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Full-Text Articles in Agriculture

Nitrogen And Water Effects On Canopy Sensor Measurements For Site-Specific Management Of Crops, Nicholas C. Ward Jul 2015

Nitrogen And Water Effects On Canopy Sensor Measurements For Site-Specific Management Of Crops, Nicholas C. Ward

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Water and nitrogen (N) are undoubtedly the two largest agricultural inputs globally. Coupled with advances in site-specific management technology their integration into production agriculture will allow for the most efficient use these crop input resources. Active canopy sensors offer the ability to measure biophysical plant traits rapidly and make assessments about plant status. Specifically, optical sensor measurements of light reflectance assess plant N status allowing for in-season and on-the-go N recommendations and applications; while infrared thermometers (IRT) measurement of canopy temperature can be used a tool for irrigation management. To evaluate how these technologies work among different plant stress environments …


Soil And Crop Response To Stover Removal From Rainfed And Irrigated Corn, Ian Kenney, Humberto Blanco-Canqui, Deann R. Presley, Charles W. Rice, Keith Janssen, Brian Olson Jan 2015

Soil And Crop Response To Stover Removal From Rainfed And Irrigated Corn, Ian Kenney, Humberto Blanco-Canqui, Deann R. Presley, Charles W. Rice, Keith Janssen, Brian Olson

Department of Agronomy and Horticulture: Faculty Publications

Excessive corn (Zea mays L.) stover removal for biofuel and other uses may adversely impact soil and crop production. We assessed the effects of stover removal at 0, 25, 50, 75, and 100% from continuous corn on water erosion, corn yield, and related soil properties during a 3-year study under irrigated and no-tillage management practice on a Ulysses silt loam at Colby, irrigated and strip till management practice on a Hugoton loam at Hugoton, and rainfed and no-tillage management practice on a Woodson silt loam at Ottawa in Kansas, USA. The slope of each soil was <1%. One year after removal, complete (100%) stover removal resulted in increased losses of sediment by 0.36–0.47 Mg ha-1 at the irrigated sites, but, at the rainfed site, removal at rates as low as 50% resulted in increased sediment loss by 0.30 Mg ha-1 and sediment-associated carbon (C) by 0.29 kg ha-1. Complete stover removal reduced wet aggregate stability of the soil at the irrigated sites in the first year after removal, but, at the rainfed site, wet aggregate stability was reduced in all years. Stover removal at rates ≥ 50%resulted in reduced soil water content, increased soil temperature in summer by 3.5–6.8 °C, and reduced tem-perature in winter by about 0.5 °C. Soil C pool tended to decrease and crop yields tended to increase with an increase in stover removal, but 3 years after removal, differences were not significant. Overall, stover removal at rates ≥50% may enhance grain yield but may increase risks of water erosion and negatively affect soil water and temperature regimes in this region.