Extensive pilot use of the grain protectant combinations,fenitrothion plus bioresmethrin and pirimiphos-methyl plus bioresmethrin

Each of the combinations, bioresmethrin (1 mg kg^?1) plus pirimiphos-methyl(6 mg kg^?1) or fenitrothion (12 mg kg^?1), was applied in 1976 to grain in 21 commercial storages. Grain condition and protectant residues were regularly monitored. Three storages became infested with Rhizopertha dominica (F.), but all storages remained free of other insect species. In two of the three infested storages, application of protectant was uneven, and the third became infested only after 8 months of storage. Despite some variations in recovered residues between sites, the mean residue levels were accurately described by predictive models. Falls in temperature during storage varied considerably, and were related to factors other than climate and bin size. There was a marked effect by aeration with ambient cold air on both the grain temperature and the rate of loss of residues. Results of collaborative studies on the determination of residues indicate a need for regular check programmes of analysis, and confirm previous conclusions that residues of fenitrothion and pirimiphos-methyl can be accurately and conventionally determined.     

Cosmic ray and solar particle investigations over the South polar regions of the sun

Observations of galactic cosmic radiation and anomalous component nuclei with charged particle sensors on the Ulysses spacecraft showed that heliospheric magnetic field structure over the south solar pole does not permit substantially more direct access to the local interstellar cosmic ray spectrum than is possible in the equatorial zone. Fluxes of galactic cosmic rays and the anomalous component increased as a result of latitude gradients by less than 50% from the equator to -80 degrees . Thus, the modulated cosmic ray nucleon, electron, and anomalous component fluxes are nearly spherically symmetric in the inner solar system. The cosmic rays and the anomalous nuclear component underwent a continuous, -26 day recurrent modulation to -80.2 degrees , whereas all recurring magnetic field compressions and recurring streams in the solar wind disappeared above approximately 55 degrees S latitude.     

Soil and water contamination by arsenic from A tannery waste

The pollution of soil by arsenic contained in tannery waste is reported. Over 81 years of operation, a variety of arsenical compounds including sodium arsenite were used as pesticides at the tannery, the arsenic finding its way to the site in question as liquid waste which was disposed of either by burial or spray issigation. X-ray Fluorescence Spectrometry (XRF) was used to determine the levels of arsenic in the soil. Concentrations recorded were comparable to those in soils polluted by agricultural use of arsenical pesticides or by contamination from mining activities. In contrast to arsenic pollution from other sources however, contamination extends to a considerable depth through the soil profile. Analysis of soil water by hydride generation atomic absorption spectrometry showed evidence of arsenic movement through this medium although penetration had not extended to the groundwater. Batch leaching of soil samples with distilled water confirmed the potential mobility of arsenic.     

Effect of cultivar, row spacing, and weed management on weed biomass, potato yield, and net crop value

Research was conducted to quantify the effects of potato cultivar, row spacing, and weed control treatments on weed biomass, crop yield, and net crop value. Cultivars evaluated included Russet Burbank, Russet Norkotah, Goldrush, Dark Red Norland, Snowden, and Atlantic. Inter-row spacings of 76 and 91 cm with an intra-row spacing of 30 cm were evaluated in 1996 and 1997. Weed control treatments included a herbicide tank-mix of metribuzin and metolachlor, cultivation, and a hilling-only control. Common lambsquarters and total weed biomass were greater in the 76-cm row spacing than in the 91-cm row spacing across all cultivars in 1996 and 1997. In 1997, chemical control resulted in less weed biomass than both the hilling-only and cultivation treatments. Total marketable yield was greater in the 91-cm row spacing than in the 76-cm row spacing across cultivars in 1996, but was similar across row spacings in 1997. Net crop value was greater across cultivars in the 91-cm row spacing than in the 76-cm row spacing in 1996. Reduced weed biomass in 1996 and 1997, coupled with greater total marketable yield and net return in 1996, indicated that the 91-cm row spacing was the optimal row spacing for Russet Burbank, Goldrush, Russet Norkotah, Snowden, and Atlantic cultivars in 1996 and 1997. Similar yields and net crop value among weed control treatments in 1996 and 1997 indicated that cultivation and possibly even hilling-only areas within fields can be viable alternatives to herbicide use.     

Effect of setting a maximum milking time,from peak lactation,on production,milking time and udder health

Abstract

AIM: To examine the effect of setting a maximum milking time, from peak lactation until drying-off, on production, duration of milking, and udder health of dairy cows.

