Digital Commons Network^™

Land Use And Water And Soil Management Practices Impacts On Potential Groundwater Recharge In Loess Regions Of South Central Nebraska, Gustavo Bosch-Rubia

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Sustainability of agro-ecosystems must consider land use and water and soil management effects on groundwater recharge. Water flow beneath the plant root zone through the intermediate vadose zone determines potential groundwater recharge. Different land uses, water and soil management practices control deep percolation as a result of changes on evapotranspiration and infiltration. This study of the impact of surface activities on deep percolation was conducted at six locations across Nebraska: Two center-pivot irrigated no-till planting systems fields were compared with one tilled center-pivot irrigated field, a furrow irrigated field with multiple tillage treatments, an eco-fallow dryland farming system, and a …

Occurrence Of An Herbicide-Resistant Plant Trait In Agricultural Field Margins, Karla L. Gag, David J. Gibson, Bryan G. Young, Julie M. Young, Joseph L. Matthews, Stephen C. Weller, Robert G. Wilson

Department of Agronomy and Horticulture: Faculty Publications

Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, …

Isolation And Identification Of Desmodium Root Exudates From Drought Tolerant Species Used As Intercrops Against Striga Hermonthica, A. M. Hooper, J. C. Caulfield, B. Hao, J. A. Pickett, C. A.O. Midega, Z. R. Khan

All Peer-Reviewed Publications

Abstract Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops was assessed for resource poor areas of rain-fed cereal production where drought conditions can persist through normal meteorological activity, or where drought may have increasing impact through climate …

Isolation Of Possible Biocontrol Endophytic Bacteria From Solanum Tuberosum Effective Against Streptomyces Scabies., Annie Flatley, Luke Ogle, Adam Noel, Erica Fraley, Alaxandra Goodman, Donna Becker

Poster Sessions

Use of biological control offers a cost effective and environmentally safe method for controlling plant diseases. Biocontrol agents that can colonize roots and live endophytically within plant tissue should allow for effective disease control. The goal of this research was to develop protocols to isolate putative Streptomyces species from potato stem and tuber tissue due to their ability to produce inhibitory compounds which could potentially reduce diseases caused by Streptomyces scabies. Endophyte isolation from Solanum tuberosum (potato) plants (stem and tuber tissues) that were grown in a biocontrol field trial were the focus of this study. Several surface …

Use Of Two Pathogen-Inhibiting Streptomyces Isolates For Biocontrol Of Scab Disease Of Raphanus Sativus, Tyler Park, Nichole Klingler, Adam Noel, Luke Ogle, Annie Flatley, Donna Becker

Poster Sessions

Streptomyces species are ubiquitous soil bacteria that are promising as biological control agents due to their prolific antibiotic production that can inhibit soil-borne plant pathogens. This includes Streptomyces scabies, which causes scab disease on underground storage organs. The goal of this research was to test two Streptomyces isolates that have known inhibitory and biocontrol abilities against S. scabies in a potato (Solanum tuberosum) agricultural system for their effectiveness in biocontrol of this pathogen in a radish (Raphanus sativus) greenhouse assay. Pathogenic S. scabies were mixed into either pasteurized or unpasteurized soil prior to planting. Radish …

Biochemical And Proteomic Profiling Of Maize Endosperm Texture And Protein Quality, Kyla J. Morton

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

The research described herein, focuses on the biochemical and proteomic analysis of the maize endosperm and what influences kernel texture. Quality Protein Maize (QPM) is a hard endosperm version of the high-lysine opaque2 (o2) mutant but the genes involved in modifying the soft o2 endosperm are unknown. Pyrophosphate (PPi)-dependent fructose 6-phosphate 1-phosphotransferase (PFP) catalyzes the ATP-independent conversion of fructose 6-phosphate to fructose 1, 6-bisphosphate in glycolysis. We found a large increase in transcript and protein levels of the alpha regulatory subunit of PFP (PFPα) in QPM endosperm. In vitro enzyme assays show a significant increase in forward PFP …

