Corn Residue Research Articles

Potential for biohydrogen production from organic wastes with focus on sequential dark- and photofermentation: the Philippine setting

Fossil fuel remains the world’s main source of energy, but its massive use leads to the exhaustion of natural energy resources as well as climate change. With this, the interest in developing alternative energy sources has emerged globally—among these is hydrogen. Among the hydrogen production approaches, biological fermentation has been attracting global attention because of its environmental and economic merits. This process utilizes diverse feedstocks including complex organic waste materials. The Philippines has a great potential to produce hydrogen from biomass primarily because it is an agricultural country. The country is abundant in various agricultural wastes such as livestock manure, and plant residues of rice, corn, sugarcane, and coconut, as well as agro-industrial and municipal organic wastes with millions of tons generated per year. A number of studies have explored the use of technologies such as the dark fermentation (DF), photofermentation (PF), and the integration of DF and PF to utilize organic wastes for biohydrogen production. This review paper provides an overview of the organic waste scenario in the Philippines including approaches to utilize different wastes for fermentative biohydrogen production. An initial estimate conducted on the biohydrogen production suggested that the Philippines can yield 0.34–2.24 × 106 t/year from agricultural residues alone using the proposed two stage DF-PF hybrid system, with a positive net energy conversion, hence validating the possibility of establishing a biohydrogen production system from organic wastes generated in the country.

Optimizing Nitrogen Recommendations for Tillage and Corn Residue Management in Irrigated Wheat, Southern Iran

ABSTRACT In southern Iran, intensive tillage operations and residue removal have been the major cause of declining crop productivity and nitrogen-use efficiency (NUE). A 2-year field experiment (2016–2017) was conducted to test four nitrogen (N) rates (0, 101, 152, and 202 kg N ha−1) and tillage practices (conventional, CT; reduced, RT; and no tillage, NT) effects on irrigated wheat (Triticum aestivum L.) grown with or without corn (Zea mays L.) residue removal, using a split-plot design with three replications near Shiraz, Iran. After 2 years, wheat yields were tended to be increased with increasing N rates from 101 to 202 kg N ha−1 under RT with residue retention. Increasing N rate decreased NUE values particularly N physiological efficiency (PEN). Likewise, the lowest NUE was obtained under NT, while RT and CT either showed similar effects or RT was superior over CT. Furthermore, the NNI value around 1 was obtained at 152 kg N ha−1 under RT, when crop residues were retained or removed. Our research has shown that replacing CT with conservation tillage (especially RT) with residue retention and 152 kg N ha−1 can greatly protect wheat yield and optimize NUE values under wheat- and corn in a rotation, but it is based on the short-term results and evaluation of long-term experiment is highly recommended.

Altered soil organic matter composition and degradation after a decade of nitrogen fertilization in a temperate agroecosystem

Nitrogen (N) fertilization has been found to alter soil carbon storage in agroecosystem as various soil organic matter (OM) components respond differently to environmental change. However, how the direction and magnitude of soil carbon storage changes in response to N fertilization remains unclear, and a lack of deep understanding on soil OM composition particularly under various fertilization rates constrains our ability to reveal soil OM dynamics. In this study, we investigated soil OM composition and degradation at the molecular-level in response to various rates of N fertilization, and the potential mechanisms that govern these alterations. Soil samples (0−10 cm) were collected from a 10-year N fertilization experiment in Southern Ontario, Canada with increasing rates (non-fertilized control, 30, 87, 145 and 260 kg ha−1 yr−1). The samples were analyzed for soil organic carbon and total N concentrations, soil OM composition (i.e. plant-derived steroids, cutin-, suberin-, lignin-derived compounds), and microbial biomass and community structure. Despite similar soil organic carbon (21.7–23.1 g/kg) and total N contents (2.0–2.2 g/kg) across all treatments, decreased concentrations of plant-derived steroids, cutin- and suberin-derived compounds under some N addition treatments were observed. This was consistent with lower alkyl carbon contents from solid-state 13C nuclear magnetic resonance (NMR) spectroscopy analysis. The lower plant-derived steroids, cutin- and suberin-derived lipids may be explained by the enhanced degradation of steroids and cutin likely associated with higher microbial biomass under N fertilization. Lignin-derived phenols were elevated under N fertilization, which is consistent with the aromatic/phenolic carbon contents (mainly from lignin) from NMR analysis. The enhanced lignin degradation, which is consistent with higher fungal biomass (lignin degraders), did not result in lower lignin-derived compound or aromatic/phenolic carbon content under N addition. As other studies reported higher lignin contents in corn residues under N fertilization, we suggest that the turnover of lignin-derived phenols may be governed not only by degradation processes but also by the quantity and quality of crop residues. Furthermore, we observed that different N rates exert various controls on soil OM cycling. For example, the increase in degradation of steroids, cutin and lignin was smaller above the threshold N rates 145 kg ha−1 yr−1, implying that the degradation of these compounds was fertilization rate-dependent. These results highlight that various N fertilization levels alter the allocation of carbon and soil OM dynamics likely through changing biodegradation and the quantity and quality of crop residues.

