Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

PDF

Iowa State University

Plant Sciences

Graduate Theses and Dissertations

Crop Production and Physiology

Publication Year

Articles 1 - 11 of 11

Full-Text Articles in Entire DC Network

Improved Production Systems For Common Bean In South-Central Uganda: I. Liddugavu Soil, Ii. Limyufumyufu Soil, Lance Henry Goettsch Jan 2016

Improved Production Systems For Common Bean In South-Central Uganda: I. Liddugavu Soil, Ii. Limyufumyufu Soil, Lance Henry Goettsch

Graduate Theses and Dissertations

Common bean (Phaseolus vulgaris L.) is the most important source of dietary protein in Uganda but current grain yields are extremely low. Beans are produced on a variety of soils in south-central Uganda but the two most important soils for bean production are the highly weathered Limyufumyufu (Ferralsol) and the relatively fertile Liddugavu (Phaeozem) soils. These two soils vary in level of pH and fertility and therefore must be managed appropriately. Beans managed under conventional systems have a yield gap of about 75% due to poor agronomic practices, soil infertility, lack of seed from improved cultivars, moisture stress, weed competition ...


Cover Crop Options And Mixes For Upper Midwest Corn-Soybean Systems, Seth R. Appelgate Jan 2016

Cover Crop Options And Mixes For Upper Midwest Corn-Soybean Systems, Seth R. Appelgate

Graduate Theses and Dissertations

The implementation of cover crops in Iowa has the potential to decrease soil erosion, weed density, and nitrate leaching while increasing soil organic carbon. This study investigated nine potential cover crops; winter rye (Secale cereale L.), winter triticale (Triticale hexaploide Lart.), two winter canola (Brassica napus L.) varieties, winter camelina [Camelina sativa (L.) Crantz], spring barley (Hordeum vulgare L.), spring oat (Avena sativa L.), purple top turnip (Brassica rapa L.), and hairy vetch (Vicia villosa Roth). Cover crops were planted as sole crops and selected binary and trinary mixtures. A control treatment of no cover crop was included. Cover crops ...


Developmental Morphology, Biomass Yield And Compositional Differences Among Upland And Lowland Switchgrass (Panicum Virgatum L.) Ecotypes Grown As A Bioenergy Feedstock Crop, Muhammad Aurangzaib Jan 2015

Developmental Morphology, Biomass Yield And Compositional Differences Among Upland And Lowland Switchgrass (Panicum Virgatum L.) Ecotypes Grown As A Bioenergy Feedstock Crop, Muhammad Aurangzaib

Graduate Theses and Dissertations

Sustainable and successful development of the bioenergy industry strongly depends upon the amount and quality of bioenergy feedstock produced. Switchgrass (Panicum virgatum L.) has been identified as a model lignocellulosic bioenergy crop in the U.S. Information regarding its growth and development is considered critical for making management decisions, production of high quality feedstock and to support simulation model calibration and subsequent analysis.

In the first study (Chapter 2), we evaluated upland (‘Cave-in-Rock’, ‘Trailblazer’ and ‘Blackwell’) and lowland (‘Kanlow’ and ‘Alamo’) ecotypes of switchgrass for harvest management, morphological (phenology and leaf area index) and biomass yield differences. A field study ...


Climate-Smart Agriculture In Midwest Cropping Systems: Evaluating The Benefits And Tradeoffs Of Cover Crops, Andrea Diane Basche Jan 2015

Climate-Smart Agriculture In Midwest Cropping Systems: Evaluating The Benefits And Tradeoffs Of Cover Crops, Andrea Diane Basche

Graduate Theses and Dissertations

Climate-smart agriculture is a framework to develop and implement agricultural systems that facilitate reduced greenhouse gas emissions and increase resilience and productivity in the context of a changing climate. Winter cover crops are known to decrease soil erosion, increase soil carbon, improve water retention and have been hypothesized to reduce nitrous oxide emissions. Therefore they offer the potential to buffer projected climate change impacts for Midwestern agriculture, including increased rainfall variability. The overall objective of this dissertation research was to evaluate the mitigation and adaptation potential of cover crops in determining their efficacy as a climate-smart agricultural practice. In a ...


Screening Of Herbicides For Selective Weed Control In African Marigold (Tagetes Erecta), Katie Jean Demers Jan 2015

Screening Of Herbicides For Selective Weed Control In African Marigold (Tagetes Erecta), Katie Jean Demers

Graduate Theses and Dissertations

African marigold (Tagetes erecta L.) was screened for tolerance to preemergence and postemergence herbicides. Three preemergence herbicides, pendimethalin, bensulide, and trifluralin, had an acceptable margin of crop safety both in the greenhouse and in the field when applied at one, two, and four times their labeled rates. Two postemergence herbicides, topramezone and encapsulated acetochlor, caused minimal visual injury to the crop and encapsulated acetochlor had a minimal effect on plant dry weight. Dry weight response to topramezone varied among experiments. Additional studies were conducted to better define African marigold tolerance to topramezone. African marigolds tolerated rates up to 36.8 ...


