The use of red clover (Trifolium pratense) in soil fertility-building: A Review

Red clover cultivation made significant contributions to soil fertility prior to the introduction of mineral nitrogen fertilizers. Its modern usage lies primarily in forage production, but reintegration into arable systems can enhance sustainability and preserve environmental integrity. Here we review red clovers nitrogen (N) contribution to subsequent crops, its capacity to fix N, and how this N is transferred to subsequent crops. The senescence of the root system following cultivation also contributes to soil organic matter, providing a suite of ecosystem services which are also reviewed. Potential contributions to allelopathic weed control and how this may be utilized to improve weed control is also discussed. Red clover varieties are diverse and can be split into categories of early/late flowering, erect/prostrate and diploid/tetraploid. This use of this diversity to different ends and purposes in fertility-building and the role of plant breeding in optimizing use of genetic resources is reviewed. Management strategies are also diverse; red clover can be grown in monoculture or with companion grasses, it can be harvested for forage or green manured (which can include or omit herbicides) and the consequence of this for soil fertility is discussed. High protein forage production is also a key benefit of red clover cultivation and the economic incentive this may provide to farmers is also reviewed

Soil mineral nitrogen availability predicted by herbage yield and disease resistance in red clover (Trifolium pratense) cropping

Nitrogen (N) is the most limiting nutrient in crop production. Legumes such as red clover can provide N through biofixation, but securing nitrogen in soil for subsequent crop production must also be considered. Variety selection and management in red clover cropping can influence soil mineral nitrogen (SMN) availability. A field trial to investigate this was conducted with six varieties, under one and two cut management, over 2 years. Dry matter (DM) and N yield, Sclerotinia resistance and SMN availability were assessed. Low DM and N yields (1.6–2.4 t DM ha−1 and 54–83 kg N ha−1) in the first year of cultivation allowed ~ 40 kg N ha−1 to become available, but high DM and N yields (10.2–14.6 t DM ha−1 and 405–544 kg N ha−1) allowed ~ 20 kg N ha−1 to become available. Wetter weather in 2015 caused significantly more SMN losses than 2016 (20 kg N ha−1 in 2015 and 5 kg N ha−1 in 2016). The varieties Amos, Maro and Milvus lost significantly more SMN in the winter period, which may have been caused by more severe infection of Sclerotinia (these varieties were 50–80% more severely infected other varieties). Varietal effect was non-significant for winter losses in 2016, where no significant varietal differences in Sclerotinia infection were observed. 1 cut made ~ 41 kg N ha−1 available in the growing season of 2015, whilst 2 cut made significantly less (37 kg N ha−1). Cutting was non-significant in 2016 but 1 cut was less susceptible to losses in the winter period. Cutting in 2015 did not significantly affect herbage DM and N yields in the first or second cut of 2016

A Proposed Interpretation of Transitional and Turbulent Energy Flow Processes

This paper discusses the consequence of a continuum analysis of turbulence using the Reynolds convention, on the cascade of energy to internal thermal energy. It is observed that there are two distinct dissipative paths or traps that the energy follows, neither of which involves vorticity. It is observed that the so-called Reynolds\u27 Stresses are not involved in these irreversible dissipative paths, but are in the reversible bridge between the mean and fluctuating flows. An effort is made to generate a consistent physical interpretation of all of the terms in the equations used rather than selecting isolated terms for explanation. Some suggestions are made for modeling the dissipative terms and an appendix is included to illustrate how information can be lost in an integration process that results in erroneously ascribing dissipative roles to perfectly reversible terms and equations

Hydrogen bonding in substituted nitroanilines : isolated nets in 1,3-diamino-4-nitrobenzene and continuously interwoven nets in 3,5-dinitroaniline

Peer reviewedPublisher PD

Initial red clover (Trifolium pratense, L.) variety evaluation for soil fertility-building

