Effects Of Agricultural Practices Research Articles

Distribution and abundance of insects colonizing cattle dung in South West England

The succession of insects colonizing cow dung in south west England was examined over 2 years, using arrays of standardized 1.5 kg artificially constructed cow‐dung pats in cattle pasture. The seasonal pattern of colonization was examined using batches of 10 pats each week for 24 weeks in 2001. Pats were left exposed in the field for 7 days, to allow colonization, and were then brought back to the laboratory to await insect emergence and identification. Overall seasonal changes in community structure were relatively gradual and subtle; Coleoptera were generally more abundant earlier and Diptera later in the season, and the number and order of species arrival broadly matched previous studies in similar habitats. The temporal pattern of colonization of individual pats was examined in six batches of 30 pats constructed in May, June, and August/September in 2002. Groups of five pats were recovered and brought back to the laboratory 1, 2, 4, 7, 14, or 21 days after construction. Overall, three broad, but statistically distinct, successional groups were identified, with the maximum number of colonizers present in pats that were 4–7 days old. The data contribute valuable information on the temporal distribution and abundance of dung‐colonizing taxa in South West England, a clear local understanding of which is essential to allow the effects of agricultural practices which may damage dung invertebrate communities, such as livestock anthelmintic treatment, to be assessed.

Effects of agricultural practices on hydraulic properties and water movement in soils in Brittany (France)

The intensive agricultural use of soils in the Brittany region (western France) has increased the need for a better understanding of soil water dynamics. The aim of the present study is to compare quantitatively the differences produced by two agricultural practices on soil hydraulic properties (water retention curve and hydraulic conductivity) as well as the infiltration and drainage fluxes in the soils. This study was carried out on two experimental plots managed in the same way for 22 years. The two practices were continuous maize fertilized with mineral fertilizer, denoted as MX, and pasture within a ray-grass/maize rotation (3/1 year) with organic fertilization (pig slurry), denoted as PR. The study consisted of measuring soil physical properties in the laboratory and in the field, and estimating water infiltration in the soil of the two plots by recording water pressure heads after simulation of 2-h artificial rainfall with an intensity of 17 mm/h. We applied the van Genuchten model to describe the water retention and hydraulic conductivity curves ( θ( h) and K( h)) for each soil horizon of the two plots. Hydrus-2D and ID softwares were used to construct a numerical model of water movement in the two soils. This model was used to quantify the infiltration rate, deep drainage and actual evaporation fluxes during the artificial rainfall experiment. The vertical influence of agricultural practices in both plots appears to be limited to the uppermost 35 cm. Deeper in the B horizon, there are only very slight differences in the hydraulic properties between the two plots. In the top soil horizons (H1–H5 and H6), the two soil properties mostly affected by practices are the hydraulic conductivity and the α parameter of the van Genuchten model. At the lowest pressure head studied here (−1.5 kPa), hydraulic conductivity in a given horizon differs by more than one order of magnitude between the two plots. The model reproduces quite satisfactorily the observed pressure heads in plot PR at all depths, in the rainy period as well as in the water redistribution period (efficiency >0.77). Results are less good for the MX plot, with efficiency ranging from 0.49 to 0.84 depending on the horizon. The different sources of simulation errors are identified and discussed. For the MX plot, the soil water movement model succeeds in reproducing the infiltration excess runoff observed in the field, allowing us to calculate that it accounts for 9% of the applied rainfall. No surface runoff or ponding appears in the PR plot during the artificial rainfall experiment. In the PR plot, the simulated deep drainage flux increases more rapidly than in the MX plot. The lower hydraulic conductivity in the top soil horizon of the MX plot compared with the PR plot appears to reduce the infiltration rate as well as the deep drainage flux. It also decreases the upward flow of water to the soil surface when the water content in the top soil layer is depleted by evaporation flux. The model simulation could be improved by a more precise representation of the soil structure, particularly the location, size and frequency of clods as well as the variability of hydraulic properties. However, we need to strike a balance between improving the quality of the simulation even further and the practical constraints and efforts involved in measuring the soil hydraulic properties.

