A century of crop yield density estimation with perspectives

Crop Production/Industries,

What Works in Conservation 2021

This book provides an assessment of the effectiveness of 2526 conservation interventions based on summarized scientific evidence. The 2021 edition contains substantial new material on bat conservation, terrestrial mammal conservation and marine and freshwater mammals, thus completing the evidence for all mammal species categories. Other chapters cover practical global conservation of primates, amphibians, bats, birds, forests, peatlands, subtidal benthic invertebrates, shrublands and heathlands, as well as the conservation of European farmland biodiversity and some aspects of enhancing natural pest control, enhancing soil fertility, management of captive animals and control of freshwater invasive species. It contains key results from the summarized evidence for each conservation intervention and an assessment of the effectiveness of each by international expert panels. The accompanying website www.conservationevidence.com describes each of the studies individually, and provides full references. This is the sixth author-approved edition of What Works in Conservation, which is revised on an annual basis

Are prices of new dwellings different? A spectral analysis of UK property vintages

The work makes two contributions to Hui’s (2011) dynamic house price classification. First, a house price ripple in cycles from Modern to Older dwellings is revealed and, second, as New housing is shown to have lower volatility than the other two. Using spectral analysis, it is argued that there is a 7½-year repeat buyer-second-hand cycle and a five year, first time buyer-New housing cycle, common to three house price vintages. These cycles reinforce each other every fifteen years, which corresponds with a Minsky super-cycle in housing finance. The equity of the owner-occupier is fortified by higher house prices whereas new builds extract embedded equity from the market. Government should support builders and facilitate access to market to first time buyers and through programmes like Help-to-Buy 1. However, to address the greater price instability that should follow, Government should impose a capital gains tax on the house seller

Experimental and modelling evidence for structural crossover in supercritical CO₂

Physics of supercritical state is understood to a much lesser degree compared to subcritical liquids. Carbon dioxide in particular has been intensely studied, yet little is known about the supercritical part of its phase diagram. Here, we combine neutron scattering experiments and molecular dynamics simulations and demonstrate the structural crossover at the Frenkel line. The crossover is seen at pressures as high as 14 times the critical pressure and is evidenced by changes of the main features of the structure factor and pair distribution functions

The origin of negative charging in amorphous Al₂O₃ films: the role of native defects

Amorphous aluminum oxide Al₂O₃ (a-Al₂O₃) layers grown by various deposition techniques contain a significant density of negative charges. In spite of several experimental and theoretical studies, the origin of these charges still remains unclear. We report the results of extensive density functional theory calculations of native defects—O and Al vacancies and interstitials, as well as H interstitial centers—in different charge states in both crystalline α-Al₂O₃ and in a-Al₂O₃. The results demonstrate that both the charging process and the energy distribution of traps responsible for negative charging of a-Al₂O₃ films (Zahid et al 2010 IEEE Trans. Electron Devices 57 2907) can be understood assuming that the negatively charged O_{i} and V_{Al} defects are nearly compensated by the positively charged H_{i}, V_{O} and Al__{i} defects in as prepared samples. Following electron injection, the states of Al_{i}, V_{O} or H_{i} in the band gap become occupied by electrons and sample becomes negatively charged. The optical excitation energies from these states into the oxide conduction band agree with the results of exhaustive photo-depopulation spectroscopy measurements (Zahid et al 2010 IEEE Trans. Electron Devices 57 2907). This new understanding of the origin of negative charging of a-Al₂O₃ films is important for further development of nanoelectronic devices and solar cells

Integrating a crop model with a greenhouse gas calculator to identify low carbon agricultural intensification options for smallholder farmers in rural South Africa

Published online: 22 Jan 2022Models that enable the estimation of crop yields and greenhouse gas (GHG) emissions concurrently are still lacking. This study develops a biophysical modelling framework encompassing a farm typology, a crop model, and a farm-focused GHG calculator to assess productivity (crop yield) and GHG emissions of crop management practices concurrently. Using this modelling framework, the study developed cropping system scenarios based on the concept of conservation agriculture (CA) to identify and design cropping systems that deliver ecological intensifcation for diferent farm types. All farm types were found to be net sources of GHG with cropping system inefciency across all farm types. However, the integration of CAbased practices independently and in combination into farm-type maize-based cropping systems showed signifcant potential in improving crop yields and lowering GHG emissions across all farm types. CA-based practices in combination were more efcient and able to deliver ecological intensifcation with high productivity and ecosystem services which contribute to climate change regulation. This study concludes that the modelling approach identifed intensifcation options that maintain or increase crop yields while reducing GHG emissions at the farm level. This can guide policy simulations and scenario analysis to tailor interventions for farm-type sustainability

The role of agri-environment schemes in conservation and environmental management.

