Establishment Techniques to Increase the Production of Italian Ryegrass (\u3cem\u3eLolium multiflorum\u3c/em\u3e) Over-Sown into an Irrigated Kikuyu (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) Pasture

Irrigated mixed pastures of kikuyu (Pennisetum clandestinum) over-sown with Italian ryegrass (Lolium multiflorum) in the cool-season (May-October) can produce large amounts of biomass in a sub-tropical environment (Botha et al. 2008). However, appropriate pasture management practices are required to suppress the aggressive growth of kikuyu prior to autumn, in order to facilitate establishment of ryegrass seedlings. The present study evaluated ryegrass establishment techniques on the dry matter (DM) production, botanical composition and forage quality of a mixed sward containing kikuyu

Balancing Water Use Efficiency and Milk Production in the Sub-Tropics

Queensland dairy farmers have had to confront in the last 5 years deregulation of the milk pricing system, resulting in a 25% reduction in farm gate price for milk in the year 2000, and drought. Many storage dams are significantly below capacity and regulatory authorities have imposed restrictions on irrigation water allocations. Major changes in farm business strategies were needed to overcome the shortfall in milk income. Production systems had to change to deliver more milk more efficiently and become more profitable. A farmlet study was developed in the sub-tropical dairy region of Queensland to evaluate 5 very different farm systems identified by a group of experts as capable of tripling production whilst achieving a 10% return on assets and 600,000 L/labour unit. This paper compares the water use efficiencies and milk production of these systems

Improving the exchange and correlation potential in density-functional approximations through constraints

We review and expand on our work to impose constraints on the effective Kohn–Sham (KS) potential of local and semi-local density-functional approximations. Constraining the minimisation of the approximate total energy density-functional invariably leads to an optimised effective potential (OEP) equation, the solution of which yields the KS potential. We review briefly our previous work on this and demonstrate with numerous examples that despite the well-known mathematical issues of the OEP with finite basis sets, our OEP equations are numerically robust. We demonstrate that appropriately constraining the ‘screening charge’ which corresponds to the Hartree, exchange and correlation potential not only corrects its asymptotic behaviour but also allows the exchange and correlation potential to exhibit a non-zero derivative discontinuity, a feature of the exact KS potential that is necessary for the accurate prediction of band-gaps in solids but very hard to capture with semi-local approximations

Modelling the potential of integrated vegetation bands (IVB) to retain stormwater runoff on steep hillslopes of Southeast Queensland, Australia

Rainfall intensity is predicted to increase under a changing climate, leading to increased risks of hillslope erosion, downstream sedimentation and flooding. For many catchments used for grazing and agricultural land uses, it will become increasingly important to maintain ecohydrological functioning despite climatic extremes. One means to achieve this is through strategic reforestation using locally endemic species, in spatial configurations that effectively intercept, retain or and redistribute overland flows. This paper adopts a modelling approach for investigating the potential of one such design termed “integrated vegetation bands” (IVB), to increase the retention of runoff across steep hillslopes, particularly in the sub-tropics where rainstorms are becoming increasingly intense. A spatially distributed simulation model (MIKE-SHE) was applied to a steep, grazed catchment (Maronghi Creek catchment, Southeast Queensland, Australia) to compare stormwater runoff characteristics between: (1) the existing pasture land cover; and (2) a series of hypothetical IVB added across this pasture land. The IVB were approximately 20 m wide, and configured at 5% gradient towards ridgelines. Results for estimates of overland flow depth and infiltration (spatial), and accumulative water balance (temporal), confirm that the area of hillslope retaining > 10 mm/day more runoff increased by 22% under IVB compared to the pasture land use. Excluding the IVB themselves, the area of hillslope where runoff retention increased was 11%. During the most intense rainfall, IVB held up to 25% greater water depth and had 10% greater infiltration at the hillslope scale. At the sub-catchment scale, discharge decreased by 7% and infiltration increased by 23%. The findings for sub-tropical landscapes presented here are consistent with studies conducted in temperate regions. Based on the results of this preliminary modelling work, the IVB concept has been established as a paired-catchment field trial in a high rainfall catchment in Southeast Queensland, Australia

Watch me if you can: imagery ability moderates observational learning effectiveness

Recent research has revealed similarities in brain activity during observational learning and motor execution. However, whilst action develops visual, motor and afferent representations during acquisition, action-observation has been proposed to only develop visual-spatial learning via visual representation. In addition, it has been suggested that the vividness of visual representations are determined by imagery ability. Thus, the purpose of the current investigation was to explore the possible moderating role of imagery ability in the effectiveness of observational learning. Participants (n=40) were assessed on their imagery ability via the VMIQ-2 and then assigned to one of four groups; high imagery ability and observational learning (HIA-OL), low imagery ability and observational learning (LIA-OL), high imagery ability control (HIA-C) and low imagery ability control (LIA-C). Following group allocation all participants performed a pre-test consisting of 5 actual practice trials of a novel gymnastics routine. The HIA-OL and LIA-OL groups then participated in a 14 day observational learning intervention whilst the HIA-C & LIA-C groups acted as controls. Following this, participants performed a post test, which was identical in nature to the pre-test, before finally completing the VMIQ-2 again. Performance on both the pre-test and post test was evaluated by two qualified gymnastics judges. Results revealed that gymnastics performance increased from pre-test to post test for both the HIA-OL and LIA-OL groups. However, this effect was greater in the HIA-OL group suggesting that the relationship between observational learning and successful imitation performance is moderated by imagery ability