Soil Science最新文献

{"title":"The higher relative concentration of K+ to Na+ in saline water improves soil hydraulic conductivity, salt-leaching efficiency and structural stability","authors":"Sihui Yan, Tibin Zhang, Binbin Zhang, Tonggang Zhang, Y. Cheng, Chun Wang, Min Luo, Hao Feng, K. Siddique","doi":"10.5194/soil-9-339-2023","DOIUrl":"https://doi.org/10.5194/soil-9-339-2023","url":null,"abstract":"Abstract. Soil salinity and sodicity caused by saline water irrigation are widely\u0000observed globally. Clay dispersion and swelling are influenced by sodium\u0000(Na+) concentration and electrical conductivity (EC) of soil solution.\u0000Specifically, soil potassium (K+) also significantly affects soil\u0000structural stability, but for which concern was rarely addressed in previous\u0000studies or irrigation practices. A soil column experiment was carried out to\u0000examine the effects of saline water with different relative concentrations\u0000of K+ to Na+ (K+ / Na+), including K+ / Na+ of 0:1\u0000(K0Na1), 1:1 (K1Na1) and 1:0 (K1Na0) at a constant EC (4 dS m−1), and\u0000deionized water as the control (CK), on soil physicochemical properties. The\u0000results indicated that at the constant EC of 4 dS m−1, the infiltration\u0000rate and water content were significantly (P<0.05) affected by\u0000K+ / Na+ values, and K0Na1, K1Na1 and K1Na0 significantly (P<0.05) reduced saturated hydraulic conductivity by 43.62 %, 29.04 % and\u000018.06 %, respectively, compared with CK. The volumetric water content was\u0000significantly (P<0.05) higher in K0Na1 than CK at both 15 and 30 cm soil depths. K1Na1 and K1Na0 significantly (P<0.05) reduced the\u0000desalination time and required leaching volume. K0Na1 and K1Na1 reached the\u0000desalination standard after the fifth and second infiltration, respectively,\u0000as K1Na0 did not exceed the bulk electrical conductivity required for\u0000the desalination prerequisite throughout the whole infiltration cycle at 15 cm\u0000soil layer. Furthermore, due to the transformation of macropores into\u0000micropores spurred by clay dispersion, soil total porosity in K0Na1\u0000dramatically decreased compared with CK, and K1Na0 even increased the\u0000proportion of soil macropores. The higher relative concentration of K+\u0000to Na+ in saline water was more conducive to soil aggregate stability,\u0000alleviating the risk of macropores reduction caused by sodicity.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82365717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Agricultural use of compost under different irrigation strategies in a hedgerow olive grove under Mediterranean conditions – a comparison with traditional systems","authors":"Laura L. de Sosa, M. Martín-Palomo, P. Castro-Valdecantos, E. Madejón","doi":"10.5194/soil-9-325-2023","DOIUrl":"https://doi.org/10.5194/soil-9-325-2023","url":null,"abstract":"Abstract. Soil and water-efficient management are key factors in ensuring the olive sector's sustainable production practices. The use of compost based on olive waste (alperujo) as fertilizer could enhance ecosystem services while the need to transition to a zero-waste approach based on a circular economy is achieved. The present work includes a comparative study of the effect of alperujo compost (AC) vs. inorganic fertilization under different management systems: a traditional adult olive grove under rainfed conditions and a young hedgerow olive system, in which a factorial test of tree irrigation\u0000regimes (full, deficit and no irrigation) is implemented as well. At the hedgerow plots, the addition of AC and soil sampling time greatly impacted\u0000soil chemical parameters and, to a lesser extent, enzymatic activities, whereas irrigation regimes did not exert a marked influence. In the traditional rainfed system, the addition of AC proved to be an efficient tool for carbon sequestration. The first soil sampling revealed a clear\u0000stoichiometric relationship between soil organic matter (SOM) and the nitrogen, phosphorus and potassium (NPK) contents in both systems, whereas the correlations were weak and scarce in the second sampling at the hedgerow plots. This fact was related to the decay of the compost effect. Compost in combination with irrigation tended\u0000to trigger a certain priming effect on the native SOM with time since the carbon stocks were reduced between 6 % and 38 % from one sampling to the other in the hedgerow system, depending on the irrigation intensity. However, the deficit irrigation caused a less intense reduction of the SOM\u0000and essential nutrients representing the best alternative to maximizing the agronomic effects of the compost under a water-saving strategy. Recurrent application of compost would be necessary to maintain soil quality, especially with high tree densities. The combined management of AC and the\u0000deficit irrigation proved to be an efficient tool toward a zero-waste circular economy and a water conservation strategy.