Digital Commons Network^™

Field Research Report: Results From The Enreec Vri Field For The 2021, 2022, And 2023 Crop Seasons, Derek M. Heeren, Ali T. Mohammed, Eric Wilkening, Christopher M. U. Neale, Alan L. Boldt, Ankit Chandra, Precious Nneka Amori, Ivo Z. Goncalves, Yeyin Shi, Guillermo R. Balboa

Department of Biological Systems Engineering: Conference Presentations and White Papers

Long-term irrigation management research has been conducted from 2014 to 2023 for corn and soybean at the Eastern Nebraska Research, Extension, and Education Center (ENREEC) Variable Rate Irrigation (VRI) Field located in subhumid east-central Nebraska (in the Lower Platte North Natural Resources District). The objective of this report was to present the overall results from the VRI Field for 2021 to 2023. Across the three growing seasons, there were the following irrigation treatments: Best Management Practice (BMP), 50% BMP, 125% BMP, rainfed, Spatial ET Modeling Interface (SETMI), SDD1, SDD2, machine-learning-based Cyber-Physical System (CPS), a student team recommended rate, and industry …

Adding Value To Crop Production Systems By Integrating Forage Cover Crop Grazing, Robert B. Mitchell, Daren D. Redfearn, Kenneth P. Vogel, Terry J. Klopfenstein, Galen Erickson, P. Steven Baenziger, Bruce E. Anderson, Mary E. Drewnoski, Jay Parsons, Steven D. Masterson, Marty R. Schmer, Virginia L. Jin

Department of Agronomy and Horticulture: Faculty Publications

In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, Nebraska, USA. Each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for …

Soybean Genetics, Genomics, And Breeding For Improving Nutritional Value And Reducing Antinutritional Traits In Food And Feed, William M. Singer, Yi-Chen Lee, Zachary Shea, Caio Canella Vieira, Dongho Lee, Xiaoying Li, Mia Cunicelli, Shaila S. Kadam, Mohammad Amir Waseem Khan, Grover Shannon, M. A. Rouf Mian, Henry T. Nguyen, Bo Zhang

Agriculture Faculty Publications

Soybean [Glycine max(L.) Merr.] is a globally important crop due to its valuable seed composition, versatile feed, food, and industrial end-uses, and consistent genetic gain. Successful genetic gain in soybean has led to widespread adaptation and increased value for producers, processors, and consumers. Specific focus on the nutritional quality of soybean seed composition for food and feed has further elucidated genetic knowledge and bolstered breeding progress. Seed components are historical and current targets for soybean breeders seeking to improve nutritional quality of soybean. This article reviews genetic and genomic foundations for improvement of nutritionally important traits, such as protein and …

Arkansas Soybean Research Studies 2022, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading soybean-producing state in the mid-southern United States. Arkansas ranked 11th in soybean production in 2022 when compared to the other soybean-producing states in the U.S. The state represented 3.04% of the total U.S. soybean production and 3.64% of the total acres planted in soybean in 2022. The 2022 state soybean average yield was 52.0 bushels per acre, tying the previous state yield record of 52 bushels per acre set in 2021. The top five soybean-producing counties in 2022 were Mississippi, Crittenden, Phillips, Poinsett, and Arkansas (Table 1). These five counties accounted for over 35.7% of the …

Supplement Type Influenced The Performance And Resiliency Against Gastrointestinal Parasites Of Nursing Lambs Raised In Woodlands, Santoshi Chaudhary, Uma Karki, Bhuwan Shrestha, Sadikshya Lamsal, Lila B. Karki

Professional Agricultural Workers Journal

Nutrition supplementation can be one of the integrated approaches to reduce gastrointestinal parasite (GIP) infestation. The study objective was to evaluate the impact of supplement type on the performance and resiliency against GIP of nursing lambs raised in woodlands. Katahdin-St. Croix cross lambs (23) with their mothers (18) were divided into two groups; they were rotationally stocked in separate sets of woodland plots and provided with ad libitum hay. Group-1 animals were supplemented with corn, and Group-2 with soybean (0.5% of live weight). Live weight, FAMACHA score, and body condition score were measured on Day 1, fortnightly, and at the …