METHODS: Forty cows were assigned in twin-pairs to be either milked until cups were removed at a milk flow-rate threshold of 0.35 kg/minute (Control), or until cups were removed at a milk flow-rate threshold of 0.35 kg/minute, or maximum time, whichever came first (MaxT). The maximum time was set by determining the milking time of the 70th percentile cow when ranked from fastest to slowest, irrespective of yield. The milking routine was typical of that practised on dairy farms in New Zealand, and involved no pre-milking preparation. The study began at peak lactation (68 (SD 7) days in milk; DIM) and continued for 26 weeks. Duration of milking and milk yield were measured for each milking. Composition of milk was determined from weekly herd tests, and milk quality from fortnightly somatic cell counts (SCC). Completeness of milking and teat condition were assessed during the study. The bacterial status of quarter milk samples was determined at the beginning and end of the study, and all treated cases of clinical mastitis recorded. ANOVA was used to examine the effect of treatment group on variables of interest.

RESULTS: Total milk, fat and protein yields during the study period did not differ between treatments. On average, 30.3% of the morning and 27.6% of the afternoon milkings of MaxT cows reached the maximum time at which cups were removed, and were therefore shortened. While the average milking time of the slowest-milking cow was longer for the Control compared with MaxT group in Weeks 1–18, the average milking time did not differ between treatments. There was no difference in overall SCC, and the incidence of clinical mastitis, or the percentage of infected quarters at drying-off, was similar for the MaxT and Control cows.

CONCLUSION: The results show that setting a maximum milking time can reduce the milking time of slower-milking cows in a herd without compromising overall herd production and udder health.

CLINICAL RELEVANCE: Although the numbers of cows in the study were small there was no evidence of a major increase in SCC, or subclinical or clinical mastitis when a maximum milking time was set for slower-milking cows.     

Influence of land-use and conservation programs on wetland plant communities of the semiarid United States Great Plains

Depressional wetlands are predominant surface hydrological features providing critical societal ecosystem services in the semiarid United States High Plains. Critical wetland properties may be threatened because this 30 million ha short-grass prairie largely was converted from grassland to cropland. Further, the United States Department of Agriculture enrolled marginal cropland into the Conservation Reserve Program (CRP). CRP reduces topsoil erosion by planting permanent cover on croplands. In the High Plains, introduced tall-grasses primarily were planted in CRP, possibly reducing precipitation runoff, an important hydroperiod driver in wetlands. We assessed land-use influence on important wetland processes (wetland area, inundation, and plant composition) in 261 depressional wetlands called playas (87 each in native grassland, CRP, and cropland). Surveys spanned six states within three High Plains sub-regions (southern, central and northern). Playas averaged 8 ha in cropland and 16 ha in other land-uses. Plant composition in grassland playas was predominately native perennials, and upland plant cover equaled wetland plant cover. Cropland playas had fewer species/ha, generally more annuals than perennials and 80% greater exposed ground than other land-uses. CRP playas had 400% greater cover of introduced species (mostly upland perennial tall-grasses), which possibly inhibited catchment runoff, as CRP playas were inundated 56% less often than other land-uses. Therefore, tall grasses should not be planted in short-grass prairie CRP catchments, as they alter inundation frequency and vegetation communities in embedded wetlands. Conservation programs containing provisions to protect playas, including planting common native species and using grass buffers to control erosion into wetlands, should be promoted.     

Last days in the Carteret Islands? Climate change,livelihoods and migration on coral atolls

It is widely assumed that the impacts of climate change on atolls will render them uninhabitable. The Carteret Islands, an iconic Pacific atoll, is experiencing physical changes, documented in the media, the outcome of multiple factors, alongside critical economic livelihood problems. Its population has sought to resettle on nearby Bougainville Island, but land has not become available. The search for migration opportunities parallels trends on coral atolls elsewhere where survival strategies have involved regional and international ties, with cultures of migration, focused on more distant international destinations. Carteret Islanders have not been able to mobilise similar relationships. For many atolls and atoll states, migration has increasingly become a livelihood strategy, irrespective of climate change. That is likely to become even more true in the future, but the outcome will be dependent on policies and practices in metropolitan destination states.     

浅谈疫病和环境

随着养殖业的发展，环境污染已逐渐成为畜牧养殖中的主要问题之一。畜禽死淘率的增高和药费支出的加大，已经提出了一个危险的信号，提示我们要加强环境的卫生管理，防止病原体污染，这是防止疫病发生的一个关键措施。