Soil SystemsPub Date : 2023-06-09DOI: 10.3390/soilsystems7020061
M. Taghvaei, M. D. Kordestani, M. Saleh, A. Mastinu
{"title":"The Reinforcement of Early Growth, Extract, and Oil of Silybum marianum L. by Polymer Organic Cover and Bacteria Inoculation under Water Deficit","authors":"M. Taghvaei, M. D. Kordestani, M. Saleh, A. Mastinu","doi":"10.3390/soilsystems7020061","DOIUrl":"https://doi.org/10.3390/soilsystems7020061","url":null,"abstract":"Early growth water stress reduces the extract and fresh oil of Silybum marianum L. (S. marianum) shoots. Two experiments were conducted to reduce the effects of early growth drought. Treatments in the first experiment were organic seed cover fillers at three levels (control, vermicompost, and peat moss), hydrogel at seven levels (control, 2, 4, and 6 g hydrogelF1 per kg OSC, and 2, 4, and 6 g hydrogelA200 per kg organic seed cover), and water deficit at three levels (100, 50, and 25% of field capacity), and in the second experiment, seeds were inoculated with bacteria at four levels (control, Pseudomonas fluorescens, Pseudomonas putida, and their combination) and water deficit at four levels (100, 50, and 25% of field capacity). Our results showed that milk thistle seeds are sensitive to water deficit at the emergence stage. Covering milk thistle (S. marianum) seeds with organic seed cover increased water retention around the seeds and improved emergence percentage. Use of organic seed cover with hydrogel increased relative water content (RWC), leaf area, and shoot length, and increased extracts and oils in fresh shoots. Bacterial inoculation also improved initial growth and reduced the effect of water stress on the plant, and increased leaf number, extract, and oil. The combination of bacteria had a positive effect on initial growth and inoculation of seeds, P. fluorescens and P. putida increased relative water content (RWC), shoot height, and specific leaf area, and increased extract and oil under water deficit conditions. A comparison of the results showed that seed inoculation is a simple method without new culture medium, and improves extract and oil under water deficit conditions.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44323071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-06-07DOI: 10.3390/soilsystems7020059
Kyle E. Smart, D. Singer
{"title":"Surface Coal Mine Soils: Evidence for Chronosequence Development","authors":"Kyle E. Smart, D. Singer","doi":"10.3390/soilsystems7020059","DOIUrl":"https://doi.org/10.3390/soilsystems7020059","url":null,"abstract":"Anthropogenic changes to soil properties and development can dominate soil systems, particularly in coal mining-impacted landscapes of the Appalachian region of the United States. Historical mining operations deposited spoils which are developing into mine soils in chronosequences, allowing for a correlation between emplacement age and rates of change in soil properties. The study site was in the Huff Run Watershed (Mineral City, OH, USA) with a series of eleven spoil piles that were deposited over a 30-year time period. Surface soils were analyzed for bulk density, loss on ignition (LOI) as a proxy for organic matter, particle size, and bulk mineralogical (by X-ray diffraction) and elemental (by X-ray fluorescence) compositions. The following linear trends were observed across the transect from older to younger mine soils: bulk density increased from 1.0 cm−3 to 1.5 g cm−3; LOI decreased from ~20% to 5%; the content of sand-sized particles and quartz decreased from ~50% to 30% and 50% to 25%, respectively, with a corresponding increase in the contribution of clay mineral from ~25% to 60%; and Fe and other trace metals (Cu, Ni, Pb, Sb, Sn, and Te) decreased in concentration, while Al, Mg, and K increased in concentration. These trends are likely the result of: (1) organic matter accumulation as vegetation becomes more abundant over time; (2) transport of clays out of more recently emplaced waste; and (3) oxidative dissolution of primary sulfides releasing Fe and other trace metals followed by re-precipitation of secondary Fe-phases and trace metal sequestration. The findings presented here provide insight into the future behavior of these materials and can potentially be used to assess the inferred age of previously unexamined mine soils across a wider geographic area. These results can also inform decisions related to reclamation activities and ecosystem restoration.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42666493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-06-07DOI: 10.3390/soilsystems7020060