Method Developments To Identify Loci And Selection Patterns Associated With Genotype By Environment Interactions In Soybean, Mary M. Happ

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

For many complex traits such as grain yield, genotype by environment (GxE) interactions are a prevalent source of phenotypic variation. Exploring the capacity of different methodologies to help describe and quantify the GxE interaction landscape for grain yield is an important step in informing plant breeders what the most viable strategies for management and exploitation of GxE may be. In this endeavor, we compared the results from multiple genome wide association studies (GWAS) that used either stability estimators as a phenotype to capture GxE variance, or directly mapped GxE in a mixed model for yield. Leading into this study, a …

Marginal Agricultural Land Identification In The Lower Mississippi Alluvial Valley, Prakash Tiwari

Theses and Dissertations

This study identified marginal agricultural lands in the Lower Mississippi Alluvial Valley using crop yield predicting models. The Random Forest Regression (RFR) and Multiple Linear Regression (MLR) models were trained and validated using county-level crop yield data, climate data, soil properties, and Normalized Difference Vegetation Index (NDVI). The RFR model outperformed MLR model in estimating soybean and corn yields, with an index of agreement (d) of 0.98 and 0.96, Nash-Sutcliffe model efficiency (NSE) of 0.88 and 0.93, and root mean square error (RMSE) of 9.34% and 5.84%, respectively. Marginal agricultural lands were estimated to 26,366 hectares using cost and sales …

Activity Level Of Helicoverpa Armigera Nucleopolyhedrovirus (Hearnpv) And Feeding Habits Of Helicoverpa Zea Larvae After Ingestion Of Hearnpv In Mississippi Soybean, Judge Tyler Fortenberry

Theses and Dissertations

HearNPV was applied to a soybean field and evaluated for residual efficacy at different time intervals (0, 12, 24, 36, 48, and 72 hours) after application in laboratory bioassays with treated leaves. Larval mortality was rated at five, seven and twelve days after larval infestation. Larval mortality increased as the number of days after infestation increased. To evaluate the feeding habits of Helicoverpa zea at the 2^nd and 3^rd instar, HearNPV exposed larvae and untreated larvae were weighed at zero (before diet exposure), four, and seven days. At four days after exposure, larval weight gain of …

Genomic Selection For Yield And Seed Composition Stability In An Applied Soybean Breeding Program, Benjamin Harms

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

Stability traits are of primary importance in plant breeding to ensure consistency in phenotype across a range of environments. However, selection efficiency and accuracy for stability traits can be hindered due to the requirement of obtaining phenotype data across multiple years and environments for proper stability analysis. Genomic selection is a method that allows prediction of a phenotype prior to observation in the field using genome-wide marker data and phenotype data from a training population. To assess prediction of stability traits, two elite-yielding soybean populations developed three years apart in the same breeding program were used. The individuals in each …

Reproducibility Evaluation Of Soybean Oligopeptides Based On Peptidomic Analyses, Yu Xiao-Yi, Xu Ju-Cai, Wu Ying, Liu Wan-Shun, Guo Dan, Li Xiao-Min

Food and Machinery

Objective: This study aimed to analyze the peptide composition and evaluate the reproducibility of the soybean oligopeptides. Methods: High performance liquid chromatography tandem high resolution mass spectrometry was employed for peptidomic analysis of the soybean oligopeptides prepared at the same condition at different batches. Generality and individuality of the samples were also discussed based on the heat map analysis and principal component analysis （PCA）. Results: About 1 000 peptides were identified from each of the materials and most of them were short peptides. From the set analysis, 101 peptides were found of detectability from all samples, but there were also …

A Leaf-Level Spectral Library To Support High-Throughput Plant Phenotyping: Predictive Accuracy And Model Transfer, Nuwan K. Wijewardane, Huichun Zhang, Jinliang Yang, James C. Schnable, Daniel P. Schachtman, Yufeng Ge

