Stover Quality Research Articles

Comparative Effects of Stovers of Four Varieties of Common Vetch on Growth Performance, Ruminal Fermentation, and Nutrient Digestibility of Growing Lambs.

Simple SummaryCommon vetch is an important legume crop of mixed crop-livestock systems, and it has the ability to satisfy food, fodder, and fertilizer demands through grain, stover, and nitrogen fixation. The aim of this study was to evaluate common vetch varietal differences in stover nutritive value, ruminal fermentation properties, nutrient digestibility, nitrogen retention, and animal performance in fattening lambs consuming a diet comprising 20% common vetch. The results showed that the substitution of alfalfa hay by varieties Lanjian No. 1 and Lanjian No. 2 stovers in ruminant diets could be advantageous in reducing dependence on imported alfalfa hay, thereby enhancing sustainability of small holder farmers on the Tibetan Plateau.This study evaluated common vetch stover as a feed in mixed rations for growing lambs. Four common vetch varieties were compared with alfalfa (control) for their effects on growth performance, ruminal fermentation, nutrient digestibility, and nitrogen retention. Male Hu lambs (n = 50) aged 3 months, with a mean body weight of 17.5 ± 0.34 kg were allocated randomly to one of the five dietary treatments, making 10 lambs per treatment. The experiment lasted 67 days with a 10-day adaptation period and a 50-day fattening period, and with the final 7 days used for a nutrient digestibility and nitrogen balance trial. All diets contained 30.0% maize straw and 50.0% concentrate, with different forage sources (on a fed basis): 20.0% alfalfa hay (control), 20.0% local common vetch variety 333A (C333A) stover, or 20.0% stover of one of three improved common vetch varieties: Lanjian No. 1 (CLJ1), Lanjian No. 2 (CLJ2), or Lanjian No. 3 (CLJ3). For stover quality, CLJ1 stover had the greatest crude protein (CP), in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME) content and the least cell wall contents, while C333A stover had the least CP, IVOMD, and ME contents and the greatest cell wall contents. Sheep fed the control diet had a greater average daily gain (ADG), apparent digestibility of organic matter (DOM), neutral detergent fiber, acid detergent fiber, and nitrogen retention, and greater ruminal total volatile fatty acids concentration than lambs fed the C333A or CLJ3 diet, but similar performance to lambs fed the CLJ1 and CLJ2 diets. The feed conversion ratio and predicted CH4 emission per unit of DOM intake and ADG of the control, CLJ1, and CLJ2 diets was significantly lower (p < 0.05) than for the other diets. Based on these results, stovers of varieties CLJ1 and CLJ2 can be recommended as an alternative to alfalfa hay and for use in a legume crop rotation with cereals on the Tibetan plateau.

Immediate measurement of fuel characteristics of bio-char using NIRS

Low temperature pyrolysis is effective to improve the fuel quality of wheat straw and corn stover. To determine the pyrolysis condition and fully utilizing the solid product (bio-char), the fuel characteristics of the bio-char should be measured. It costs a lot of time and money to finish all the measurement, which really retards the development of the biomass industry. This study is supposed to immediately predict the proximate analysis parameters, ultimate analysis parameters and heat value of sixty-five bio-char using NIRS. The results show the fuel characteristics of the bio-char vary in a very big range. The NIRS models can predict the VM, FC, ash, HHV, oxygen, carbon, hydrogen contents of the bio-char accurately. The Rc and Rcv2 value are all bigger than 0.92 and the RPD are bigger than 3.59. The NIRS models can also tell the high or low content of moisture and nitrogen. Only for the sulphur, more work need to do to improve the accuracy of the NIRS models. Predicting the fuel characteristic of the bio-char only by scanning the NIR spectrum, which costs only 10 seconds, will really be helpful for the biomass industry.

Chemical composition, characteristics concerned with fermentative quality and microbial population of ensiled pearl millet and sorghum stover in semi-arid West Africa.

