Effects of no-tillage and subsoil loosening on soil physical properties and crop performance : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Soil Science at Massey University

Much of New Zealand's lowland agriculture integrates animal and crop production on poorly drained, easily compacted soils. Over the years, conventional cultivation has given rise to degraded soil structure on many farms. No-tillage has been shown to avoid many of these problems but the question remains: "Where soils are compact, what combination of deep tillage and/or drainage systems and no-tillage allow for the most efficient transition from conventional cultivation to no-tillage crop establishment?" The objective of this study was to ascertain if soil properties, and crop (Brassica campestis x Brassica napus cv "Pasja" followed by wheat Triticum aestivum cv "Kohika") establishment and yield on land converted from a conventionally tilled system to a no-tillage system could be improved by various subsoiling and mole plough operations. Plots on a Milson silt loam (Argillic Perch-Gley Pallic Soil) (Typic Ochraqualf) were paraplowed (PP), straight-legged subsoiled (SL), mole ploughed (M) or were left as non-subsoiled controls (C) in the autumn of 1997. Forage brassica was then sown with a Cross-Slot™ no-tillage drill. Wheat was established on the same plots with the same no-tillage drill in the spring of 1997. Subsoiling initially reduced soil strength by a significant amount. Shortly after subsoiling cone indices showed disruption to 300 mm with PP, 350 mm with SL and 100 mm with M. At the same time, approximately 20% of profile cone indices from subsoiled treatments were greater than 2 MPa, compared to approximately 52% for C and M. At 267 days after subsoiling, PP continued to have lower cone index values than C and M. Subsoiling initially reduced bulk density. When measured in May, the bulk density of PP plots was significantly lower than SL, M and C although reconsolidation in all plots was observed in February 1998 after the wheat was harvested. Air permeability in PP, SL and M was significantly greater than in C. Despite the differences in soil strength and bulk density (but not air permeability), subsoiling and mole ploughing did not produce differences in plant populations or yield for either the winter brassica or spring-sown wheat crops. The lack of any differences for brassica crop performance criteria were in spite of the vertical rooting depth being greater in the PP treatment. The lack of differences in plant establishment and yield was thought to be due to the relatively dry autumn and winter soil conditions and the use of the Cross-Slot™ no-tillage opener which is reported to be tolerant of variable soil conditions

Symplectic fibrations and Riemann-Roch numbers of reduced spaces

In this article we give formulas for the Riemann-Roch number of a symplectic quotient arising as the reduced space corresponding to a coadjoint orbit (for an orbit close to 0) as an evaluation of cohomology classes over the reduced space at 0. This formula exhibits the dependence of the Riemann-Roch number on the Lie algebra variable which specifies the orbit. We also express the formula as a sum over the components of the fixed point set of the maximal torus. Our proof applies to Hamiltonian G-manifolds even if they do not have a compatible Kahler structure, using the definition of quantisation in terms of the Spin-C Dirac operator.Comment: 11 pages; part of the Ph.D. thesis of the first author. Section 2 revised (Section 2.1, also Theorem 2.4 and new Proposition 2.5

Inferring black-hole orbital dynamics from numerical-relativity gravitational waveforms

Binary-black-hole dynamics cannot be related to the resulting gravitational-wave signal by a constant retarded time. This is due to the non-trivial dynamical spacetime curvature between the source and the signal. In a numerical-relativity simulation there is also some ambiguity in the black-hole dynamics, which depend on the gauge (coordinate) choices used in the numerical solution of Einstein's equations. It has been shown previously that a good approximation to the direction of the binary's time-dependent orbital angular momentum $\mathbf{\hat{L}}(t)$ can be calculated from the gravitational-wave signal. This is done by calculating the direction that maximises the quadrupolar $(\ell=2,|m|=2)$ emission. The direction depends on whether we use the Weyl scalar $\psi_4$ or the gravitational-wave strain $h$, but these directions are nonetheless invariant for a given binary configuration. We treat the $\psi_4$-based direction as a proxy to $\mathbf{\hat{L}}(t)$. We investigate how well the the binary's orbital phase, $\phi_{\rm orb}(t)$, can also be estimated from the signal. For this purpose we define a quantity $\Phi(t)$ that agrees well with $\phi_{\rm orb}(t)$. One application is to studies that involve injections of numerical-relativity waveforms into gravitational-wave detector data.Comment: 12 pages with 10 figure

Culture-Based Environmental Microbiology Monitoring of Crop-Based Space Food Systems (veggie Monitoring)

Crewmembers live and work in a closed environment that is monitored to ensure their health and safety. Quarterly monitoring of the microorganisms in the International Space Station (ISS) environment supports crew safety and contributes to a large set of microbial concentration and diversity data from air, surfaces and water samples. This study leverages quarterly operational Environmental Health System (EHS) sampling by collecting additional microbial samples from the surface of the stations Veggie plant production system. Longer exploration missions may require spaceflight-based systems for growth of plants, and this investigation is expected to provide additional data to help establish requirements to protect these systems, plants, and crew, mitigating adverse microbial exposure

Fish, feather, fur and forest: exploitation of wild mammals in medieval Novgorod and its territory

The city of Novgorod the Great in north-west Russia has been subjected to extensive excavation of its superbly preserved medieval anaerobic deposits for many decades. Situated on the River Volkhov near Lake Ilmen and surrounded by mixed boreal and deciduous woodland and seasonally flooded meadowlands, Novgorod was well-placed for the exploitation of local wild fauna and flora. It was also the focus for international trade in furs obtained from a much broader catchment area. Although its inhabitants relied heavily on domestic animals and crops for their food, evidence for the acquisition of wild resources is also provided by animal bones, plant macrofossils, birch-bark documents and other archaeological finds. Pollen analysis has also provided information about landscape history of its hinterland. Even from a limited programme of sieved sampling, it is clear that a very large number of fish bones were present in the deposits. The main taxa are cyprinids, pike and zander, whereas birch-bark documents, largely concerned with tribute, mention salmonids and sturgeon, rare amongst the excavated remains. The wild bird assemblage is dominated by various species of ducks. Other waterfowl were utilised as well as large game birds such as capercaillie. Birds of prey are also present and other remains such as jackdaws reveal the local bird life in town. Wild mammals contributed little to the Novgorodian diet: bones of hare, beaver and elk being the most frequently found. Very few bones of fur-bearing mammals were recovered. The few remains include bear claws and bones of squirrel, marten, otter, and fox, in addition to beaver. Their paucity can be explained by the fact that most would have arrived from the hunting grounds to the north as prepared pelts without bones. Evidence for the hunting for these species is provided on sites deep within the forest zone such as Minino. Most of the wild animals eaten in Novgorod itself were obtained from the land and waters of its near hinterland. The paper discusses the character of the local forest based on pollen and other evidence. Models are being developed to provide a more detailed understanding of the changes in the composition of the forest during the medieval period and the consequences this had for wildlife. The paper demonstrates the benefits of developing a multi-disciplinary approach comparing urban assemblages with contemporary sites in its hinterland and further afield, to understand more fully how wild species were exploited in complex societies