Conventional Corn Research Articles

The effects of source and concentration of dietary fiber, starch, and fatty acids on the daily patterns of feed intake, rumination, and rumen pH in dairy cows

The daily patterns of feed intake and rumination influence rumen fermentation, rumen pH, and timing of absorbed nutrients in the dairy cow, but the effects of diet composition on these patterns are not well characterized. Data from 3 previously published experiments were examined to determine the influence of dietary starch, fiber, and fatty acids (FA) on daily patterns of intake, rumination, and rumen pH. Dietary neutral detergent fiber (NDF) and starch were investigated in 2 experiments, each with duplicated 4 × 4 Latin square designs with a 2 × 2 factorial arrangement of treatments in cows fed cows 1×/d at 1200 and 1400 h, respectively. To investigate fiber content and digestibility in the first experiment, brown midrib or isogenic conventional corn silage were fed in low- and high-NDF diets (29 and 38%, respectively). To investigate starch source and concentration in the second experiment, ground high-moisture corn or dry ground corn were fed in low- and high-starch diets (21 and 32%, respectively). Effect of fat concentration and saturation was investigated in the third experiment using a replicated 4 × 4 Latin square design that fed cows 1×/d at 0900 h; treatments included a control diet with no added fat and 2.5% added saturated FA, unsaturated FA, or a mixture of the saturated and unsaturated FA. In the first 2 experiments, intake followed a similar daily pattern regardless of starch and NDF concentration or digestibility. Rumination displayed a treatment by time interaction for both NDF and starch concentration, with high-fiber, low-starch diets causing greater rumination overnight but not midday. High-starch diets decreased total daily rumen pH equally across the day, but did not change the daily pattern. Type of corn silage did not affect the daily patterns of rumination or rumen pH, but pH was reduced throughout the day in brown midrib diets. In the third experiment, no interactions between fatty acid supplement and time of day were observed for intake, rumination, or rumen pH. Within all experiments, rumination fit or tended to fit a 24-h rhythm regardless of diet, with the amplitude of the rumination being reduced in low-starch diets and diets containing saturated FA or a mixture of saturated and unsaturated FA. Overall, intake, rumination, and rumen pH follow a daily pattern that was minimally modified by dietary fiber and starch type and level or fat level and fatty acid profile.

Long term biochar effects on corn yield, soil quality and profitability in the US Midwest

Corn production in the US Midwest has the potential to generate a large amount of crop residue for bioenergy production. However, unconstrained harvesting of crop residues is associated with a long-term decline in soil quality. Biochar applications can mitigate many of the negative effects of residue removal but data and economic analyses to support decision making are lacking. To explore sustainable and profitable practices for residue harvesting in central Iowa we used 11 years of soil, crop yield, and management data to calibrate the Agricultural Production Systems sIMulator (APSIM) biochar model. We then used the model to evaluate how different biochar types and application rates impact productivity and environmental performance of conventional corn and corn-soybean cropping systems in Iowa under different N fertilizer application rates and residue harvesting scenarios. A cost-benefit analysis was also employed to identify the economically optimal biochar application rate from both producer and societal perspectives. Modeling results showed for both continuous corn and corn-soybean rotations that as biochar application rate increased (0–90 Mg ha−1) nitrate leaching decreased (2.5–20%) and soil carbon levels increased (8–115%), but there was only a small impact on corn yields (–2.6 to 0.6%). The cost-benefit analysis revealed that public benefits, evaluated from decreased nitrate leaching and increased soil carbon levels, significantly outweighed the private revenue accrued from crop yield gains, and that a biochar application rate of 22 Mg ha−1 was more cost-effective (per ton) compared to higher biochar rates. Overall, this study found that applying biochar once at a rate of 22 Mg ha−1 allows for the sustainable annual removal of 50% of corn residue for 32 years, is profitable for farmers even with minimal impact on grain yield, and beneficial to society through reduced nitrate leaching and increased soil organic carbon levels.

