Master of Science / Department of Agronomy / Scott A. Staggenborg / With the increase in bio-energy production there is also an increase in by-products. Without proper disposal, these by-products might cause future economic and/or ecological problems. Land application has potential as a disposal and/or nutrient cycling method if these by-products have nutritive value for agricultural crops. The purpose of the study was to compare the use of two by-products of bio-energy production, dry distillers grains (ethanol) and charcoal(pyrolysis), as fertilizer with urea in corn (Zea mays L.). The experiment consisted of four location-years in Kansas. Treatments were dry distiller’s grains (DDG) no-till and tilled for four location-years and char no-till and tilled for three location-years. No-till urea was used as a baseline for comparison at all location-years. The Nitrogen rates ranged from 45 to 180 kg N ha-1. All source material was spring applied before tillage and planting. The corn yields for DDGs and urea were the almost the same across tillage treatments and locations. For DDG no-till, DDG tilled, and urea, the rates at which to achieve the same yields were 97, 111, 78 kg N ha-1, respectively. Corn yields for char at all rates and tillage treatments were the same as no fertilizer. The char, because of immobilization or lack of decomposition, did not contribute to the nitrogen needs of the corn. Neither material showed any inhibitory or otherwise negative effects on the corn in terms of grain yield compared with the control. But both DDGs and char had to have large amounts of material applied to achieve the same amount of nitrogen as urea. Land application of DDGs and char has potential merit for disposal/nitrogen cycling with DDGs being preferred for its nitrogen contribution.

Master of Science / Department of Agronomy / William T. Schapaugh Jr / Fusarium virguliforme, the soilborne fungus which causes sudden death syndrome (SDS) of soybean, and Heterodera glycines Ichinohe, soybean cyst nematode (SCN), are two economically important pathogens in the Midwest. The pathogens are often found together in soybean (Glycine max (L.) Merr.) fields. This study was conducted to determine the effect of soybean genotype, F. virguliforme populations, and H. glycines populations have upon yield and to examine the interaction between the two pathogens. In 2008 and 2009, four genotypes with different levels of resistance to SDS and H. glycines were planted at seven environments. F. virguliforme and H. glycines soil populations were quantified at planting, midseason, and harvest. At the end of the growing season, area under the disease progress curves of SDS, F. virguliforme root populations, and H. glycines reproductive indices were determined and plots harvested for seed yield. Soil populations of F. virguliforme and H. glycines at planting, midseason, and harvest varied across environments. Within environments, generally, they were not significantly different. Seed yield varied within and across environments. As disease pressure increased, the performance of resistant genotypes increased compared to susceptible genotypes. Genotypes resistant to SDS yielded higher than susceptible genotypes. There were negative correlations between yield and disease rating and F. virguliforme root populations. F. virguliforme soil populations and H. glycines populations at planting were positively correlated. It is important to manage both SDS and H. glycines in fields with a history of the two diseases. This can be achieved through genetic resistance. Information in this study will improve decisions regarding genotype selection to minimize losses to SDS and H. glycines.

Master of Science / Department of Grain Science and Industry / Hulya Dogan / Kansas is the top wheat-producing state, providing about 1/5 of the yearly wheat crop in the U.S. Therefore, the quality of wheat grown in Kansas is a primary concern of the milling and baking industry. Quality of wheat flour is measured through analysis of protein, dough rheology, and baked product characteristics. This study characterized four commonly-grown Kansas hard red winter wheat cultivars chosen to span the largest possible range of protein contents and baking qualities. Flour protein content and moisture was determined by NIR, and composition was assessed using SE-HPLC. Dough empirical rheological and mixing characteristics were determined by farinograph and mixograph recording dough mixers. Rheological measurements of fundamental dough properties were performed through strain sweeps, frequency sweeps, temperature sweeps, creep-relaxation, and stress relaxation on a rheometer. All cultivar flours were baked to assess baking quality through evaluation of loaf volume, texture profile analysis (TPA), C-cell, and x-ray microtomography (XMT). Overley and Karl 92 have the two highest protein contents, respectively, and are not significantly different in percent of unextractable polymeric protein (UPP). Generally, cultivars with higher protein and percent UPP (Overley and Karl 92) gave larger loaves, much more expanded air cells, thinner cell walls, greater void fractions, and better mixing properties. Lower TPA firmness was found for Overley, corresponding with its larger XMT fragmentation index, existence of large air cells, and high void fraction. In contrast, 2137 gave the lowest XMT fragmentation index, low void fraction, larger cell wall thicknesses, and a significantly firmer (P< 0.05) crumb structure. Protein content was found to have an inverse relationship with the elastic nature of dough in fundamental rheological measurements since small amplitude measurements generally do not give good correlations to baking quality. Stress relaxation gave the most useful information about flour quality through its relaxation spectra. Flours with high total polymeric protein percentages could be identified through their higher relaxation spectra. Starch gelatinization properties of the flours were different for RVA and rheometer temperature sweeps. All of these tests have helped characterize the four Kansas wheat cultivars chosen for this study.