International Attention for Zoonotic Infections

International Attention for Zoonotic Infections

Effect of above‐ground plant species on soil microbial community structure and its impact on suppression of Rhizoctonia solani AG3

The extent of soil microbial diversity is seen to be critical to the maintenance of soil health and quality. Different agricultural practices are able to affect soil microbial diversity and thus the level of suppressiveness of plant diseases. In a 4-year field experiment, we investigated the microbial diversity of soil under different agricultural regimes. We studied permanent grassland, grassland turned into arable land, long-term arable land and arable land turned into grassland. The diversity of microbial communities was described by using cultivation-based and cultivation-independent methods. Both types of methods revealed differences in the diversities of soil microbial communities between different treatments. The treatments with higher above-ground biodiversity generally maintained higher levels of microbial diversity. Moreover, a positive correlation between suppression of Rhizoctonia solani AG3 and microbial diversity was observed. Permanent (species-rich) grassland and grassland turned into maize stimulated higher microbial diversities and higher levels of suppressiveness of R. solani AG3 compared with the long-term arable land. Effects of agricultural practices on Bacillus and Pseudomonas communities were also observed and clear correlations between the levels of suppressiveness and the diversities of these bacterial groups were found. This study highlighted the importance of agricultural management regime for soil microbial community structure and diversity as well as the level of soil suppressiveness.

Nitrate leaching in intensive agriculture in Northern France: Effect of farming practices, soils and crop rotations

The efficacy of ‘Good Agricultural Practices’ (GAP) for reducing nitrate pollution is tested on the scale of a small catchment area (187 ha) which is almost entirely under arable agriculture. GAP have been introduced on all fields since 1990. They consist in applying carefully planned N fertiliser recommendations, establishing catch crops (CC) before spring crops and recycling all crop residues. Soil water and mineral nitrogen (SMN) were measured three times each year on 36 sites representative of crops (wheat, sugarbeet, pea, barley, oilseed rape) and soil materials (loam, loamy clay and rocks, sand loam and limestone, sand) during 8 years (1991–1999). These measurements (about 3600 soil samples) were used in LIXIM model to calculate water and nitrogen fluxes below the rooting zone. The model could reproduce satisfactorily the water and SMN contents measured at the end of winter. It simulated reasonably well the nitrate concentration measured in the subsoil (3–10 m deep) of nine fields. The mean calculated amounts of drained water and leached nitrogen below the rooting depth were 231 mm year−1 and 27 kg N ha−1 year−1, corresponding to a nitrate concentration of 49 mg L−1. Leached N varied by a five-, four- and three-fold factor according to the year, crop and soil type, respectively. Nitrate concentration was primarily affected by soil type: it varied from 31 mg L−1 in deep loamy soils to 92 mg L−1 in shallow sandy soils, and was linked to the soil water holding capacity. The sugarbeet–wheat rotation gave the lowest concentration (38 mg L−1) and the pea–wheat rotation the highest one (66 mg L−1). In spite of their moderate growth (mean biomass = 0.8 Mg ha−1), the catch crops allowed to reduce the mean concentration by 50% at the annual scale and 23% at the rotation scale. Straw incorporation was also beneficial since net mineralisation between harvest and late autumn was reduced by 24 kg N ha−1 when straw residues were incorporated. Reducing fertilisation below the recommended rate did not significantly reduce further nitrate leaching. Although GAP were not all optimal and therefore less efficient than in well controlled experiments, they appear essential in intensive agriculture in order to comply with the EU standard for nitrate concentration.

