Soil Nutrient Content Distribution in Gully in Loess Hilly Region

Assessing the spatial distribution of organic matter and total nitrogen in soil is essential for management and optimum utilization of fertilizers. Therefore, the present field experiment was conducted to evaluate the impact of different planting pattern arrangements on the spatial distribution of soil total nitrogen and organic matter content under a maize/soybean strip relay intercropping system. The planting was arranged in a manner such that soil sampling could be done from continuous maize/soybean relay strip intercropping (MS1), maize/soybean relay strip intercropping in rotation (MS2), traditional maize/soybean intercropping (MS3), sole maize (M), sole soybean (S), and fallow land (FL) from 2018 to 2020. The results showed significant variations for soil organic matter and total nitrogen content under different planting pattern arrangements of maize and soybean in the strip relay intercropping system. Across all systems, the highest soil organic matter (29.19 g/kg) and total nitrogen (10.19 g/kg) were recorded in MS2. In contrast, the lowest soil organic matter (1.69 g/kg) and total nitrogen (0.64 g/kg) were observed in FL. Soil organic matter and total nitrogen in MS2 increased by 186.45% and 164.06%, respectively, when compared with FL. Soil organic matter and total nitrogen in MS2 increased by 186.45% and 164.06%, respectively, when compared with FL. Furthermore, under MS2, the spatial distribution of soil organic matter was higher in both maize and soybean crop rows as compared with other cropping patterns, whereas the soil total nitrogen was higher under soybean rows as compared with maize in all other treatment. However, correlation analysis of the treatments showed variations in organic matter content. It can be concluded that different planting patterns can have varying effects on soil organic matter and total nitrogen distribution under the strip relay intercropping system. Moreover, it is recommended from this study that MS2 is a better planting pattern for the strip relay intercropping system, which can increase the spatial distribution of soil organic matter and total nitrogen, thereby improving soil fertility, C:N ratio, and crop production. This study will serve as a foundation towards the scientific usage of chemical fertilizers in agricultural sector.

A field trial was conducted in 2007 and 2008 to investigate the difference in soil nutrients and grain yield of spring wheat (Triticum aestivum) as influenced by regulated deficit irrigation (RDI) in an arid area. Three RDI treatments and a no-water-deficit control (CK) were designed to subject wheat to various degrees of soil water deficit at different crop developmental stages. Significant differences (p<0.05) occurred in soil organic matter (SOM) and soil available potassium (SAK) contents in both growing seasons, but no difference (p>0.05) occurred among the RDI treatments. Meanwhile, no differences were found in soil total nitrogen (STN) and soil total phosphorus (STP) contents among the treatments and CK. SOM content was improved by 6.2% to 7.2% in RDI treatments than in the CK over the two growing seasons, while the STN, STP, and SAK contents were increased by 1.2% to 2.5%, 1.4% to 5.6%, and 9.0% to 11.2%, respectiely. The STP (t=10.900, p<0.001), soil available phosphorus (SAP, t=8.894, p<0.001), and SAK (t=11.706, p<0.001) contents in 0~40 cm soil layer at wheat harvest were significantly lower in 2008 than in 2007, while the SOM (t=-2.513, p<0.05) and STN (t=-9.950, p<0.001) contents were significantly higher in 2008. Soil organic C, STN, and SAP balance was greatly influenced by RDI in two growing seasons. Compared to the no-water-deficit control, grain yields over the two years were respectively improved by 16.5% to 24.9% in RDI plots.The relationship between grain yield and the soil nutrients was described as y=15843.4 +713.3SOM-20989.1STN+38.7SAN-15.0SAP-39.7SAK (R2=1, p<0.001).

