1,669 research outputs found
Refining physical aspects of soil quality and soil health when exploring the effects of soil degradation and climate change on biomass production: an Italian case study
This study focuses on soil physical aspects of soil
quality and health with the objective to define procedures with worldwide
rather than only regional applicability, reflecting modern developments in
soil physical and agronomic research and addressing important questions
regarding possible effects of soil degradation and climate change. In
contrast to water and air, soils cannot, even after much research, be
characterized by a universally accepted quality definition and this hampers
the internal and external communication process. Soil quality expresses the
capacity of the soil to function. Biomass production is a primary function,
next to filtering and organic matter accumulation, and can be modeled with
soil–water–atmosphere–plant (SWAP) simulation models, as used in the
agronomic yield-gap program that defines potential yields (Yp) for any
location on earth determined by radiation, temperature and standardized crop
characteristics, assuming adequate water and nutrient supply and lack of
pests and diseases. The water-limited yield (Yw) reflects, in addition, the
often limited water availability at a particular location. Actual yields
(Ya) can be considered in relation to Yw to indicate yield gaps, to be
expressed in terms of the indicator (Ya/Yw)×100.
Soil data to calculate Yw for a given soil type (the genoform) should
consist of a range of soil properties as a function of past management
(various phenoforms) rather than as a single representative dataset. This way
a Yw-based characteristic soil quality range for every soil type is
defined, based on semipermanent soil properties. In this study effects of
subsoil compaction, overland flow following surface compaction and erosion
were simulated for six soil series in the Destra Sele area
in Italy, including effects of climate change. Recent proposals consider soil
health, which appeals more to people than soil quality and is now defined by
separate soil physical, chemical and biological indicators. Focusing on the
soil function biomass production, physical soil health at a given time of a
given type of soil can be expressed as a point (defined by a measured Ya)
on the defined soil quality range for that particular type of soil, thereby
defining the seriousness of the problem and the scope for improvement. The
six soils showed different behavior following the three types of land
degradation and projected climate change up to the year 2100. Effects are
expected to be major as reductions of biomass production of up to 50 %
appear likely under the scenarios. Rather than consider soil physical,
chemical and biological indicators separately, as proposed now elsewhere for
soil health, a sequential procedure is discussed, logically linking the
separate procedures.</p
Sediment supply explains long-term and large-scale patterns in saltmarsh lateral expansion and erosion
Salt marshes often undergo rapid changes in lateral extent, the causes of which lack common explanation. We combine hydrological, sedimentological, and climatological data with analysis of historical maps and photographs to show that long‐term patterns of lateral marsh change can be explained by large‐scale variation in sediment supply and its wave‐driven transport. Over 150 years, northern marshes in Great Britain expanded while most southern marshes eroded. The cause for this pattern was a north to south reduction in sediment flux and fetch‐driven wave sediment resuspension and transport. Our study provides long‐term and large‐scale evidence that sediment supply is a critical regulator of lateral marsh dynamics. Current global declines in sediment flux to the coast are likely to diminish the resilience of salt marshes and other sedimentary ecosystems to sea level rise. Managing sediment supply is not common place but may be critical to mitigating coastal impacts from climate change
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Non-Coding RNA Sequencing of Equine Endometrium During Maternal Recognition of Pregnancy.
Maternal recognition of pregnancy (MRP) in the mare is not well defined. In a non-pregnant mare, prostaglandin F2α (PGF) is released on day 14 post-ovulation (PO) to cause luteal regression, resulting in loss of progesterone production. Equine MRP occurs prior to day 14 to halt PGF production. Studies have failed to identify a gene candidate for MRP, so attention has turned to small, non-coding RNAs. The objective of this study was to evaluate small RNA (<200 nucleotides) content in endometrium during MRP. Mares were used in a cross-over design with each having a pregnant and non-mated cycle. Each mare was randomly assigned to collection day 11 or 13 PO (n = 3/day) and endometrial biopsies were obtained. Total RNA was isolated and sequencing libraries were prepared using a small RNA library preparation kit and sequenced on a HiSeq 2000. EquCab3 was used as the reference genome and DESeq2 was used for statistical analysis. On day 11, 419 ncRNAs, representing miRNA, snRNA, snoRNA, scaRNA, and vaultRNA, were different between pregnancy statuses, but none on day 13. Equine endometrial ncRNAs with unknown structure and function were also identified. This study is the first to describe ncRNA transcriptome in equine endometrium. Identifying targets of these ncRNAs could lead to determining MRP
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