Novel β-glucanases along with xylanase identified in Thermomyces lanuginosus secretome for enhanced saccharification of different lignocellulosics

The LC/MS-based exo-proteome analysis of thermophilic fungus Thermomyces lanuginosus showed 22.59% (40 proteins) of the total identified proteins (177) as CAZymes (carbohydrate-active enzymes). The CAZymes were primarily represented by glycosyl hydrolases (72.5%) belonging to 21 different GH families. Xylanase (GH11) was found to be the major protein (24.3%) in addition to the β-glucanase and another complex polysaccharide-degrading (carbohydrate-active enzymes) CAZymes in the secretome. FPLC-based fractionation of secretome was employed to identify proteins responsible for enhancing the catalytic efficacy of Cellic Ctec2 during hydrolysis of acid pre-treated lignocellulosics and eventually xylanase (GH11) and β-glucanases (GH64 and GH81) were identified and purified. The purified xylanase when supplemented with Cellic Ctec2 resulted in 2.05-, 1.79-, and 1.60-fold increase in the release of glucose from acid-treated bagasse at 10, 15, and 20% substrate loading rate, respectively when compared with the control. Similarly, enhanced hydrolysis of acid pre-treated corn residue and rice straw was observed upon supplementation with xylanase. Spiking benchmark cellulase with purified GH64 and GH81 also resulted in 1.18- and 1.23-fold enhanced hydrolysis of acid pre-treated sugarcane bagasse. The supplementation of xylanase (1000 units/g substrate) was found to reduce the Cellic Ctec2 loading rate from 36 mg/g substrate by 2.70-, 2.88-, and 2.57-fold required for hydrolysis of acid treated bagasse, corn residue, and rice straw, respectively, at high substrate loading rate (20%) and thus, it is an important candidate for economizing the 2G ethanol process.

MICROBIOLOGICAL PROCESSES OF TRANSFORMATION OF CORN PLANT RESIDUES UNDER INTRODUCTION OF DESTRUCTING MICROORGANISMS IN THE AGROCENOSES

Objective. Investigate the microbiological processes of transformation of plant residues in corn under introduction of microorganisms — producers of cellulase enzyme complexes in the agrocenoses, which play an important role in the biodegradation of fresh organic matter. Methods. Field, microbiological, biochemical, statistical. Results. In the conditions of long-term field experiment on leached chernozem (short-rotation crop rotation: corn for grain – buckwheat – soybean), the microbiological processes at mineralization of 8 t/ha of leaf-stem weight of corn have been investigated. It was found that during the growing season of buckwheat in the soil (the first year after the introduction of corn residues) and soybeans (the second year after the introduction of residues), the number of cellulolytic microorganisms increases. Their number was the highest in buckwheat agrocenoses in the variant using Microbacterium sp. 6633 and amounted to 17.7 million/g of soil, whilst a value in the control variant was 11.3 million/g of soil. The second year after the application of corn residues, the highest rates of the number of these microorganisms were reported in the variant with Bacillus sp. 6605 — 15.6 million/g of soil with control parameters of 11.1 million/g of soil. Under the action of destruction bacteria of organic matter, the enzymatic activity of the soil increased, namely: cellulase, peroxidase and polyphenol oxidase ones. Cellulase activity when using Pseudomonas sp. 6650 and Microbacterium sp. 6633 increased 1.9 times. An increase in the biochemical coefficient of humus accumulation by Muromtsev under the influence of microorganisms introduced into agrocenoses was reported. Conclusion. Under the action of representatives of the genera Bacillus, Microbacterium, Pseudomonas, the processes of mineralization of corn leaf mass in leached chernozem are activated: the number of cellulolytic microorganisms, cellulase, peroxidase and polyphenol oxidase activity increases. Parameters of the biochemical coefficient of accumulation of humus according to Muromtsev indicate an increase in the intensity of decomposition of fresh organic matter under the introduction of plant residues. These microorganisms are promising for the development of a microbial preparation designed to optimize the processes of mineralization-immobilization using crop by-products.

