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Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
John E. Sawyer
Objectives of this project were to study corn nitrogen (N) fertilization requirement and corn/soybean yield response when grown in a rye cover cropping system. Multiple rates of N fertilizer were applied, with measurement of corn yield response to applied N and soybean yield with and without a fall planted winter rye cover crop. The study was conducted at multiple research farms, with the intent for comparison of with and without a cover crop system across varying soil and climatic conditions in Iowa.
Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
Corn And Soybean Production With A Winter Rye Cover Crop, John E. Sawyer, Jose L. Pantoja, Daniel W. Barker
John E. Sawyer
Objectives of this project were to study corn nitrogen (N) fertilization requirement and corn/soybean yield response when grown in a rye cover cropping system. Multiple rates of N fertilizer were applied, with measurement of corn yield response to applied N and soybean yield with and without a fall planted winter rye cover crop. The study was conducted at multiple research farms, with the intent for comparison of with and without a cover crop system across varying soil and climatic conditions in Iowa.
Carbon Dioxide Assimilation Efficiency Of Maize Leaves Under Nitrogen Stress At Different Stages Of Plant Development, John Settimi, Jerry Maranville
Carbon Dioxide Assimilation Efficiency Of Maize Leaves Under Nitrogen Stress At Different Stages Of Plant Development, John Settimi, Jerry Maranville
John R. Settimi
Sub-optimal nitrogen (N) affects the N-rich carbon dioxide (CO2) assimilation enzymes which can limit maize (Zea mays) production. The status of the carboxylation system is closely correlated to the Assimilation Efficiency Index (AEI) which is the initial slope of the CO2 assimilation rate versus intercellular leaf CO2 concentrations. Experiments were undertaken to ascertain the effect of soil N nutrition on the AEI, determine genotypic variability for AEI under N-deficiency, determine how leaf and plant development affect treatment differences, and examine correlations between the AEI and plant development. Studies were conducted in the field and greenhouse on five maize genotypes on …
Fractal Analysis For Morphological Description Of Corn Roots Under Nitrogen Stress, John Settimi, Bahman Eghbal, Jerry Maranville, Anne Parkhurst
Fractal Analysis For Morphological Description Of Corn Roots Under Nitrogen Stress, John Settimi, Bahman Eghbal, Jerry Maranville, Anne Parkhurst
John R. Settimi
A means of quantification of plant root branching, specifically under stress, is of importance for evaluating the contribution of plant roots to water and nutrient uptake and subsequently plant growth. An experiment was conducted to describe the morphology of corn (Zea mays L.) root systems using fractal analysis and also to determine if a roots fractal dimension (D) is altered by N stress. Corn genotypes (B73 ✕ LHI05 and N74 ✕ Mo17) were planted in peg boxes, 1.2 m long, 1.2 m deep, and 0.05 m wide filled with 20:80 soil to sand mixture and were grown with N rates …
Fractal Analysis For Morphological Description Of Corn Roots Under Nitrogen Stress, John Settimi, Bahman Eghball, Anne Parkhurst, Jerry Maranville
Fractal Analysis For Morphological Description Of Corn Roots Under Nitrogen Stress, John Settimi, Bahman Eghball, Anne Parkhurst, Jerry Maranville
John R. Settimi
A means of quantification of plant root branching, specifically under stress, is of importance for evaluating the contribution of plant roots to water and nutrient uptake and subsequently plant growth. An experiment was conducted to describe the morphology of corn (Zea mays L.) root systems using fractal analysis and also to determine if a root's fractal dimension (D) is altered by N stress. Corn genotypes (B73 X LH105 and N74 X Mo17) were planted in peg boxes, 1.2 m long, 1.2 m deep, and 0.05 m wide filled with 20:80 soil to sand mixture and were grown with N rates …
Photoperiod And Planting Date Effects On The Spatial Distribution Of Branch Development In Soybean, John Settimi, James Board
Photoperiod And Planting Date Effects On The Spatial Distribution Of Branch Development In Soybean, John Settimi, James Board
John R. Settimi
Reduced branch development in late-planted soybean [Glycine max (L.) Merr.] is a cause of yield reductions in the southeastern USA. To determine the effects of photoperiod and planting date on the spatial distribution of branches, photoperiod simulations of an optimal (24 May) and a nonoptimal late planting date (24 June) at Baton Rouge, LA (30°N Lat), were imposed on ‘Centennial’ soybean in growth chambers. In a field study, ‘Lee 74’ was planted at optimal (mid-May) and nonoptimal (early July) planting dates in 1984 and 1985 at Baton Rouge, LA, on an Olivier silt loam (fine-silty, mixed thermic Aquic Fragiudalf) soil. …
Photoperiod Requirements For Flowering And Flower Production In Soybean, John Settimi, James Board
Photoperiod Requirements For Flowering And Flower Production In Soybean, John Settimi, James Board
John R. Settimi
Photoperiod has been recognized as playing a major role in soybean [Glycine max (L.) Merr.] growth and development. The objective of these studies was to determine the number of short days (13.5h) representative of early spring daylengths in the southeastern United States necessary to cause anthesis and adequate flower production in soybean. Growth chamber studies were conducted at the Phytotron at North Carolina State University, during the first 26 wk of 1985. The soybean cultivar Tracy-M and the delayed flowering genotype D77-12480 were subjected to treatments in which they were transferred either from short-day (13.5-h) to long-day (16-h) or long-day …
Photoperiod Effect Before And After Flowering On Branch Development In Determinate Soybean, John Settimi, James Board
Photoperiod Effect Before And After Flowering On Branch Development In Determinate Soybean, John Settimi, James Board
John R. Settimi
Previous research indicated that restricted branch development was a factor associated with soybean [Glycine max (L.) Merr.] seed yield reductions at late planting dates in the southeastern United States. The present studies were conducted to outline the progress of branch development at different planting dates and to determine the role of photoperiod in branch restriction at late planting dates. In field studies, eight cultivars were planted at early April (nonoptimal), mid-May (optimal), and mid-June (nonoptimal) planting dates in 1982 and 1983 at Baton Rouge, LA (30°N Lat), on an Olivier silt loam (fine-silty, mixed, thermic Aquic Fraguidalf) soil. Plants were …