The effects of multiple beneficial management practices on hydrology and nutrient losses in a small watershed in the Canadian prairies

Most beneficial management practices (BMPs) recommended for reducing nutrient losses from agricultural land have been established and tested in temperate and humid regions. Previous studies on the effects of these BMPs in cold-climate regions, especially at the small watershed scale, are rare. In this study, runoff and water quality were monitored from 1999 to 2008 at the outlets of two subwatersheds in the South Tobacco Creek watershed in Manitoba, Canada. Five BMPs-a holding pond below a beef cattle overwintering feedlot, riparian zone and grassed waterway management, grazing restriction, perennial forage conversion, and nutrient management-were implemented in one of these two subwatersheds beginning in 2005. We determined that >80% of the N and P in runoff at the outlets of the two subwatersheds were lost in dissolved forms, ≈ 50% during snowmelt events and ≈ 33% during rainfall events. When all snowmelt- and rainfall-induced runoff events were considered, the five BMPs collectively decreased total N (TN) and total P (TP) exports in runoff at the treatment subwatershed outlet by 41 and 38%, respectively. The corresponding reductions in flow-weighted mean concentrations (FWMCs) were 43% for TN and 32% for TP. In most cases, similar reductions in exports and FWMCs were measured for both dissolved and particulate forms of N and P, and during both rainfall and snowmelt-induced runoff events. Indirect assessment suggests that retention of nutrients in the holding pond could account for as much as 63 and 57%, respectively, of the BMP-induced reductions in TN and TP exports at the treatment subwatershed outlet. The nutrient management BMP was estimated to have reduced N and P inputs on land by 36 and 59%, respectively, in part due to the lower rates of nutrient application to fields converted from annual crop to perennial forage. Overall, even though the proportional contributions of individual BMPs were not directly measured in this study, the collective reduction of nutrient losses from the five BMPs was substantial.     

Citizenship, civicness and social capital in local agenda 21

Local Agenda 21s are now being widely produced throughout Britain. Whilst there is wide variation in the nature of such exercises, many are exceeding original expectations and opening up important new opportunities for community involvement in sustainable development. This paper argues that, if LA21s unlock the energies necessary to engage widespread participation in local quality of life issues, they can become an influential and enduring part of the governance of the local state. This raises a number of theoretical and practical issues relating to types of citizenship, social capital, appropriate participatory mechanisms, and the respective contributions of lay and technical expertise. Individual people who are pivotal to the dynamics of local sustainability strategies must themselves be sustained and supported throughout the process.     

Prenatal diagnosis for women aged 37 years and over: to have or not to have

Forty percent of pregnant women aged 37 years and over do not have prenatal diagnosis despite being eligible for a free test. The present study aimed to determine how often, and which, untested women were making a choice about this, how many declined an offer and why. A questionnaire was given to untested women, aged 37 years and over, at no less than 24 weeks gestation. A total of 375 (81.5%) women declined, 72 (16%) were not offered a test and 13 presented too late antenatally. There was a three-fold increased likelihood (OR 3.10 95% CI 1.44, 6.65) of no offer for urban non-English speaking background women, compared with the reference group (metropolitan, English speaking). Unpartnered women were also significantly less likely to receive an offer (OR 3.18, 95% CI 1.19, 8.46). Risk to the baby was the main reason for declining. When offered non-invasive prenatal screening, most decliners of prenatal diagnosis accepted, even those who declined because they were opposed to abortion. We estimate that overall 33% of older pregnant women were being offered and declining amniocentesis and/or chorion villus sampling (CVS). Only 6% were not offered a test, but this small proportion is over-represented by minority groups who must be given equal opportunity to make this choice. Copyright © 2001 John Wiley & Sons, Ltd.     

Physiological and Biochemical Effects of Atmospheric Oxidants on Plants

Photochemically produced oxidants in the atmosphere cause injury to plants primarily through inhibition of basic metabolic processes. Plants vary in their response to the oxidants and this variation must be dependent in part on the variation in metabolic activity with age or environmental conditions for growth, to a large degree not understood. Data are presented in this paper to show: (1) The changes in permeability of leaf tissue to exogenous substrate and in catabolic utilization of this substrate after exposure of plants to ozone but before visible symptoms appear; (2) The change in leaf carbohydrates as a result of exposure to ozone; (3) The protective effect of red light (700 mμ) during exposure of bean plants to peroxyacetyl nitrate (PAN); (4) The correlation of sulfhydryl (SH) content in bean leaf tissue with age of plants and light regime; and (5) Effect of light regime and age of plants on incorporation of C¹⁴ from C¹⁴-PAN by bean leaf tissue.