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79062872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Managing soil organic carbon in tropical agroecosystems: evidence from four long-term experiments in Kenya","authors":"Moritz Laub, M. Corbeels, Antoine Couëdel, 3. SamuelMathuNdungu, Prof Monicah Wanjiku Mucheru-Muna, D. Mugendi, 6. Magdalena Necpalova 1, Wycliffe Waswa 3, M. Broek, B. Vanlauwe, 1. JohanSix","doi":"10.5194/soil-9-301-2023","DOIUrl":"https://doi.org/10.5194/soil-9-301-2023","url":null,"abstract":"Abstract. In sub-Saharan Africa, maize is one of the most important staple crops, but long-term maize cropping with low external inputs has been associated with the loss of soil fertility. While adding high-quality organic resources combined with mineral fertilizer has been proposed to counteract this fertility loss, the long-term effectiveness\u0000and interactions with site properties still require more understanding. This study used repeated measurements over time to assess the effect of different quantities and qualities of organic resource addition combined with mineral nitrogen (N) on the change of soil organic carbon (SOC) contents over time (and SOC stocks in the year 2021) in four ongoing long-term experiments in Kenya. These experiments were established with identical treatments in moist to dry climates, on coarse to clayey soil textures, and have been conducted for at least 16 years. They received organic resources in quantities equivalent to 1.2 and 4 t C ha−1 yr−1 in the form of Tithonia diversifolia (high quality, fast turnover), Calliandra calothyrsus (high quality, intermediate turnover), Zea mays stover (low quality, fast turnover), sawdust (low quality, slow turnover) and local farmyard manure (variable quality, intermediate turnover). Furthermore, the addition of 240 kg N ha−1 yr−1 as mineral N fertilizer or no fertilizer was the split-plot treatment.\u0000At all four sites, a loss of SOC was predominantly observed, likely because the sites had been converted to cropland only a few decades before the start of the experiments. Across sites, the average decline of SOC content over 19 years in the 0 to 15 cm topsoil layer ranged from 42 % to 13 % of the initial SOC content for the control and the farmyard manure treatments at 4 t C ha−1 yr−1, respectively. Adding Calliandra or Tithonia at 4 t C ha−1 yr−1 limited the loss of SOC contents to about 24 % of initial SOC, while the addition of sawdust, maize stover (in three of the four sites) and sole mineral N addition showed no significant reduction of SOC loss over the control.\u0000Site-specific analyses, however, did show that at the site with the lowest initial SOC content (about 6 g kg−1), the addition of 4 t C ha−1 yr−1 farmyard manure or Calliandra with mineral N led to a gain in SOC contents. The other sites lost SOC in all treatments, albeit at site-specific rates. While subsoil SOC stocks in 2021 were little affected by organic resource additions (no difference in three of the four sites), the topsoil SOC stocks corroborated the results obtained from the SOC content measurements (0–15 cm) over time.\u0000The relative annual change of SOC contents showed a higher site specificity in farmyard manure, Calliandra and Tithonia treatments than in the control treatment, suggesting that the drivers of site specificity in SOC buildup (soil mineralogy, soil texture, climate) need to be better understood for effective targeting management of organic resources.\u0000Farmyard manure showed the highest potential","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89007857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accuracy of regional-to-global soil maps for on-farm decision-making: are soil maps “good enough”?","authors":"J. Maynard, E. Yeboah, S. Owusu, Michaela Buenemann, J. Neff, J. Herrick","doi":"10.5194/soil-9-277-2023","DOIUrl":"https://doi.org/10.5194/soil-9-277-2023","url":null,"abstract":"Abstract. A major obstacle to selecting the most appropriate crops and\u0000closing the yield gap in many areas of the world is a lack of site-specific\u0000soil information. Accurate information on soil properties is critical for\u0000identifying soil limitations and the management practices needed to improve\u0000crop yields. However, acquiring accurate soil information is often difficult\u0000due to the high spatial and temporal variability of soil properties at fine\u0000scales and the cost and inaccessibility of laboratory-based soil analyses.