The renewable natural resources (RNR) of Senegal form the basis of socioeconomic development for the population of this Sahelian country of West Africa. However, because of the current maladapted policies and practices, these resources are in a crisis that has led to a major degradation of the socioeconomic and environmental conditions. To solve these socioeconomic and environmental problems, many solutions have been developed and implemented. However, because of their disregard for both socioeconomic and traditional cultural values, these attempted solutions have often contributed to the problems. To resolve this crisis, Senegal needs to adopt a new integrated management approach along with new integrated natural resources tenure and decentralization policies. Considering the country's limited economic means, the urgent need for policy change, and the necessary progressive implementation of a new policy, this new natural resources policy will need to be developed incrementally. It should take into account the existing policies and examine different alternatives from the current ecological, economic, and sociocultural situation.

Master of Science / Department of Agronomy / Nathan O. Nelson / Phosphorus (P), an essential nutrient for plant growth and animal needs, has been identified as an ubiquitous water quality impairment in the United States. In Kansas, a major agricultural state, P loading to the surface waters is a top priority because of the critical role of P enrichment in eutrophication processes and resultant water quality degradation. The objective of this study was to quantify the P sorption and desorption of both stream sediments and upland soils in two Kansas watersheds with contrasting degrees of animal agriculture; Upper West Emma Creek (UWEC) and Red Rock Creek (RRC) watersheds. In-stream sediments were collected from banks, pools, riffles and depositional features. Soils were sampled from wheat, row crop, pasture, and manure-amended fields. Stream water samples were taken under baseflow and storm flow conditions. Our analyses of sediments and soils included equilibrium P concentration at zero net P sorption (EPC[subscript]0), maximum adsorption capacity (P[subscript]max), anion exchange extractable P (P[subscript]lab) and degree of P saturation (DPS). Water samples were analyzed for dissolved reactive phosphorous (DRP). Bank erosion pins were installed in order to estimate bank erosion rates in both watersheds. Results showed that in-stream sediments do not have much more sorption capacity remaining indicated by low P[subscript]max and high DPS. A comparison between mean P[subscript]lab of stream sediments (8.8 mg P kg[superscript]-1 soil) versus field soils (61.2 mg P kg[superscript]-1 soil) reflected that they represent a relatively minor long-term P supply. Of the stream sediments, bank soils had the highest Plab concentrations (24.8 mg P kg[superscript]-1 soil) and would be the largest in-stream P source. Manure-amended fields had the highest Plab (118.6 mg P kg[superscript]-1 soil) due to continued inputs of manure-based P; therefore, representing a large available P pool. Bank erosion contributed about 41% and 11% of the total sediment load in UWEC and RRC respectively. Sediments loads indicated that RRC has more upland sediment inputs than UWEC. Moreover, DRP during storm flow was higher at RRC than UWEC, indicating higher P inputs in RRC from upland soils. Finally, in order to minimize P inputs to the stream system, bank stabilization should be addressed in UWEC and upland best management practices should be implemented in RRC.