Mixed planting of fir and broadleaf trees is an effective management method for improving the productivity. We investigated soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents, along with their stoichiometric ratios across 10 different combinations of Chinese fir and broadleaf species (Mytilaria laosensis, Michelia macclurei, Michelia maudiae, Cinnamomum porrectum, Castanopsis hystrix, Cinnamomum burmanni, Liquidambar formosana, Michelia chapensis, Schima superba, and Michelia odora, respectively) with the stand age of 20 yr. Additionally, we examined the activities and stoichiometric characteristics of various enzymes: β-1,4-glucosidase, β-xylosidase, cellobiohydrolase, β-1,4-N-acetylaminoglucosidase, leucine aminopeptidase, and acid phosphatase to analyze nutrient limitation status in different mixed stands. The results showed that: 1) In the 0-10 cm and 10-30 cm soil layers, the highest SOC and TN contents were found in M. macclurei, whereas in the 30-50 cm soil layer, the highest contents were observed in S. superba. The highest TP content across all three soil layers was recorded in C. burmanni. Soil SOC and TN contents of the 10 forest stands decreased with the soil depth, while TP was not affected by the soil depth. 2) The measured ranges across the 10 stand types were 4.82-32.69 g·kg-1 for SOC, 0.50-2.16 g·kg-1 for TN, and 0.24-0.55 g·kg-1 for TP, indicating nutrient deficiency. Only the stands of M. macclurei and S. superba reached national average levels for SOC and TN, while the TP content of all forest stands was below the national average. 3) The results of the enzyme quantification vector model indicated that soil microbial metabolism was jointly limited by nitrogen and phosphorus. 4) Redundancy analysis revealed that TN, available phosphorus (AP), ammonium (NH4+-N), soil water content (SWC), pH, and TP were the primary factors influencing enzyme activities. Additionally, pH, AP, TP, SWC, and the carbon-to-phosphorus (C:P) ratio emerged as key determinants of enzymatic stoichiometry. In summary, M. macclurei and S. superba were effective in promoting soil nutrient levels in mixed forests of fir and broadleaf trees, being the optimal tree species for the mixed forest renovation in the South subtropical region. Given the prevalent limitations of nitrogen and phosphorus, external nitrogen and phosphorus inputs should be considered in future management practices.

Poyang Lake, Dongting Lake, and Taihu Lake are the largest freshwater lakes in the middle and lower reaches of the Yangtze River, China. In recent years, the eutrophication level of lakes has increased with the development of the social economy and caused many environmental and social problems. The concentrations of total nitrogen (TN) and total phosphorus (TP) are the key indicators of the degree of eutrophication, but the traditional ground monitoring methods are not capable of capturing such parameters in whole lakes with high spatial-temporal resolution. In this paper, empirical models are established and evaluated between the TN and TP and remote sensing spectral factors in the three lakes using Landsat 8 Operational Land Imager (OLI) satellite data and in-situ data. The results show that the inversion accuracy is higher than 75%. The TN and TP concentrations in the three lakes are inversed based on the Google Earth Engine (GEE) platform from 2014 to 2020 and their spatial-temporal variations are analyzed. The results show that the concentrations of TN and TP in Poyang Lake were decreased by 5.99% and 7.13% over 7 years, respectively, and the TN in Dongting Lake was decreased by 5.25% while the TP remained stable. The temporal changes in TN and TP concentrations displayed seasonal variations. A low concentration was observed in summer and high concentrations were in spring and winter. The average concentrations of TN and TP in Taihu Lake were higher than that of the other two lakes. The TP concentration was increased by 17.3% over 7 years, while the TN concentration remained almost stable. The variation in TN in Taihu Lake was the same as the growth cycle of algae, with higher value in spring and winter and lower value in summer, while the concentration of TP was lower in spring and winter and higher in summer. The spatial distribution of TN and TP concentrations in the three major lakes was significantly affected by human activities, and the concentrations of TN and TP were higher in areas near cities and agricultural activities.

