Does a Carbonatite Deposit Influence Its Surrounding Ecosystem?

Carbonatites are unusual alkaline rocks with diverse compositions. Although previous work has characterized the effects these rocks have on soils and plants, little is known about their impacts on local ecosystems. Using a deposit within the Great Lakes–St. Lawrence forest in northern Ontario, Canada, we investigated the effect of a carbonatite on soil chemistry and on the structure of plant and soil microbial communities. This was done using a vegetation survey conducted above and around the deposit, with corresponding soil samples collected for determining soil nutrient composition and for assessing microbial community structure using 16S/ITS Illumina Mi-Seq sequencing. In some soils above the deposit a soil chemical signature of the carbonatite was found, with the most important effect being an increase in soil pH compared with the non-deposit soils. Both plants and microorganisms responded to the altered soil chemistry: the plant communities present in carbonatite-impacted soils were dominated by ruderal species, and although differences in microbial communities across the surveyed areas were not obvious, the abundances of specific bacteria and fungi were reduced in response to the carbonatite. Overall, the deposit seems to have created microenvironments of relatively basic soil in an otherwise acidic forest soil. This study demonstrates for the first time how carbonatites can alter ecosystems in situ

Soil chemistry aspects of predicting future phosphorus requirements in Sub-Saharan Africa

Phosphorus (P) is a finite resource and critical to plant growth and therefore food security. Regional‐ and continental‐scale studies propose how much P would be required to feed the world by 2050. These indicate that sub‐Saharan Africa soils have the highest soil P deficit globally. However, the spatial heterogeneity of the P deficit caused by heterogeneous soil chemistry in the continental scale has never been addressed. We provide a combination of a broadly adopted P‐sorption model that is integrated into a highly influential, large‐scale soil phosphorus cycling model. As a result, we show significant differences between the model outputs in both the soil‐P concentrations and total P required to produce future crops for the same predicted scenarios. These results indicate the importance of soil chemistry for soil‐nutrient modelling and highlight that previous influential studies may have overestimated P required. This is particularly the case in Somalia where conventional modelling predicts twice as much P required to 2050 as our new proposed model. Plain language summary Improving food security in Sub‐Saharan Africa over the coming decades requires a dramatic increase in agricultural yields. Global yield increase has been driven by, amongst other factors, the widespread use of fertilisers including phosphorus. The use of fertilisers in Sub‐Saharan Africa is often prohibitively expensive and thus the most efficient use of phosphorus should be targeted. Soil chemistry largely controls phosphorus efficiency in agriculture, for example iron and aluminium which exist naturally in soil reduce the availability of phosphate to plants. Yet soil chemistry has not been included in several influential large‐scale modelling studies which estimate phosphorus requirements in Sub‐Saharan Africa to 2050. In this study we show that predictions of phosphorus requirement to feed the population of Sub‐Saharan Africa to 2050 can significantly change if soil chemistry is included (e.g. Somalia with up to 50% difference). Our findings are a new step towards making predictive decision‐making tool for phosphorus fertiliser management in Sub‐Saharan Africa considering the variability of soil chemistry

Drifting Communities : Relationships Between Soil Chemistry, Plant and Microbial Communities Along an Urban Watershed

