Abbreviations: CT, fall tillage with a chisel plow and spring finisher; CT-C, fall tillage and unmanured control treatment; CT-D, fall tillage treatment with December manure application timing; CT-J, fall tillage treatment with January manure application

Abbreviations: CT, chisel tillage; NSE, Nash-Sutcliffe model efficiency; NT, no-till; RSR, the ratio of root mean square error to the standard deviation of observed values; SWE, snow-water equivalent; WEP, water-extractable phosphorus.

Environmental conditions and management practices affect nutrient losses in surface runoff, but their relative impacts on phosphorus (P) loss during frozen and nonfrozen ground periods have not been well quantified. More specifically, the relative importance of manure application, tillage, and soil-test P (STP) has not been assessed at the field scale. In this study, we compiled a dataset composed of 125 site-years of data from 26 fields that were continually monitored for edge-of-field P loss during snowmelt and storm events. Regression tree analyses were performed to rank the level of influence each environmental and management factor had on nutrient loads. Dissolved P (DP) was the majority of the total P (TP) during frozen conditions, but a small portion of TP during nonfrozen conditions. Manure application had a greater influence on the flow-weighted mean concentrations (FWMCs) of TP and DP during frozen conditions than during nonfrozen conditions. No-till resulted in greater TP and DP FWMCs during frozen conditions than conventional tillage, whereas the opposite effect for TP FWMC was seen during nonfrozen conditions. However, regression tree analysis revealed that STP (0-to 5-cm depth) was the most important factor in predicting DP and TP FWMCs during frozen conditions and DP FWMC during nonfrozen conditions. Extremely high STP values were associated with late-frozen manure applications and grazed pastures. Reducing surface P loss in seasonally frozen landscapes will require prioritizing management strategies that avoid manure application through early-and late-frozen conditions and lead to a drawdown of STP, particularly in the top 5 cm.

is a waterborne pathogen known to have a significant reservoir in bovine manure. Land-dependent manure disposal may not result in significant or reliable pathogen attenuation and, therefore, presents a risk for transport of pathogenic spp. to groundwater. One factor missing in the existing literature is the role soil characteristics play in affecting oocyst transport. Of specific concern in regions with carbonate geology are macropores and other soil structures that contribute to preferential flow. Therefore, research is needed to understand soil type effects and important transport pathways for pathogens such as oocysts to drinking water wells. This study investigated transport potential in several soils overlying Wisconsin's vulnerable carbonate aquifer and related the soil transport to soil series and textural class. Experimental work involved monitoring the transport of oocysts through intact soil columns of different soil series under simulated rain conditions. Results demonstrate that a significant portion of oocysts will sorb or be physically entrapped in the soil, especially in soil with high clay content. However, silt loam soils with comparatively lower clay content demonstrated an ability to transport oocysts through the soil profile primarily via the first flush of water infiltrating through soil macropores. The rate of oocyst migration in silt loam soils paralleled the bromide tracer front, thus bypassing the soils' ability to strain or adsorb oocysts out of infiltrating water. Nevertheless, proper manure treatment and management are necessary to minimize public health risks.

Core Ideas Cryptosporidium extraction from the soil matrix is absent in USEPA Method 1623.1. Our S3PEG soil extraction is compatible with USEPA Method 1623.1. S3PEG extraction meets quality control recoveries specified by USEPA Method 1623.1. Irradiated Cryptosporidium oocysts are suitable soil surrogate for live oocysts. Cryptosporidium, a parasitic pathogen, when present in drinking water supplies poses a significant risk to human health. The soil environment provides a critical linkage between Cryptosporidium parent material (bovine manure) and the surface and groundwaters used by susceptible human populations for drinking water. The lack of a USEPA published analysis for the determination of Cryptosporidium in soil is a barrier to standardized investigation of Cryptosporidium transport in soils. Methodologies have been published in the absence of a USEPA analysis, yet they lack sufficient detail and quality controls to be generally applicable. This study developed and evaluated a Cryptosporidium soil extraction method capable of producing an extracted fluid containing Cryptosporidium that could be purified and enumerated using USEPA Method 1623.1.