Master of Science / Department of Agronomy / Allan K. Fritz / Fusarium head blight (FHB), caused by Fusarium graminearum, is an important cereal disease in humid and semi-humid wheat growing regions. In recent FHB epidemics in the USA, FHB dramatically reduced wheat yields and grain quality due to mycotoxin contamination. Five types of FHB resistance have been reported, but resistance to disease spread within a spike (Type II) and low deoxynivalenol (DON) accumulation in infected kernels (Type III) have drawn the most attention. A Chinese Spring-Sumai3 chromosome 7A substitution line (CS-SM3-7ADSL) was reported to have a high level of Type II resistance, but quantitative trait locus (QTL) on chromosome 7A has never been mapped. To characterize QTL on chromosome 7A, we developed 191 Chinese Spring-Sumai3-7A chromosome recombinant inbred lines (CRIL) from a cross between Chinese Spring and CS-SM3-7ADSL and evaluated the CRIL in a greenhouse for both types of resistance in three experiments. Two major QTL with Sumai 3 (SM3) origin, conditioning Type II and Type III resistance were mapped in chromosomes 3BS and 7AC. QTL on chromosome 3BS corresponds to Fhb1, previously reported from SM3, whereas 7AC QTL, designated as Fhb5, is a novel QTL identified from SM3 in this study. Fhb5 explains 22% phenotypic variation for Type II resistance and 24% for Type III resistance. Marker Xwmc17 is the closest marker to Fhb5 for both types of resistance. Fhb1 and Fhb5 were additive and together explained 56% variation for Type II and 41% for Type III resistance and resulted in 66% reduction in FHB severity and 84% in DON content. Both QTL showed significant pleiotropy effects on Type II and Type III resistance, suggesting both types of resistance may be controlled by the same gene(s). Haplotype analysis of SM3’s parents revealed that Fhb5 originated from Funo, an Italian cultivar. A survey of worldwide germplasm collection of 400 accessions showed that Fhb5 is present mainly in Chinese cultivars, especially in Funo-related accessions. Further, Fhb5 is the second major QTL from SM3 and have potential to be used in improving wheat cultivars for both types of resistance.

Steps to reduce the use of pesticides in agriculture have been pursued by consumers and non-profit organizations, mainly from wealthy countries, pressuring governments to develop laws against the use of pesticides. Despite legislation that bans or severely restricts highly toxic pesticides, their production and use continue to take place in both developed and developing countries. The demand for healthy food and an improved quality of the environment, however, has led to the development of a new market niche for agricultural commodities grown without industrial inputs. Small-scale farmers from Chiapas are producing chemical free coffee and without government regulations or support. Chiapas has become the leading producing state of certified Environmentally-Friendly (EF) coffee production, and Mexico has become the leading country in exports of EF coffee This research project examines factors that have allowed impoverished small-scale farmers to make the investments necessary to use certified EF production and markets. Surprisingly, given the controversies in the literature about EF farming and Industrial Agriculture (IA), no one so far has investigated this question at an individual level. According to the literature on this issue, the reasons farmers have shifted to EF methods are: the fall in global coffee price; the rising price of pesticides; international economic support; the demand for quality coffee; tradition; promotion by private companies; direct trade links, and participation from NGOs and religious leaders However, the results of the study indicate that leading factors in the farmers' decisions were based on organization, more so than prices. Although the literature claims that the fall in the price of coffee and the rise in the costs of IA accounts for the switch to EF coffee, this project provides evidence farmers were more likely to engage in EF agriculture when they had previous knowledge of costs and benefits of IA and EF farming, received the technical knowledge to engage in EF agriculture, their farms had appropriated physical conditions for coffee production, and had low cost access to compost and other relevant organic inputs. In addition, the survey data show that organizational efforts done principally by a religious and other civic leaders, as well as subsequent monitoring and enforcement services by international organizations, such as Fair Trade created the institutional structure necessary for the EF market. This suggests that farmers sought economic security more than maximization of wealth and the factors above allowed them to find it with EF coffee / acase@tulane.edu

During the past two decades, the Mexican agricultural policy has endured significant changes. These changes have impacted the lives of campesino families in a remarkable manner and the services provided by the State institutions supporting the agricultural sector. This study analyses these impacts in the context of a rural development program in Mexico that has experienced both the previous and the most recent policy frameworks developed by the Mexican State during this period The primary purpose of this research is to evaluate 20 years of agricultural development policy, resulting from recent changes in the country's economic policy, within the context of the Plan Llanos de Serdan program in central Mexico. This program was developed in 1975 in the framework of an agricultural-economic model suggesting that increases in yield of corn would result into betterment of overall household conditions It is argued in this study that this program has successfully achieved the goals related to adoption of technology and increments in yields; however its impact in household welfare has not been significant due to the inappropriateness of the agricultural policy formulated by the Mexican State in behalf of campesinos / acase@tulane.edu