\u0000With recent advancements in predictive soil mapping, there is a growing\u0000expectation that soil map predictions can provide much of the information\u0000needed to inform soil management. Yet, it is unclear how accurate current\u0000soil map predictions are at scales relevant to management. The main\u0000objective of this study was to address this issue by evaluating the\u0000site-specific accuracy of regional-to-global soil maps, using Ghana as a\u0000test case. Four web-based soil maps of Ghana were evaluated using a dataset\u0000of 6514 soil profile descriptions collected on smallholder farms using the\u0000LandPKS mobile application. Results from this study revealed that publicly\u0000available soil maps in Ghana lack the needed accuracy (i.e., correct\u0000identification of soil limitations) to reliably inform soil management\u0000decisions at the 1–2 ha scale common to smallholders. Standard measures of\u0000map accuracy for soil texture class and rock fragment class predictions\u0000showed that all soil maps had similar performance in estimating the correct\u0000property class. Overall soil texture class accuracies ranged from 8 %–14 %\u0000but could be as high as 38 %–64 % after accounting for uncertainty in the\u0000evaluation dataset. Soil rock fragment class accuracies ranged from\u000026 %–29 %. However, despite these similar overall accuracies, there were\u0000substantial differences in soil property predictions among the four maps,\u0000highlighting that soil map errors are not uniform between maps. To better\u0000understand the functional implications of these soil property differences,\u0000we used a modified version of the FAO Global Agro-Ecological Zone (GAEZ)\u0000soil suitability modeling framework to derive soil suitability ratings for\u0000each soil data source. Using a low-input, rain-fed, maize production\u0000scenario, we evaluated the functional accuracy of map-based soil property\u0000estimates. This analysis showed that soil map data significantly\u0000overestimated crop suitability for over 65 % of study sites, potentially\u0000leading to ineffective agronomic investments by farmers, including\u0000cash-constrained smallholders.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"47 15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76420951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biochar promotes soil aggregate stability and associated organic carbon sequestration and regulates microbial community structures in Mollisols from northeast China","authors":"Jing Sun, Xinrui Lu, Guoshuang Chen, Nana Luo, Qi-long Zhang, Xiujun Li","doi":"10.5194/soil-9-261-2023","DOIUrl":"https://doi.org/10.5194/soil-9-261-2023","url":null,"abstract":"Abstract. Since the 1950s, heavy plowing of Mollisols, combined\u0000with a lack of organic matter intake, has resulted in severe soil\u0000degradation in northeast China. The use of biochar in combination with\u0000fertilizer is a sustainable method of improving soil quality. In this paper,\u0000we conducted field experiments to explore the response of the stability\u0000mechanism of the soil aggregate, the dynamic properties of organic carbon,\u0000and changes in the microbial community structure to biochar. The biochar\u0000input levels were C1, C2, and C3 (9.8, 19.6, and 29.4 Mg C ha−1,\u0000respectively), while the nitrogen (N) fertilizer rates were N1/2 (300 kg N ha−1) and N (600 kg N ha−1). Results indicated that biochar\u0000combined with N fertilizer effectively increases soil carbon storage and\u0000aggregates stability (P<0.05). And C2N treatment increased the\u0000aggregate contents of the >2 mm and 0.25–2 mm fractions by\u000056.59 % and 23.41 %, respectively. The phospholipid fatty acid (PLFA)\u0000analysis revealed that microbial community structure was effectively\u0000improved with biochar combined with N fertilizer application (P<0.05). The F/B ratio increased by 25.22 % and the gram-positive\u0000(Gm+) to gram-negative (Gm−) ratio by 4.65 % under the C2N1/2\u0000treatment. This study concluded that the response of Mollisols to biochar is\u0000primarily determined by the interplay of aggregate, organic carbon, and\u0000microorganisms. Therefore, the use of biochar combined with N fertilizer\u0000might mitigate soil degradation of Mollisols under an optimal application\u0000ratio, but the underlying mechanism still requires further exploration. This\u0000study will provide a scientific basis for the conservation and sustainable\u0000utilization of Mollisols resources.