Water‐stable aggregates and organic matter pools in a calcareous vineyard soil under four soil‐surface management systems

Abstract. Vineyards in Champagne, France are generally situated on slopes where the soils are subject to erosion. Therefore it is important to find a soil‐surface management practice that protects the soil against water erosion. We assessed the potential of mulches or grass covers to stabilize soil aggregates in a calcareous sandy loam from a vineyard in Champagne after 9 years under different management systems. Four different treatments were studied: (i) a bluegrass (Poa pratensis) surface cover between the vine rows (GC) with bare soil under the vines (R); two organic mulches of (ii) coniferous (CB) or (iii) poplar (PB) bark that covered the entire soil surface, and (iv) bare soil between the rows as a control. The bark amendments were applied every 3 years at rates of 61 and 67 t ha−1 for the PB and CB treatments, respectively. The kinetics of soil disaggregation in water fitted a power law (A=K t−D), in which K was the fraction of water‐stable >200 μm aggregates remaining after 1 hour of wet‐sieving. In the 0–5 cm layer, aggregate stability was greater for GC (K=21.7), CB (K=15.2) and PB (K=13.6) than for the control (K=10.5) and R (K=11.8). In the 0–20 cm layer, CB also stabilized soil aggregates (K=14.0–15.0); but PB did not. Structural stability was more strongly related to total organic carbon (R2=0.64, P <0.001) than to microbial biomass carbon (R2=0.54, P<0.001). A bluegrass cover enhanced structural stability in the 0–5 cm and 0–20 cm layers (K=14.2), probably because of intense root development and rhizodeposition enhancing microbially produced metabolites, such as carbohydrates. Establishing grass cover or applying bark mulch are effective agricultural practices that improve soil aggregate stability and thus should reduce soil erosion. The vegetative growth of the vines was greater on the soils amended with bark mulches and less on the grass covered soils compared with the control soil; however, no difference in wine quality was observed among the different treatments.

Nontrade Concerns: Reconciling Domestic Policy Objectives with Freer Trade in Agricultural Products

Since the conclusion of the Uruguay Round of trade negotiations in 1994, there has been increasing debate about the implications of freer trade for domestic or “nontrade” objectives in agriculture. These range from traditional concerns, such as food security and rural development, to more recent issues such as the relationship between agriculture and the environment, and the effects of agricultural practices on human health and animal welfare. For countries reluctant to reduce agricultural protection, a key issue is the extent to which domestic policy objectives would need to be sacrificed under freer trade. For countries espousing trade liberalization, the issue is whether domestic policy objectives will be used as a guise to undermine freer trade in agricultural products. In this paper, we focus on two areas of concern that are stressed by rich, developed countries—the linkage between agriculture and the environment, and animal welfare. Environmental issues are prominent in Asia, Europe and, increasingly in North America, while animal welfare is a major issue in Europe. It is generally acknowledged that agricultural support, provided through implicit consumer taxes and direct subsidies in developed countries, generates much of the distortion in global agricultural trade. The more than $300 billion of agricultural support that is provided annually by OECD countries, disadvantages developing country exporters and causes distortions in importers. Ensuring that there are effective disciplines on trade-distorting forms of support will be vital to the suc

Evaluation of oilseed crop rotations with agro-environmental indicators

The European Common Agricultural Policy is shifting an increasing part of the subsidies to eco-conditionality. Henceforth, it becomes essential to evaluate the environmental effect of agricultural practices, and more generally performances of cropping and farming systems, in order to design and to develop more sustainable systems. This assessment is being implemented for the main cropping systems of some French regions, using environmental indicators. Eleven exposure indicators were chosen in order to represent a wide range of specific sustainability objectives dealing with water, soil, air, non-renewable resources, biodiversity, and landscape. The results present the sustainability assessment for the crop rotations of Champagne Berrichonne region in the Centre of France.

Wind erosion in a semiarid agricultural area of Spain: the WELSONS project

The co-ordinated European research project Wind Erosion and Loss of SOil Nutrients in semiarid Spain (WELSONS) was carried out from 1996 to 1999 to understand and predict the potential impacts of land-use change and management on soil degradation by wind erosion on agricultural land in Central Aragon, a semiarid desertification-threatened region in NE Spain. This paper gives a description of the project's experimental approach and an overview of the main results regarding the effects of agricultural practices (i.e. conventional, CT, versus reduced tillage, RT) on surface conditions affecting wind erosion, the mobilisation of soil particles in the saltation layer and the atmospheric emission of fine dust into the suspension layer. The characterisation of the soil surface showed that soil erodibility by wind under RT was lower than that under CT. Though strong Cierzo wind events occurred during the experimental period, only a limited amount of material was available for wind erosion mainly due to soil crusting, a common feature in the area. In spite of this, saltation transport flux was measured at CT plots for different erosion episodes. Also, significant vertical emission of dust was observed only in the CT plot. Finally, the sandblasting efficiency calculated in the present experiment could be interpreted as the result of a higher binding energy for the particles of the silt loam experimental soil compared to soils with a lighter texture.