Long-Term Effects Of Alternative Residue Management Practices On Near-Surface Soil Properties And Soybean Production In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Christopher Ryan Norman

Graduate Theses and Dissertations

Adoption of management practices that maintain or increase soil organic matter (SOM), which contains 58% carbon (C) on average, may help to mitigate climate change by sequestering atmospheric C. Therefore, the main objective of this study was to determine the long-term trends in SOM, soil C and nitrogen (N), bulk density, various soil chemical properties (i.e., pH, electrical conductivity [EC], and Mehlich-3-extractable nutrients) in the top 10 cm, and soybean yield as affected by residue burning (burning and non-burning), tillage (conventional and no-tillage), irrigation (irrigated and non-irrigated), and N-fertilization/residue level (high and low) in a wheat (Triticum aestivum L.)-soybean [Glycine …

Prokaryotic Diversity In The Rhizosphere Of Organic, Intensive, And Transitional Coffee Farms In Brazil, Adam Caldwell, Livia Silva, Cynthia Da Silva, Cleber Ouverney

Faculty Publications, Biological Sciences

Despite a continuous rise in consumption of coffee over the past 60 years and recent studies showing positive benefits linked to human health, intensive coffee farming practices have been associated with environmental damage, risks to human health, and reductions in biodiversity. In contrast, organic farming has become an increasingly popular alternative, with both environmental and health benefits. This study aimed to characterize and determine the differences in the prokaryotic soil microbiology of three Brazilian coffee farms: one practicing intensive farming, one practicing organic farming, and one undergoing a transition from intensive to organic practices. Soil samples were collected from 20 …

Predicting The Impact Of Temperature Change On The Future Distribution Of Maize Stem Borers And Their Natural Enemies Along East African Mountain Gradients Using Phenology Models, Sizah Mwalusepo, Henri E.Z. Tonnang, Estomih S. Massawe, Gerphas O. Okuku, Nancy Khadioli, Tino Johansson, Paul André Calatayud, Bruno Pierre Le Ru

All Peer-Reviewed Publications

Lepidopteran stem borers are among the most important pests of maize in East Africa. The objective of the present study was to predict the impact of temperature change on the distribution and abundance of the crambid Chilo partellus, the noctuid Busseola fusca, and their larval parasitoids Cotesia flavipes and Cotesia sesamiae at local scale along Kilimanjaro and Taita Hills gradients in Tanzania and Kenya, respectively. Temperature-dependent phenology models of pests and parasitoids were used in a geographic information system for mapping. The three risk indices namely establishment, generation, and activity indices were computed using current temperature data record from local …

Comparing Yield Monitors With Weigh Wagons For On-Farm Corn Hybrid Evaluation, Bjorn P. Nelson, Roger Wesley Elmore, Andrew W. Lenssen

Department of Agronomy and Horticulture: Faculty Publications

For many years, on-farm yield evaluations of corn (Zea mays L.) hybrids were done with weigh wagons, handheld moisture testers, and measuring wheels. Today, most combines have continuous flow yield and moisture sensors. Published research results comparing the accuracy of combine-mounted sensor systems with that of weigh wagons are limited for on-farm corn hybrid evaluation. This study examined the accuracy of combine-mounted yield sensors with traditional weigh wagon methodology in on-farm corn hybrid strip trials. Data from combine-mounted sensors for plot weight, moisture percentage, and yield were compared with weigh wagon weight, handheld moisture testers, and calculated yield …

Genetic Engineering Online Lessons Improve Teaching And Increase Knowledge And Accepting Attitudes Among Students, Grace Troupe

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

Genetic engineering has been used in the production of food in the U.S. for nearly three decades, however, science literacy in genetic engineering among consumers is still low. To address this problem, an online resource called The Journey of a Gene (passel.unl.edu/ge) was created to help incorporate genetic engineering education in high school and college curriculums. Here we report two studies conducted to evaluate the effectiveness of The Journey of a Gene in 1) improving student knowledge and attitudes about genetic engineering and 2) helping teachers increase their knowledge as well as quantity and quality of genetic engineering instruction. In …

Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla

Journal of Applied Packaging Research

Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.

