Soil & Tillage Research最新文献

{"title":"Relationship between calcium forms and organic carbon content in aggregates of calcareous soils in northern China","authors":"Xiaolu Dou ,&nbsp;Congzhi Zhang ,&nbsp;Jiabao Zhang ,&nbsp;Donghao Ma ,&nbsp;Lin Chen ,&nbsp;Guixiang Zhou ,&nbsp;Yan Duan ,&nbsp;Lu Tao ,&nbsp;Junxu Chen","doi":"10.1016/j.still.2024.106210","DOIUrl":"https://doi.org/10.1016/j.still.2024.106210","url":null,"abstract":"<div><p>The agricultural soil organic carbon (SOC) pool is one of the most active C pools in terrestrial ecosystems, and soil aggregates are the main site of SOC fixation. Mineral sorption plays a crucial role in SOC accumulation. Calcium (Ca) is a typical soil mineral element that plays a crucial role in SOC accumulation and is fundamental for the formation of soil aggregates. Although Ca has been shown to regulate the stability of SOC, the relationship between different forms of Ca and SOC within aggregates in northern China remains unclear. In this study, we selected five soils (black soil, light chernozem soil, fluvo-aquic soil, sierozem soil, and loess soil) with different calcium carbonate (CaCO₃) contents as the target materials. Water-stable aggregates were separated using the wet-sieving method. Soil respiration was measured using the static alkali absorption method (carbon dioxide [CO₂] absorption by NaOH solution). The CaCO₃ content was quantified using the CO₂ gas volume method, and the continuous leaching method was used to analyze the different forms of Ca (water soluble-Ca, exchangeable-Ca, acid soluble-Ca, and bound to organic-Ca). In-situ field sampling was used to reveal the associations between different forms of Ca and SOC within aggregates. The results showed that besides the CaCO₃ form, exchangeable-Ca (20.06 %–57.86 %) and bound to organic-Ca (26.69 %–73.91 %) were major Ca forms in calcareous soils. There was a nonsignificant negative correlation between CaCO₃, acid soluble-Ca, and exchangeable-Ca and SOC in the bulk soil. However, there was a significant negative correlation among CaCO₃, acid soluble-Ca, and exchangeable-Ca with SOC in macro-aggregates (&gt; 0.25 mm) and micro-aggregates (0.25–0.053 mm). A 90-day incubation experiment was conducted to verify the previous speculations, which revealed that CaCO₃ increased SOC mineralization and reduced the content of SOC, while enhancing the acid soluble-Ca and bound to organic-Ca content. In the treatment with added CaCO₃, there was a negative correlation between acid soluble-Ca and bound to organic-Ca and SOC in bulk soil and macro-aggregates (&gt; 0.25 mm). The effect of Ca²⁺ on SOC should not be ignored. Excessive Ca²⁺ may be converted into different forms of Ca to occupy the bonding sites for SOC on the surface of soil particles with silt and clay particles, forming a pseudo-aggregate structure, and the SOC traveling between soil particles, which is not conducive to SOC stabilization and accumulation.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141325404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A geospatial approach for evaluating impact and potentiality of conservation farming for soil health improvement at regional and farm scale","authors":"Fabio Castaldi ,&nbsp;Gabriele Buttafuoco ,&nbsp;Flavio Bertinaria ,&nbsp;Piero Toscano","doi":"10.1016/j.still.2024.106212","DOIUrl":"https://doi.org/10.1016/j.still.2024.106212","url":null,"abstract":"<div><p>Soil organic matter (SOM) is a key factor in sustaining soil fertility, sequestering greenhouse gases and reducing soil erosion, in this regard, an accurate estimation and monitoring of the SOM content is crucial for sustainable land management and climate change mitigation strategies. In recent years, there has been a growing consciousness of the need to better understand the dynamics of SOM across different farm management in time and space.</p><p>In this context, the main objective of the study is to improve understanding regarding the relationship between SOM and the main farming systems adopted in Italy by taking spatial correlation into account. For this purpose, a large dataset consisting of topsoil SOM values (0–20 cm) and environmental and farming information was collected in 597 locations (145 fields and 62 farms) representative of the whole agricultural area of Po Valley in Italy. This sizable dataset was analyzed by a novel geospatial analysis using a de-clustering approach in combination with polygon kriging for detecting and understanding the SOM variability over the different fields characterized by irregular shapes and different farming systems.</p><p>The results provided clear evidences of the spatial correlation between SOM, farming systems and soil types. Higher SOM contents were detected in Cambisols (3.11 %) and in field managed according conservation agriculture practices (3.22 %) as compared to other farming systems. Moreover the inclusion of fodder crops in the rotation and the use of no-tillage are two of the most effective practices for increasing and preserving SOM according to our findings.