Department of Agronomy and Horticulture: Faculty Publications

Leaf-level hyperspectral reflectance has become an effective tool for high-throughput phenotyping of plant leaf traits due to its rapid, low-cost, multi-sensing, and non-destructive nature. However, collecting samples for model calibration can still be expensive, and models show poor transferability among different datasets. This study had three specific objectives: first, to assemble a large library of leaf hyperspectral data (n=2460) from maize and sorghum; second, to evaluate two machine-learning approaches to estimate nine leaf properties (chlorophyll, thickness, water content, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur); and third, to investigate the usefulness of this spectral library for predicting external datasets …

Recombination Hotspots In Soybean [Glycine Max (L.) Merr.], Samantha Mcconaughy, Keenan L. Amundsen, Qijian Song, Vince Pantalone, D. Hyten

Department of Agronomy and Horticulture: Faculty Publications

Recombination allows for the exchange of genetic material between two parents, which plant breeders exploit to make improved cultivars. This recombination is not distributed evenly across the chromosome. Recombination mostly occurs in euchromatic regions of the genome and even then, recombination is focused into clusters of crossovers termed recombination hotspots. Understanding the distribution of these hotspots along with the sequence motifs associated with them may lead to methods that enable breeders to better exploit recombination in breeding. To map recombination hotspots and identify sequence motifs associated with hotspots in soybean [Glycine max (L.) Merr.], two biparental recombinant inbred lines …

Effect Od Different Sources And Application Rates Of Sulfur On Corn And Soybean Production Systems In Louisiana, Diego Mayorga Valladares

LSU Master's Theses

Sulfur (S) is a structural component of amino acids such as cysteine and methionine and is involved in important functions within the plant like photosynthesis, carbon and nitrogen metabolism, protein synthesis of oils, and detoxification mechanisms. Sulfur deficiency in crops has intensified around the world. Some of the reasons are improvement in controlling SO₂ emissions from industries, growing usage of high analysis S-free fertilizers and augmented cropping intensity. Sulfur fertilization has become an important factor in crop production systems and fertilization guidelines for S need to be up-to-date to improve use efficiency and compensate for rising prices of fertilizers. …

Effect Of Row Spacing Under Maize-Soybean Relay Intercropping System On Yield, Competition, And Economic Returns, Muhammad Hayder Bin Khalid, Liang Cui, Ghulam Abbas, Muhammad Ali Raza, Adeel Anwar, Zaheer Ahmed, Abdul Waheed, Amjad Saeed, Waqas Ahmed, Muhammad Jawad Babar, Shakeel Ahmad, Rezwan Tariq, Muhammad Maroof Ajmal, Ali Ahsan Bajwa, Hülya Doğan

Turkish Journal of Agriculture and Forestry

Interrow spacing of intercrop species directly affects yield and competition indices such as land equivalent ratio of intercropping. The objectives of this research were to analyze (i) the maize and soybean yields under different spatial arrangements in maize-soybean relay strip intercropping (MSR) and (ii) the interspecies competition to provide a basis for optimization of rowspacing in MSR. The field trial was conducted in 2011 and 2012 at the Research Farm of the Sichuan Agricultural University in Ya'an to determine the impacts of various interrow planting distances on yield and competition indices in cereal (maize crop)-legume (soybean crop) relay strip intercropping. …

Metagenomic Analysis Of Root-Associated Microbiome Of Healthy And Taproot Decline-Affected Soybeans And Identification Of Healthy Soybean Root Endophytes With Protective Activity Against The Causal Agent, Xylaria Necrophora, Uyen Wesser

Theses and Dissertations

Plant roots are associated with a diverse microbial community of bacteria and fungi. The root microbiome communities associate with the root surface or penetrate the superficial layers of root tissues. It is of high agronomic interest to characterize root microbiomes and identify microbes with beneficial effects on plant defense against pathogens. Soybean taproot decline (TRD) is an emerging soil-borne disease caused by a fungus classified as Xylaria necrophora, challenging to control and with devastating effects on yield. Our group has initiated a study of the soybean root microbiome with three primary experiments: (I) perform a comparative study of root …