Brown-midrib corn silage in finishing steer diet: effects on animal performance, in vivo digestibility and ruminal kinetics disappearance

Lower lignin content in brown-midrib corn silage (BMRCS) than in conventional corn silage results in greater digestibility and dry-matter intake. Despite this advantage, the use of BMRCS has not been widely evaluated in beef cattle. The aim of the present study was to determine the effects of BMRCS chopped at 22-mm as the main component (79% DM basis) for finishing steer diet on digestion, animal performance and ruminal kinetics disappearance. In a first trial, 56 Angus and crossbred steers (339 ± 18 kg initial bodyweight) were divided into 14 pens that were randomly assigned to one of the following two treatments: BMR total mixed ration (BMRT) or conventional total mixed ration. Data were analysed under a completely randomised design using pen as the experimental unit (n = 7). In a second trial, BMRCS and conventional corn silage were incubated (0, 3, 6, 12, 24, 36, 72 and 120 h) in the rumen of three ruminally cannulated cows. Data were analysed under a completely randomised block (cow) design. The inclusion of BMRCS in 79% corn silage diet for finishing steers improved total diet neutral detergent fibre and acid detergent fibre digestibility, but did not improve DM digestibility. While there was no significant improvement in animal performance, carcass yield was improved in BMRT. Future studies are needed to evaluate the improvement of carcass weight in steers fed BMRT.

The importance of leaf area index in mapping chlorophyll content of corn under different agricultural treatments using UAV images

ABSTRACTThe impact of structural parameters of agricultural crops on the retrieval of chlorophyll content presents a real challenge for the remote-sensing community. Canopy reflectance can differ between crops of different canopy structure even when they have the same canopy chlorophyll content. Thus, structural properties should be incorporated in chlorophyll mapping to reduce modelling errors. The empirical relationships between vegetation indices and chlorophyll content are well established and commonly used in precision agriculture. Recent advances in using unmanned aerial vehicle (UAV/drone) technology offer successful retrieval of crop structural and biochemical parameters. However, transfer of empirical algorithms derived from satellite to UAV-based analyses introduces new challenges mainly due to fine spatial resolution and details such as crop rows and between- and within-canopy gaps that are more pronounced in UAV images. There are two components of the analysis in this study. The first part is related to heterogeneity of leaf area index (LAI) and chlorophyll content of corn under four agricultural treatments (conventional ploughed, conventional with no tilling, biological with reduced chemical inputs, and certified organic) at the Kellogg Biological Station Long-Term Ecological Research (KBS LTER) site in Michigan, USA. The second part examines the necessity and importance of LAI in chlorophyll mapping using UAV images collected over the heterogeneous KBS LTER parcels at peak growing season. The UAV-derived normalized difference red edge index (NDRE) is found to be highly correlated with canopy chlorophyll, calculated as a product of leaf chlorophyll content and LAI. The coefficient of determination changes from R2 = 0.177 to R2 = 0.774 when LAI is added to the empirical model. NDRE is also found to be highly correlated with LAI (R2 = 0.620). The findings suggest that the conventional corn treatment with no-tilled soil exhibits the highest crop vigour during the peak growing season. The herbicide management applied earlier in the season may have a strong effect on weeds, reducing the crop–weeds competition for nutrients.

Regenerative agriculture: merging farming and natural resource conservation profitably.

Most cropland in the United States is characterized by large monocultures, whose productivity is maintained through a strong reliance on costly tillage, external fertilizers, and pesticides (Schipanski et al., 2016). Despite this, farmers have developed a regenerative model of farm production that promotes soil health and biodiversity, while producing nutrient-dense farm products profitably. Little work has focused on the relative costs and benefits of novel regenerative farming operations, which necessitates studying in situ, farmer-defined best management practices. Here, we evaluate the relative effects of regenerative and conventional corn production systems on pest management services, soil conservation, and farmer profitability and productivity throughout the Northern Plains of the United States. Regenerative farming systems provided greater ecosystem services and profitability for farmers than an input-intensive model of corn production. Pests were 10-fold more abundant in insecticide-treated corn fields than on insecticide-free regenerative farms, indicating that farmers who proactively design pest-resilient food systems outperform farmers that react to pests chemically. Regenerative fields had 29% lower grain production but 78% higher profits over traditional corn production systems. Profit was positively correlated with the particulate organic matter of the soil, not yield. These results provide the basis for dialogue on ecologically based farming systems that could be used to simultaneously produce food while conserving our natural resource base: two factors that are pitted against one another in simplified food production systems. To attain this requires a systems-level shift on the farm; simply applying individual regenerative practices within the current production model will not likely produce the documented results.