Effects of farming practices on spatial behaviour of common voles

This study aimed to reveal changes in spatial behaviour of common voles (Microtus arvalis) after alteration of their habitat by farming practices. Radio-collared common voles were tracked before and after mulching, mowing, harvesting wheat, and ploughing in the flood plain of the river Unstrut in central Germany. Voles undisturbed by agricultural practices were tracked on a mulchland, an abandoned pasture, and a cattle pasture. There was a large decrease in home-range size after harvesting wheat (96%, P<0.001). Changes after mowing (–74%, P=0.06) were almost significant whereas changes after mulching were not (+14%, P=0.60). On the cattle pasture we found a decrease in home-range size (42%, P=0.03) possibly due to increased spatial activity of cattle in autumn. There was a positive correlation of home-range size and vegetation height for plots with and without farming activity but no correlation with vegetation cover, population density, and breeding. Radio-collared common voles did not show evasive movements and farming practices did not cause a shift of centres of activity. Common voles clearly reacted to sudden changes in vegetation height, which may indicate an immediate response to predation risk.

Effects of farming practices on spatial behaviour of common voles

Effects of farming practices on spatial behaviour of common voles

Effects of farming practices in Tibet on wintering Black necked Crane ( Grus nigricollis ) diet and food availability

Effects of farming practices in Tibet on wintering Black necked Crane ( Grus nigricollis ) diet and food availability

Iron-rich spinel phases from sand fraction of three Chilean soils developing on volcanic materials

The magnetic separates from the sand fraction of three Chilean soils forming on volcanic materials were studied by powder XRD, RT and 80 K Mössbauer spectroscopy, saturation magnetization measurements, and scanning electron microprobe analysis. Soil samples were collected from the B-horizon of pedons from native and cultivated areas. Results, particularly from powder x-ray diffractometry, Mössbauer spectroscopy, and chemical analysis, reveal relatively complex magnetic mineral assemblages in all samples. Fe (>70 mass% Fe2O3), Ti (ranging from ~2 to ~26 mass% TiO2), Al (from 1 to ~6 mass% Al2O3) and Mg (from 1 to ~6 mass% MgO) are the main elements found in the iron oxide-spinel structures. In at least one sample, namely the magnetically separated portion from the sand fraction of the fertilized Collipulli soil, the 80 K Mössbauer spectrum indicates that magnetite undergoes the Verwey transition. This sample, with saturation magnetization being of order of 40 J T−1 kg−1, is also the most magnetic of all magnetic separates. Results on the iron oxide spinels, from electron microprobe data, reveal a large variability not only of chemical composition, but also of crystalline structure and magnetic properties of these magnetic minerals. The effect of agricultural practices, particularly the continuous chemical fertilization and soil acidity correction over several years, on the iron oxide mineralogy could not be unequivocally established, but the present data provide a relatively detailed description of the magnetic iron oxide assemblages of these Chilean volcanic soils.

The Effects of Founding Events and Agricultural Practices on the Genetic Structure of Three Metapopulations of Globodera pallida

To assess the genetic constitution of the Globodera pallida populations in the Netherlands and the effects of agricultural practices, three geographically separated metapopulations, in total consisting of 226 local populations, were analyzed by two-dimensional gel electrophoresis (2-DGE) of total proteins. This technique allows the accurate assessment of allele frequencies in homogenates of mixtures of individuals. Based on the estimated average heterozygosity, the average proportion of polymorphic loci and the average number of alleles per locus, the genetic diversity among 226 local G. pallida populations was small. The small genetic basis of G. pallida in the Netherlands will facilitate the identification of Solanum genotypes with a broad and durable resistance to G. pallida. Instead of clusters of local populations with unique alleles, a continuous range of allele frequencies was observed. Analysis of the three metapopulations by the Shannon-Weaver index and Nei's G(ST) revealed that the metapopulation from a region with sandy-loam soils was clearly distinguishable from the remaining two; the local populations within this metapopulation were more similar and the genetic diversity within the individual local populations was significantly higher than the local populations from the two remaining regions. These regions are characterized by wider crop rotation schemes and a very limited use of nematicides. The less intensive cultivation of potatoes in these regions with sandy-clay soils resulted in relatively little variation within and more variation between local nematode populations. To our knowledge, the effects of agricultural practices on the genetic constitution of potato cyst nematode populations have not been pinpointed before.