Correction of soil acidity with shell lime and dolomitic limestone in a Latossolo Vermelho distrófico in Paraná state, Brazil

Soil acidity is a limiting factor for agricultural production, and the correction is carried out by liming, with the variable response with characteristics of the soil and the source used. The study aimed to analyze the effect of liming on a Latossolo Vermelho distrófico (stands for the oxisols in soil taxonomy and Ferralsols in WRB-FAO). The experiment was conducted in a completely randomized design in a 2x2x3 factorial scheme, with two soil textures (medium and clayey), two types of limestone (dolomitic and shell), and three soil cover conditions (without cover, with corn residues, and with soy residues). Liming carried out considering the chemical characteristics of the soil, the neutralization power of the sources, and the quantity determined by the base saturation method. The data were submitted to analyses of variance, and the means were compared by the Scott-Knott test, with 5% significance. The acidity correction occurred in less time in clayey soil. The coverage on the soil surface influenced the acidity correction, with a dynamic response concerning the analyzed conditions. Shell and dolomitic lime showed adequate efficiency in correcting acidity in both soil textures, with non-standard differences in conditions.

In-Field Corn Residue Management for Bioenergy Use: Potential Effects on Selected Soil Health Parameters

In the U.S. biofuel industry is using corn (Zea mays L.) residue mix (CRM) consisting of corncob and stover for cellulosic ethanol and biogas production. The field storage method left different depths of CRM on the field after its removal, where negative effects on plant growth were observed. The objective of this study is to evaluate the CRM effect on selected soil health indicators. The field study conducted with four different depths of CRM, two tillage systems (no-till (NT) and chisel plow (CP), and three nitrogen (N) rates (0, 180, and 270 kg⋅N⋅ha−1) in a randomized complete block design with split-split arrangements in three replications in a continuous corn system from 2010 to 2012 at the Agronomy Research Farm at Iowa State University. The findings of this study showed a negative effect on soil organic carbon (SOC) change across all treatments at 0 - 15 cm (−0.35 to −0.03 Mg⋅ha−1⋅yr−1), while at 15 - 30 cm there was an increase in SOC rate (0.13 to 0.40 Mg⋅ha−1⋅yr−1) after 2-yr. In addition, soil aggregate-associated C of macro-aggregates decreased by 8%, while micro-aggregates increased by 2%. Soil microbial biomass carbon (MBC) across tillage and N rates for 2.5 & 7.5 CRM treatments increased by 14% in June to July 2011, while in 2012 increased by 9%. However, at the 15 cm soil depth, soil bulk density (ρb), soil penetration resistance (SPR), and soil pH showed no significant differences among CRM treatments. The findings of this study showed that in-field CRM management can affect certain soil health parameters in the short term.

Using edge‐of‐field monitoring to characterize water quality: A farmer cooperative case study in northern Missouri

AbstractEdge‐of‐fieldwater quality monitoring was conducted in cooperation with private landowners through the Mississippi River Basin Healthy Watershed Initiative, a landscape conservation program first offered through the USDA‐NRCS in 2010. The study objective was to quantify effectiveness of individual conservation practice or practice combinations on water quality on corn (Zea mays L.)‐soybean [Glycine max (L.) Merr.] watersheds. Water samples from northern Missouri farms were collected and analyzed by runoff event for sediment (total suspended solids [TSS]), N, and P to evaluate the effects of crop production, residue types, and conservation land treatment on runoff. The presence of living vegetation in the winter, whether established as a cover crop or cash crop, significantly reduced the sediment loads (p < .0001) and nutrient loads (p ≤ .0077). Additional benefits occurred on sites that produced higher residues, like corn or corn with winter wheat (Triticum aestivum L.). Significantly low TSS losses occurred during soybean years with corn and winter wheat residues. Sites that implemented full land treatment, having conservation practices that serve to avoid, control, and trap a pollutant, were more effective than those with fewer treatments, especially with respect to P loading. The mean rank for orthophosphates was 45% lower from sites with avoid, control, and trap practices instead of control practices only. Data support the conclusion that conservation structural and management practices are effective and can mitigate some negative impacts generated by agriculture. Although an intricate endeavor, edge‐of‐field water quality monitoring can serve to complement other forms of environmental analysis and inform landowners about efficient farming practices.