To effectively utilize crop by‐product resources for ruminant feed in semi‐arid West Africa, we studied the chemical composition, characteristics concerned with fermentative quality, and microbial population of ensiled pearl millet stover (PMS) and sorghum stover (SS) in Mozambique. After panicle harvest, the PMS and SS were exposed in the field for 7, 21, 35, 49, 63, 77, 91, and 120 days under natural weather conditions. The fresh stover silages were prepared and stored for 120 days. With increased exposure time, the dry matter, neutral detergent fiber, acid detergent lignin, and neutral detergent insoluble nitrogen contents increased, whereas the crude protein, ether extract, gross energy, digestible energy, metabolizable energy, and true protein contents decreased. After 120 days of field exposure, aerobic bacteria dominated both stovers, and lactic acid bacteria (LAB) decreased to below detectable levels. After 120 days of ensiling, LAB dominated the silage of both crops, while the harmful microorganisms as aerobic bacteria, coliform bacteria, yeast, and mold were reduced or below detectable levels. Both silages did not produce more lactic acid to reduce the pH value, but they preserved nutrients well during ensiling. Therefore, PMS and SS can be prepared as silage for ruminant feed in semi‐arid West Africa.

Nutritional potential, in vitro ruminal fermentation kinetics and methanogenesis of stover from newer cultivars of sorghum (Sorghum bicolor) in buffalo

Context In developing countries of south Asia and Africa, cereal crop residues provide important fodder resources for ruminants. Genetic improvement through plant breeding for high-quality crop residues as well as for grain yield is gaining in demand among mixed crop–livestock farmers. Aims The present study investigated the potential nutritional quality, in vitro ruminal fermentation kinetics, gas production, enzyme activities and methane production of stover of newly developed brown midrib cultivars of sorghum (Sorghum bicolor (L.) Moench) compared with other cultivars in buffalo (Bubalus bubalis). Methods Stover from seven sorghum cultivars – brown midrib sorghum (SPV-2017, SPV-2018), normal grain sorghum (CSV-27), forage sorghum (SSG-59-3, CSV-32F) and sweet sorghum (CSH 22SS, CSV 24SS) – was analysed for chemical composition. Stover samples (200 ± 5 mg dry matter) from each cultivar were incubated with buffered rumen fluid (30 mL) in 100-mL calibrated glass syringes at 39°C for 72 h following a standard in vitro gas-production protocol for gas production and fermentation kinetics. Key results Stover chemical composition varied significantly (P &amp;lt; 0.05) among cultivars, with highest organic matter in forage sorghum SSG-59-3 and lowest in sweet sorghum CSV-24SS. Acid detergent lignin was lowest in stover of the brown midrib cultivars (1.27% in SPV-2018 and 1.67% in SPV-2017) and highest in forage sorghum SSG-59-3 (9.42%). The brown midrib cultivars showed highest (P &amp;lt; 0.001) total gas production, truly degradable dry matter, organic matter digestibility and metabolisable energy content. The brown midrib cultivars and forage sorghum CSV-32F had highest (P &amp;lt; 0.05) production of volatile fatty acids (acetate, propionate and butyrate) and activity of ruminal enzymes (carboxymethyl cellulase and xylanase) during fermentation. Conclusions This study demonstrates that stover from brown midrib sorghum cultivars (SPV-2017 and SPV-2018) and forage sorghum CSV-32F could be preferred over stover of other cultivars for animal feed owing to their potential for enhanced utilisation. Implications This study provides information on nutritional quality of stover from newly developed sorghum cultivars for large-scale utilisation as animal feed in smallholder production systems of developing countries.

Pleurotus Ostreatus and Volvariella Volvacea Can Enhance the Quality of Purple Field Corn Stover and Modulate Ruminal Fermentation and Feed Utilization in Tropical Beef Cattle.