Control of Photosystem II– and 4-Hydroxyphenylpyruvate Dioxygenase Inhibitor–Resistant Palmer Amaranth (Amaranthus palmeri) in Conventional Corn

AbstractPalmer amaranth, a dioecious summer annual weed species, is the most troublesome weed in agronomic crop production systems in the United States. Palmer amaranth resistant to photosystem (PS) II- and 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors is of particular concern in south central Nebraska. The objectives of this study were to determine the effect of PRE followed by POST herbicide programs on PS II- and HPPD-inhibitor-resistant Palmer amaranth control, crop yield, and net economic return in conventional corn. A field study was conducted in 2014, 2015, and 2016 in a grower’s field infested with PS II- and HPPD-inhibitor-resistant Palmer amaranth near Shickley in Fillmore County, Nebraska. A contrast analysis suggested that mesotrione+S-metolachlor+atrazine applied PRE provided 83% Palmer amaranth control at 21 d after application compared to 78 and 72% control with pyroxasulfone+fluthiacet-ethyl+atrazine and saflufenacil+dimethenamid-P, respectively. Most of the PRE followed by POST herbicide programs provided ≥85% Palmer amaranth control. Based on contrast analysis, POST application of dicamba+diflufenzopyr provided 93% Palmer amaranth control compared to 87, 79, and 42% control with dicamba, dicamba+halosulfuron, and acetochlor, respectively, at 28 d after POST. All PRE followed by POST herbicide programs, aside from mesotrione+S-metolachlor+atrazine followed by acetochlor (2,530 to 7,809 kg ha−1), provided 9,550 to 10,500 kg ha−1corn yield compared with 2,713 to 6,110 kg ha−1from nontreated control. Similarly, PRE followed by POST herbicide programs, except for mesotrione+S-metolachlor+atrazine followed by acetochlor ($191 and $897 ha−1), provided similar net return of $427 to $707 ha−1and $1,127 to $1,727 ha−1in 2014 and 2015-16, respectively. It is concluded that herbicide programs based on multiple sites of action are available for control of PS II- and HPPD-inhibitor-resistant Palmer amaranth in conventional corn.

Justice across Real and Imagined Food Worlds: Rural Corn Growers, Urban Agriculture Activists, and the Political Ontologies They Live By

AbstractThe article examines two seemingly disparate case studies, one involving conventional corn producers and agriculture professionals located in North Dakota, the other focusing on participants in a diverse urban agriculture cooperative in an anonymized U.S. city. Drawing on qualitative interviews and data‐presenting devices known as “word clouds,” the article explores how, and to a lesser extent why, understandings of the terms “social justice” and “autonomy” varied between these spaces. While these imagined political ontologies differed greatly, the article describes each case as grounded in a shared neoliberal (“real”) world that negatively impacts both populations, a realization that could provide a source of recognition and reconciliation between groups. The article concludes by asking why those interviewed in the rural space failed to understand their marginalization to be an artifact of the neoliberal highly individualistic worldview that their articulated imaginaries appear to support, while also exploring how the divergent political ontologies between the groups can be brought into better conversation with each other.

Effect of irrigation on physicochemical properties and bioethanol yield of drought tolerant and conventional corn

As the availability of water decreases, deficit irrigation is an essential approach for optimizing water use efficiency. Limited or deficit irrigation may significantly affect crop yields, grain quality, and end uses. The objective of this study was to investigate the effect of irrigation capacity on physiochemical properties, bioconversion efficiency, and bioethanol yield of drought tolerant (DT) and conventional corn. Both DT and conventional corn were planted at Southwest Research-Extension Center near Garden City, Kansas with five different irrigation levels (1 inch every 4, 6, 8,10, or 12 days) and dryland in 2015 and 2016 growing seasons. It was found that test weight of corn increased as irrigation capacity increased. Starch and protein contents of corn ranged from 67.41 to 72.67 and 7.63 to 9.75%, respectively. Starch pasting temperature and peak time of pasting decreased as irrigation level increased. Irrigation capacity had a positive impact on bioethanol yield, whereas the corn hybrid and year did not significantly affect bioethanol yield resulting from above normal rainfall received during the growing seasons.