Grassland conversion to croplands impacted soil pore parameters measured via X‐ray computed tomography

AbstractSoil porosity estimated conventionally cannot provide the spatial distribution and geometrical properties of pore networks. This on‐farm study assessed the impacts of grassland–cropland conversion on soil pore characteristics. This study aimed to quantify the microscale changes in pores near the soil surface (0–10 cm) under grasslands converted to croplands managed with a rotation of corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] (CS); an integrated crop–livestock system (ICLS) of corn–soybean–oats (Avena sativa L.)–cover crops (CCs), with livestock grazing on corn and soybean residue after harvest and on CCs; and the native grassland (NG). Intact soil cores (diameter: 76.2 mm; length: 76.2 mm) were collected in three replications from CS, ICLS, and NG areas located adjacent to each other. Soil cores were scanned via X‐ray computed tomography (CT) (pixel resolution: 0.226 by 0.226 mm; slice thickness: 0.5 mm). Soils under CS converted from NG significantly decreased CT‐measured macroporosity eightfold. However, it increased sevenfold when CS was converted to ICLS. Higher connected porosity, connection probability, and macroporosity under ICLS and NG enhanced the saturated hydraulic conductivity (Ksat) compared with CS. The soil organic carbon (SOC) stock was increased by 13% at 0‐ to 10‐cm depth, when soils under CS were converted to improved management (ICLS). Significant correlations of CT‐measured pore parameters were found with Ksat. We conclude that CS converted from grasslands degraded SOC, pores, and other hydro‐physical properties, which can be enhanced by integrating CCs and grazing on CCs and crop residues.

The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent

The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent

Effect of modified corn residue biochar on chemical fractions and bioavailability of cadmium in contaminated soil

ABSTRACT In order to study the effects of FeCl2 modified corn residue biochar (Fe-MCB) on the bioavailability and chemical fractions of cadmium (Cd) in a contaminated calcareous soil, an experiment was conducted as a factorial in completely randomised design with three replications. This research investigated two factors: levels of Cd concentration (0, 15, and 30 mg kg−1) and type of biochar [control: without any biochar application, biochar (CB) and Fe-MCB]. Results indicated that the use of CB and Fe-MCB increased soil pH, the cation exchange capacity (CEC) of soil and soil organic matter content (SOM). The application of CB and Fe-MCB significantly decreased Cd bioavailability by 26.52 and 37.75%, respectively. The results of sequential extraction showed that the exchangeable and carbonate fractions of Cd decreased while organically bounded Cd and Fe/Mn-oxide-bounded Cd increased after Fe-MCB was applied. The application of Fe-MCB increased the IR values, but decreased MF values, demonstrating a decrease in the mobility of Cd in the soil. Overall, this study showed that Fe-MCB application especially at high concentrations of Cd can effectively immobilise Cd, thus decreasing its mobility in contaminated soils and improving the quality of soil environment and reducing remediation costs.

An Observation of Corn Tar Spot Dispersal from Agricultural Fields to an Isolated Urban Plot

Tar spot of corn is a fairly new disease to the United States, and since its introduction in 2015 it has spread to over 310 counties across nine states. Little is understood of the biology and epidemiology of the causative agent of tar spot of corn, Phyllachora maydis. Published research from Latin America indicates that spores can only travel a distance of 75 m; however, rapid progression and spread in the United States, in addition to widespread observations of top-down infection, indicate distal dispersal is likely more important. We observed an isolated plot of decorative corn in an urban setting, isolated from agricultural fields. We assessed nearby fields for crop, tar spot, cropping history, and distance from the urban site. Based on our observations, the propagules infecting the urban plot arrived from at least 560 m if from corn residue, and from at least 1,249 m if from active infections from nearby corn. Although this observation is not replicated, it does indicate that dispersal values from Latin America may not reflect the potential dispersion in Midwest topographies.

