the extreme precipitation events altered the overall soil microbial activity, but did not impact how the processes would occur, since soil microbial community structure remained unchanged.

submitted time 2018-11-23 From cooperative journals:《Journal of Arid Land》 Hits12332Downloads1575 Comment 0

10. chinaXiv:201807.00075 [pdf]


袁立竹; 盛宇平; 盛春蕾; 郭书海
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science


submitted time 2018-07-26 Hits9993Downloads1697 Comment 2

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