To better understand carbon, nitrogen, and phosphorus dynamics within small-scale gradients of tidal and vegetation interaction, 13 study sites were established along three transects (near, far, and along a tidal creek) within a salt marsh in northern Jiangsu, China, and soil samples were collected during both the growing and non-growing season; the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents were measured. Spatiotemporal variation in SOC, TN, and TP in coastal salt marsh soils was influenced not only by the physical and chemical properties of the elements themselves, but also by the distribution of local vegetation and repetitive tidal action. Complex interactions between the vegetation and tidal flooding determined spatiotemporal patterns in SOC, TN, and TP. Compared to tidal effects, vegetation effects were more stable and persistent. The spatial distributions of SOC and TN in salt marsh soils (sediment) were relatively consistent, with both SOC and TN levels being higher in vegetated zones as compared to the mudflat. Nutrient levels were also higher further from the tidal creek, and the SOC/TN content was maximized in the S. alterniflora marsh. The TP content was higher in the tidal-creek transect versus the other two transects; among sites, the TP content was higher in the mudflat than the vegetated sites. Within the vegetated sites, the S. alterniflora marsh had the highest TP levels. Seasonal variation in SOC, TN, and TP was minimal compared to differences among vegetated sites within each transect. Differences between transects were also minimal compared to those among vegetated sites within transects. Significant spatial variation was identified in C:N:P stoichiometry across the study area; the comprehensive effects of vegetation and tidal flooding on nutrient stoichiometry in coastal salt marshes dominated by S. alterniflora in eastern China are elevation-dependent. The N/P ratio measured 0.62 ± 0.41, suggesting that plant growth in the study area may be nitrogen limited. Together, the local vegetation and repetitive tidal flooding shaped SOC, TN, and TPs in salt marsh soils, producing similar patterns in nutrient element accumulation, constraining the geochemical behavior and fate of elements, and controlling the spatiotemporal distribution of soil elements. Therefore, it is critical to consider interactions between vegetation and tidal effects, as well as the nonlinear relationship between nutrient input and ecological response in salt marsh ecosystems when managing coastal zones, supporting ecosystem functioning, and conducting ecological risk assessments.

The Qaidam Basin is situated in the arid region of northwestern China, characterized by extensive areas of saline–alkali land and significant soil salinization, which severely impedes the sustainable development of local agriculture. This study focuses on the saline soils of the Qaidam Basin Artificial grassland, where 109 surface soil samples (0–20 cm depth) were collected to analyze the salinity characteristics and soil fertility across varying degrees of salinization. The relationship between soil salinity ions and soil fertility indicators is investigated. The results indicate: (1) All samples were categorized into five salinization levels based on total salt content: non-salinized, lightly salinized, moderately salinized, heavily salinized, and saline soil, with average total salt contents of 0.75, 2.30, 3.45, 8.90, and 14.95 g/kg, respectively. Among the soil salt ions, the anion SO42− constituted the highest proportion. The primary anionic components in the study area were SO42− and Cl−, while the predominant cations were Na+ and Ca2+. As salinity increased, the proportion of Na+ and Cl− within the total ions gradually increased, whereas the proportions of Ca2+, Mg2+, and HCO3− ions progressively decreased. (2) As salinity increased, soil total nitrogen, total phosphorus, total potassium, alkali-hydrolysable nitrogen, and available potassium content all showed an upward trend, while soil pH exhibited a downward trend. Soil organic matter content fluctuated across different salinity levels, but no significant differences were observed in organic matter content between soils of varying salinity degrees. (3) The correlation analysis revealed that the contents of total nitrogen, total phosphorus, total potassium, alkali-hydrolysable nitrogen, and readily available potassium were highly positively correlated with total salinity. Among these, the strongest correlation was observed between total salinity and readily available potassium, with a correlation coefficient of 0.828, followed by total nitrogen at 0.767. The pH level exhibited a highly significant negative correlation with total salinity, while demonstrating a highly significant positive correlation with HCO3−. Soil organic matter demonstrated highly significant positive correlations with K+ and SO42−, along with a significant positive correlation with Ca2+. (4) Redundancy analysis indicated a negative correlation between soil organic matter and HCO3−, while total nitrogen, total potassium, alkali-hydrolysable nitrogen, available phosphorus, and available potassium were positively correlated with K+. In both non-salinized and saline soils, the pH level showed a positive correlation with HCO3−. K+ and Na+ exerted substantial influence on soil fertility, and as salinization increased, the impact of total salinity on soil fertility progressively intensified. This study aims to analyze the relationship between soil salinity and soil fertility, facilitating subsequent in-depth investigations into the spatial variation characteristics of soil fertility and salinity. It endeavors to provide a theoretical basis for the remediation of saline–alkali soils in the Qaidam Basin.