Abstracts, Alberta Regional Meeting, The Canadian Phytopathological Society, 2000

Identification of fungicides for controlling saskatoon diseases. P.S. Bains, H.S. Bennypaul, and R.J. Howard. Crop Diversification Centre North, Alberta Agriculture, Food and Rural Development, R.R. 6, Edmonton, AB T5B 4K3, Canada; and (R.J.H.) Crop Diversification Centre South, Alberta Agriculture, Food and Rural Development, SS4, Brooks, AB T1R 1E6, Canada. Calcium mobilization in Yr-18 gene mediated adult-plant stripe rust [Puccinia striiformis]resistance in spring wheat. S.A. Elahinia and J.P. Tewari. Department of Plant Protection, University of Guilan, Rasht, Iran; and (J.P.T.) Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada. Susceptibility of Brassica napus cultivars to fusarium wilt. R.M. Lange, D. Blais, L. Harrison, and P.D. Kharbanda. Alberta Research Council, P.O. Bag 4000, Vegreville, AB T9C 1T4, Canada; (D.B.) Canola Council of Canada, Box 37, Delmas, SK S0M 0P0, Canada; and (L.H.) Alberta Agriculture, Food and Rural Development, Beaverlodge Research Farm, Box 29, Beaverlodge, AB T0H 0C0, Canada. Barley leaf epicuticular wax in relation to the scald disease. A. Mukerji and J.P. Tewari. Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada. Efficacy of crown (carbathiin and thiabendazole) to control seed-borne ascochyta blight on Kabuli chickpea. A. Matus, J. Atchison, E. Pensaert, and R. McLeod. Gustafson 10-2712-37 Ave. NE, Calgary, AB T2E 1E5, Canada. A genetic study of adult plant resistance to stripe rust (Puccinia striiformis) and leaf rust (Puccinia triticina) in spring wheat. A. Navabi, R.P. Singh, J.P. Tewari, and K.G. Briggs. Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; and (R.P.S.) International Maize and Wheat Improvement Center (CIMMYT), Apartado Postal 6-641, 0660 Mexico, D.F., Mexico. Slow-scalding in barley, a novel strategy for disease management. B. Sorkhilalehloo, J.P. Tewari, T.K. Turkington, F. Capettini, K.G. Briggs, B. Rossnagel, and R.P. Singh. Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.K.T.) Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; (F.C.) International Center for Agricultural Research in Dry Areas (ICARDA), c/o International Maize and Wheat Improvement Center (CIMMYT), Apartado Postal 6-641, 0660 Mexico, D.F., Mexico; (B.R.) Crop Development Centre, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; and (R.P.S.) CIMMYT, Mexico. The impact of fall versus spring seeding on sclerotinia stem rot and black spot of canola. T.K. Turkington, G.W. Clayton, and K.N. Harker. Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada. Evaluation of resistance to Alternaria brassicae in some Chinese crucifer-genotypes. R. Wang and J.P. Tewari. Department of Horticulture, Inner Mongolia Agriculture University, Huhhot, Inner Mongolia, China; and (J.P.T.) Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada. Studies on disease suppressiveness of compost. J. Yang, P.D. Kharbanda, and J.P. Tewari. Alberta Research Council, P.O. Box 4000, Vegreville, AB T9C 1T4, Canada; and (J.P.T.) Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada. Evaluation of Paenibacillus polymyxaPKB1 for biocontrol of Pythium disease of cucumber in hydroponic systems. J. Yang, P.D. Kharbanda, and M. Mirza. Alberta Research Council, Vegreville, AB T9C 1T4, Canada; and (M.M.) Crop Diversification Centre North, Alberta Agriculture, Food and Rural Development, R.R. 6, Edmonton, AB T5B 4K3, Canada. Streptomycete ecology: effects of agricultural practices and suppression of fungi. B. Zaitlin, D. Parkinson, K. Turkington, and G. Clayton. Department of Biological Science, University of Calgary, Calgary, AB T2N 1N4, Canada; and (K.T., G.C.) Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada.

