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2006

Iowa State University

Agricultural Science

Theses/Dissertations

Sustainable agriculture

Articles 1 - 2 of 2

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Effects Of Crop Rotation And Nitrogen Fertilization On Soil Nitrate Concentration And Corn Yield , Enrique Ortiz-Torres Jan 2006

Effects Of Crop Rotation And Nitrogen Fertilization On Soil Nitrate Concentration And Corn Yield , Enrique Ortiz-Torres

Retrospective Theses and Dissertations

Increasing concerns about production cost and environmental impacts of N fertilization require improving N management. The objectives of this study were to evaluate effects of cropping sequences and N fertilization on (1) corn yield and yield stability and (2) soil nitrate concentration in two Iowa long-term rotation experiments and (3) to assess the performance of the late spring nitrate test (LSNT) to assess N availability for corn in several cropping sequences. The experiments were near Kanawha (20 yrs) and Nashua (26 yrs) and N fertilization rates for corn were 0, 90, 180, 270 kg N ha -1. Rotations in Kanawha ...


Soil Quality Response To Manure Or Compost Amendments In Alternative Iowa Farm Systems , Kevin Frederick Jensen Jan 2006

Soil Quality Response To Manure Or Compost Amendments In Alternative Iowa Farm Systems , Kevin Frederick Jensen

Retrospective Theses and Dissertations

This study was conducted to improve understanding of carbon (C) and nitrogen (N) cycling in alternative agricultural systems. In order to generate information that is directly applicable to farm contexts, the study was conducted in farmer fields. The focus of this study was the soil phase of the C and N cycle, where physical and biological processes transform C and N. However, the design of the study, featuring on-farm research in partnership with farmers, ensured that soil and plant performance factors were integrated with the practical logistics and judgment calls that are exercised by farmers.