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86948528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of contrasting fertilizer technologies on N dynamics from subsurface bands of “pure” or blended fertilizer applications","authors":"Chelsea K. Janke, M. Bell","doi":"10.5194/soil-9-243-2023","DOIUrl":"https://doi.org/10.5194/soil-9-243-2023","url":null,"abstract":"Abstract. Enhanced efficiency fertilizer (EEF) technologies that\u0000employ product coatings to delay nitrogen (N) release or are chemically\u0000stabilized to inhibit key steps of N transformations in soil offer\u0000potential for improving N use efficiency (NUE) in agricultural systems.\u0000However, the dynamics of N release and transformation from single\u0000technologies may result in a spatial or temporal mismatch of N supply and\u0000demand during a growing season. This may be overcome by use of blends of\u0000different technologies, provided the reduction in the concentration of\u0000stabilizing products does not reduce effectiveness. Laboratory incubations\u0000quantified the N dynamics around bands of controlled-release fertilizer\u0000(CRF) and nitrification-inhibited (NI) urea and varying blends of these\u0000technologies and referenced this against conventional urea and\u0000biodegradable, plant-oil-coated urea (POCU) applied at the same rates in two\u0000contrasting soils over 60 d. Blends of NI urea (3,4-dimethylpyrazole\u0000phosphate, DMPP urea) and a CRF (polymer-coated urea, PCU) typically\u0000resulted in N concentrations and distribution that were intermediate to those\u0000of the constituent products in unblended applications. Changes in the\u0000proportions of each product were mirrored by urea nitrogen (urea-N) concentrations around\u0000the bands in both soils, while the proportions of DMPP urea in each blend\u0000were only related to the extent of nitrification inhibition in the Vertisol.\u0000A proportion of the POCU granules burst during the early stages of\u0000incubation, resulting in initially higher mineral N concentrations compared to PCU.\u0000However, both CRFs delayed N release and formation of nitrate nitrogen (NO3-N) relative to\u0000granular urea, and mineral N distribution was similar within each soil. Soil\u0000type had a significant impact on banded N dynamics. Where there was little\u0000effect of N-fertilizer treatment on NO3-N production in the Ferralsol,\u0000the higher impedance to solute transport in the Vertisol contributed to a\u0000significant inhibitory effect of NI urea on nitrification in both pure and\u0000blended DMPP urea treatments. Using NO3-N production as a benchmark for\u0000the risk of environmental loss, the efficacy of fertilizer treatments in\u0000this soil was of DMPP urea / PCU blends (higher ratio of PCU may offer small\u0000but insignificant benefit) > DMPP urea = PCU > urea.\u0000These findings highlight the importance of soil properties in determining\u0000the N dynamics from different banded EEF products. Insights into the\u0000efficacy of biodegradable alternatives to polymer coatings and the efficacy\u0000of blended EEF products can improve the reliability of N supply while\u0000reducing environmental impacts, therefore offering greater opportunities to\u0000sustainably improve fertilizer NUE in cropping systems.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86799380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elemental stoichiometry and Rock-Eval® thermal stability of organic matter in French topsoils","authors":"Amicie Delahaie, P. Barré, F. Baudin, D. Arrouays, A. Bispo, L. Boulonne, C. Chenu, C. Jolivet, M. Martin, C. Ratié, N. Saby, Florence Savignac, L. Cécillon","doi":"10.5194/soil-9-209-2023","DOIUrl":"https://doi.org/10.5194/soil-9-209-2023","url":null,"abstract":"Abstract. The quality and quantity of soil organic matter (SOM) are\u0000key elements that impact soil health and climate regulation by soils. The\u0000Rock-Eval® thermal analysis technique is becoming more commonly used, as\u0000it represents a powerful method for SOM characterization by providing\u0000insights into bulk SOM chemistry and thermal stability. In this study, we\u0000applied this technique on a large soil sample set from the first campaign\u0000(2000–2009) of the French Soil Quality Monitoring Network (RMQS – Réseau de mesures de la qualité des sols). Based on\u0000our analyses of ca. 2000 composite surface (0–30 cm) samples collected across\u0000mainland France, we observed a significant impact of land cover on both the SOM\u0000thermal stability and elemental stoichiometry. Cropland soils had a lower\u0000mean hydrogen index value (a proxy for the SOM H/C ratio) and a higher\u0000thermal stability than grasslands and forests. Regarding the oxygen index (a\u0000proxy for the SOM O/C ratio), we observed significant differences among the values for\u0000croplands, grasslands, and forests. Positive correlations of the\u0000temperature parameters with the clay content and pH highlight the protective effect of clay on organic matter as well as the\u0000impact of pH on microorganisms' mineralization activity. Surprisingly, we\u0000found weak effects of climatic parameters on the thermal stability and\u0000stoichiometry of SOM. Our data suggest that topsoil SOM is on average more\u0000oxidized and biogeochemically stable in croplands. More generally, the high\u0000number and even distribution of data across the whole French territory allow one to\u0000build a national interpretative reference for these indicators in surface\u0000soils.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89553132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Only a minority of bacteria grow after wetting in both natural and post-mining biocrusts in a hyperarid phosphate mine","authors":"Talia Gabay, Eva Petrova, O. Gillor, Y. Ziv, Roey Angel","doi":"10.5194/soil-9-231-2023","DOIUrl":"https://doi.org/10.5194/soil-9-231-2023","url":null,"abstract":"Abstract. Biological soil crusts (biocrusts) are key contributors to desert ecosystem\u0000functions, therefore, biocrust restoration following mechanical disturbances\u0000is imperative. In the Negev Desert hyperarid regions, phosphate mining has\u0000been practiced for over 60 years, destroying soil habitats and fragmenting\u0000the landscape. In this study, we selected one mining site restored in 2007,\u0000and we used DNA stable isotope probing (DNA-SIP) to identify which bacteria\u0000grow in post-mining and adjacent natural biocrusts. Since biocrust\u0000communities activate only after wetting, we incubated the biocrusts with\u0000H218O for 96 h under ambient conditions. We then evaluated the\u0000physicochemical soil properties, chlorophyll a concentrations, activation,\u0000and functional potential of the biocrusts. The DNA-SIP assay revealed low\u0000bacterial activity in both plot types and no significant differences in the\u0000proliferated communities' composition when comparing post-mining and natural\u0000biocrusts. We further found no significant differences in the microbial\u0000functional potential, photosynthetic rates, or soil properties. Our results\u0000suggest that growth of hyperarid biocrust bacteria after wetting is minimal.\u0000We hypothesize that due to the harsh climatic conditions, during wetting,\u0000bacteria devote their meager resources to prepare for the coming drought, by\u0000focusing on damage repair and organic compound synthesis and storage rather\u0000than on growth. These low growth rates contribute to the sluggish recovery\u0000of desert biocrusts following major disturbances such as mining. Therefore,\u0000our findings highlight the need for implementing active restoration\u0000practices following mining.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78236348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Masked diversity and contrasting soil processes in tropical seagrass meadows: the control of environmental settings","authors":"G. N. Nóbrega, X. L. Otero, D. J. Romero, H. M. Queiroz, D. Gorman, Margareth S. Copertino, M. Piccolo, T. O. Ferreira","doi":"10.5194/soil-9-189-2023","DOIUrl":"https://doi.org/10.5194/soil-9-189-2023","url":null,"abstract":"Abstract. Seagrass meadows are among the most valuable ecosystems on Earth. However, in tropical countries, there is a substantial knowledge gap in “seagrass science”. To address this gap, seagrass soils from three\u0000Brazilian coastal regions were investigated (the northeastern, southeastern, and southern coasts). Soil profiles from different geological and bioclimatic settings were sampled,\u0000described, and analyzed. Thus, detailed macromorphological descriptions, soil classification, physicochemical analysis (soil particle size, soil pH,\u0000pHoxidation, Eh, total organic carbon: TOC), Fe partitioning, and X-ray diffractometry were performed. Additionally, water samples were analyzed for\u0000pH, salinity, and ion concentrations. Different environmental settings in\u0000the coastal compartments produced contrasting geochemical conditions, which\u0000caused different intensities of pedogenetic processes. On the northeastern coast, the denser plant coverage favored higher TOC contents (2.5 ± 0.1 %) and\u0000an anaerobic environment (Eh = +134  ± 142 mV) prone to an intense sulfidization (i.e., pyrite formation: Py-Fe). Py-Fe contents in northeastern soils were 6- and 2-fold higher than in southeastern and southern coastal soils, respectively.