E. Thomaz, Julliane P. Kurasz
{"title":"Long Term of Soil Carbon Stock in No-Till System Affected by a Rolling Landscape in Southern Brazil","authors":"E. Thomaz, Julliane P. Kurasz","doi":"10.3390/soilsystems7020060","DOIUrl":"https://doi.org/10.3390/soilsystems7020060","url":null,"abstract":"In the 1960s, a conservationist agricultural practice known as a “no-tillage system” was adopted. Several benefits such as soil erosion reduction and soil carbon sequestration, among others, could be ascribed to no-till systems. Therefore, it is important to evaluate the long-term sustainability of this agricultural system in different environments. This study has the objective to evaluate the soil organic carbon dynamic in a no-till system (40-year) and on a rolling landscape in Southern Brazil. A systematic grid with four transversal–longitudinal transects was used for soil sampling. Soil samples from 0–20, 20–40, and 40–60 cm depths were collected (16 trenches × 3 depths × 1 sample per soil layer = 48), and a forest nearby was used as control (4 trenches × 3 depths × 1 sample = 12). The soil at the forest site showed 20% more carbon stock than no-till at the 0–20 cm soil depth. However, the entire no-till soil profile (0–60 cm) showed similar soil carbon as forest soil. The soil carbon stock (0–20 cm) in no-till was depleted at a rate of 0.06 kg C m−2 year−1, summing up to a carbon loss of 2.43 kg C m−2. In addition, the non-uniform hillslope affected the soil carbon redistribution through the landscape, since the convex hillslope was more depleted in carbon by 37% (15.87 kg C m−2) when compared to the concave sector (25.27 kg C m−2). On average, the soil carbon loss in the subtropical agroecosystem was much lower than those reported in literature, as well as our initial expectations. In addition, the no-till system was capable of preserving soil carbon in the deepest soil layers. However, presently, the no-till system is losing more carbon in the topsoil at a rate greater than the soil carbon input.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46461226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-06-01DOI: 10.3390/soilsystems7020058
Masamichi Takahashi, I. Kosaka, S. Ohta
{"title":"Water Retention Characteristics of Superabsorbent Polymers (SAPs) Used as Soil Amendments","authors":"Masamichi Takahashi, I. Kosaka, S. Ohta","doi":"10.3390/soilsystems7020058","DOIUrl":"https://doi.org/10.3390/soilsystems7020058","url":null,"abstract":"Superabsorbent polymers (SAPs) are used as a soil amendment for retaining water, but suitable methods for the application of SAPs have not yet been developed. Here, we characterized a variety of soil–SAP mixtures prepared using four different types of SAP in terms of their water absorption and release characteristics. The teabag method was applied to characterize the soil–SAP mixtures, except for measurements of the matric potential. The results showed that the variations in water absorbency among the four SAPs in isolation became insignificant when they were mixed with sandy soils. The rates of water released from the soil–SAP mixtures under heated conditions were mitigated with decreasing water content, which prolonged the time until desiccation of the mixtures. The water absorbency of the SAPs significantly decreased in salt solutions (KCl and CaCl2), but their absorbency mostly recovered following immersion in tap water. The soil–dry SAP mixtures retained a larger amount of water than the soil–gel SAP mixtures. Swollen SAPs predominantly retained water in the range of −0.98 to −3.92 kPa, suggesting that SAP induces a transition from gravitational water to readily plant-available water by swelling itself. SAPs barely increased the amount of plant-available water in a potential range of −3.92 to −98.1 kPa, but significantly increased the soil water at <−98.1 kPa. The soil water content increased with an increasing SAP application rate, whereas the proportion of plant-available water declined. Our findings indicated that the performance of SAPs depends on the pore space and a saline environment in the soil and that low SAP application rates are suitable for maximizing the water available to plants in sandy soils.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47572765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-06-01DOI: 10.3390/soilsystems7020057
Theresa Reinersmann, Michael Herre, B. Marschner, S. Heinze