</p><p>Spatial information, such those provided in this study, could facilitate the delineation of tailored solutions for each European Member State for targeting future actions related to carbon farming, and offering crucial insights to support advancements in agriculture for enhancing soil fertility and health and for fostering sustainable agricultural practices.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0167198724002137/pdfft?md5=80e8242b4631ad40b4bddd583e2dbbd0&pid=1-s2.0-S0167198724002137-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141325403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defoliation decreases soil aggregate stability by reducing plant carbon inputs and changing soil microbial communities","authors":"Bin Wei ,&nbsp;Yuqi Wei ,&nbsp;Tongtian Guo ,&nbsp;Yue Pang ,&nbsp;Warwick Badgery ,&nbsp;Yingjun Zhang ,&nbsp;Nan Liu","doi":"10.1016/j.still.2024.106180","DOIUrl":"https://doi.org/10.1016/j.still.2024.106180","url":null,"abstract":"<div><p>Soil aggregation and its stability are fundamental in ensuring soil function and ecosystem service provision, which can be greatly altered by ungulate disturbance, particularly the indirect effects from biomass removal by defoliation and direct effects from hoof trampling, but the mechanisms underlying the effect of defoliation and trampling on soil aggregation remains largely unexplored. Here, we conducted a 3-year manipulative experiment to investigate the effects of defoliation and trampling of ungulates and their interaction on soil aggregate stability in a semiarid grassland of Inner Mongolia, China. We found that defoliation rather than trampling dominantly affected soil aggregate stability. Defoliation disintegrated macroaggregates, reducing aggregate stability (-5 %), mainly attributed to the direct influence of a decline in plant inputs (aboveground biomass: −32 %) and the indirect effects of soil microbial biomass (-5 %). Moreover, compared to no defoliation plots, defoliation significantly decreased soil fungal diversity and altered fungal communities, particularly decreasing the relative abundance of <em>Glomeraceae</em> fungal taxa favorable to the formation of soil aggregates. Trampling only slightly attenuates the involvement of microorganisms (indirectly, −7 %) in aggregate formation by increasing soil compaction (directly, −4 %), and the positive effects from accelerating litter-derived C inputs due to trampling disturbance may counteract these limited negative effects. Our results highlight the negative effect of biomass removal by ungulates on soil aggregation, and suggest that the role of plant inputs and soil microbial properties on soil function and their correlation with soil aggregate stability needs to be explored under a diversity of grazing management strategies to refine management to improve soil conservation, C persistence and restore grasslands.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141325422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of different management measures on soil nutrients and stoichiometric characteristics for sloping farmland under erosive environments in the Three Gorges Reservoir Area, China","authors":"Lidong Pan ,&nbsp;Dongmei Shi ,&nbsp;Guangyi Jiang ,&nbsp;Ying Xu","doi":"10.1016/j.still.2024.106173","DOIUrl":"https://doi.org/10.1016/j.still.2024.106173","url":null,"abstract":"<div><p>Soil erosion exacerbates the loss of soil nutrients and directly affects the soil stoichiometric characteristics. However, the impacts of different erosion conditions and farmland management measures on soil nutrients and their stoichiometry remain unclear. Herein, field observations were conducted in purple-soil sloping farmland in the Three Gorges Reservoir Area, China, using the artificial shovel soil test method. The soil nutrient contents and stoichiometric characteristics of the topsoil under three management measures (no fertilization, CK; chemical fertilizer, F; biochar+chemical fertilizer, BF) and five erosion conditions (erosion thicknesses of 0, 5, 10, 15, and 20 cm) were analyzed. The SOC, TN, TP, TK, AN, AP, and AK contents of the three management measures followed overall decreasing trends with increasing erosion thickness. Under the same erosion condition, the content of nutrient elements in the three treatments followed the trends of BF &gt; F &gt; CK, and the soil nutrient content of the BF treatment was significantly higher than that of the CK treatment (<em>P</em> &lt;0.05). With the increasing erosion thickness, soil C/N, C/P, and N/P ratios of the three treatments showed decreasing trends. The average soil C/N, C/P and N/P ratios for the three treatments were 10.55, 16.92, and 2.09, respectively, i.e., lower than the global and national averages. A lower C/N ratio indicats a faster SOM mineralization rate in the region, with the SOM cumulative rate lower than the decomposition rate. Lower C/P and N/P ratios indicated that crop growth was limited by N, resulting in a state of N deficiency and P enrichment in the soil nutrient in this region, thereby limiting soil productivity. Based on multi-attribute decision making, soil nutrient recovery index, and the characteristics of the response surface, the application of biochar+chemical fertilizer is conducive to alleviating the supply-demand contradiction between crops and soil nutrients, representing an effective way of improving soil fertility. However, further research is required to determine when the application of biochar leads to SOM accumulation that exceeds decomposition. These results provide a scientific basis for the restoration and reconstruction of soil ecosystems in sloping farmlands.