Predicting the risk of soybean rust in Minnesota based on an integrated atmospheric model.

To minimize crop loss by assisting in timely disease management and reducing fungicide use, an integrated atmospheric model was developed and tested for predicting the risk of occurrence of soybean rust in Minnesota. The model includes a long-range atmospheric spore transport and deposition module coupled to a leaf wetness module. The latter is required for spore germination and infection.

The ozone component of global change: potential effects on agricultural and horticultural plant yield, product quality and interactions with invasive species.

The productivity, product quality and competitive ability of important agricultural and horticultural plants in many regions of the world may be adversely affected by current and anticipated concentrations of ground-level ozone (O3). Exposure to elevated O3 typically results in suppressed photosynthesis, accelerated senescence, decreased growth and lower yields. Various approaches used to evaluate O3 effects generally concur that current yield losses range from 5% to 15% among sensitive plants.

Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City.

Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at the University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane.

Uncertainties in the current knowledge of some atmospheric trace gases associated with U.S. agriculture: a review.

Approximately 80 different crop species are grown in the United States in widely differing geographic areas, climatic and edaphic conditions, and management practices. Although the majority of cultivated acreage in the United States is planted with only about 10 primary crops, uncertainties associated with trace gas emissions arise from: (1) limited data availability, (2) inaccurate estimates because of large temporal and spatial variability in trace gas composition and magnitude of trace gas emissions from agricultural activities, (3) differing characteristics of pollutant emissions from highly dispersed animal feed-lots, and (4) limited understanding of the emissions of semi-volatile organic compounds (SVOCs) associated with agriculture. Although emission issues are of concern, so also is atmospheric deposition to cropping systems, including wet and dry nitrogen, minerals, and organic compounds.

Introduction of Asian Soybean Rust Urediniospores into the Midwestern United States-A Case Study.

In 2005, weekly rain samples collected at 124 National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites in the eastern and central United States were screened for Asian soybean rust (ASR; Phakopsora pachyrhizi) urediniospores. Application of a quantitative polymerase chain reaction method detected P. pachyrhizi DNA in the filter residue of rain samples collected during the week of 19 to 26 July 2005 in Minnesota, Missouri, and South Dakota.

Joint effects of elevated levels of ultraviolet-B radiation, carbon dioxide and ozone on plants.

There is growing interest regarding the joint effects of elevated levels of surface ultraviolet B (UV-B) radiation, carbon dioxide (CO2) and ozone (O3) on plants. Our current knowledge of this subject is too limited to draw any specific conclusions, although one might state that such effects are likely to be highly species dependent and may be more than additive, additive or less than additive. There are a number of uncertainties associated with the experimental protocols used and the conclusions reached in many studies.

Atmosphere and agriculture in the new millennium.

Effects of changing climate (CO(2), O(3), aerosols, UV-B radiation, temperature and precipitation) on crops are predominantly based on univariate studies. Limited bivariate studies suggest rising CO(2) levels would be beneficial to crops but may be offset by adverse O(3) effects. Elevated UV-B and ambient crop yields are difficult to project due also to limited research.

Sampling and physico-chemical analysis of precipitation: a review.

Wet deposition is one of two processes governing the transfer of beneficial and toxic chemicals from the atmosphere on to surfaces. Since the early 1970s, numerous investigators have sampled and analyzed precipitation for their chemical constituents, in the context of "acidic rain" and related atmospheric processes. Since then, significant advances have been made in our understanding of how to sample rain, cloud and fog water to preserve their physico-chemical integrity prior to analyses.

An integrative analysis of the role of atmospheric deposition and land management practices on nitrogen in the US agricultural sector.

Additions of anthropogenic nitrogen (N) compounds constitute one of the major classes of air pollutants of significance to human health and the environment. Reliance on wet deposition measurements alone can lead to considerable underestimates (by 40-60%) of the total (wet + dry) atmospheric N deposition. In addition, wet deposition of N are about 20% of the levels that are lost due to volatilization (primarily ammonia).