The impact of three pre-plant herbicides, pendimethalin, prometryn and trifluralin on the incidence and the development of Rhizoctonia solani-induced cotton seedling damping-off, on biocontrol activity of Burkholderia cepacia against R. solani, and on the efficacy of commonly used fungicides (metalaxyl, triadimenol, thiram) against R. solani-induced cotton seedling damping-off was investigated in the microcosm and in the field. In the microcosm experiments, pendimethalin, prometryn and trifluralin were applied to the soil at 2.4, 3.6 and 1.8 μg a.i. g⁻¹ soil, respectively (equivalent to the respective recommended field concentrations of 0.9, 1.3 and 0.7 kg a.i. ha⁻¹ In the microcosm experiments application of prometryn, to the soil caused a significant (P < 0.05) increase in pre-emergence damping-off incidence. Post emergence damping-off increased significantly (P < 0.05) in the presence of pendimethalin and prometryn. Biocontrol activity of B. cepacia (isolate D1) in controlling cotton seedling damping-off was significantly (P < 0.05) reduced by pendimethalin and prometryn in the microcosm experiments. In a field experiment conducted in Safford, Arizona, pre-plant application of pendimethalin or prometryn caused significant (P < 0.05) increases in disease incidence. In another field experiment in Tucson, Arizona, significant (P < 0.05) increase in disease incidence was observed in plots treated with prometryn. In both microcosm and field experiments, application of herbicides affected disease development as judged by the slope of disease progress curves. Biocontrol activity of an indigenous isolate (D1) of B. cepacia also was reduced significantly by pendimethalin and prometryn in both field experiments. Commercially available isolate (Deny®) of B. cepacia as a soil drench and as a seed treatment failed to protect cotton seedlings against R. solani-induced damping-off in both field experiments. The efficacy of commonly used fungicides (metalaxyl, triadimenol, thiram) against R. solani in the field was not significantly affected by herbicides in two field experiments at final assessment time. Pendimethalin and prometryn mediated changes in cotton seedling damping-off incidence and biocontrol activity of B. cepacia seem to be due to the changes in cotton seedlings susceptibility and changes in populations and structure of antagonistic bacteria in the plant rhizosphere.

<p> The western corn rootworm, or WCR, (<i>Diabrotica virgifera virgifera </i> LeConte) is the most significant pest of field corn (<i>Zea mays</i>) in the United States, and has recently expanded its range into Europe. Since 2004, hybrid corn containing Bt toxins targeting the corn rootworm complex have been heavily adopted and are now the primary control measure for this pest in North American corn production. </p><p> The evolution of resistance is an ongoing concern, and to ensure Bt products will retain their usefulness, insect resistance management (IRM) tactics using various refuge structures have been adopted. One of the key tenets of the refuge strategy is that males and females emerging from Bt and refuge plantings mate randomly. A violation of this largely untested assumption would lead to acceleration of resistance development. </p><p> To generate empirical field data on mating rates between beetles emerging from Bt and refuge plants, field cage studies using field populations of WCR in Indiana were utilized. Various refuge configurations were tested; all refuge plants were labeled using the stable isotope N15. This mark persists in the adult beetles after eclosion, allowing for collection and analysis of isotopic ratios of beetles in mating pairs. This approach was used to test the random mating assumption in Bt and refuge beetles collected from field cages. Other data collected include emergence rates, timing and sex ratios for each of the treatments. </p><p> Results indicate that mating based on natal host may not be as important of a factor as initially thought. Mixed mating occurs at a high rate when there are higher numbers of susceptible rootworms even though the measured fitness parameters between <i>Cry3Bb1</i> and refuge adults were significantly different (p&lt; 0.05). The main indication from this study is that not enough susceptible individuals are produced from a 5% refuge-in-a-bag strategy which is the dominant form of refuge planting in the United States. </p>