Development and evaluation of a low-cost precision seeding control system for a corn drill

Precision seeding requires that the corn drill drop seeds into the soil by a specific in-row spacing while its travelling speed fluctuates due to unevenness of the field ground. This paper presents a low-cost precision seeding control system for a conventional corn drill with mechanical metering devices of finger-pickup type. A median filtering method was implemented in the control system to process measurements from a rotary encoder in order to acquire stable values of the corn drill travelling speed. The metering unit was driven by an electric motor controlled by the metering ECU according to the actual travelling speed and the desired in-row spacing in real-time. A user interface was programmed to communicate with ECUs for configuring parameters and displaying operating information during working. The newly-developed precision seeding control system was first calibrated in terms of speed measurement and control for two ECUs. Experiments were conducted on a seeding test platform in the laboratory for evaluating its accuracy in dropping seeds by giving different in-row spacing under different travelling speeds of the conveyor sticky belt. Results showed that the average spacing error was less than 2 cm and the maximum RMS error was 0.78 cm for all spacing values including 25 cm, 30 cm and 35 cm under the travelling speed of 1.0-8.0 km/h. These indicated that the low-cost precision seeding control system worked in a both accurate and stable way. Keywords: precision seeding, corn drill, control system, travelling speed, in-row spacing DOI: 10.25165/j.ijabe.20181105.3369 Citation: Yin X, Noguchi N, Yang T X, Jin C Q. Development and evaluation of a low-cost precision seeding control system for a corn drill. Int J Agric & Biol Eng, 2018; 11(5): 95–99.

Análise microscópica do amido extraído de milho (Zea mays) convencional e transgênico

Os programas de melhoramento genético têm desenvolvido uma grande variedade de sementes de milho, com características que conferem maior resistência às adversidades do plantio, e permitem a extensão do seu cultivo nas mais diversas condições climáticas. A análise microscópica de grãos é uma ferramenta de grande relevância na caracterização das matérias primas e modificações do amido. Levando-se em conta o fato do uso de transgênicos em alimentos ser ainda controverso, e principalmente para os consumidores, o considerável aumento de sua utilização como ingrediente em produtos alimentícios, o presente trabalho investigou a possibilidade de detectar, por meio de microscopia, a variação das características dos grãos de amido de milho transgênico em comparação com os grãos de amido de milho convencional. Os resultados indicaram diferenças entre os grãos de amido extraídos de milho convencional e naqueles extraídos de milho transgênico. O amido extraído de milho convencional, em sua maioria, caracterizou-se pela presença de grânulos de formato poliédrico, alguns ligeiramente abaulados, com hilo em formato estrelado. No amido extraído dos grãos de milho transgênico, o hilo apresentou formato linear, pontual ou ausente. Estas propriedades serão úteis para caracterizá-los nos trabalhos de pesquisa e de identificação em produtos alimentícios.

Meteorological fluctuations define long-term crop yield patterns in conventional and organic production systems

Variability in meteorological patterns presents significant challenges to crop production consistency and yield stability. Meteorological influences on corn and soybean grain yields were analyzed over an 18-year period at a long-term experiment in Beltsville, Maryland, U.S.A., comparing conventional and organic management systems. Precipitation and temperature variables explained much of the yield variability, with precipitation and heat stress during the late vegetative and early reproductive phases of crop growth accounting for the majority of yield variability in all crops and management systems. Crop yields under conventional and organic management followed similar periodic patterns, but yields were 31% and 20% lower in organic than conventional corn and soybean, respectively. The efficiency of grain yield per unit precipitation was higher under conventional than organic management, highlighting the importance of crop management for optimizing production in response to meteorological variability. Periodic yield and precipitation patterns did not consistently align with global meteorological cycles such as the El Niño Southern Oscillation.

Agronomic performance of insect-protected and herbicide-tolerant MON 89034 × TC1507 × NK603 × DAS-40278–9 corn is equivalent to that of conventional corn