The management of lowland neutral grasslands in Britain: effects of agricultural practices on birds and their food resources

Summary The effects of agricultural intensification on biodiversity in arable systems of western Europe have received a great deal of attention. However, the recent transformation of grassland systems has been just as profound. In Britain, the management of grassland has changed substantially in the second half of the 20th century. A high proportion of lowland grassland is managed intensively. The major changes include a doubling in the use of inorganic nitrogen, a switch from hay to silage, and increased stocking densities, particularly of sheep. Structurally diverse and species‐rich swards have been largely replaced by relatively dense, fast‐growing and structurally uniform swards, dominated by competitive species. Most of these changes have reduced the suitability of grassland as feeding and breeding habitat for birds. The most important direct effects have been deterioration of the sward as nesting and wintering habitat, and loss of seed resources as food. Short uniform swards afford poor shelter and camouflage from predators, whereas increased mowing intensities and trampling by stock will destroy nests and young. Increased frequency of sward defoliation reduces flowering and seed set, and hence food availability for seed‐eating birds. The indirect effects of intensification of management on birds relate largely to changes in the abundance and availability of invertebrate prey. The effects of management vary with its type, timing and intensity, and with invertebrate ecology and phenology, but, in general, the abundance and diversity of invertebrates declines with reductions in sward diversity and structural complexity. Low input livestock systems are likely to be central to any future management strategies designed to maintain and restore the ecological diversity of semi‐natural lowland grasslands. Low additions of organic fertilizer benefit some invertebrate prey species, and moderate levels of grazing encourage sward heterogeneity. There is now a need to improve understanding of how grassland management affects bird population dynamics. Particularly important areas of research include: (i) the interaction between changes in food abundance, due to changes in fertilizer inputs, and food accessibility, due to changes in sward structure; (ii) the interaction between predation rates and management‐related changes in habitat; and (iii) the impact of alternative anti‐helminithic treatments for livestock on invertebrates and birds.

Chesapeake Bay eutrophication: scientific understanding, ecosystem restoration, and challenges for agriculture.

Chesapeake Bay has been the subject of intensive research on cultural eutrophication and extensive efforts to reduce nutrient inputs. In 1987 a commitment was made to reduce controllable sources of nitrogen (N) and phosphorous (P) by 40% by the year 2000, although the causes and effects of eutrophication were incompletely known. Subsequent research, modeling, and monitoring have shown that: (i) the estuarine ecosystem had been substantially altered by increased loadings of N and P of approximately 7- and 18-fold, respectively; (ii) hypoxia substantially increased since the 1950s; (iii) eutrophication was the major cause of reductions in submerged vegetation; and (iv) reducing nutrient sources by 40% would improve water quality, but less than originally thought. Strong public support and political commitment have allowed the Chesapeake Bay Program to reduce nutrient inputs, particularly from point sources, by 58% for P and 28% for N. However, reductions of nonpoint sources of P and N were projected by models to reach only 19% and 15%, respectively, of controllable loadings. The lack of reductions in nutrient concentrations in some streams and tidal waters and field research suggest that soil conservation-based management strategies are less effective than assumed. In 1997, isolated outbreaks of the toxic dinoflagellate Pfiesteria piscicida brought attention to the land application of poultry manure as a contributing factor to elevated soil P and ground water N concentrations. In addition to developing more effective agricultural practices, emerging issues include linking eutrophication and living resources, reducing atmospheric sources of N, enhancing nutrient sinks, controlling sprawling suburban development, and predicting and preventing harmful algal blooms.