{"title":"Soil Enzyme Activity Response to Substrate and Nutrient Additions on Undisturbed Forest Subsoil Samples","authors":"Theresa Reinersmann, Michael Herre, B. Marschner, S. Heinze","doi":"10.3390/soilsystems7020057","DOIUrl":"https://doi.org/10.3390/soilsystems7020057","url":null,"abstract":"Previous studies have found that C turnover is bound to hotspots of microbial activity. The objective of this study was to analyze the effects of pure energy substrate (glucose), nutrient (mineral N or P) and combined substrate and nutrient (glucose + N, glucose + P, sterile DOC, artificial root exudate extract) additions to enzyme activity inside and outside hotspots as a proxy for microbial C turnover in a subsoil. By means of different substrate and nutrient additions, we tested how the limitations of our site were distributed on a small scale and depth-dependently to contribute to an increase in knowledge of subsoil mechanistics. The study site is a sandy Dystric Cambisol under an over 100-year-old beech forest stand in Lower Saxony, Germany. Forty-eight undisturbed soil samples from two depth increments (15–27 cm and 80–92 cm) of three profiles were sprayed homogeneously with easily available C, N and P sources to investigate the impacts of substrates and nutrients on three enzyme activities (acid phosphatase, β-glucosidase and N-acetylglucosaminidase) by using the soil zymography approach. Comparisons of upper and lower subsoils showed significantly fewer and smaller hotspots in the lower subsoil but with a high degree of spatial variation in comparison to the upper subsoil. Different patterns of enzyme distribution between upper and lower subsoil suggest microbial communities with a lower diversity are found in deeper soil regions of the site. Both substrate and nutrient additions stimulated enzyme activities significantly more outside the initial hotspots than within. Because of this, we conclude that microorganisms in the initial hotspots are less limited than in the surrounding bulk soil. Changes in enzyme activities owing to both substrate and nutrient addition were stronger in the lower subsoil than in the upper subsoil, showing differences in limitations and possible changes in microbial community structure with increasing depth. The results of our study emphasize the need to consider spatial factors in microbial turnover processes, especially in lower subsoil regions where stronger substrate and nutrient limitations occur.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49613786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-05-30DOI: 10.3390/soilsystems7020056
C. S. B. Bonini, Thais Monique de Souza Maciel, B. R. D. A. Moreira, José Guilherme Marques Chitero, Rodney Lúcio Pinheiro Henrique, M. C. Alves
{"title":"Long-Term Integrated Systems of Green Manure and Pasture Significantly Recover the Macrofauna of Degraded Soil in the Brazilian Savannah","authors":"C. S. B. Bonini, Thais Monique de Souza Maciel, B. R. D. A. Moreira, José Guilherme Marques Chitero, Rodney Lúcio Pinheiro Henrique, M. C. Alves","doi":"10.3390/soilsystems7020056","DOIUrl":"https://doi.org/10.3390/soilsystems7020056","url":null,"abstract":"Healthy soil biota is the key to meeting the world population’s growing demand for food, energy, fiber and raw materials. Our aim is to investigate the effect of green manure as a strategy to recover the macrofauna and the chemical properties of soils which have been anthropogenically degraded. The experiment was a completely randomized block design with four replicates. Green manure, Urochloa decumbens, with or without application of limestone and gypsum, composed the integrated systems. The macroorganisms as well as the soil fertility were analyzed after 17 years of a process of soil restoration with the aforementioned systems. The succession of Stizolobium sp. with Urochloa decumbens, with limestone and gypsum, was teeming with termites, beetles and ants. This integrated system presented the most technically adequate indexes of diversity and uniformity. Multivariate models showed a substantial increase in the total number of individuals due to the neutralization of harmful elements and the gradual release of nutrients by limestone and plaster. These conditioners have undergone multiple chemical reactions with the substrate in order to balance it chemically, thus allowing the macroinvertebrates to grow, develop, reproduce and compose their food web in milder microclimates. It was concluded that the integration of green manure together with grass is an economical and environmentally correct strategy to restore the macrofauna properties of degraded soil in the Brazilian savannah.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47045681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-05-27DOI: 10.3390/soilsystems7020055