ABSTRACTAgronomic characteristics of genetically modified (GM) MON 89034 × TC1507 × NK603 × DAS-40278–9 (PowerCore™ Enlist™), MON 89034 × TC1507 × NK603 (PowerCore™), and DAS-40278–9 (Enlist™) corn, a non-GM near-isogenic hybrid, and 2 commercial non-GM hybrids were assessed in a field study to determine if the agronomic performance of the GM corn hybrids is equivalent to that of non-transgenic hybrid corn. The MON 89034 × TC1507 × NK603 × DAS-40278–9 hybrid corn was developed through stacking of 4 individual transgenic events, MON 89034, TC1507, NK603, and DAS-40278–9 by traditional breeding and contains the cry1A.105 and cry2Ab2 (MON 89034), cry1F and pat (TC1507), cp4 epsps (NK603) and aad-1 (DAS-40278–9) transgenes. These transgenes encode the proteins Cry1A.105, Cry2Ab2, and Cry1F, which confer insect resistance, PAT, CP4 EPSPS, and AAD-1, which confer herbicide tolerance. The following agronomic characteristics were assessed in the study: initial and final stand count, seedling vigor, time to silk, time to pollen shed, pollen viability, plant height, ear height, stalk lodging, root lodging, days to maturity, stay green, disease incidence, insect damage, herbicide injury, and yield. The agronomic assessment was conducted in 2 regions of Brazil (Indianopolis-MG; Cravinhos-SP). The agronomic attributes for all GM entries were statistically indistinguishable from the non-GM near-isogenic hybrid. In addition, most of the agronomic assessments fell within the range of the commercial varieties included in the study. Taken together, MON 89034 × TC1507 × NK603 × DAS-40278, MON 89034 × TC1507 × NK603, and DAS-40278–9 were found to be agronomically equivalent to non-GM corn.

A comparative study of anthocyanin distribution in purple and blue corn coproducts from three conventional fractionation processes

The aim was to compare the distribution of ANCs in purple and blue corn coproducts from three conventional corn fractionation processes and linking ANC partitioning in different coproducts to corn kernel phenotype. Total monomeric anthocyanin (TA) from purple corn extract was 4933.1±43.4mg cyanidin-3-glucoside equivalent per kg dry corn, 10 times more than blue corn. In dry milled purple corn, maximum ANCs were present in the pericarp (45.9% of total ANCs) and in wet-milling they were concentrated in steeping water (79.1% of total ANCs). For blue corn, the highest TA was in small grits and gluten slurry in dry-milling and wet-milling coproducts, respectively. HPLC showed the highest concentration of each ANC in steeping water for purple corn coproducts. Micrographs of kernel showed pigments concentrated in pericarp layer of purple but only in aleurone of blue corn. ANCs can concentrate in certain coproducts depending upon physical distribution of pigments in kernel.

A model for evaluating production and environmental performance of kenaf in rotation with conventional row crops

The potential inclusion of kenaf (Hibiscus cannabinus L.) into the conventional corn (Zea mays L.) and soybean (Glycine max L.) rotation of the U.S. Midwest requires investigation. A new kenaf model within the Agricultural Production Systems Simulator (APSIM) was developed and subsequently used to address questions needed for decision making: 1) what is the optimum planting date of kenaf under water-nitrogen limited and non-limited conditions in central Iowa; 2) does soil nitrate accumulation vary among kenaf, corn, and soybean crops?; 3) is soil organic matter (SOC) influenced in the long term?; and 4) how do kenaf water use efficiency (WUE) and nitrogen use efficiency (NUE) compare to corn and soybean? The model indicated that simulated optimum planting date for maximizing kenaf production ranged from April 15 to June 1. Model analysis of different rotation systems showed that there was a slight tradeoff between kenaf stem biomass and soybean yield. Long term soil organic carbon simulations (30 years) indicated a slight decrease over time while inclusion of kenaf in the corn-soybean (C-S) rotation did not affect this trend. In conclusion, this study brings to the scientific literature a new kenaf model that provided information that was missing for decision support.

Valuation of ecosystem services of commercial shrub willow (Salix spp.) woody biomass crops.

The development of shrub willow as a bioenergy feedstock contributes to renewable energy portfolios in many countries with temperate climates and marginal croplands due to excessive moisture. However, to fully understand the potential of shrub willow as an alternative crop on marginal cropland, more research is needed to understand the potential of shrub willow for providing a variety of ecosystem services. At the same time, there is much need for research developing strategies to value ecosystem services beyond conventional valuation systems (e.g., monetary, intrinsic). In this context, this project investigates the ecosystem services of shrub willow woody biomass from an environmental science perspective, and proposes a new avenue to assess ecosystem services for management purposes based on the relative value of key ecosystem services under various land management strategies (i.e., willow vs. corn vs. hay). On marginal cropland in the US Northeast, shrub willow may be used to replace crops like corn or hay. Transitioning from conventional corn or hay to willow tends to reduce nutrient loss and erosion, improve biodiversity and adaptability to climate change, and increase access to recreational activities. However, it is unlikely to change soil carbon pools or greenhouse gas emissions at the soil-atmosphere interface. By encouraging decision makers to weigh the pros and cons of each management decision (i.e., willow vs. corn vs. hay) based on the situation, the ecosystems services valuation method used here provides a clear framework for decision making in a watershed management context.