In order to explore different forest types effects on soil chemical properties, four stand types, namely pure Cunninghamia lanceolata forest, pure Cryptomeria fortunei forest, pure Liriodendron chinense forest and Cryptomeria fortune × Phoebe zhennan mixed forest, were selected as the research objects, and the difference of soil chemical properties and the organic contents of different forest types were analyzed by variance analysis. The results showed that there were significant differences in soil pH, available potassium, total phosphorus, total potassium and total nitrogen among different forest types, but there were no significant differences in available phosphorus, alkali-hydrolyzable nitrogen, and soil organic matter. The soil pH value of the four forest stands was between 4.02 and 5.33, which was acidic, and increased with the increase of soil depth. The contents of soil organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable and available phosphorus in different forests types all decreased with the increase of the soil depth. The 0~10cm total phosphorus content of soil in four different forest stands was higher than that of 10~20 cm. The soil total potassium content of pure C. lanceolata forest, pure C. fortunei forest and pure L. chinense forest all fluctuated up and down with the increase of the soil depth, while the content of C. fortune × P. zhennan mixed forest increased gradually. The contents of soil alkali-hydrolyzable nitrogen and available phosphorus in soil of four forest stands all decreased with the increase of soil depth. The soil available potassium content of pure C. lanceolata forest and pure C. fortunei forest increased first and then decreased, while that of pure L. chinense forest and C. fortune × P. zhennan mixed forest increased gradually. The average phosphorus supply intensity of the four stands at the soil layer of 0~10cm, 10~20cm, 20~40cm and 40~60cm was 2.64%, 2.71%, 2.57% and 2.61%, respectively. Soil K supply intensity of pure L. chinense forest and C. fortunei × P. zhennan mixed forest increased with the increase of soil layer, while that of pure C. fortunei forest first increased and then decreased.

BackgroundTo analyze the effects of different cultivation patterns on the structure and diversity of the microbial community in the rhizosphere soil of Trichosanthes kirilowii (T. kirilowii) arms to establish reasonable and effective strategies to mitigate the continuous cropping barriers and promote the high-quality cultivation of T. kirilowii.MethodsThree distinct cultivation patterns were investigated: open-field cultivation (TM1), film-mulched cultivation (TM2), and soybean intercropping cultivation (TM3). High-throughput sequencing and bioinformatic analyses were employed to evaluate the rhizosphere microbiome, and redundancy analysis was utilized to investigate the relationship between the microbial communities and soil nutrient indicators.ResultsTM2 and TM3 increased soil bacterial community diversity, reduced fungal community diversity, elevated the relative abundance of beneficial bacterial genera, and reduced the abundance of detrimental fungal genera in the rhizosphere soil. The relative abundance of Pseudarthrobacter, unclassified_Steroidobacteraceae, and Nocardioides in TM2 and TM3 was markedly higher than in TM1. Conversely, the relative abundance of Fusarium, Rhizoctonia, Ceratobasidium, and Plectosphaerella in TM2 and TM3 was significantly reduced compared to TM1. The contents of available potassium (AK), total nitrogen (TN), total phosphorus (TP), and pH in the rhizosphere soil of TM2 and TM3 were significantly higher than those in TM1. The distribution of soil bacterial genera was significantly influenced by the contents of TN and AK, while the distribution of soil fungal genera was significantly or extremely significantly impacted by the contents of TP, total potassium (TK), soil organic matter (SOM), and pH. The content of AK was extremely significantly positively correlated with the relative abundance of Nocardioides, whereas the content of TK showed an extremely negative correlation with the relative abundance of Ceratobasidium. Similarly, pH demonstrated an extremely negative correlation with the relative abundance of Rhizoctonia and Ceratobasidium.ConclusionsFilm-mulched cultivation and soybean intercropping cultivation altered the soil nutrients, as well as the structure and diversity of soil microbial communities. Thus, in agricultural production, film-mulched cultivation and soybean intercropping cultivation can serve to regulate soil nutrients and microbial communities, thereby mitigating the barriers of continuous cropping of T. kirilowii.

