Author
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Sassenrath, Gretchen |
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ALARCON, V - MISSISSIPPI STATE UNIV. |
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Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only Publication Acceptance Date: 8/10/2005 Publication Date: 10/6/2005 Citation: Sassenrath, G.F., Alarcon, V.J. 2005. Crop water stress in two production systems under humid growing conditions. American Society of Agronomy, Meeting Abstracts. No. 143b. Interpretive Summary: Crop plants use large amounts of moisture from the soil in exchange for carbon for photosynthesis. This transpired water also serves to cool the plants. The moisture available in the soil impacts crop growth and performance, and changes with production practices. We are exploring the change in soil moisture with two different production systems to determine the impact on cotton crop growth, yield and lint quality, and the need for irrigation. In conventional production systems, deep soil tillage has been suggested to increase water movement into the soil and maintain soil moisture available for crop growth. Cover crops used in conservation production systems have also been suggested to improve the permeability of the upper soil layer, increasing the soil moisture. We are measuring the soil moisture levels in two different soil types, and following plant growth and yield response for the humid growing conditions of the Mississippi Delta. The reflectance of the crop canopy is measured with a spectroradiometer, to develop signatures specific to the onset of moisture stress. This information will be useful for cotton producers in knowing the timing and amount of water from irrigation that is needed to maintain yield under various cropping production practices. Technical Abstract: Crop moisture status is dependent on the evaporative demands of the crop and the available moisture in the soil. We are exploring alternative production practices for their ability to provide increased soil available moisture for cotton (Gossypium hirsutum) crops under the humid growing conditions of the Mississippi Delta. Deep tillage, or subsoiling, has been suggested to increase the infiltration of water into the soil profile during winter rain events, increasing the soil available moisture during the growing season. Increased soil organic matter from winter cover crops has also been suggested to increase soil surface permeability and subsequent soil moisture. We are measuring the plant and soil moisture levels under two production systems: conventional production, with deep tillage; and conservation production, reduced tillage with a winter wheat cover crop. Watermark soil moisture monitors are used to measure the moisture in the soil profile and indicate rooting depth. Plant growth characteristics and fruiting patterns are measured to determine plant stress levels. Hyperspectral imagery is being taken to develop spectral signatures of water stress in cotton crops, and develop remote sensing systems for early detection of crop water stress. Plots are either rain fed or irrigated. Plots are replicated across two predominant soil types of the lower Mississippi alluvial flood plain. Differences in yield and cotton fiber quality are determined at harvest. |