Effects of solid oxygen fertilizers and biochars on nitrous oxide production from agricultural soils in Florida

Elevated levels of nitrous oxide (N2O) emissions are a matter of concern in agricultural soils especially when flooding (hypoxic conditions) results from over irrigation or frequent rains. This study is the first to report the use of two solid oxygen fertilizers (SOFs, calcium peroxide and magnesium peroxide) to reduce N2O production in mineral and organic soils amended with N fertilizer in a short-term laboratory incubation besides two biochars. In general, organic soil had greater N2O production than mineral soil. Soils amended with nitrogen fertilizer exhibited increased N2O production, by 74 times in mineral soil and 2 times in organic soil. Both solid oxygen fertilizers in mineral soil (98–99%) and calcium peroxide in organic soil (25%) successfully reduced N2O production than corresponding N fertilized treatments. Additionally, a greater level of available nitrate–N (52–57 and 225 mg kg−1 in mineral and organic soil, respectively) was recorded with the solid oxygen fertilizers. Corn residue biochar with N fertilizer increased N2O production in mineral soil but decreased in organic soil, while pine bark biochar with N did not affect the N2O production in either soil. Depending on soil, appropriate SOFs applied were able to reduce N2O production and maintain greater nitrate–N levels in flooded soil. Thus, solid oxygen fertilizers can potentially be used as an effective way to reduce N2O emission from hypoxic soil in agricultural production systems.

Techno-economic assessment of a biomass torrefaction plant for pelletized agro-residues with flue gas as a main heat source

Torrefaction combined with densification for upgrading biomass to torrefied biomass pellets is increasingly of great interest since torrefied biomass pellets are considered as a major renewable energy source. Especially in the application of co-firing with coal, torrefaction may be easily integrated into an existing co-firing power plant, whose flue gases from the power plant could be used to torrefy biomass pellets. This could also help to improve the overall carbon efficiency of the power plant and reduce emissions of greenhouse gases. In the present work, a torrefaction plant for corn residue pellets to produce torrefied solid fuels using flue gases as a main heat source was simulated in Aspen Plus® software. Torrefaction module was successfully modelled by an RYield reactor, which was programmed with the two-steps-in-series kinetic for the decomposition of biomass pellets as well as the volatile formation for by-products. The model can, therefore, provide the distribution and yield of both torrefied biomass pellets and volatile by-products. From the validation, the simulation results appeared to show good agreement with available experimental data in the literature. At the suggested conditions of 260 °C wet flue gas and 20 min residence time, thermal energy of 460 J/g and 380 J/g were required for the drying and the torrefaction modules, respectively. At these conditions, the performance of the whole process was found to be almost 95%. This plant produced 75% w/w torrefied biomass pellets yield with HHV of 21.9 MJ/kg. The by-products mainly included 10.7% w/w water, 7.4% w/w CO2, and 1.7% w/w CO. Our findings provide a feasible outlook for integrating a torrefaction process of biomass pellets into a co-firing power plant, utilizing a realistic heat of waste flue gases for the process.

1 Alternative heifer development systems utilizing corn residue and cover crops

Abstract Spring-born heifers (n = 1,012) weaned at 148 ± 17 d were used in a 3-yr study to evaluate performance in winter development systems which utilized cover crop and corn residue grazing. Heifers were assigned to 1 of 3 treatments: grazing corn residue with dried distillers grains (CD) or wheat midds (CW) supplementation, or grazing late summer planted oat-brassica cover crop followed by corn residue supplemented dried distillers grains (CC). Grazing of corn residue (CD and CW) and cover crop (CC) began in early November. Supplementation during the corn residue phase was adjusted to target ~55% of mature BW (338 kg) at breeding. After 63 d, CC were moved to corn residue; on d 77 CD and CW began receiving grower ration. In mid-February (d 98), heifers were comingled and managed in a single group. Breeding season began in June and lasted for 29 d. Prior to corn residue grazing, ADG of CC was greater (0.76 kg/d; P< 0.01) than CD or CW (0.58 kg/d and 0.49 kg/d, respectively). Gain during the last 35 d of the winter period for CC was 0.13 kg/d less than CW (P< 0.01) but not different from CD. Overall winter ADG was greater (P< 0.05) for CC (0.62 kg/d) than CD (0.53 kg/d) or CW (0.50 kg/d). Percent of mature BW prior to breeding was 52% for CC and 50% for CD and CW. May reproductive tract scores did not differ (P=0.26) between CC and CW but were greater (P< 0.05) in CC than CD. Pregnancy rates were affected by treatment (P< 0.01), with CC (76%) being greater than CD (68%) and CW (64%). Utilizing oat-brassica cover crops early in the winter followed by a lower rate of gain while grazing corn residue appear to be effective for developing beef heifers. USDA is an equal opportunity employer and provider.

