Evaluating the surface irrigation soil loss (SISL) model

Although the percentage of surface irrigated land in the United States is declining, it is still used on 43% of the irrigated land, and 51% of the surface irrigated land is irrigated down furrows or rows (USDA, 2004). Water flowing in irrigation furrows often detaches and transports soil, reducing crop productivity and impairing off-site water quality. Crop yields were at least 25% less on fields eroded from over 80 years of furrow irrigation in south-central Idaho (Carter et al., 1985). Measured soil loss from furrow irrigated fields in this area varied from 1 to 141 Mg ha-1 annually (Berg and Carter, 1980) while the annual average soil loss from the entire irrigated tract was 0.46 Mg ha-1 in 1971 (Brown et al, 1974). This soil, and associated nutrients, is transported with irrigation water as it returns to the Snake River. The Natural Resources Conservation Service (NRCS) and other land planning agencies need a tool to predict furrow irrigation erosion to assess the extent of the problem and to compare conservation practices applied to irrigated land. An evaluation of the Water Erosion Prediction Project (WEPP) model indicated that it could not be used to predict furrow irrigation erosion without substantially adjusting erodibility parameter values (Bjorneberg et al., 1999). The model also over-predicted sediment transport capacity resulting in no predicted sediment deposition on the lower end of fields, although data and observations document much on-field deposition (Bjorneberg et al., 1999). The Idaho NRCS, in consultation with scientists and engineers at the Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, developed a simple empirical model for estimating annual irrigation-induced soil loss from furrow irrigated fields. The SISL (surface irrigation soil loss) model was developed in 1991 based on over 200 field-years of data from southern Idaho. This model estimates soil loss at the end of the furrow and does not account for deposition or additional erosion that may occur in the drainage ditch at the end of the field. The only published documentation of this model is Idaho NRCS Agronomy Technical Note No. 32. Idaho NRCS uses this model to assess benefits of conservation practices, such as converting from furrow to sprinkler irrigation, but this model has not been independently evaluated. Therefore, the objective of this study was to compare the SISL model with erosion data collected from furrow irrigated fields near Kimberly, Idaho and Prosser, Washington

Evaluating the surface irrigation soil loss (SISL) model

Although the percentage of surface irrigated land in the United States is declining, it is still used on 43% of the irrigated land, and 51% of the surface irrigated land is irrigated down furrows or rows (USDA, 2004). Water flowing in irrigation furrows often detaches and transports soil, reducing crop productivity and impairing off-site water quality. Crop yields were at least 25% less on fields eroded from over 80 years of furrow irrigation in south-central Idaho (Carter et al., 1985). Measured soil loss from furrow irrigated fields in this area varied from 1 to 141 Mg ha-1 annually (Berg and Carter, 1980) while the annual average soil loss from the entire irrigated tract was 0.46 Mg ha-1 in 1971 (Brown et al, 1974). This soil, and associated nutrients, is transported with irrigation water as it returns to the Snake River. The Natural Resources Conservation Service (NRCS) and other land planning agencies need a tool to predict furrow irrigation erosion to assess the extent of the problem and to compare conservation practices applied to irrigated land. An evaluation of the Water Erosion Prediction Project (WEPP) model indicated that it could not be used to predict furrow irrigation erosion without substantially adjusting erodibility parameter values (Bjorneberg et al., 1999). The model also over-predicted sediment transport capacity resulting in no predicted sediment deposition on the lower end of fields, although data and observations document much on-field deposition (Bjorneberg et al., 1999). The Idaho NRCS, in consultation with scientists and engineers at the Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, developed a simple empirical model for estimating annual irrigation-induced soil loss from furrow irrigated fields. The SISL (surface irrigation soil loss) model was developed in 1991 based on over 200 field-years of data from southern Idaho. This model estimates soil loss at the end of the furrow and does not account for deposition or additional erosion that may occur in the drainage ditch at the end of the field. The only published documentation of this model is Idaho NRCS Agronomy Technical Note No. 32. Idaho NRCS uses this model to assess benefits of conservation practices, such as converting from furrow to sprinkler irrigation, but this model has not been independently evaluated. Therefore, the objective of this study was to compare the SISL model with erosion data collected from furrow irrigated fields near Kimberly, Idaho and Prosser, Washington

Membrane currents in cultured human intestinal smooth muscle cells.

Tropical peatlands store ~75 Pg carbon and have operated as long-term net carbon sinks throughout the Holocene. However, intensive land development is destabilizing these reservoirs, resulting in large carbon emissions to the atmosphere and loss of valuable low-latitude peat paleorecords

Modulation of metal-azolate frameworks for the tunable release of encapsulated glycosaminoglycans

Glycosaminoglycans (GAGs) are biomacromolecules necessary for the regulation of different biological functions. In medicine, GAGs are important commercial therapeutics widely used for the treatment of thrombosis, inflammation, osteoarthritis and wound healing. However, protocols for the encapsulation of GAGs in MOFs carriers are not yet available. Here, we successfully encapsulated GAG-based clinical drugs (heparin, hyaluronic acid, chondroitin sulfate, dermatan sulfate) and two new biotherapeutics in preclinical stage (GM-1111 and HepSYL proteoglycan) in three different pH-responsive metal-azolate frameworks (ZIF-8, ZIF-90, and MAF-7). The resultant GAG@MOF biocomposites present significant differences in terms of crystallinity, particle size, and spatial distribution of the cargo, which influences the drug-release kinetics upon applying an acidic stimulus. For a selected system, heparin@MOF, the released therapeutic retained its antithrombotic activity while the MOF shell effectively protects the drug from heparin lyase. By using different MOF shells, the present approach enables the preparation of GAG-based biocomposites with tunable properties such as encapsulation efficiency, protection and release.Miriam de J. Velásquez-Hernández, Efwita Astria, Sarah Winkler, Weibin Liang, Helmar Wiltsche, Arpita Poddar, Ravi Shukla, Glenn Prestwich, John Paderi, Pablo Salcedo-Abraira, Heinz Amenitsch, Patricia Horcajada, Christian J. Doonan and Paolo Falcar

Potential of Natural Biomaterials in Nano-scale Drug Delivery

Background: The usage of natural biomaterials or naturally derived materials intended for interface with biological systems has steadily increased in response to the high demand of amenable materials, which are suitable for purpose, biocompatible and biodegradable. There are many naturally derived polymers which overlap in terms of purpose as biomaterials but are equally diverse in their applications. Methods: This review examines the applications of the following naturally derived polymers; hyaluronic acid, silk fibroin, chitosan, collagen and tamarind polysaccharide (TSP); further focusing on the biomedical applications of each as well as emphasising on individual novel applications. Results: Each of the polymer was found to demonstrate a wide variety of successful biomedical applications fabricated as wound dressings, scaffolds, matrices, films, sponges, implants or hydrogels to suit the therapeutic need. Interestingly, blending and amelioration of polymer structures were but two of a selection of strategies to modify the functionality of the polymers to suit the purpose. Further these polymers have shown promise to deliver small molecule drugs, proteins and genes as nano-scale delivery systems. Conclusion: The review highlights the breadth and depth of applications of the aforementioned polymers as biomaterials. Hyaluronic acid, silk fibroin, chitosan, collagen and TSP have been successfully utilised as biomaterials in the subfields of implant enhancement, wound management, drug delivery, tissue engineering and nanotechnology. Whilst there are a number of associated advantages (i.e. biodegradability, biocompatibility, non-toxic, non-antigenic as well as amenability) the select disadvantages of each individual polymer provide significant scope for their further exploration and overcoming challenges like feasibility of mass production at a relatively low cost