Methane production, ruminal fermentation characteristics, nutrient digestibility, nitrogen excretion, and milk production of dairy cows fed conventional or brown midrib corn silage

The objective of this study was to examine the effect of replacing conventional corn silage (CCS) with brown midrib corn silage (BMCS) in dairy cow diets on enteric CH4 emission, nutrient intake, digestibility, ruminal fermentation characteristics, milk production, and N excretion. Sixteen rumen-cannulated lactating cows used in a crossover design (35-d periods) were fed (ad libitum) a total mixed ration (forage:concentrate ratio = 65:35, dry matter basis) based (59% dry matter) on either CCS or BMCS. Dry matter intake and milk yield increased when cows were fed BMCS instead of CCS. Of the milk components, only milk fat content slightly decreased when cows were fed the BMCS-based diet compared with when fed the CCS-based diet (3.81 vs. 3.92%). Compared with CCS, feeding BMCS to cows increased yields of milk protein and milk fat. Ruminal pH, protozoa numbers, total VFA concentration, and molar proportions of acetate and propionate were similar between cows fed BMCS and those fed CCS. Daily enteric CH4 emission (g/d) was unaffected by dietary treatments, but CH4 production expressed as a proportion of gross energy intake or on milk yield basis was lower for cows fed the BMCS-based diet than for cows fed the CCS-based diet. A decline in manure N excretion and a shift in N excretion from urine to feces were observed when BMCS replaced CCS in the diet, suggesting reduced potential of manure N volatilization. Results from this study show that improving fiber quality of corn silage in dairy cow diets through using brown midrib trait cultivar can reduce enteric CH4 emissions as well as potential emissions of NH3 and N2O from manure. However, CH4 emissions during manure storage may increase due to excretion of degradable OM when BMCS diet is fed, which merits further investigation.

Hydrological heterogeneity in agricultural riparian buffer strips

Riparian buffer strips (RBS) may protect surface water and groundwater in agricultural settings, although their effectiveness, observed in field-scale studies, may not extend to a watershed scale. Hydrologically-controlled leaching plots have often shown RBS to be effective at buffering nutrients and pesticides, but uncontrolled field studies have sometimes suggested limited effectiveness. The limited RBS effectiveness may be explained by the spatiotemporal hydrological heterogeneity near non-irrigated fields. This hypothesis was tested in conventional corn and soy fields in the St. Lawrence Lowlands of southern Quebec (Canada), where spring melt brings heavy and rapid runoff, while summer months are hot and dry. One field with a mineral soil (Saint-Roch-de-l’Achigan) and another with an organic-rich soil (Boisbriand) were equipped with passive runoff collectors, suction cup lysimeters, and piezometers placed before and after a 3m-wide RBS, and monitored from 2011 to 2014. Soil topography of the RBS was mapped to a 1cm vertical precision and a 50cm sampling grid. On average, surface runoff intersects the RBS perpendicularly, but is subject to substantial local heterogeneity. Groundwater saturates the root zones, but flows little at the time of snowmelt. Groundwater flow is not consistently perpendicular to the RBS, and may reverse, flowing from stream to field under low water flow regimes with stream-aquifer connectivity, thus affecting RBS effectiveness calculations. Groundwater flow direction can be influenced by stratigraphy, local soil hydraulic properties, and historical modification of the agricultural stream beds. Understanding the spatiotemporal heterogeneity of surface and groundwater flows is essential to correctly assess the effectiveness of RBS in intercepting agro-chemical pollution. The implicit assumption that water flows across vegetated RBS, from the field to the stream, should always be verified.