Livia da Silva Freitas, Rodrigo de Lima Brum, Alícia da Silva Bonifácio, L. Volcão, F. M. R. da Silva Júnior, D. Ramos
{"title":"Assessment of the Impact of Ceftriaxone on the Functional Profile of Soil Microbiota Using Biolog EcoPlateTM","authors":"Livia da Silva Freitas, Rodrigo de Lima Brum, Alícia da Silva Bonifácio, L. Volcão, F. M. R. da Silva Júnior, D. Ramos","doi":"10.3390/soilsystems7020055","DOIUrl":"https://doi.org/10.3390/soilsystems7020055","url":null,"abstract":"Background: Antibiotics are essential to the treatment of diseases, but they have also brought about concerns in terms of their environmental, economic, and health impacts. Antibiotics can be excreted in unchanged form or as metabolites, which can cause toxicity by contaminating different environmental compartments, including soil. Soil is a critical compartment due to the numerous functions it performs and its direct impact on the communities of microorganisms, plants, and animals that make up the soil ecosystem. The functional profile of soil microbiota has emerged as a promising tool to assess soil quality. This study aimed to evaluate the functional profile of soil microbiota and the gut microbiota of earthworms in ceftriaxone-contaminated soil using Biolog EcoPlate. Methods: Soil samples contaminated with varying concentrations of ceftriaxone (0, 1, and 10 mg/kg) were incubated for 14 days in the presence or absence of the earthworm Eisenia andrei. After exposure, the physiological profile of the soil microbiota and the gut microbiota of the earthworms were evaluated using Biolog EcoPlate. Results: No significant differences were observed in the parameters evaluated using different concentrations of the antibiotic. The functional profile of the microbiota in the soil with and without earthworms was found to be similar, but interestingly, it differed from the profile of the intestinal microbiota of the earthworms. Conclusion: The findings of this study indicate that the presence of earthworms did not significantly alter the functional profile of the soil microbiota in ceftriaxone-contaminated soil. Further studies are necessary to investigate the potential impact of ceftriaxone and other antibiotics on soil microbiota and the role of earthworms in this regard.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48503215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-05-27DOI: 10.3390/soilsystems7020054
César Santos, Sheila Isabel do Carmo Pinto, Douglas Guelfi, Sara Dantas Rosa, Adrianne Braga da Fonseca, Tales Jesus Fernandes, Renato Avelar Ferreira, Leandro Barbosa Satil, Ana Paula Pereira Nunes, Konrad Passos e Silva
{"title":"Corn Cropping System and Nitrogen Fertilizers Technologies Affect Ammonia Volatilization in Brazilian Tropical Soils","authors":"César Santos, Sheila Isabel do Carmo Pinto, Douglas Guelfi, Sara Dantas Rosa, Adrianne Braga da Fonseca, Tales Jesus Fernandes, Renato Avelar Ferreira, Leandro Barbosa Satil, Ana Paula Pereira Nunes, Konrad Passos e Silva","doi":"10.3390/soilsystems7020054","DOIUrl":"https://doi.org/10.3390/soilsystems7020054","url":null,"abstract":"The adoption of technologies for N fertilization has become essential for increasing the N use efficiency in no-till (NT) systems in Brazil. Thus, this study aimed to quantify ammonia losses, N removal in grains, and second crop season yield in no-till and conventional (T) areas that received the application of different N fertilizers and their technologies. Ammonia volatilization, N extraction in grains, and corn yield in response to the application of conventional fertilizers were compared to urea treated with urease inhibitors in NT and conventional systems. The treatments were: no-N (Control); Prilled urea (PU); urea + N-(n-Butyl) thiophosphoric triamide (UNBPT); urea + Cu + B (UCuB); ammonium nitrate (AN), and ammonium sulfate (AS). In the NT system, the N-NH3 losses were 49% higher than in the conventional; without differences in corn yield. The fertilizers AN and AS had the lowest N-NH3 losses, regardless of the tillage system. UNBPT reduced the mean N-NH3 loss by 33% compared to PU. UNBPT (1200 mg kg−1) and UNBPT (180 mg kg−1) reduced the N-NH3 losses by 72% and 22%, respectively, compared to PU in the NT system. We noticed that the NBPT concentration to be used in soils under NT should be adjusted, and a reduction of N-NH3 losses does not directly reflect an increase in yield and N extraction by corn.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":"343 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135945643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-05-26DOI: 10.3390/soilsystems7020053