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141314717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of phosphorus activation in charosphere and non-charosphere: The priming effect of biochar","authors":"Ping Xue ,&nbsp;Renjie Hou ,&nbsp;Qiang Fu ,&nbsp;Tianxiao Li ,&nbsp;Mo Li ,&nbsp;Song Cui ,&nbsp;Qinglin Li","doi":"10.1016/j.still.2024.106195","DOIUrl":"https://doi.org/10.1016/j.still.2024.106195","url":null,"abstract":"<div><p>Biochar is widely used in soil to increase the soil phosphorus content, but a special ecological zone called the “charosphere” zone is formed where biochar comes into contact with soil. The physical and chemical properties of charosphere soil are different from those of the original soil and the biochar itself, leading to uncertainty regarding the effect of charosphere soil on the phosphorus cycle. Hence, we designed a barrier device to separate biochar from soil and analyzed the impact of biochar diffusion on soil nutrient content and microbial activity. Then, the variation characteristics of the community structure of <em>phoD</em>-harboring bacteria and fungi in the carbonosphere (group B) and non-carbonosphere (group C) were explored. Finally, the key factors and potential driving mechanisms of soil phosphorus activation were explored. The results show that biochar improved soil microbial activity and stimulated the soil nutrient recycling, resulting in a 67.28 % greater percentage of the labile P fraction in group B than in group C. The alpha diversity and nutrient transfer efficiency of the <em>phoD</em>-harboring bacterial community in group B were greater than those in group C, while the <em>phoD</em>-harboring bacterial co-occurrence network of group C was more complex. Moreover, the synergy between the co-occurrence networks of the soil fungal community was stronger than that of the bacterial community. Biochar stimulates microbial activation of phosphorus by increasing the DOC content and pH in the charosphere, and the <em>phoD</em>-harboring bacterial community dominates soil phosphorus activation. These findings offer a new perspective on how biochar regulates soil phosphorus cycling, providing crucial information to guide the application of biochar in agroecosystems.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141314716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Artificially cultivated grasslands decrease the activation of soil detachment and soil erodibility on the alpine degraded hillslopes","authors":"Yulei Ma ,&nbsp;Yifan Liu ,&nbsp;Jesús Rodrigo-Comino ,&nbsp;Manuel López-Vicente ,&nbsp;Zhihua Shi ,&nbsp;Gao-Lin Wu","doi":"10.1016/j.still.2024.106176","DOIUrl":"https://doi.org/10.1016/j.still.2024.106176","url":null,"abstract":"<div><p>Artificial restoring degraded grasslands has shown positive effects on topsoil conservation, leading to reduced soil erodibility and the activation of soil detachment. However, only a few studies have quantified the expected changes in both processes resulting from artificial restoration. In this study, we aim to survey the effects of grassland restoration on soil erodibility and soil loss in alpine degraded hillsides by changing vegetation and soil properties using artificially cultivated. We assessed soil erodibility K-factor (<em>K</em>), mean weight diameter of soil aggregates (<em>MWD</em>), soil saturated hydraulic conductivity (<em>Ks</em>) soil cohesion (<em>Coh</em>) using a structural equation modeling. Our results demonstrated that artificially cultivated grassland restoration effectively reduced soil erodibility on severely degraded hillslopes. The soil erodibility index <em>Coh</em>, <em>MDW</em> and <em>Ks</em> increased by 161.3, 53.4 and 8.6 %, respectively, while <em>K</em> decreased by 5.1 %. Additionally, the artificial grassland proved to be effective in reducing soil loss, with increasing age of artificial restoration. Over the study period from 2019 to 2022, sediment concentration and soil erosion rate decreased by −188.3–41.9 % and from −239.4–20.4 %, respectively. We concluded that artificially cultivated grassland is an efficient approach for reducing soil degradation activation on alpine degraded hillslopes. The findings suggest that this approach could be applicable worldwide under various parent material and climate conditions, providing a promising solution for addressing soil erosion in degraded areas.