To assess soil microbial response to global warming in cool temperate semi‐natural grassland, we conducted an in situ warming experiment in grassland located in the mountains of central Japan. Five pairs of plots (control and warmed) of Zoysia japonica were established. For each pair of plots, one was warmed by ca. 2 °C using infrared heaters during the growing seasons of 2009–2011. Above‐ground biomass of Z.japonica was estimated using the modified point‐frame method. Soil organic matter contents, soil total carbon and nitrogen contents, as well as inorganic nitrogen (ammonium and nitrate) contents were determined from soil samples. Total phospholipid fatty acid (PLFA) contents and PLFA compositions were determined and used as indices for total microbial biomass and community structure, respectively. Analyses showed that the warming increased the above‐ground biomass of Z. japonica significantly. Soil organic matter and soil total nitrogen contents were significantly decreased, while soil ammonium content was significantly increased in the warmed plots. Soil microbial biomass (especially fungal biomass) was lower in the warmed plots, probably reflecting higher temperature, lower soil water content, and/or depletion in available nutrients. The significant decrease in fungal biomass, in combination with our PLFA composition data, suggests that the soil microbial community structure shifted from a fungal‐dominated to a bacteria‐dominated one, causing changes in community‐level physiological activity.

<p>Re-vegetation has been widely carried out to prevent land degradation, reduce soil erosion, and improve soil quality. In order to investigate the characteristics of soil nutrients content in different land use types of karst gabin basin, soil organic matter, soil total nitrogen, soil total phosphorus, soil total potassium, soil pH, and soil texture in woodland, agricultural land, orchard, and grassland were surveyed in Mengzi Gabin Basin, Southwest of China. The difference of soil indicators between vegetation types was analyzed, and soil fertility quality of four land use types was comprehensively evaluated by the soil quality index (SQI). The results showed that land use significantly affected soil organic matter content. Soil organic matter content was the highest in grassland, followed by agricultural land and forest land, while orchard was lowest. There was a significant difference in soil total nitrogen content between different land uses. The total nitrogen content in farmland soil was the highest, followed by grassland and woodland, and the lowest in the orchard. Woodand had the highest total potassium content and the lowest total phosphorus content. The grassland soil had the highest total phosphorus content and the lowest total potassium content. pH value in the four land use types was acidic, ranged from 5.82 to 6.67. The soil quality index showed that woodland had the highest soil fertility quality. The results of the study could provide the basis of soil nutrients variation and status in Gabin basin, and also provides support for evaluating the soil improvements during vegetation restoration in fragile Karst ecosystems.</p>

Ecological stoichiometry is an important index that reflects the element cycle and ecosystem stability. In this study, two sites (sunny and shady slopes) and five forest ages (young stage, half-mature stage, near-mature stage, mature stage, and over-mature stage) in a Pinus tabuliformis plantation were chosen to illustrate the effects of forest ages and site conditions on the biomass and stoichiometric characteristics of leaves and soils in the temperate mountainous area of China. Except for young stage, the biomass of the leaves of P. tabuliformis on sunny slopes were higher than those on shady slopes in other forest ages, the average carbon content of the leaves in sunny slopes was higher than that in shady slope, while the average total nitrogen contents and average total phosphorus contents of the leaves showed the opposite of this. The biomass of leaves increased on sunny slopes, and increased first and then decreased in shady slopes with increasing forest ages. The contents of soil total carbon (STC) and soil total nitrogen (STN) decreased with increasing soil depth, while the soil total phosphorus (STP) and soil available phosphorus (SAP) contents displayed the opposite. In addition to SAP, the average content of STC, STN, and STP in shady slopes was higher than that in sunny slopes, and the ratio was the opposite. Except for STC: STN on shady slopes, the other ratios showed a downward trend with an increase in soil depth. Excluding the topsoil, the change trend of STC : STP and STN : STP in shady slopes and sunny slopes was consistent with forest ages. The results showed that forest ages and site conditions had significant effects on leaf biomass. The biomass of the leaves is mainly limited by nitrogen. These results have important significance in improving the refinement of local forestry management of Pinus tabuliformis plantations in the temperate mountainous area of China.