J. McGarr, E. Mbonimpa, D. McAvoy, M. Soltanian
{"title":"Fate and Transport of Per- and Polyfluoroalkyl Substances (PFAS) at Aqueous Film Forming Foam (AFFF) Discharge Sites: A Review","authors":"J. McGarr, E. Mbonimpa, D. McAvoy, M. Soltanian","doi":"10.3390/soilsystems7020053","DOIUrl":"https://doi.org/10.3390/soilsystems7020053","url":null,"abstract":"Per- and polyfluorinated alkyl substances (PFAS) are an environmentally persistent group of chemicals that can pose an imminent threat to human health through groundwater and surface water contamination. In this review, we evaluate the subsurface behavior of a variety of PFAS chemicals with a focus on aqueous film forming foam (AFFF) discharge sites. AFFF is the primary PFAS contamination risk at sites such as airports and military bases due to use as a fire extinguisher. Understanding the fate and transport of PFAS in the subsurface environment is a multifaceted issue. This review focuses on the role of adsorbent, adsorbate, and aqueous solution in the fate and transport of PFAS chemicals. Additionally, other hydrogeological, geochemical, ecological factors such as accumulation at air–water interfaces, subsurface heterogeneity, polyfluorinated PFAS degradation pathways, and plant interactions are discussed. This review also examines several case studies at AFFF discharge sites in order to examine if the findings are consistent with the broader PFAS literature. We present the most crucial future research directions and trends regarding PFAS and provide valuable insights into understanding PFAS fate and transport at AFFF discharge sites. We suggest a more comprehensive approach to PFAS research endeavors that accounts for the wide variety of environmental variables that have been shown to impact PFAS fate and transport.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43643198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil SystemsPub Date : 2023-05-18DOI: 10.3390/soilsystems7020052
Dolly Autufuga, Seth Quintus, K. Yoo, Stephanie S. Day, J. Huebert, J. Deenik, N. Lincoln
{"title":"Distribution of Soil Nutrients and Ancient Agriculture on Young Volcanic Soils of Ta‘ū, American Samoa","authors":"Dolly Autufuga, Seth Quintus, K. Yoo, Stephanie S. Day, J. Huebert, J. Deenik, N. Lincoln","doi":"10.3390/soilsystems7020052","DOIUrl":"https://doi.org/10.3390/soilsystems7020052","url":null,"abstract":"Soils and agriculture are inextricably linked, in the past as well as today. The Pacific islands, which often represent organized gradients of the essential soil-forming factors of substrate age and rainfall, represent excellent study systems to understand interactions between people and soils. The relationship between soil characteristics and indigenous agricultural practices are well documented for some locations, but there is a paucity of data for much of the region. Given the extent of ecological adaptation that has been documented, specifically for Hawai‘i, new Pacific datasets are expected to provide important insights into indigenous agricultural practices. To contribute to this discussion, we analyzed patterns in soil chemistry and vegetation in the Manu‘a islands of American Samoa. Soils were sampled along transects that crossed through precontact settlement zones in the upland of Fiti‘uta on Ta‘ū island, a location characterized by young (<100 ky) volcanic substrates and very high (>3800 mm y−1) annual rainfall. Soils were analyzed for several soil fertility properties that have been proposed as predictors of intensive rainfed tuber production in Hawai‘i and Rapa Nui. Surveys of remnant economic plants were conducted to assess patterns of past land use. Soils demonstrated moderate values of soil fertility as measured by pH, base saturation, exchangeable calcium, and total and exchangeable phosphorus, despite the high rainfall. Previously identified soil fertility indicators had some application to the distribution of traditional agriculture, but they also differed in important ways. In particular, low exchangeable calcium in the soils may have limited the agricultural form, especially the cultivation of tubers. Significant shifts in both soil parameters and remnant economic crops were documented, and alignment suggests cropping system adaptation to soil biochemistry. Archaeological samples combined with surveys of relict vegetation suggest that agroforestry and arboriculture were key components of past agricultural practices.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45406516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}