\u0000Conversely, lower TOC contents (0.35 ± 0.15 %) and a suboxic\u0000environment (Eh + 203 ± 55 mV) in the southeastern soils, along with the Fe-rich geological surroundings, decreased the intensity of gleization. The\u0000contrasting intensities in the soil processes, related to the (seemingly\u0000subtle) differences in the geochemistry of each environment, ultimately\u0000caused relevant pedodiversity among the studied sites. Our findings contribute to a better understanding of the general functioning of tropical\u0000seagrass meadows but also have significant environmental implications for\u0000studies focused on carbon sequestration in these ecosystems.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89029969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oil-palm management alters the spatial distribution of amorphous silica and mobile silicon in topsoils","authors":"Britta Greenshields, Barbara von der Lühe, H. Hughes, C. Stiegler, S. Tarigan, A. Tjoa, D. Sauer","doi":"10.5194/soil-9-169-2023","DOIUrl":"https://doi.org/10.5194/soil-9-169-2023","url":null,"abstract":"Abstract. Effects of oil-palm (Elaeis guineensis Jacq.) management on silicon (Si) cycling under smallholder oil-palm plantations have hardly been investigated. As oil palms are Si accumulators, we hypothesized that management practices and topsoil erosion may cause Si losses and changes in spatial Si concentration patterns in topsoils under oil-palm cultivation. To test this hypothesis, we took topsoil samples under mature oil-palm plantations in well-drained and riparian areas of Jambi Province, Indonesia. The samples were taken from four different management zones within each oil-palm plot: palm circles, oil-palm rows, interrows, and below frond piles. We quantified mobile Si (SiM) and Si in amorphous silica (SiAm) by the extraction of CaCl2 and NaCO3, respectively. Both fractions are important Si pools in soils and are essential for plant–soil Si cycling. We further installed sediment traps on sloping, well-drained oil-palm plantations to estimate the annual loss of soil and SiAm caused by erosion. In well-drained areas, mean topsoil SiAm concentrations were significantly higher below frond piles (3.97 ± 1.54 mg g−1) compared to palm circles (1.71 ± 0.35 mg g−1), oil-palm rows (1.87 ± 0.51 mg g−1), and interrows (1.88 ± 0.39 mg g−1). In riparian areas, the highest mean topsoil SiAm concentrations were also found below frond\u0000piles (2.96 ± 0.36 mg g−1) and in grass-covered interrows (2.71 ± 0.13 mg g−1), whereas topsoil SiAm concentrations of palm circles were much lower (1.44 ± 0.55 mg g−1). We attributed the high SiAm concentrations in topsoils under frond piles and in grass-covered interrows to phytolith release from decaying oil-palm fronds, grasses, and sedges. The significantly lower SiAm concentrations in palm circles (in both well-drained and riparian areas), oil-palm rows, and unvegetated interrows (only in well-drained areas) were explained by a lack of litter return to these management zones. Mean topsoil SiM\u0000concentrations were in the range of ∼ 10–20 µg g−1. They tended to be higher in riparian areas, but the differences between well-drained and riparian sites were not statistically significant.\u0000Soil-loss calculations based on erosion traps confirmed that topsoil erosion was considerable in oil-palm interrows on slopes. Erosion estimates were in the range of 4–6 Mg ha−1 yr−1, involving SiAm losses in a range of 5–9 kg−1 ha−1 yr−1. Based on the observed spatial\u0000Si patterns, we concluded that smallholders could efficiently reduce erosion and support Si cycling within the system by (1) maintaining a grass cover in oil-palm rows and interrows, (2) incorporating oil-palm litter into plantation management, and (3) preventing soil compaction and surface-crust formation.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"67 11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91315683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}