Arkansas Soybean Research Studies 2021, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading soybean-producing state in the mid-southern United States. Arkansas ranked 11th in soybean production in 2021 compared to the other soybean-producing states in the U.S. The state represented 3.49% of the total U.S. soybean production and 3.49% of the total acres planted in soybean in 2021. The 2021 state soybean average yield was 52.0 bushels per acre, setting a new state record and surpassing the previous yield record of 51.5 bushels per acre set in 2020. The top five soybean-producing counties in 2021 were Mississippi, Phillips, Crittenden, Poinsett, and Arkansas (Table 1). These five counties accounted for …

Removal Of Redox-Sensitive Rubisco Activase Does Not Alter Rubisco Regulation In Soybean, Christopher M. Harvey, Amanda P. Cavanagh, Sang Yeol Kim, David A. Wright, Ron G. Edquilang, Kayla S. Shreeves, Juan Alejandro Perdomo, Martin H. Spalding, Donald R. Ort, Carl J. Bernacchi, Steven C. Huber

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Rubisco activase (Rca) facilitates the catalytic repair of Rubisco, the CO2-fixing enzyme of photosynthesis, following periods of darkness, low to high light transitions or stress. Removal of the redox-regulated isoform of Rubisco activase, Rca-α, enhances photosynthetic induction in Arabidopsis and has been suggested as a strategy for the improvement of crops, which may experience frequent light transitions in the field; however, this has never been tested in a crop species. Therefore, we used RNAi to reduce the Rca-α content of soybean (Glycine max cv. Williams 82) below detectable levels and then characterized the growth, photosynthesis, and Rubisco activity of the …

Determination Of Soybean And Wheat Allergens In Food By Dual Real-Time Fluorescence Pcr, Jin Ping, Ding Hong-Liu, Zhang Min, Jin Xiao-Hong

Food and Machinery

Objective: A multiplex fluorescence PCR method based on TaqMan probe was developed for simultaneous detection of soybean and wheat allergens in food. Methods: TaqMan probe dual PCR was designed and established based on wheat gliadin gene and soybean lectin gene, respectively. The soybean Lectin gene was detected with FAM marker, and the wheat gliadin gene was detected with HEX marker. Moreover, the eukaryotic 18S rRNA was used as internal reference gene to ensure the effectiveness of the detection system. Results: The multiplex fluorescence PCR method for detection of soybean and wheat allergens created in this …

Difference In Seasonal Peak Timing Of Soybean Far-Red Sif And Gpp Explained By Canopy Structure And Chlorophyll Content, Genghong Wu, Chongya Jiang, Hyungsuk Kimm, Sheng Wang, Carl Bernacchi, Caitlin E. Moore, Andy Suyker, Xi Yang, Troy Magney, Christian Frankenberg, Youngryel Ryu, Benjamin Dechant, Kaiyu Guan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Recent advances in remotely sensed solar-induced chlorophyll fluorescence (SIF) have provided an exciting and promising opportunity for estimating gross primary production (GPP). Previous studies mainly focused on the linear correlation between SIF and GPP and the slope of the SIF-GPP relationship, both of which lack rigorous consideration of the seasonal trajectories of SIF and GPP. Here, we investigated the timing of seasonal peaks of far-red SIF and GPP in soybean fields by integrating tower data, satellite data, and process-based Soil Canopy Observation of Photosynthesis and Energy (SCOPE, v2.0) model simulations. We found inconsistency between the seasonal peak timing of far-red …

High-Throughput Characterization, Correlation, And Mapping Of Leaf Photosynthetic And Functional Traits In The Soybean (Glycine Max) Nested Association Mapping Population, Christopher M. Montes, Carolyn Fox, Álvaro Sanz-Sáez, Shawn P. Serbin, Etsushi Kumagai, Matheus D. Krause, Alencar Xavier, James E. Specht, William D. Beavis, Carl J. Bernacchi, Brian W. Diers, Elizabeth A. Ainsworth