Fishing For A Sustainable Future: Aquaponics As A Method Of Food Production, Richard Ramsundar

Student Theses 2015-Present

This thesis compares and explains the advantages aquaponics farming has over modern industrial intensive farming. Through a comparison natural capital usage, conservation, recycling and cost, the thesis advocates for the expansion of aquaponics usage in urban settings. The thesis also explains the history of intensive farming and aquaponics in America, the science of how aquaponics operates, the economic and environmental costs of modern intensive farming versus aquaponics farming, and the social implications of aquaponics. Lastly, I propose a policy that reallocates farm subsidies by modifying the Farm Bill. Then I propose policies that support creating a new standard of farm …

Characterization Of A Novel Clade Of Transporters In Phytophthora, Stephanie Padula, Paul F. Morris Dr, Howard Casey Cromwell Dr., Menaka Ariyaratne, Andrew Wagner

Honors Projects

The oomycete Phytophthora parasitica has a worldwide distribution and is an economically important pathogen of more than 100 species⁴. RNA-seq analysis showed that one gene, PPTG_16698 has the 5^th highest level of expression of all transport proteins in the zoospore stage, and is highly conserved throughout Phytophthora species. This project attempts to characterize the important biological role that PPTG_16698 plays in P. parasitica and other oomycetes. Three strategies have been implemented to accomplish this goal: growth analysis by heterologous expression in yeast, metabolite analysis in yeast, and construction of a GFP fusion protein to enable localization of …

Seasonal Activity And Sampling Methods For The Dectes Stem Borer, Dectes Texanus Leconte, In Nebraska Soybeans, Zachary D. Rystrom

Department of Entomology: Dissertations, Theses, and Student Research

The Dectes stem borer, Dectes texanus Leconte, has caused significant economic damage to soybean fields in south central Nebraska during recent years. Most economic injury occurs when soybean plants become susceptible to late season lodging due to larval girdling. Developing a comprehensive management plan for Dectes stem borer in Nebraska is limited by lack of knowledge of seasonal activity and effective sampling plans to monitor adult populations. Field studies were conducted in 2013 and 2014 to describe Dectes stem borer adult emergence patterns, female ovipositional period and adult densities in soybean fields. Calendar date predictions for adult emergence varied, while …

Assessment Of Variation In Susceptibility Of The Fall Armyworm, Spodoptera Frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), To Bacillus Thuringiensis Toxins, Karen Ferreira Da Silva

Department of Entomology: Dissertations, Theses, and Student Research

The fall armyworm, Spodoptera frugiperda, is a polyphagous insect pest affecting multiple crops. Fall armyworm is managed with insecticides and corn hybrids expressing insecticidal proteins derived from Bacillus thuringiensis. The early detection of insect resistance is important for making appropriate management decisions informs IPM and IRM recommendations.

The objective of the first study was to establish baseline susceptibility of fall armyworm populations to the Cry1F Bt insecticidal protein, emphasizing collections from locations where fall armyworm overwinters in the U.S. Fall armyworm neonates were exposed to artificial diet treated with increasing Cry1F concentrations, and mortality and growth inhibition were …

Restoration Strategies To Migrate Shrub Encroachment Into Coastal Prairies, Erick Mark Verderber

Theses and Dissertations - UTB/UTPA

Shrub encroachment into grasslands is a phenomenon facilitated by fire suppression, climate warming, and overgrazing of grasses by cattle, and if left unmanaged, can alter ecosystem structure and function. In this study, I compare the effectiveness and cost/benefit of various restoration strategies (prescribed fire, mechanical, and chemical) used singly and in different combinations at decreasing two shrubs, honey mesquite (Prosopis glandulosa Torr.) and huisache (Acacia farnesiana (L.) Willd.), and promoting growth and survival of gulf cordgrass (Spartina spartinae (Trin.) Merr. ex Hitchc.), the dominant coastal prairie grass within the Laguna Atascosa National Wildlife Refuge-Bahia Grande Unit in deep south Texas. …