The goal of this study was to investigate plant and soil communities along a riparian corridor at four sites in the Toms River Watershed of Ocean County, NJ. This research assessed how these communities differ between the upland and floodplain habitats by examining both biotic and abiotic factors. To accomplish this, plant communities were assessed upon tree basal area, woody shrub cover, herbaceous cover and presence/absence of “all-vegetation”. Soil microbial community composition was also measured at the same four sites. At each of the four sites, I surveyed three transects that were parallel, perpendicular and upland from the river. These transects were then classified into two habitat types; floodplain and upland. Soil samples were returned to the lab for microbial DNA fingerprinting (terminal restriction fragment length polymorphism- TRFLP). Soil chemistry samples were also taken at all four sites. Plant and fungal communities were significantly different among the four sites, however bacterial communities were not significantly different. Plant, fungal and bacterial communities were all significantly different between the floodplain and the upland habitats. Soil chemistry did not vary significantly among the sites. However, soil chemistry did vary significantly between the floodplain and upland for both soil moisture and pH. Soil moisture and pH correlated strongly with the distribution and composition of plant and microbial communities sampled in this study. Bacterial communities were unique in that they correlated with NH4 as well as pH, but did not correlate with soil moisture. Bacterial communities also did not correlate with any of the plant groups or with fungi. Fungal communities correlated with plant communities as well as soil moisture and pH. These results show that soil chemistry, particularly soil pH, correlates most often with plant and soil microbial community distribution in this study

News from members: New Zealand

This year we are celebrating 50 years since the first soil/ permafrost scientific expedition in the Ross Sea Region of Antarctica. It was undertaken by Prof. John D. McCraw and Dr Graeme G. Claridge. They set off from Scott Base on the Massey Fergusson tractors that Sir Edmund Hillary took to the South Pole in 1957/58 and drove to New Harbour, from which they travelled on foot for several weeks exploring the Taylor Valley and adjacent areas. Graeme Claridge went on to become an expert on Antarctic soil chemistry and, with Iain Campbell, authored the most authoritative book available on the soils of Antarctica. Both McCraw and Claridge are fit and well - (permafrost and cryosol research must be good for you) and we will be holding a celebration to mark their original journey in November this year

Soil acidity as calcium (fertility) deficiency

Presented at the Joint Meeting of Commission II (Soil chemistry) and Commission IV (Soil Fertility and Plant Nutrition), International Society of Soil Science, Dublin, July, 1952--P. 2.Digitized 2007 AES.Includes bibliographical references (pages 18-19)

Lanthanide Soil Chemistry and Its Importance in Understanding Soil Pathways: Mobility, Plant Uptake, and Soil Health

The lanthanide elements or rare earth elements (REEs) are an active soil science research area, given their usage as micro-fertilizers, documented cases of environmental impact attributed to industry/mining, and their ability to identify lithologic discontinuities and reveal active soil processes. To fully understand REEs requires an understanding of their chemical reactivity, both for the individual elements and their behavior as a group of elements. The elements of the lanthanide series, including La and Y, may have subtle to very perceptible chemical differences that when viewed collectively reveal information that gives emphasis to soil processes that clarify soil behavior or soil genesis. This chapter concentrates on lanthanide soil chemistry and shows how the soil chemistry of REEs may support soil science investigations

Soil bacterial communities of a calcium-supplemented and a reference watershed at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA

Soil Ca depletion because of acidic deposition-related soil chemistry changes has led to the decline of forest productivity and carbon sequestration in the northeastern USA. In 1999, acidic watershed (WS) 1 at the Hubbard Brook Experimental Forest (HBEF), NH, USA was amended with Ca silicate to restore soil Ca pools. In 2006, soil samples were collected from the Ca-amended (WS1) and reference watershed (WS3) for comparison of bacterial community composition between the two watersheds. The sites were about 125 m apart and were known to have similar stream chemistry and tree populations before Ca amendment. Ca-amended soil had higher Ca and P, and lower Al and acidity as compared with the reference soils. Analysis of bacterial populations by PhyloChip revealed that the bacterial community structure in the Ca-amended and the reference soils was significantly different and that the differences were more pronounced in the mineral soils. Overall, the relative abundance of 300 taxa was significantly affected. Numbers of detectable taxa in families such as Acidobacteriaceae, Comamonadaceae, and Pseudomonadaceae were lower in the Ca-amended soils, while Flavobacteriaceae and Geobacteraceae were higher. The other functionally important groups, e.g. ammonia-oxidizing Nitrosomonadaceae, had lower numbers of taxa in the Ca-amended organic soil but higher in the mineral soil