Effectiveness of Agricultural Practices in Decreasing Radionuclide Transfer to Plants in Natural Meadows

Agricultural practices (discing+ploughing, reseeding, liming and the use of NPK fertilisers) were used to decrease 137Cs (RCs) and 90Sr (RSr) transfer to plants in natural meadows in Russia, Belarus and Ukraine. Experiments were carried out in the 1997-1999 period. Results from field experiments showed that RCs transfer in control meadows was in most cases higher than in ploughed plots (up to 3-4 times). Discing+ploughing was the most effective treatment. In addition, there was a significant trend in decreasing RCs transfer when using increasing amounts of NPK fertiliser. A time dependence was noticed, since the overall transfer was lower in the following years after the start of the experiments. Regarding RSr, no significant effect was observed in the first year. However, the effect of ploughing caused a transfer decrease by 2-4 times in the second year. Laboratory experiments showed that changes in RCs soil sorption properties are likely after ploughing, and that NPK fertilisation and liming rates used were not sufficient to ensure K and Ca+Mg concentrations in soil solution high enough to achieve the maximum decrease in radionuclide transfer.

Austria: precautionary blockage of agricultural biotechnology

Austria has interpreted the precautionary principle and Directive 90/220 in a more stringent way than other EU member states. It continues to ban the import of Bt maize despite the Commission’s recurrent warnings. The Austrian standard of GMO risk assessment emphasizes a broad definition of adverse effects beyond a purely technical account of risk, including effects of agricultural practices. Boundaries between plant, seed, food, and feed assessments tend to blur. It asks implicitly for the demonstration of safety and uses organic farming as a normative reference point. The understanding of precaution goes beyond the Danish approach in extensively interpreting the scope of Directive 90/220. This policy originated from the Environment Agency (UBA) and developed out of the division of labour among government agencies. It is in line with the inherent paternalism of Austrian governance as well as with Austrian public sensitivities concerning organic agriculture and food. When public opinion turned hostile to agricultural biotechnology, the Austrian standard became entrenched and led to Austria’s initially lone stance among EU member states.

Impact of nitrogen cycling associated with production and consumption of food on nitrogen pollution of stream water

We evaluated the impact of nitrogen (N) cycling on N pollution of stream water, with emphasis on N disposed of (hereafter referred to as “disposal N”) from human and livestock excrement and the N surplus in cropland, compared to the total-N concentration of stream water, in seven zones of Asahikawa City characterized by various types of land use. In order to estimate N cycling, we used the Nitrogen Flow Model, composed of the N budgets of human, livestock, and cropland subsystems. The urban area with a population density of over 4,000 persons km-2 generated a very large amount of disposal N (about 2,700 kg N ha-1 cropland y-1). Based on the amount of disposal N and the volume of domestic sewage water used, the N concentration estimated for the urban area was 34 mg N L-1, which found in the effluent from the sewage treatment facility (24–28 mg N L-1), regardless of the season. Thus, it was indicated that most of the disposal N in the urban area was discharged directly to streams through the sewage treatment facilities, contributing to a point source of N pollution of stream water. In addition, the disposal N from livestock facilities was larger in pig and poultry farming areas than in other farming areas, contributing to some extent to a potential source of N pollution. As a result, the concentrations increased above 1 mg N L-1 in the urban and surrounding areas. On the other hand, the N surplus in cropland was practically determined by the N flows associated with chemical fertilizer, livestock excrement as manure, and crop uptake. The N surplus was similar among the seven zones, ranging from 69 to 99 kg N ha-1 y-1. The N concentration estimated from the amount of N surplus and 50% of mean annual precipitation as a discharge rate was 13.6–19.5 mg N L-1. Most of the surplus N was indicated to be leached out. However, the total-N concentration measured in the major streams flowing through Asahikawa City was mostly below 1 mg N L-1 except for the urban and surrounding areas. The surplus N in cropland may not reach the streams, even if N leaching occurs, probably due to N removal by plant uptake, denitrification, and sedimentation in the riparian zone and stream channels. Thus the effect of agricultural practices on N pollution of stream water was not appreciable.