Microsatellite Variations Of Elite Setaria Varieties Released During Last Six Decades In China, Guanqing Jia, Xiaotong Liu, James C. Schnable, Zhengang Niu, Chunfang Wang, Yuhui Li, Shujun Wang, Suying Wang, Jinrong Liu, Erhu Guo, Hui Zhi, Xianmin Diao

Department of Agronomy and Horticulture: Faculty Publications

Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, …

Understanding Perceptions Of Genetically Modified Food Among Natural Food Shoppers In Southern Nevada, Christian Murua-Aceves

UNLV Theses, Dissertations, Professional Papers, and Capstones

Today, 85% of corn, 93% of soybeans, and 88% of cotton in the U.S. are genetically modified (GM). Using laboratory methods, genes from one species, such as a plant, can be transferred to an unrelated species, such as an animal. Genetically modified crops may lead to higher yields, have improved food quality, texture, and nutritional value, and have an increased shelf life.

Despite these promising benefits, the potential health risks relating to the consumption of GM food remain inadequately assessed. Genetically modified food is not subjected to rigorous safety testing, such as epidemiologic studies, to identify potential health risks. Two …

Soil Total Organic Carbon And Farmers’ Perceptions Associated With Bokashi Application In Cerro Punta, Panama, Emma Searson

Independent Study Project (ISP) Collection

Sustainable use and maintenance of agricultural soils are important for maintaining long-term agricultural productivity and environmental quality. These issues are especially important in Cerro Punta, known as the breadbasket of Panama, which is experiencing severe erosion. While current practices and agrochemical usage damage soil health and function over time, application of organic material improves soil physic-chemical properties such as nutrient and total organic carbon (TOC) content. Bokashi, a fermented organic soil amendment with effective microorganisms (EM), is thought to be especially beneficial due to its ability to augment populations of soil microbes, which deliver plant-available nutrients to crops and improve …

Comparing Avian Diversity And Anthropogenic Disturbance At Sendero Los Quetzales Cerro Punta, Panamá, Sloane Merdinger

Independent Study Project (ISP) Collection

This report summarizes the survey of land and avian diversity along a transect that runs from the exterior to the interior of the Los Quetzales Trail of Parque Nacional Volcán Barú in Cerro Punta, Chiriquí, Panamá. The region of Cerro Punta is Panamá’s primary producer of produce and also home to one of the most biodiverse land reserves in the world. Despite protection efforts the area is continuously threatened by human development. The study juxtaposes calculated Shannon-Wiener Biodiversity Indices across graduated levels of anthropogenic disturbance to determine if there is a significant difference in biodiversity between areas with low, intermediate, …

Produktivitas Tanaman Dan Kehilangan Hasil Tanaman Padi (Oryza Sativa L.) Kultivar Ciherang Pada Kombinasi Jarak Tanam Dengan Frekuensi Penyiangan Berbeda, Dedi Widayat, C. O. Purba

Jurnal Kultivasi

Tujuan penelitian ini adalah untuk menge-tahui pengaruh kombinasi jarak tanam dan frekuensi penyiangan gulma yang berbeda terhadap produktivitas dan kehilangan hasil padi sawah kultivar Ciherang. Percobaan ini dilak-sanakan di lahan sawah Sanggar Penelitian Latihan dan Pengembangan Pertanian (SPLPP) Fakultas Pertanian Universitas Padjadjaran unit Ciparay dari bulan November 2010 sampai Februari 2011. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK) terdiri dari dua belas perlakuan, dengan tiga kali ulangan. Adapun perlakuan yang digunakan adalah sebagai berikut: A (jarak tanam 25 x 25 cm dengan tanpa penyiangan), B (jarak tanam 25 x 25 cm dengan disiang satu kali), C (jarak tanam …