293 Evaluation of the Water Footprint of Beef Cattle Production in Nebraska

Abstract Data were compiled from an experiment evaluating the effects of month of calving, wintering system, and calf management on cow and calf performance to model the amount of water (green and blue) required to produce beef in Nebraska production systems. The referenced study was conducted over four years utilizing 217 cow/calf pairs per year. Cows were wintered on either native range or corn residue and month of calving was March, June, or August. Calves were managed as calf-feds or yearlings and only steer calves were included in the model. A 365-d period was utilized to estimate the cow’s contribution of water inputs based on dry matter intake throughout the year varying by production system. Diet characteristics, dry-matter intake, days on feed, average daily gain, and hot carcass weight were measurements used to estimate water utilization by the calves. The total water footprint was calculated by dividing the total amount of water used for each system (L) by the amount of boneless beef produced (kg). Production systems where cows were wintered on corn residue utilized 18% less water than systems utilizing native range as a wintering source, because of water allocations using the value fraction method. Increasing the dietary inclusion of distillers grains from 0% to 40% decreased the water footprint in the finishing phase by 29%. Utilizing by-products in replacement of primary crops decreases the overall water footprint of production. Across all scenarios modeled, more than 50% of the water footprint was allocated to the cow grazing rainfed pasture (green water) and over 98% of the water footprint was allocated to growing feed. Improvements in crop water use efficiency will benefit livestock production. The water footprint of the beef systems analyzed was 80% green water as rain, minimizing the environmental impact of beef production on freshwater use and ecological water balance.

PSIX-15 Intake of corn stover plant parts by feedlot beef steers

Abstract Corn stover supports feedlot operations in intensive corn producing regions. A single-pass corn grain and stover harvest system was developed to increase efficiency of field operations and capture different anatomical fractions than are typically harvested with conventional corn stover. The objectives were to feed beef steers diets that included a roughage component consisting of harvested corn residue in chopped form from conventional corn stover bales (CST) or single-pass bales (SPB). Whole-plant corn silage (WPCS) served as a control. Steers (n = 90, 5 pens/treatment) were fed during Grow (84 d) and Finish (66 d) phases to assess consumption of corn plant botanical fractions and calculate net energy values of the stover feeds. Cattle consumed a larger proportion of stover as cob (P < 0.001) and less as stalk (P = 0.001) when stover was offered as SPB rather than CST. These differences are consistent with the fractional distribution of botanical components offered. During the Grow phase, cattle fed WPCS had greater (P = 0.018) daily gains (1.27 kg d-1) than cattle fed the SPB (1.14 kg d-1) and CST (1.08 kg d-1), and were more efficient than CST cattle. Steers sorted corn stover during both phases and consumed 52.5% of corn stover offered. SPB cob intake was 70% greater than CST cob intake (P < 0.01) indicating if more cob fraction is available, cattle will consume more. There was no treatment effect on final body weight (P = 0.37) or growth rate (P = 0.12) during the Finish phase. Stover NEm and NEg were calculated using Dairy NRC (2001) methods for SPB (1.04 and 0.49 Mcal kg-1) and CST (0.98 and 0.44 Mcal kg-1), respectively. In conclusion, there is evidence that CST and SPB can substitute for WPCS in beef feedlot diets without adverse effects on overall steer performance.

Intensification of pre-treatment and fractionation of agricultural residues

Lignocellulose biomass is a unique renewable and sustainable source that can be used in energy generation, production of transport fuels and in chemical industries to replace petroleum-based resources. However, due to its recalcitrance to chemical and enzyme breakdown, it needs to be pre-treated prior to processing. In this study, ultrasound assisted ozone was used to pre-treat the agricultural processing residues corn cob and spelt husk. Following organosolv fractionation, about 90 % and 94 % of lignin with high purity (95 %) were recovered for corn cob and spelt husk with guaiacyl-syringyl lignin the major fraction from corn cob and guaiacyl lignin from spelt husk respectively. In addition, cellulose pulp of 83.6 % and 85.2 % with 78 % purity were recovered for corn cob and spelt husk respectively with a 19 % decrease in cellulose crystallinity and 17 % decrease in degree of polymerization (DP). Thus, the improved quality separation of biomass components will enhance downstream conversion to value added products thereby improving the sustainability and cost effectiveness of the process.