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141250431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent accumulation of microbial necromass and plant lignin phenol induced by adding maize straw to fertilized soils","authors":"Xu Liu ,&nbsp;Roland Bol ,&nbsp;Tingting An ,&nbsp;Yaocen Liu ,&nbsp;Yingde Xu ,&nbsp;Shuangyi Li ,&nbsp;Jingkuan Wang","doi":"10.1016/j.still.2024.106177","DOIUrl":"https://doi.org/10.1016/j.still.2024.106177","url":null,"abstract":"<div><p>Plant carbon (C) inputs and their subsequent microbial transformation affect the build-up process of soil organic C (SOC) pool. Nevertheless, there are knowledge gaps on how crop straw addition modifies SOC composition at molecular-level, especially in soils with different fertilization practices. Here, long-term fertilized Mollisols (unfertilized control, NF; inorganic fertilization, IF; inorganic fertilization plus manure, IFM) were incubated with or without maize straw addition in a 900-day field mesocosm experiment. The microbial necromass and plant lignin components contents were synchronously quantified based on amino sugar and lignin phenol biomarkers, respectively. And changes in SOC chemical composition were examined using solid-state ¹³C nuclear magnetic resonance spectroscopy. Relative to the NF treatment, long-term fertilization increased amino sugar and lignin phenol contents, and manure application enhanced the accumulation of plant lignin components more than that of microbial necromass. Compared with the NF treatment, the IF treatment decreased the relative proportion of alkyl C and SOC content, suggesting that changes in microbial necromass and lignin phenol were not always consistent with changes in SOC. For the NF and IF treatments, maize straw incorporation increased both amino sugar content and its contribution to SOC, indicating that microbial anabolism was important for SOC accumulation after adding maize straw in C-poor soils. For the IFM treatment, maize straw addition decreased lignin phenol content (27 %) and its contribution to SOC but increased the contribution of amino sugar to SOC, reflecting an enlarged contribution of microbial necromass to soil C pool formation under manure application after maize straw addition. The contribution of lignin phenol to SOC was decreased from days 360–900, whereas fungal necromass C content and the contribution of amino sugar to SOC were increased from days 360–900 under the IFM soil with maize straw addition, indicating that plant lignin components might be converted into fungal biomass and its necromass with increasing maize straw decomposition under manure application. Overall, we concluded that maize straw addition favored microbial immobilization in all fertilization treatments.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141241511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of straw mulching in longitudinal furrows on hillslope soil erosion and deposition in the Chinese Mollisol region","authors":"Hongqiang Shi ,&nbsp;Fenli Zheng ,&nbsp;Ting Zhao ,&nbsp;Ximeng Xu ,&nbsp;Gang Liu","doi":"10.1016/j.still.2024.106178","DOIUrl":"https://doi.org/10.1016/j.still.2024.106178","url":null,"abstract":"<div><p>In the Northeast Mollisol region of China, straw mulching has a great effect on preventing soil loss from ridge tillage, but how furrow straw mulching (FSM) impacts the spatial distribution of erosion-deposition and sediment sources in longitudinal ridge tillage systems is still unclear. Therefore, this study was to quantify the effects of the FSM on the spatial distribution of soil erosion-deposition and sediment sources in longitudinal ridge tillage systems by using the magnetism tracing methodology and indoor simulation rainfall experiments. The experimental treatments included two surface treatments: without the FSM (NFSM) and with the FSM of 0.30 kg·m⁻² amount, two rainfall intensities of 50 and 100 mm h⁻¹ were included; each experiment was run for 60 min at a soil pan with a 5° slope gradient, 6.2 m length, 1.3 m width and 0.7 m depth. The results indicated that, compared with the NFSM treatment, the total slope runoff and soil loss in the FSM treatment at two rainfall intensities were decreased by 41.6 % and 99.5 % and by 37.9 % and 97.7 %, respectively, and the reduction in slope runoff and soil loss decreased with an increase of rainfall intensity. The total mass of sediments intercepted by straw mulching on the entire slope accounted for 36.9 % and 10.4 % of the total soil loss in the NFSM treatment, respectively. Erosion regimes dominated on the hillslope of the NFSM treatment with strong-weak alternation at two rainfall intensities, while for the FSM treatment, only deposition regime was observed at 50 mm h⁻¹ rainfall intensity; a slight change with erosion-deposition on the ridge tops was observed and deposition in the furrows was observed at 100 mm h⁻¹ rainfall intensity. Furthermore, the FSM treatment changed the main sediment source from ridge tops to furrows on the hillslope compared to the NFSM treatment, whose sediment contributions from the ridge tops and the furrows at the two rainfall intensities were approximately 16.4 % and 83.6 %, respectively. In conclusion, FSM should be promoted due to its high efficiency in decreasing slope runoff and intercepting sediments. The findings of this study served as a scientific reference for effectively controlling soil erosion along slopes in the Chinese Mollisol region.