Respon Kualitas Dan Ketahanan Simpan Cabai Merah (Capsicum Annuum L.) Dengan Penggunaan Jenis Bahan Pengemas Dan Tingkat Kematangan Buah, Yayat Rochayat Suradinata, V. R. Munika

Jurnal Kultivasi

Penelitian ini bertujuan untuk mengetahui pengaruh kombinasi jenis bahan pengemas dan tingkat kematangan buah terhadap respon kualitas simpan cabai merah (Capsicum annuum L). Penelitian ini dilaksanakan pada bulan Maret sampai Juli 2012 di Cikole Lembang, dilanjut dengan pengamatan di Laboratorium Hortikul-tura, Fakultas Pertanian, Universitas Padja-djaran, Jatinangor, Kabupaten Sumedang, Jawa Barat. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK) pola tunggal yang terdiri sepuluh kombinasi dan diulang tiga kali untuk setiap perlakuan. Tingkat kematangan buah yang digunakan yaitu kematangan 50–60% (K₁) dan kematangan 60–70 % (K₂). Jenis bahan pengemas yang digunakan adalah wadah Styrofoam tanpa tutup (P₁), wadah styrofoam di …

Pemanfaatan Urin Kelinci Dan Urin Sapi Sebagai Alternatif Pupuk Organik Cairpada Pembibitan Kakao (Theobroma Cacao L.), Santi Rosniawaty, Rija Sudirja, H. Afrianto

Jurnal Kultivasi

Pembibitan merupakan awal dari pertum-buhan tanaman. Bibit yang baik akan menghasil-kan tanaman yang berproduksi baik pula. Pemupukan merupakan salah satu hal penting dalam menghasilkan bibit yang baik. Peman-faatan urin kelinci dan urin sapi diharapkan dapat menjadi pupuk alternatif untuk pembi-bitan kakao. Percobaan telah di laksanakan pada bulan April-Agustus 2013 di Kebun Percobaan Ciparanje fakultas Pertanian Unpad, dengan ordo Inceptisol dan tipe curah hujan menurut klasifikasi Schmidt Ferguson. Perlakuan yang digunakan adalah beberapa konsentrasi urin kelinci, konsentrasi urin sapi dan kombinasi urin dengan pupuk anorganik. Urin kelinci dan urin sapi difermentasikan terlebih dahulu sebelum digunakan. Rancangan percobaan yang diguna-kan adalah Rancangan …

Pertumbuhan Dan Hasil Kacang Hijau Kultivar Kenari Dan No. 129 Dalam Tumpangsari Bersisipan Di Antara Padi Gogo, Yuyun Yuwariah, Ade Ismail, I. N. Hafhittry

Jurnal Kultivasi

Penelitian ini bertujuan untuk mendapat-kan waktu penyisipan dua kultivar kacang hijau dalam tumpangsari bersisipan yang terbaik di antara padi gogo terhadap pertumbuhan dan hasil kacang hijau. Percobaan dilaksanakan dari bulan Desember 2010 sampai Juli 2011 di kebun percobaan Ciparanje Fakultas Pertanian Univer-sitas Padjadjaran, Jatinangor, Sumedang. Perco-baan ditata dalam Rancangan Acak Kelompok (RAK) dengan tiga ulangan yang terdiri atas 10 perlakuan yaitu A25 = kultivar Kenari + Waktu Penyisipan 25 hari sebelum panen padi gogo, A20 = kultivar Kenari + waktu penyisipan 20 hari sebelum panen padi gogo, A15 = kultivar Kenari + waktu penyisipan 15 hari sebelum panen padi gogo, …

Evaluation And Association Mapping Of Resistance To Tan Spot And Stagonospora Nodorum Blotch In Adapted Winter Wheat Germplasm, Zhaohui Liu, Ibrahim El-Basyoni, Gayan Kariyawasam, Guorong Zhang, Allan Fritz, Jana Hansen, Francois Marais, Andrew Friskop, Shiaoman Chao, Eduard Akhunov, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Tan spot and Stagonospora nodorum blotch (SNB), often occurring together, are two economically significant diseases of wheat in the Northern Great Plains of the United States. They are caused by the fungi Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, both of which produce multiple necrotrophic effectors (NE) to cause disease. In this work, 120 hard red winter wheat (HRWW) cultivars or elite lines, mostly from the United States, were evaluated in the greenhouse for their reactions to the two diseases as well as NE produced by the two pathogens. One P. nodorum isolate (Sn4) and four Pyrenophora tritici-repentis isolates (Pti2, …