Removal of Cd and Ni Ions from Water Using Biosorbent Based on Corn Residues

Water sources have become unsafe for human consumption, but also for use in agriculture for irrigation or for the food industry. The deteriorating water quality has led to a shortage of drinking water supply. The aim of this study was to examine the possibility of using agricultural waste, specifically corn residues, (corn cob and silk) as a bioadsorbent to remove Ni and Cd ions from water. Experimental results have shown that corn residues (corn cob and corn silk) have a certain potential for use as bioadsorbents. The possibility of application was tested for corn cob and corn silk (corn cob 3.5g and corn silk 1.5g) for metal concentrations of 20, 40, 100 mg/L for corn cob, and 40 mg/L and 100 mg/L for corn silk. The tests were performed at pH 3 and 6 at a contact time to reach equilibrium of 3.5 hours. Adsorption parameters were determined using the Freundlich isotherm. The morphology of biosorbents before and after the adsorption process was monitored to observe differences in the structure of the biosorbents used. The results showed that in the case of Cd2 + ions, with an initial concentration of 100 mg/L the highest removal efficiency was achieved for all samples used, while in the case of Ni2+ ions the highest removal efficiency was achieved at an initial concentration of 40 mg/L for all samples, while the corn silk based of the maize (Zea mays L.) sample proved to be the best for the removal of these ions where the influence of pH has a great influence on the removal efficiency as well as the physico-chemical properties of the metal. Morphological analysis of samples before and after the adsorption process showed significant differences in the structure of the biosorbents used, which lead to the conclusion that sorption is associated with chemical changes on the surface of the biosorbent. The calculated values ​​of the parameters used in the Freundlich isotherm indicated the existence of high-energy sorption centers in the bisorbent of corn cob and corn silk hybrids maize, and that the adsorption was more pronounced at lower pH values. The corn cob-based of the maize (Zea mays L.) biosorbent used has been shown to be a heterogeneous surface biosorbent with moderate sorption intensity to Ni and Cd ions, and good sorption intensity to Ni and Cd ions in corn silk-based biosorbent.

Influence of corn residue biochar on water retention and penetration resistance in a calcareous sandy loam soil

Biochar can be potentially used as an amendment to beneficially enhance the physicochemical qualities of agricultural soils. In this study the effects of corn (Zea mays L. cv. Maxima) residue and its biochar on the soil–water characteristic curve (SWCC), the soil penetration resistance curve (SPRC, penetration resistance versus matric suction), plant available water (PAW) content, least limiting water range (LLWR) and integral water capacity (IWC) were examined in greenhouse experiments. Indices of soil physical quality and hard-setting (soil compaction during the drying processes) behavior were also measured. Pots (5 kg) were filled with a calcareous sandy loam mixed with raw corn residue or its biochars at rates of 1, 2, and 4 percent (w/w). Low and high temperature biochars, produced by slow pyrolysis process at 350 and 650 °C were evaluated. Both biochar amendments significantly ameliorated soil physical properties such as bulk density, total porosity, water retention and penetration resistance (Q) compared to the un-amended soil. Pore size distribution was significantly altered in favor of a greater fraction of wider pores (i.e. macro and mesoporosity) in the biochar amended soils. The lowest Q value was observed for the unmodified corn residue at a 4% application rate (CR 4%) in all of the matric suctions. The increase in Q with drying was attributed to Q’s strong relationship with the effective stress which originated from the matric suction. The hard-setting indices inferred from the SWCC and SPRC and shown by the slope of power model b (0.709), ΔQ (3.31 MPa), ΔQ/Q3000 (1.98), hard-setting index related to structural pores, H1 (789 hPa) and hard-setting index proposed by Dexter (2004b), HDexter (1163 hPa), were more pronounced in the untreated compared to the treated soils. Overall the changes in soil available water (SAW) for plants following biochar application was compared using three different indices, PAW, LLWR and IWC. Applying biochar could increase soil water availability such that PAW increased from 0.100 in the control to 0.156 cm3 cm−3 in BC-650 4%, LLWR100 increased from 0.079 in CR1% to 0.122% cm3 cm−3 in BC-350 2% and IWC increased from 0.072 in the control to 0.166 cm3 cm−3 in CR4%. The positive correlations between PAW, LLWR and IWC with soil physical quality indices like S1 and S2 (slopes of SWCC at first and second inflection points, related to structural and matrix pores, respectively) indicated these quantities were a potentially useful tool for evaluating soil physical quality.