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Open Access Thesis

Keywords

Soil erosion--Environmental aspects--Iowa--Munns Creek Region; Soil erosion--Environmental aspects--Iowa--Grundy County; Soil fertility--Iowa--Munns Creek Region; Soil fertility--Iowa--Grundy County; Soil erosion--Environmental aspects; Soil fertility; Iowa--Grundy County; Academic theses;

Abstract

The temporal distribution of chloride, nitrate, and sulfate in the hydrologic environment were studied in Grundy County, Iowa from June to September 2004. The goal of the project was to investigate the rate of soil erosion and the subsequent loss of nutrients from the agricultural fields of the study area. Water samples were collected weekly from 6 different sites along Munns Creek in the study area near Grundy Center, Iowa. Each sample was analyzed for chloride, nitrate, and sulfate by ion chromatography. Soil core samples were collected from 22 locations in the surrounding agricultural fields. At each location, soil was collected from two different depths (surface, and 6 inch). Subsequently, the soil samples were analyzed for the Total Phosphorus (TP). The Universal Soil Loss Equation (USLE) was used to measure soil erosion from the croplands. A significant loss of P is associated with soil erosion by suspended sediments transported in overland flow. The highest TP was found in some of the upstream areas of the drainage network. In June samples, the surface soils had much higher TP than the deeper samples. This is because P was freshly released from the fertilizers applied to the fields in May. Later, there was significant leaching of P to deeper soils following major rain events in the area. As a result, all samples collected in July, August and September had much higher Pin deeper soils. However, the loss of P from the upper soil is also attributed to the rapid soil erosion in the area. The Total Phosphorus loads ranged from 0.4 µg Pig to 377.5 µg Pig with an average of 50.7 µg Pig. It was concluded from this study that soil erosion can significantly impact the temporal distribution of nutrients in agricultural fields. Also, it was observed that dissolved oxygen was quite variable, ranging from 13.9 mg/L to 5.3 mg/L. On the other hand, pH was relatively stable, and ranged from 8.39 to 6.84. In June, nitrate in sediments was found to be much higher (99.6 mg/L) than chloride (18.0 mg/L) and sulfate (17.4 mg/L). Over the period of study, nitrate concentration at most sites gradually decreased, whereas sulfate concentration increased.

Year of Submission

2006

Degree Name

Master of Science

Department

Department of Geology

First Advisor

Mohammad Z. Iqbal

Second Advisor

James C. Walters

Third Advisor

Maureen E. Clayton

Comments

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Date Original

2006

Object Description

1 PDF file (101 leaves)

Language

en

File Format

application/pdf

Included in

Geology Commons

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