Straw return can increase maize yield by regulating soil bacteria and improving soil properties in arid and semi-arid areas

Response of soil nutrient concentrations and stoichiometry, and greenhouse gas carbon emissions linked to change in land-use of paddy fields in China

PDF HTML阅读 XML下载 导出引用 引用提醒 三江平原碟形洼地-岛状林土壤氮磷空间分布及生态化学计量特征 DOI: 10.5846/stxb201808231793 作者: 作者单位: 吉林师范大学,唐山师范学院,吉林师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41271113）；吉林省科技厅项目（20180101085JC） Spatial distribution and ecological stoichiometric characteristics of nitrogen and phosphorus in soils from saucer-shaped depressions to island forests in the Sanjiang Plain Author: Affiliation: jilin normal university,tangshan normal university,jilin normal university Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明由碟形洼地-岛状林方向土壤养分的空间分布特征，选取非生长季中国科学院三江平原沼泽湿地生态试验站内的碟形洼地为研究对象，探讨土壤全氮和全磷含量及其化学计量比的空间分布特征及其影响因素。结果表明：由碟形洼地-岛状林方向，全氮、全磷和氮磷比在各样点的平均值分别呈"V "字、倒" N"字和"V"字型分布，土壤全氮、全磷与氮磷比含量的平均值分别为2278.11 mg/kg、820.50 mg/kg与2.44，变异系数为全氮（51.77%） > 氮磷比（36.07%） > 全磷（13.65%）。在0-50 cm土层内，全氮、全磷和氮磷比总体呈随土壤深度增加而逐渐降低的趋势，其中全氮主要集中于不同样点土壤的中上层，各样点的最高值均分布在土壤表层区域；全磷的富集深度与全氮相同，但在土壤20 cm深度各样点含量相近，后在20-50 cm深度内呈逐渐下降趋势；氮磷比在各样点的最高值与全氮和全磷分布总体一致，富集深度与两元素呈基本一致趋势。相关性分析表明，碟形洼地-岛状林方向土壤全氮与全磷之间均呈现出良好的相关关系，其中土壤有机质的分布，植物与水文状况、季节变化和土壤温度也在养分分布中起重要作用。 Abstract:In order to illuminate the spatial distribution characteristics of soil nutrients from saucer-shaped depressions to island forests, this paper chose the saucer-shaped depression within the wetland ecological test station on the Sanjiang Plain, part of the Chinese academy of sciences, as a study site during the non-growing season, and discusses the spatial distribution characteristics of total nitrogen (TN) content, total phosphorus (TP) content, and their stoichiometric ratios and influential factors. The results showed that the average TN, TP and N/P, respectively, displayed a tendency towards "V", inverted "N", and "V" type distributions in soil from saucer-shaped depression to island forests, the average of each was 2278.11 mg/kg, 820.50 mg/kg and 2.44 respectively, and the Coefficient of Variation (CV) was TN (51.77%) > N/P (36.07%) > TP (13.65%). In soil layers from 0 to 50 cm, TN, TP, and N/P decreased gradually with increasing soil depth, but TN was mainly concentrated in the upper middle layer of soil at the different points, and the highest values at all points were found in the surface area of soil. The enrichment depth of total phosphorus was the same as that of TN, but the content was similar at various points at the depth of 20 cm in the soil, and gradually decreased within the depth of 20-50 cm. The maximum value of N/P at various points was consistent with the distribution of TN and TP, and the enrichment depth was consistent with the two elements. The correlation analysis showed that TN and TP in soils both had a good correlation from saucer-shaped depressions to island forests, and the distribution of soil organic matter (SOM), plants, hydrological conditions, seasonal variation, and soil temperature played an important role in nutrient distribution. 参考文献 相似文献 引证文献

The spatial patterns of soil total nitrogen and organic matter was investigated for the Shangsha shoal of Jiuduansha shoals in Yangtze Estuary. Soils had a distinctive seasonal variation in the content of total nitrogen and organic matter, and these changes could be separated into three phases. The soil concentrations of total nitrogen and organic matter were negatively correlated with depth with the surface layer being characteristically accessible, with higher nitrogen content and a wavy surface while the other three deeper layers contained root masses and lower contents of both total nitrogen and organic matter. As expected, the concentrations of soil total nitrogen and organic matter content were positively correlated. This study provides background information for programs involving the environmental protection of the Jiuduansha wetlands.