scholarly journals Gypsum amendment as a means to reduce agricultural phosphorus loading: an economic appraisal

2012 ◽  
Vol 21 (3) ◽  
pp. 307-324 ◽  
Author(s):  
Antti Iho ◽  
Marita Laukkanen
Keyword(s):  
Soil Phosphorus ◽  
Threshold Level ◽  
Economic Feasibility ◽  
Mitigation Measures ◽  
Phosphorus Loading ◽  
Phosphorus Fertilization ◽  
Soil Test ◽  
Dissolved Phosphorus ◽  
Soil Test Phosphorus ◽  
Phosphorus Losses

This study analyzes the economic feasibility of gypsum amendment as a means to reduce particulate and dissolved phosphorus loads from arable areas. To this end, an optimization model is developed that includes gypsum amendment as well as matching phosphorus fertilization to crop need and the level of soil phosphorus reserves as phosphorus load mitigation measures, with soil phosphorus reserves measured by soil test phosphorus (STP). The optimal extent of gypsum amendment is then determined simultaneously with optimal fertilization use as a function of field STP level. The results indicate that whether or not gypsum amendment is economically feasible depends on field erosion susceptibility and STP level. When accounting for the costs and benefits to the society on the whole, gypsum treatment suits best to mitigation of phosphorus losses from soils with excessively high phosphorus reserves; once a threshold STP level is reached, gypsum amendment is optimally given up. This threshold level depends on field slope and on society’s willingness to pay for water quality.

scholarly journals Linking Soil Phosphorus to Dissolved Phosphorus Losses in the Midwest

ael ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 170004 ◽  
Author(s):  
Emily W. Duncan ◽  
Kevin W. King ◽  
Mark R. Williams ◽  
Greg LaBarge ◽  
Lindsay A. Pease ◽  
...  
Keyword(s):  
Soil Phosphorus ◽  
Dissolved Phosphorus ◽  
Phosphorus Losses

Mapping areas at risk of diffuse phosphorus losses to water: a pilot study of Lake Haderslev Dam, Denmark

2008 ◽  
Vol 58 (11) ◽  
pp. 2173-2178 ◽  
Author(s):  
Hans Estrup Andersen ◽  
Goswin Heckrath ◽  
Hans Thodsen
Keyword(s):  
At Risk ◽  
Pilot Study ◽  
Point Sources ◽  
Mitigation Measures ◽  
Phosphorus Loading ◽  
Ecological Quality ◽  
Risk Areas ◽  
Lake Catchment ◽  
Phosphorus Losses ◽  
Total P

Haderslev Dam is a 272 ha lake in southern Denmark with a high recreational value. For decades the lake has been severely eutrophicated due to excessive phosphorus loading. Major point sources were cut off in the early 1990s and an upstream wetland was recreated. However, the ecological quality remains unsatisfactory. In this study we estimate the importance of agriculture on diffuse phosphorus (P) input to the lake by modelling combined with independent estimates for contributions from scattered dwellings not connected to a sewer and from background losses. We apply a newly developed Danish P index to the lake catchment for mapping of risk areas for diffuse phosphorus losses. For risk areas we suggest mitigation measures and estimate the effect of the mitigation measures on the total P loading of the lake as well as the associated costs.

scholarly journals Modelling Dissolved Phosphorus Losses from Accumulated Soil Phosphorus and Applied Fertilizer and Manure for a National Risk Indicator

2021 ◽  
Author(s):  
Keith Reid ◽  
Kimberley D. Schneider
Keyword(s):  
Soil Phosphorus ◽  
Field Measurements ◽  
The United States ◽  
Accurate Estimation ◽  
Risk Indicator ◽  
Runoff Water ◽  
Dissolved Phosphorus ◽  
P Loss ◽  
P Accumulation ◽  
Phosphorus Losses

Balancing the weighting of various components of phosphorus loss in models is a critical but often overlooked step in accurate estimation of risk of P loss under field conditions. This study compared the P loss coefficients used to predict dissolved P losses from desorption from accumulated P in the soil, and those incidental to applications of P as fertilizer or manure, with extraction coefficients determined from actual P losses reported in literature for sites in Canada, with the addition of some sites with similar soils and climate from the northern tier of the United States. The extraction coefficients for dissolved P measured in runoff water was greater by a factor of 6.5X in year-round edge-of-field measurements than in runoff boxes, indicating that models using P extraction coefficients derived from runoff box experiments will be underestimating the magnitude of losses from P accumulation in soil. Differences among the measurement methods (runoff box, rainfall simulator or edge-of-field) were not evident for incidental losses from applied P, but current models appear to over-predict the losses of applied P. Good fit between measured and modelled DP concentrations were achieved by applying coefficients of 0.275 to the fertilizer equations, and 0.219 to the manure equations, implying that 72.5% of fertilizer P and 78% of manure P are not available for runoff. This study underlines the importance of considering the relative weights of the various components of P loss as new models are developed and validated.

scholarly journals Gypsum amendment of soils reduces phosphorus losses in an agricultural catchment

2012 ◽  
Vol 21 (3) ◽  
pp. 279-291 ◽  
Author(s):  
Petri Ekholm ◽  
Pasi Valkama ◽  
Elina Jaakkola ◽  
Mikko Kiirikki ◽  
Kirsti Lahti ◽  
...  
Keyword(s):  
Ionic Strength ◽  
High Flow ◽  
Soil Test ◽  
Covariance Model ◽  
Online Data ◽  
Dissolved Phosphorus ◽  
Rivers And Lakes ◽  
Manual Sampling ◽  
High Flow Period ◽  
Phosphorus Losses

We estimated the changes in the losses of particulate and dissolved phosphorus (P) after treating 93 ha of agriculturalfields with gypsum (4 t ha–1) in a 245 ha catchment in southern Finland. Runoff was monitored using onlinesensors and manual sampling during one high-flow period before and six periods after the gypsum amendment.Turbidity recorded by the sensors correlated with particulate P analysed in the laboratory, which enabledthe evaluation of changes in particulate P from the online data. Using a covariance model, gypsum amendmentwas estimated to have reduced the loss of particulate P by 64%. The loss of dissolved reactive P appeared to decreaseby one third, but was estimated with less precision. No such changes were found during the same periodin a nearby ‘reference’ catchment, where gypsum was not used. Gypsum did not affect soil test values for P, K, Mgor Ca, but it did increase the ionic strength and soil test SO4. In clayey catchments discharging into the sea, gypsummay provide an efficient means to reduce P losses from field cultivation. The duration of the gypsum effect andimpact of SO4 associated with gypsum amendment on the ecology of rivers and lakes has yet to be determined.

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