11 research outputs found
OH Module Assembly Stand
There is an OR module assembly stand in use at IB4. This design has been approved by safety, as presented by Mike Foley, and has been successfully used. Another one is needed at the D-zero assembly building, but some modifications need to be made. This report will show that the new modified design is at least as strong, if not stronger, than the older IB4 design in every aspect. Since the weight distribution of the OR modules on the sling is indeterminate, this report compares three cases of support for the entire assembly: the lowest two beams only, the lowest four beams only, and all six beams. In each of these cases, the new design is stronger than the old design in maximum allowable weight. The ability of the the cradle to support the weight is also shown. For all of the failure conditions except for two, the cradle is stronger than the beams that it supports. In the two excepted situations, the calculated limit of the cradle is less than the beams it supports. This is because no credit is taken for the sling and strongback, which in reality will relieve much of the horizontal load
Phosphorus status and microbial community of paddy soil with the growth of annual ryegrass (Lolium multiflorum Lam.) under different phosphorus fertilizer treatments*
Annual ryegrass (Lolium multiflorum Lam.) was grown in paddy soil in pots under different phosphorus (P) fertilizer treatments to investigate changes of P fractions and microbial community of the soil. The treatments included Kunyang phosphate rock (KPR) applications at 50 mg P/kg (KPR50) and 250 mg P/kg (KPR250), mono-calcium phosphate (MCP) application at 50 mg P/kg (MCP50), and the control without P application. The results showed that KPR50, KPR250, and MCP50 applications significantly increased the dry weight of the ryegrass by 13%, 38%, and 55%, and increased P uptake by 19%, 135%, and 324%, respectively. Compared with MCP50, the relative effectiveness of KPR50 and KPR250 treatments in ryegrass production was about 23% and 68%, respectively. After one season of ryegrass growth, the KPR50, KPR250, and MCP50 applications increased soil-available P by 13.4%, 26.8%, and 55.2%, respectively. More than 80% of the applied KPR-P remained as HCl-P fraction in the soil. Phospholipid fatty acid (PLFA) analysis showed that the total and bacterial PLFAs were significantly higher in the soils with KPR250 and MCP50 treatments compared with KPR50 and control. The latter had no significant difference in the total or bacterial PLFAs. The KPR50, KPR250, and MCP50 treatments increased fungal PLFA by 69%, 103%, and 69%, respectively. Both the principal component analysis and the cluster analysis of the PLFA data suggest that P treatments altered the microbial community composition of the soils, and that P availability might be an important contributor to the changes in the microbial community structure during the ryegrass growth in the paddy soils
A test of a winter farm management option for mitigating nitrous oxide emissions from a dairy farm
Cereal landraces for sustainable agriculture. A review
Modern agriculture and conventional breeding and the liberal use of high inputs has
resulted in the loss of genetic diversity and the stagnation of yields in cereals in less
favourable areas. Increasingly landraces are being replaced by modern cultivars which are
less resilient to pests, diseases and abiotic stresses and thereby losing a valuable
source of germplasm for meeting the future needs of sustainable agriculture in the context
of climate change. Where landraces persist there is concern that their potential is not
fully realised. Much effort has gone into collecting, organising, studying and analysing
landraces recently and we review the current status and potential for their improved
deployment and exploitation, and incorporation of their positive qualities into new
cultivars or populations for more sustainable agricultural production. In particular their
potential as sources of novel disease and abiotic stress resistance genes or combination
of genes if deployed appropriately, of phytonutrients accompanied with optimal
micronutrient concentrations which can help alleviate aging-related and chronic diseases,
and of nutrient use efficiency traits. We discuss the place of landraces in the origin of
modern cereal crops and breeding of elite cereal cultivars, the importance of on-farm and
ex situ diversity conservation; how modern genotyping approaches can help both
conservation and exploitation; the importance of different phenotyping approaches; and
whether legal issues associated with landrace marketing and utilisation need addressing.
In this review of the current status and prospects for landraces of cereals in the context
of sustainable agriculture, the major points are the following: (1) Landraces have very
rich and complex ancestry representing variation in response to many diverse stresses and
are vast resources for the development of future crops deriving many sustainable traits
from their heritage. (2) There are many germplasm collections of landraces of the major
cereals worldwide exhibiting much variation in valuable morphological, agronomic and
biochemical traits. The germplasm has been characterised to variable degrees and in many
different ways including molecular markers which can assist selection. (3) Much of this
germplasm is being maintained both in long-term storage and on farm where it continues to
evolve, both of which have their merits and problems. There is much concern about loss of
variation, identification, description and accessibility of accessions despite
international strategies for addressing these issues. (4) Developments in genotyping
technologies are making the variation available in landraces ever more accessible.
However, high quality, extensive and detailed, relevant and appropriate phenotyping needs
to be associated with the genotyping to enable it to be exploited successfully. We also
need to understand the complexity of the genetics of these desirable traits in order to
develop new germplasm. (5) Nutrient use efficiency is a very important criterion for
sustainability. Landrace material offers a potential source for crop improvement although
these traits are highly interactive with their environment, particularly developmental
stage, soil conditions and other organisms affecting roots and their environment. (6)
Landraces are also a potential source of traits for improved nutrition of cereal crops,
particularly antioxidants, phenolics in general, carotenoids and tocol in particular. They
also have the potential to improve mineral content, particularly iron and zinc, if these
traits can be successfully transferred to improved varieties. (7) Landraces have been
shown to be valuable sources of resistance to pathogens and there is more to be gained
from such sources. There is also potential, largely unrealised, for disease tolerance and
resistance or tolerance of pest and various abiotic stresses too including to toxic
environments. (8) Single gene traits are generally easily transferred from landrace
germplasm to modern cultivars, but most of the desirable traits characteristic of
landraces are complex and difficult to express in different genetic
backgrounds.Maintaining these characteristics in heterogeneous landraces is also
problematic. Breeding, selection and deployment methods appropriate to these objectives
should be used rather than those used for high input intensive agriculture plant breeding.
(9) Participatory plant breeding and variety selection has proven more successful than the
approach used in high input breeding programmes for landrace improvement in stress-prone
environments where sustainable approaches are a high priority. Despite being more complex
to carry out, it not only delivers improved germplasm, but also aids uptake and
communication between farmers, researchers and advisors for the benefit of all. (10)
Previous seed trade legislation was designed primarily to protect trade and return royalty
income to modern plant breeders with expensive programmes to fund. As the desirability of
using landraces becomes more apparent to achieve greater sustainability, legislation
changes are being made to facilitate this trade too. However, more changes are needed to
promote the exploitation of diversity in landraces and encourage their use