At What Rate Do Farmers Substitute Manure For Commercial Fertilizers?

Water quality has implications for the health of our ecosystem and the welfare of our population. Agriculture is one of the major contributors of non-point source pollution that contaminates our nation's water supplies. Understanding how farmers substitute manure for commercial fertilizers allows us to better understand the level of nitrogen that enters the soil and can seep into our waterways. In this paper, we explore the factors that help determine farmers' substitution rates between the two types of fertilizers. Location, crop type, and time all could play important roles. We analyze USDA farm level survey data for both crop and livestock farms covering the years 1996 to 2002 to create substitution rate estimates used on corn, soybean, and wheat fields. While the substitution rates we found did not appear to change over the time frame examined, we did find that crop type and location significantly affected the rates that farmers use. Additionally, and perhaps most importantly, the substitution rates we did find did not conform to the "perfect substitution" between N coming from commercial sources and manure used in much of the literature. This means that previous studies could have underestimated the potential level of pollution of our water by our nations' farms.Farm Management,

Dairy Resource Management: A Comparison of Conventional and Pasture-Based Systems

Facing rapid and significant change in the sector, U.S. dairy production trends from 1993-2005 were tracked and performance measures (scale and technical efficiency and returns on assets) were estimated for conventional and pasture-based dairy farms using data from USDA's Agricultural Resource Management Survey. Comparisons of relative economic performance of dairy farms by size and type are made.dairy operations, pasture-based systems, technical efficiency, Livestock Production/Industries,

Productivity and the Determinants of Efficiency in Irish Agriculture (1996-2006)

The competitiveness and productivity of Irish agriculture has been at the forefront of debate in recent times given successive and impending changes to agricultural policy. This paper examines the trend in total factor productivity in Irish agriculture over the recent past and explores the effects of specific variables on relative efficiency levels. The findings of this research have shown that productivity growth was highest in the Cattle Rearing sector followed by the Dairy, Cattle Finishing, Sheep and Cereals sectors during the period 1996 to 2006. The research has also shown that efficiency levels are, in general, positively correlated with extension use soil quality, the overall size of the farm, the level of intensification and the level of specialisation. The use of artificial insemination was also positively correlated with efficiency in the Dairy sectorProduction Economics,

Analysis of repeated high-intensity running performance in professional soccer

The aims of this study conducted in a professional soccer team were two-fold: to characterise repeated high-intensity movement activity profiles in official match-play; b) to inform and verify the construct validity of tests commonly used to determine repeated-sprint ability in soccer by investigating the relationship between the results from a test of repeated-sprint ability and repeated high-intensity performance in competition. High-intensity running performance (movement at velocities >19.8 km/h for a minimum of 1-s duration) in 20 players was measured using computerised time motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 out of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of 6 consecutive 6s sprints separated by 20s passive recovery intervals. In all players, the majority of consecutive high-intensity actions in competition were performed after recovery durations ≥61s, recovery activity separating these efforts was generally active in nature with the major part of this spent walking, and players performed 1.1±1.1 repeated high-intensity bouts (a minimum of 3 consecutive high-intensity with a mean recovery time ≤20s separating efforts) per game. Players reporting lowest performance decrements in the repeated-sprint ability test performed more high-intensity actions interspersed by short recovery times (≤20s, p<0.01 and ≤30s, p<0.05) compared to those with higher decrements. Across positional roles, central-midfielders performed a greater number of high-intensity actions separated by short recovery times (≤20s) and spent a larger proportion of time running at higher intensities during recovery periods while fullbacks performed the most repeated high-intensity bouts (statistical differences across positional roles from p<0.05 to p<0.001). These findings have implications for repeated high-intensity testing and physical conditioning regimens

Profits, Costs, and the Changing Structure of Dairy Farming

U.S. dairy production is consolidating into fewer but larger farms. This report uses data from several USDA surveys to detail that consolidation and to analyze the financial drivers of consolidation. Specifically, larger farms realize lower production costs. Although small dairy farms realize higher revenue per hundredweight of milk sold, the cost advantages of larger size allow large farms to be profitable, on average, even while most small farms are unable to earn enough to replace their capital. Further survey evidence, as well as the financial data, suggest that consolidation is likely to continue.Dairy farming, economies of scale, economies of size, dairy farm structure, milk costs, Farm Management, Industrial Organization, Livestock Production/Industries,

Refractive and corneal astigmatism in white school children in Northern Ireland

To study the prevalence of and relation between refractive and corneal astigmatism in white school children in Northern Ireland and to describe the association between refractive astigmatism and refractive error

Refractive error and visual impairment in school children in Northern Ireland

To describe the prevalence of refractive error (myopia and hyperopia) and visual impairment in a representative sample of white school children