Tank mixture of pesticides for Spodoptera frugiperda control in maize with triflumuron

Nowadays, few studies have been conducted to evaluate the effect of tank mixture of pesticides on pest chemical control in maize crops, however the farmers are often using these mixtures, without any technical support. The current study focused on assessing some pesticide mixtures to control Spodoptera frugiperda with triflumuron in a conventional corn hybrid. Moreover, this experiment aimed to assess likely plant physiological effects, as well as physical-chemical characteristics of these tank mixes. To this end, four treatments were carried out in a randomized block design with five replications, being repeated in two seasons. Treatments consisted of different pesticide mixtures, such as insecticide (INS) + adjuvant (ADJ); INS + ADJ + fungicide (FUN); INS + ADJ + FUN + foliar fertilizers (FF); control (Ctrl). The treatments underwent analyses of mixture physical-chemical characteristics, sampled caterpillar number and size, leaf gas exchange (IRGA), and amount of chlorophyll a and b. Spray liquid characteristics changed with used mixture. Fertilizer addition caused major changes in spray liquid properties as increasing pH and electrical conductivity. No effect was observed by mixing azoxystrobin, cyproconazole, zinc oxide and manganese sulfate to triflumuron concerning control effectiveness of Spodoptera frugiperda in the corn plants. Conversely, each pesticide mixture had a distinct effect on plant physiological variables.

Promoting deep-sowing germinability of corn (Zea mays) by seed soaking with gibberellic acid

ABSTRACTThe effects of seed soaking with gibberellic acid (GA3) on germinability of conventional corn variety ‘Nongda 108’ and super sweet corn variety ‘Chaotian 3’ were investigated under deep-sowing condition. GA3 soaking significantly improved seed germination and mesocotyl elongation of both varieties under 10 or 6 cm sowing depth. The most significant promotion occurred at 0.175 g L−1 GA3 in ‘Nongda 108’ and 0.035 g L−1 GA3 in ‘Chaotian 3’. To further illustrate the physiological explanations, seed respiration was estimated from dehydrogenase activity test and oxygen-sensing test. Dehydrogenase activities of both varieties were dramatically promoted after GA3 soaking. Compared with water soaking, the dehydrogenase activity in 0.175 g L−1 GA3-soaked seeds of ‘Nongda 108’ and 0.035 g L−1 GA3-soaked ones of ‘Chaotian 3’ was increased by 15.4% and 78.8%, respectively. Oxygen-sensing test showed that increased metabolism time (IMT) critical oxygen pressure (COP) and relative germination time (RGT) were decreased while oxygen metabolism rate (OMR) and relative germination rate (RGR) were increased in GA3-soaked seeds, suggesting that exogenous GA-accelerated seed respiration. Our results suggested that seed soaking with exogenous GA3 was a simple and practicable method to improve deep-sowing tolerance during corn seed germination, and the significant promotions were attributed to vigorous respiratory metabolism.

Dry-grind processing using amylase corn and superior yeast to reduce the exogenous enzyme requirements in bioethanol production.

BackgroundConventional corn dry-grind ethanol production process requires exogenous alpha and glucoamylases enzymes to breakdown starch into glucose, which is fermented to ethanol by yeast. This study evaluates the potential use of new genetically engineered corn and yeast, which can eliminate or minimize the use of these external enzymes, improve the economics and process efficiencies, and simplify the process. An approach of in situ ethanol removal during fermentation was also investigated for its potential to improve the efficiency of high-solid fermentation, which can significantly reduce the downstream ethanol and co-product recovery cost.ResultsThe fermentation of amylase corn (producing endogenous α-amylase) using conventional yeast and no addition of exogenous α-amylase resulted in ethanol concentration of 4.1 % higher compared to control treatment (conventional corn using exogenous α-amylase). Conventional corn processed with exogenous α-amylase and superior yeast (producing glucoamylase or GA) with no exogenous glucoamylase addition resulted in ethanol concentration similar to control treatment (conventional yeast with exogenous glucoamylase addition). Combination of amylase corn and superior yeast required only 25 % of recommended glucoamylase dose to complete fermentation and achieve ethanol concentration and yield similar to control treatment (conventional corn with exogenous α-amylase, conventional yeast with exogenous glucoamylase). Use of superior yeast with 50 % GA addition resulted in similar increases in yield for conventional or amylase corn of approximately 7 % compared to that of control treatment. Combination of amylase corn, superior yeast, and in situ ethanol removal resulted in a process that allowed complete fermentation of 40 % slurry solids with only 50 % of exogenous GA enzyme requirements and 64.6 % higher ethanol yield compared to that of conventional process.ConclusionsUse of amylase corn and superior yeast in the dry-grind processing industry can reduce the total external enzyme usage by more than 80 %, and combining their use with in situ removal of ethanol during fermentation allows efficient high-solid fermentation.