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141244882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent changes in particulate and mineral-associated organic carbon under natural revegetation along a soil texture gradient in temperate grasslands of China","authors":"Peipei Wang ,&nbsp;Zhengchao Zhou ,&nbsp;Wenfei Yu ,&nbsp;Fang Liu ,&nbsp;Yuying Cao ,&nbsp;Jun’e Liu ,&nbsp;Ning Wang","doi":"10.1016/j.still.2024.106171","DOIUrl":"https://doi.org/10.1016/j.still.2024.106171","url":null,"abstract":"<div><p>The natural revegetation of grasslands can stimulate belowground carbon inputs and facilitate the storage of soil organic carbon (SOC), which is conducive to the restoration of grassland ecosystems. Previous studies have investigated the dynamics of organic carbon (OC) in bulk soil, but paid little attention to OC fractions within aggregates. This study explored the response of OC changes in functionally distinct fractions, namely particulate organic matter (POM) and mineral-associated organic matter (MAOM), to natural restoration through systematic measurements of two grassland vegetation species at three study sites along a soil texture gradient in the Loess Plateau. In naturally restored grasslands, the SOC and OC contents of POM (POM_C) and MAOM (MAOM_C) within bulk soil and aggregates were significantly (<em>p</em> &lt; 0.05) higher relative to bare land, with more effective improvement of POM_C (1.01−6.55 times) than MAOM_C (0.88−4.26 times). Compared to cover type (6.01 %−26.04 %), soil texture explained the variance of OC fractions to a greater extent (56.39 %−88.16 %). Soil texture had a larger contribution to MAOM_C in bulk soil with standardized path coefficients for total effect of 0.78 than POM_C, which had a coefficient of 0.67 (<em>p</em> &lt; 0.05). Moreover, the growth rate of the MAOM_C pool exhibited a gradual decline (<em>p</em> &lt; 0.001), which subsequently approached saturation level despite a persistent increase in total SOC in both bulk soil and aggregates. During soil carbon sequestration, aggregate fractions with relatively smaller particle size reached the MAOM_C saturation more easily than fractions with larger size. The findings of this study highlight the important role of soil texture in determining the saturation level of the MAOM_C pool at the regional scale. In the development of soil carbon sequestration strategies, more attention should be paid to the divergent behaviors of different SOM fractions and their distinct responses to natural restoration at larger spatiotemporal scales.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141244881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorus fertilizer input threshold shifts bacterial community structure and soil multifunctionality to maintain dryland wheat production","authors":"Lei Liu ,&nbsp;Zhiyuan Gao ,&nbsp;Weihang Liu ,&nbsp;Haifeng Li ,&nbsp;Zhaohui Wang ,&nbsp;Jinshan Liu","doi":"10.1016/j.still.2024.106174","DOIUrl":"https://doi.org/10.1016/j.still.2024.106174","url":null,"abstract":"<div><p>As an important factor affecting crop yield in agroecosystems, phosphorus (P) fertilizer addition can significantly alter the soil microbial community, functional gene composition, and multifunctionality. However, the major factors that determine wheat grain yield and the changes in wheat yield caused by the P fertilizer input threshold in dryland wheat production have not been adequately characterized. Based on a long-term field experiment (18 years) with five P addition gradients (0, 50, 100, 150, and 200 kg P₂O₅ ha⁻¹ yr⁻¹) in the Loess Plateau of China, amplicon (16 S rRNA) and metagenomic sequencing were used to investigate the effects of long-term P fertilization on soil bacterial communities, rhizosphere microbial functions, soil multifunctionality, and wheat grain yield. Long-term P input significantly affected the compositions and functions of the soil bacterial communities. Conversely, long-term high-P treatment (P200) inhibited soil bacterial diversity and soil P cycling genes but increased carbon (C) cycling genes and soil multifunctionality. Meanwhile, there is a threshold of P fertilizer (71.6−78.1 kg ha⁻¹ yr⁻¹) input for wheat grain yield, beyond which the grain yield of wheat did not significantly increase. In addition, the rhizosphere selection effect significantly increased the complexity of the rhizosphere network and microbial interactions and directed the recruitment of microorganisms and genes with special functions to maintain wheat grain yield. Therefore, this study revealed that the threshold of P fertilizer input can provide a basis for reducing P fertilizer and regulating microorganisms to maintain soil multifunctionality and network complexity in the dryland agriculture system of the Loess Plateau to maintain wheat grain yield.</p></div>","PeriodicalId":49503,"journal":{"name":"Soil & Tillage Research","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141250430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}