Influence Of Bradyrhizobium Inoculation And Fungicide Treatment On Development And Yield Of Selected Pulse Crops; Nutritional Composition Of Pulse Legume Leaves And The Impact Of Leaf Removal On Yield, Rosemary Bulyaba Jan 2015

Influence Of Bradyrhizobium Inoculation And Fungicide Treatment On Development And Yield Of Selected Pulse Crops; Nutritional Composition Of Pulse Legume Leaves And The Impact Of Leaf Removal On Yield, Rosemary Bulyaba

Graduate Theses and Dissertations

Part 1

Declining soil fertility due to inadequate nitrogen in most soils limits farmers’ goals of increasing yield. There is environmental and agricultural benefit of reducing dependence on nitrogen fertilizer by emphasizing adaptation of favorable farming practices that minimize nitrogen fertilizer. Cowpea [Vigna unguiculata (L.) Walp.] and lablab (Lablab purpureus (L.)] are pulses with potential for grain, forage, and cover crops in the Midwest of United States, but little is known about their growth, development, and productivity potential in Iowa. We conducted a two-year field study to determine the influence of rhizobia inoculation and fungicide seed treatment of selected pulses ...


Influence Of Corn Seeding Rate, Soil Attributes, And Topographic Characteristics On Grain Yield, Yield Components, And Grain Composition, Mark Allen Licht Jan 2015

Influence Of Corn Seeding Rate, Soil Attributes, And Topographic Characteristics On Grain Yield, Yield Components, And Grain Composition, Mark Allen Licht

Graduate Theses and Dissertations

Adoption of variable seeding rates has increased dramatically in recent years due to ability and feasibility of determining soil and topographic variability within fields. This research explores soil and topographic attribute interactions with seeding rate and the effect they have on corn yield, yield components, and grain composition. Experimental treatments included five seeding rates (61,750; 74,100; 86,450; 98,800; and 111,150 seeds ha-1) in a randomized complete block design in three central Iowa fields from 2012 to 2014. Soil samples were analyzed for available P, exchangeable K, pH, soil organic matter, cation exchange capacity, and texture ...


Biosynthetically Produced Amino Acid Byproducts Can Replace Nitrogen Fertilizers For Corn Production, Juan Carlos Quezada Rivera Jan 2015

Biosynthetically Produced Amino Acid Byproducts Can Replace Nitrogen Fertilizers For Corn Production, Juan Carlos Quezada Rivera

Graduate Theses and Dissertations

Commercial biosynthesis of the amino acids tryptophan (TRP) and lysine (LYS) results in byproducts that are rich in both organic and inorganic compounds. Their nitrogen (N) content may have value as fertilizer N replacement in corn (Zea mays L.) production. We conducted a two-year field study where soil applied pure TRP, its biosynthesis byproduct and LYS byproduct were evaluated as replacements for synthetic N fertilizers in corn production. In-season plant measurements leaf area index , normalized difference vegetation index, grain quality (grain protein and oil concentration) and total N accumulation were not affected by N treatments. Additionally, TRP and LYS biosynthesis ...


Suitability Of Winter Canola (Brassica Napus) For Enhancing Summer Annual Crop Rotations In Iowa, Rafael A. Martinez-Feria Jan 2015

Suitability Of Winter Canola (Brassica Napus) For Enhancing Summer Annual Crop Rotations In Iowa, Rafael A. Martinez-Feria

Graduate Theses and Dissertations

Winter canola (Brassica napus) could be a good candidate for enhancing cropping systems in Iowa because of its potential to provide environmental benefits and produce a marketable crop compatible with existing grain production and distribution schemes. However, it is still uncertain whether this crop would be suitable for helping balance environmental and financial goals of conventional cropping systems under the environmental and market conditions unique to Iowa. The work presented in this thesis is an effort to assess the suitability of winter canola for providing environmental benefits while fitting within the logistic and economic constrains of current cropping systems. Based ...


The Physiological Effects Of The Seed Treatment Stamina On Maize Seedling Length, Adp:O Ratios, And Respiration Rates, Katy Lynn Darrah-Wiedemeier Jan 2015

The Physiological Effects Of The Seed Treatment Stamina On Maize Seedling Length, Adp:O Ratios, And Respiration Rates, Katy Lynn Darrah-Wiedemeier

Graduate Theses and Dissertations

Zea mays L. is an important crop in the Midwest, and each year there is a push to plant earlier in the spring. Early planting can leave seeds and seedlings vulnerable to low temperature stress. Low temperature stress causes damage to maize seedlings. It has been postulated that Strobilurin fungicides have positive physiological related effects on growth and yield. The goal of this study was to determine if the strobilurin Stamina protects maize seedlings against mitochondrial damage due to low temperature stress. In this study, three seed treatments and two seed lots/hybrids were used. Treatments included: Stamina (binders plus ...


Interactions Between Cover Crops And Weed Management In Iowa's Conventional Cropping Systems, Meaghan Jean Bryan Anderson Jan 2014

Interactions Between Cover Crops And Weed Management In Iowa's Conventional Cropping Systems, Meaghan Jean Bryan Anderson

Graduate Theses and Dissertations

The effect of different levels of cereal rye (Secale cereale L.) residue on common waterhemp (Amaranthus rudis Sauer) and common lambsquarters (Chenopodium album L.) emergence was determined. Cereal rye seeding date had a greater effect on rye biomass accumulation and percent cover than seeding rate. Common waterhemp emergence was equal to or increased in the presence of cereal rye residue in both 2013 and 2014 compared to the control. Common lambsquarters emergence was increased in two treatments in 2014 but was otherwise unaffected by cereal rye. The presence of cereal rye residue increased the time to 10% and 50% emergence ...