Nitrogen fixation by legume crops within arable rotations can build soil-fertility, produce a home-grown, highprotein fodder and provide a suite of ecosystem services. Although red clover (Trifolium pratense, L.) is primarly associated with grassland livestock production in the UK, it can also improve the performance of subsequent crops when grown alone or in monoculture (Doel 2013, Moyo 2015). Appropriate variety and foliage management selection could optimize this improvement. The goal of this project is to evaluate six red clover varieties, under treatments of one and two cuts, for fertility-building capacity. The yield and quality of subsequent bioassay crops will be used to assess this capacity

The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups

We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal knots and one dIrr. Both tidal knots are located within a prominent HI tidal tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC 3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and four HI knots. Deep CFHT imaging confirms that the optical component of AGC 208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its purported parent galaxies. Combining the results for these groups with those from the NGC 871/6/7 group reported earlier, we find that the HI properties, estimated stellar ages and baryonic content of the gas-rich dwarfs clearly distinguish tidal features from their classical counterparts. We optimistically identify four potentially long-lived tidal objects associated to three separate pairs of interacting galaxies, implying that TDGs are not readily produced during interaction events as suggested by some recent simulations. The tidal objects examined in this survey also appear to have a wider variety of properties than TDGs of similar mass formed in current simulations of interacting galaxies, which could be the result of pre- or post-formation environmental influences.Comment: 18 pages, 14 figures, accepted for publication in MNRA

Umklapp scattering of pairs in BCS superconductivity theory

The BCS theory of superconductivity is extended to recognize pairing of electrons by both normal and umklapp scattering. Application of the variational approach shows that coexistence of normal and umklapp scattering frustrates superconductivity.Comment: 9 pages, 5 figures. to be published in Journal of Physics: Condensed Matte

Red clover (Trifolium pratense) in conservation agriculture: a compelling case for increased adoption

The rapidly growing population will soon require a near doubling of food production. This increase must be achieved in a manner that maintains environmental integrity, preserves public health and resolves food access and distribution equalities. The use of forage legumes in arable rotations can make significant and multidimensional contributions to this sustainable intensification and this paper reviews the potential contribution of red clover (Trifolium pratense L.), with particular reference to sustainable cereal production in conservation agriculture systems. The use of red clover as a tool in soil fertility-building and the multiple benefits to the cropping system in which it is used is described. The benefits discussed include atmospheric nitrogen fixation, soil conservation, structural soil improvements and a suite of agroecosystem services including increased soil microbial activity, the phytoremediation of polluted soils and the provision of food for pollinators. Reported allelopathic weed suppression by red clover cover crops and the role of modern plant breeding in creating new varieties that further enhance system sustainability is also discussed. Finally, as economic considerations will always impact on adoption rates, the profitability of red clover rotations in terms of silage value and yield benefits is taken into account

Weed development in spring wheat after contrasting soil tillage and nitrogen management

Soil tillage and nitrogen (N) management effects on weed species composition were evaluated in 2013 and 2014 on a clayey soil after 5-years of organic management at the Royal Agricultural University's Harnhill Manor Farm, UK. Three tillage systems – Conventional Tillage (CT), and High and Low Intensity Non-inversion Tillage (HINiT & LINiT) – were compared at four N fertiliser rates of 0, 70, 140 and 210 kg N ha−1. Broad-spectrum herbicide was applied before soil operations across the site in both years. Previous organic management legacy of high weed biomass promoted greater weed prevalence in 2013 while 2-years of herbicide inclusion reduced weed biomass. Contrasting weather conditions across the seasons affected weed incidence. In the 2014 wet season, early weed dry weight (DM) was higher under HINiT than CT and LINiT, while no differences were observed in the 2013 dry year. At midseason, weed DM was higher under HINiT than CT and LINiT in both years, which was related to higher DM of the dominant weeds Stellaria media (L.) Vill. and Sinapis arvensis L. Grass weed DM was higher under non-inversion tillage than CT. N fertilisation increased midseason total weed DM and weed prevalence at harvest. Spring wheat yield was the highest under CT while LINiT produced 17% higher yields than HINiT. Despite higher but still tolerable weed prevalence under both non-inversion tillage systems and with the application of N, weeds alone was not the only yield-limiting factor. However, results show that CT is the most reliable option for weed control in changing weather, while N fertilisation rates needs to be considered