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Photosynthesis is a key target to improve crop production in many species including soybean [Glycine max (L.) Merr.]. A challenge is that phenotyping photosynthetic traits by traditional approaches is slow and destructive. There is proof-of-concept for leaf hyperspectral reflectance as a rapid method to model photosynthetic traits. However, the crucial step of demonstrating that hyperspectral approaches can be used to advance understanding of the genetic architecture of photosynthetic traits is untested. To address this challenge, we used full-range (500-2,400 nm) leaf reflectance spectroscopy to build partial least squares regression models to estimate leaf traits, including the rate-limiting processes of photosynthesis, …

Determining Residual Control And Systemic Activity Of Commonly Used Insecticides In Soybean And Cotton, Jacob H. Smith

Theses and Dissertations

Chemical control is a critical component of integrated pest management in cotton and soybean production. Residual efficacy of foliar insecticides can be highly variable and difficult to quantify due to several factors. The purpose of this research was to determine residual control and concentrations in flowering structures of commonly used insecticides. This research focused on the concentrations of active ingredient within the plant as well as efficacy over time. Previous research suggested chlorantraniliprole had a long residual and was highly lethal on corn earworm up to 28 days after treatment (DAT) in soybean; however, the results found in cotton were …

Re-Evaluation Of Late Season Action Thresholds And The Effect Of Seed Treatments On Early Season Colonization Of Threecornered Alfalfa Hopper, Spissistilus Festinus (Say), In Louisiana Soybean, Glycine Max (L) Merr, Tyler Ray Tagle Musgrove

LSU Master's Theses

Soybean, Glycine max (L.) Merr, is considered the most economically important oil and feed crop in the US and is grown on nearly 35,000,000 ha on an annual basis. Factors that limit yield include weed pressure, disease infection, and of particular interest to entomologists, insect herbivory. Soybean is targeted by a range of above and below ground pests which are primarily controlled by insecticides. Neonicotinoids are a recently popularized insecticide class that when applied as a seed treatment, can provide protection from early season pests. The most economically significant early season pest is threecornered alfalfa hopper, Spissistilus festinus (Say), whose …

Fine Mapping And Cloning Of The Major Seed Protein Quantitative Trait Loci On Soybean Chromosome 20, Christina E. Fliege, Russell A. Ward, Pamela Vogel, Hanh Nguyen, Truyen Quach, Ming Guo, João Paulo Gomes Viana, Lucas Borges Dos Santos, James Specht, Thomas Clemente, Matthew E. Hudson, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is a unique crop species because it has high levels of both protein and oil in its seed. Of the many quantitative trait loci (QTL) controlling soybean seed protein content, alleles of the cqSeed protein-003 QTL on chromosome 20 exert the greatest additive effect. The high-protein allele exists in both cultivated and wild soybean (Glycine soja Siebold & Zucc.) germplasm. Our objective was to fine map this QTL to enable positional-based cloning of its underlying causative gene(s). Fine mapping was achieved by developing and testing a series of populations in which the chromosomal region surrounding …

Understanding The Cellular And Physiological Mechanisms Of Fertilization And Early-Stage Seed Development, Mohammad Foteh Ali

Theses and Dissertations--Plant and Soil Sciences

Flowering plants have evolved a unique double-fertilization process. Two sperm cells fuse with two female gametophytic cells, the egg and central cells within the ovule, giving rise to the embryo and endosperm, respectively. Sperm cells in flowering plants are nonmotile and delivered in close proximity to the egg and central cells by the pollen tube. Flowering plants have established filamentous actin (F-actin) based sperm nuclear migration system for successful fertilization. Prior to fertilization, the female gamete forms a mesh-like structure of F-actin that shows constant inward movement from the plasma membrane periphery to the center of the cell where the …

Photoperiod And Temperature Sensitivity In Early Soybean Accessions From The Vir Collection In Leningrad Province Of The Russian Federation, Liubov Novikova, Irina Seferova, Inna Matvienko, Zoya Shchedrina, Margarita Vishnyakova