Over half of the European landscape is under agricultural management and has been for millennia. Many species and ecosystems of conservation concern in Europe depend on agricultural management and are showing ongoing declines. Agri-environment schemes (AES) are designed partly to address this. They are a major source of nature conservation funding within the European Union (EU) and the highest conservation expenditure in Europe. We reviewed the structure of current AES across Europe. Since a 2003 review questioned the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta-analyses examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in response to AES, with the size of the effect depending on the structure and management of the surrounding landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We examined the change in effect size over time by merging the data sets of 3 recent meta-analyses and found that schemes implemented after revision of the EU's agri-environmental programs in 2007 were not more effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production (such as field margins and hedgerows) are more effective at enhancing species richness than those aimed at productive areas (such as arable crops or grasslands). Outstanding research questions include whether AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in intensively farmed areas, whether they are more or less cost-effective for farmland biodiversity than protected areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson from the European experience is that AES can be effective for conserving wildlife on farmland, but they are expensive and need to be carefully designed and targeted.This is the final published version. It first appeared from Wiley http://dx.doi.org/10.1111/cobi.1253

Emergence of contact injuries in invasion team sports : an ecological dynamics rationale

The incidence of contact injuries in team sports is considerable, and injury mechanisms need to be comprehensively understood to facilitate the adoption of preventive measures. In Association Football, evidence shows that the highest prevalence of contact injuries emerges in one-on-one interactions. However, previous studies have tended to operationally report injury mechanisms in isolation, failing to provide a theoretical rationale to explain how injuries might emerge from interactions between opposing players. In this position paper, we propose an ecological dynamics framework to enhance current understanding of behavioural processes leading to contact injuries in team sports. Based on previous research highlighting the dynamics of performer–environment interactions, contact injuries are proposed to emerge from symmetry-breaking processes during on-field interpersonal interactions among competing players and the ball. Central to this approach is consideration of candidate control parameters that may provide insights on the information sources used by players to reduce risk of contact injuries during performance. Clinically, an ecological dynamics analysis could allow sport practitioners to design training sessions based on selected parameter threshold values as primary and/or secondary preventing measures during training and rehabilitation sessions

Flora nas fazendas.

Na atualidade, a conservação da biodiversidade e dos serviços ambientais representa um dos maiores desafios globais, em função do elevado nível das pressões antrópicas sobre os ecossistemas naturais. Neste contexto, a devastação da Caatinga vem se tornando cada vez mais preocupante não só para os amantes da conservação da natureza, mas também para os diversos setores produtivos que estão direta ou indiretamente ligados a exploração de seus recursos naturais. Apesar de a Caatinga ser o único bioma exclusivamente brasileiro, este ainda é pouco valorizado e carente de estudos. Assim, estamos perdendo um patrimônio único no mundo mesmo antes de conhecer seu potencial. Diante desse cenário de desconhecimento e destruição, ações voltadas para a sustentabilidade da Caatinga se fazem cada vez mais urgentes a fim de revertermos esse quadro. Nessa ótica, o projeto Manejo Sustentável de Fruteiras da Caatinga (SUFICA), em parceria com produtores da região do Vale do Submédio São Francisco, vem buscando identificar formas mais amigáveis de uso das áreas agrícolas, visando o desenvolvimento de uma agricultura sustentável. Nessa publicação, vamos falar sobre a vegetação da Caatinga e sua importância para a manutenção dos serviços ambientais nos agroecossistemas e apresentar parte dos resultados obtidos nas áreas de estudo do projeto