Proceedings Of The 42nd Annual Meeting, Southern Soybean Disease Workers (March 11-12, 2015, Pensacola Beach, Florida), Craig Rothrock, Ed Sikora, Trey Price, Danise Beadle, Myra Purvis, Tom Allen, Loren Giesler

Southern Soybean Disease Workers: Conference Proceedings

Contents

Schedule

Southern United States Soybean Disease Loss Estimates for 2014. TW Allen, JP Damicone, NS Dufault, TR Faske, DE Hershman, CA Hollier, T Isakeit, RC Kemerait, NM Kleczewski, SR Koenning, HL Mehl, JD Mueller, C Overstreet, P Price, EJ Sikora, and H Young

Graduate student competition (Trey Price, moderator)

Effect of Secondary Nutrient Applications on Suppression of Charcoal Rot in Soybean. T Wilkerson, M Tomasu-Peterson, BR Golden, S Lu, AB Johnson, and TW Allen

Molecular Characterization of the G143A Mutation Leading to QoI Fungicide Resistance among Fungal Pathogens Causing Cercospora Leaf Blight and Purple Seed Stain of Soybean. S …

Optimizing Western Flower Thrips Management On French Beans By Combined Use Of Beneficials And Imidacloprid, Johnson O. Nyasani, Sevgan Subramanian, Hans Michael Poehling, Nguya K. Maniania, Sunday Ekesi, Rainer Meyhöfer

All Peer-Reviewed Publications

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.), and an insecticide (imidacloprid) were tested for their efficacy to reduce WFT population density and damage to French bean (Phaseolus vulgaris L.) pods under field conditions in two planting periods. Metarhizium anisopliae was applied as a foliar spray weekly at a rate of one litre spray volume per plot while imidacloprid was applied as a soil drench every two weeks at a rate of two …

Morphological And Moisture Availability Controls Of The Leaf Area-To-Sapwood Area Ratio: Analysis Of Measurements On Australian Trees, Henrique Furstenau Togashi, Iain Colin Prentice, Bradley John Evans, David Ian Forrester, Paul Drake, Paul Feikema, Kim Brooksbank, Derek Eamus, Daniel Taylor

Natural Resources Research Articles

1. The leaf area-to-sapwood area ratio (LA:SA) is a key plant trait that links photosynthesis to transpiration. The pipe model theory states that the sapwood cross-sectional area of a stem or branch at any point should scale isometrically with the area of leaves distal to that point. Optimization theory further suggests that LA:SA should decrease toward drier climates. Although acclimation of LA:SA to climate has been reported within species, much less is known about the scaling of this trait with climate among species.
2. We compiled LA:SA measurements from 184 species of Australian evergreen angiosperm trees. The pipe model was …

Compost Carryover: Nitrogen Phosphorous And Ft-Ir Analysis Of Soil Organic Matter, Dave J. R. Olsen, Jeffrey B. Endelman, Astrid R. Jacobson, Jennifer R. Reeve

Plants, Soils, and Climate Faculty Publications

Compost plays a central role in organic soil fertility plans but is bulky and costly to apply. Determining compost carryover is therefore important for cost-effective soil fertility planning. This study investigated two aspects of nutritive carryover [nitrogen and phosphorus (P)], and an indicator of non-nutritive carryover [soil organic matter (SOM)] to determine the residual effect of a one-time compost application applied at four rates in a corn-squash rotation. Crop yield was measured as an integrated carryover indicator of nutritive and non-nutritive effects. Functional groups of compost and SOM were investigated using FT-IR spectroscopy and soil organic carbon (SOC). While year …