Turkish Journal of Agriculture and Forestry

The photoperiod and temperature sensitivity of the onset of flowering in 106 soybean accessions from the VIR collection has been studied for 8 years in a vegetation experiment in the conditions of Leningrad Province at 59°N, the northernmost point of soybean evaluation in the world. The accessions were previously field-assessed for the ability to form fully developed seeds in this region. The experimental conditions were extreme for soybean in terms of both photoperiod and heat supply. The emergence to flowering period length (L_EF) in the sample set was 7.9 days longer, and the sum of the temperatures required …

Field Validation Of A Farmer Supplied Data Approach To Close Soybean Yield Gaps In The Us North Central Region, José F. Andrade, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Shawn P. Conley, John Gaska, Herman J. Kandel, Laura E. Lindsey, Seth Naeve, Scott Nelson, Maninder P. Singhi, Laura J. Thompson, James E. Specht, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

CONTEXT: Producer-reported data can be used to identify suites of management practices that lead to higher yield and profit. However, a rigorous validation of the approach in relation to its potential impact on farmer yield and profit is lacking.

OBJECTIVE: This study aimed to validate a producer-data approach on its capability to guide on-farm evaluation of management practices with greatest potential for increasing producer yield and profit. We show proof of concept using soybean in the North Central US region as a case study.

METHODS: We used a combination of regression tree analysis and a spatial framework to determine practices …

Design Of Affordable Polyaniline - Based Wearable Sensor For Real Time Plant Growth Monitoring, Temitope Borode

Electronic Theses and Dissertations

The need for precision agriculture in today and future farming cannot be overstressed. Recent agriculture is characterized by numerous challenges such as environmental stressors and resource constraints resulting in low crop yield and unsustainable agriculture practices. Understanding plant growth mechanism and growth rate under the external influence is a bedrock towards precision agriculture practices ensuring optimum yield and sustainable utilization of resources. The current study addresses this need by developing and applying an affordable and stable sensor for monitoring plant growth. The sensor was fabricated by in-situ chemical polymerization of aniline on an elastic band substrate by dip coating. The …

Soybean (Glycine Max) Response To Multiple, Sublethal Exposures Of 2,4-D And Dicamba From Vegetative Through Reproductive Growth, Graham Robert Oakley

Theses and Dissertations

This study was conducted to determine whether soybean productivity is affected by multiple, sublethal herbicide exposures. The effects of dicamba and 2,4-D on soybean (Glycine max) productivity was investigated at 17 site-years. Relative to a single exposure of dicamba at R1, an additional exposure at either V3 or R3 reduced yield up to 23%. Three or more applications did not further decrease yields relative to an R1&R3 exposure. For 2,4-D, a single application to V3, R1, R3, or R5 soybean did not affect grain yield. However, two exposures of 2,4-D occurring from V3 through R3 reduced yield 5 to 7%. …

Arkansas Soybean Research Studies 2020, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2020 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations. Several research reports in this publication will appear in other University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research …

Rhizosphere Microbiomes In A Historical Maize-Soybean Rotation System Respond To Host Species And Nitrogen Fertilization At The Genus And Subgenus Levels, Michael A. Meier, Martha G. Lopez-Guerrero, Ming Guo, Marty Schmer, Josh Herr, James Schnable, James R. Alfano, Jinliang Yang

Department of Agronomy and Horticulture: Faculty Publications

Root-associated microbes are key players in plant health, disease resistance, and nitrogen (N) use efficiency. It remains largely unclear how the interplay of biological and environmental factors affects rhizobiome dynamics in agricultural systems. In this study, we quantified the composition of rhizosphere and bulk soil microbial communities associated with maize (Zea mays L.) and soybean (Glycine max L.) in a long-term crop rotation study under conventional fertilization and low-N regimes. Over two growing seasons, we evaluated the effects of environmental conditions and several treatment factors on the abundance of rhizosphere- and soil-colonizing microbial taxa. Time of sampling, host plant species, …