Simple SummaryThe use of purple field corn stover contains enriched anthocyanin. Moreover, the effect of anthocyanin in purple field corn could inhibit methane (CH4) synthesis by changing hydrogen from the CH4 route to form propionic acid. However, purple field corn was found to have poor digestibility owing to its fiber linkage structure. Pleurotus ostreatus and Volvarialla volvacea are species of white-rot fungal mushroom, famous and abundant in tropical regions. These fungi have potential to decrease indigestion of cell wall contents and increase cell wall digestibility of rice straw material by secondary metabolites namely lignin peroxidase, manganese peroxidase, and laccase enzyme, and showed the structural polymer found in rice straw and purple field corn residue. Accordingly, feeding purple field corn stover fermented with P. ostreatus or V. volvacea will increase feed utilization and reduce CH4 production in beef cattle.This objective is to elucidate the effect of purple field corn stover treated with Pleurotus ostreatus and Volvarialla volvacea on feed utilization, ruminal ecology, and CH4 synthesis in tropical beef cattle. Four male Thai native beef cattle (100 ± 30 kg of body weight (BW) were assigned randomly as a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. Factor A (roughage sources) was rice straw and purple field corn stover and factor B was species of white-rot fungi (P. ostreatus and V. volvacea). After fermentation, crude protein (CP) was increased in rice straw and purple field corn stover fermented with P. ostreatus and V. volvacea. The unfermented purple field corn stover contained 11.8% dry matter (DM) of monomeric anthocyanin (MAC), whereas the MAC concentration decreased when purple field corn stover was fermented with white rot fungi. There were no changes (p > 0.05) in DM intake of body weight (BW) kg/d and g/kg BW0.75 among the four treatments. The organic matter (OM), CP, and acid detergent fiber (ADF) intake were different between rice straw and purple field corn stover and were the greatest in the purple field corn stover group. Moreover, the current study showed that neutral detergent fiber (NDF) and ADF digestion was higher in purple field corn stover than in rice straw, but there were no significant differences between P. ostreatus and V. volvacea. There were significant effects of roughage sources on ammonia nitrogen (NH3-N) at 4 h after feeding. Bacterial population was changed by feeding with purple field corn stover fermented with P. ostreatus and V. volvacea. On the other hand, the number of protozoa was reduced by approximately 33% at 4 h after feeding with purple field corn stover (p < 0.01). Propionic acid concentration was different between roughage sources (p < 0.01) enhanced with purple field corn stover fermented with P. ostreatus and V. volvacea. In addition, methane production decreased by 15% with purple field corn stover fermented with P. ostreatus and V. volvacea compared to rice straw. There were significant differences on all nitrogen balances parameters (p < 0.05), except the fecal N excretion (p > 0.05) were not changed. Furthermore, microbial crude protein and efficiency of microbial N synthesis were enhanced when purple field corn stover fermented with P. ostreatus and V. volvacea was fed compared to rice straw group. Base on this study, it could be summarized that P. ostreatus or V. volvacea can enhance the quality of purple field corn stover and modulate rumen fermentation and feed digestion in Thai native beef cattle.

Dynamics of fermentation quality, physiochemical property and enzymatic hydrolysis of high-moisture corn stover ensiled with sulfuric acid or sodium hydroxide

A better understanding of biomass usability during storage would offer basis for management decisions in production. High-moisture corn stover was ensiled with sulfuric acid (H2SO4, 0.3% and 0.6%) or sodium hydroxide (NaOH, 0.5% and 1.0%) and ensiling characteristics, lignocellulosic profile and enzymatic saccharification were investigated on day 3, 7, 15, 30 and 60 of ensiling. The results showed that 0.6% H2SO4 reduced dry matter loss (9.81% to 6.34%) and ammonia-N content (3.89 to 1.04 g/kg DM) during ensiling, whereas it was converse for NaOH treatment (19.89%, 5.74 g/kg DM). Hemicellulose was reduced (27.98% to 22.61%, 16.81% DM) by 0.6% H2SO4 or 1.0% NaOH. Saccharification yield was decreased (306 to 229 mg/g DM) during ensiling, which was improved (229 to 356, 277 mg/g DM) by H2SO4 and NaOH treatments. This study suggests that ensiling with addition of 0.6% H2SO4 could improve nutrient preservation and saccharification yield of high-moisture corn stover.

A lower cost method of preparing corn stover for Irpex lacteus treatment by ensiling with lactic acid bacteria.

ObjectiveThis study investigated a method of preparing corn stover for Irpex lacteus (I. lacteus) treatment to improve its in vitro rumen degradability under non-sterile conditions.MethodsCorn stover was inoculated with Lactobacillus plantarum (L. plantarum), Lactobacillus buchneri (L. buchneri), and an equal mixture of these strains, and ensiled for 0, 3, 7, 14, and 28 days. After each period, a portion of the silage was sampled to assess the silage quality, and another portion of the silage was further treated with I. lacteus at 28°C for 28 d. All the samples were analyzed for fermentation quality, chemical composition, and in vitro gas production (IVGP) as a measure of rumen fermentation capacity.ResultsLactic acid bacteria (LAB) was found to improve the silage quality of the corn stover, and the corn stover silage inoculated with L. plantarum produced more lactic acid and higher IVGP than other silage groups. The I. lacteus colonies flourished in the early stage of corn stover silage, especially on the 3-d corn stover silage inoculated with both L. plantarum and L. buchneri. This led to an 18% decrease in the acid detergent lignin content, and a 49.6% increase in IVGP compared with the raw stover.ConclusionThe combination of ensiling with the mixed LAB inoculation and I. lacteus treatment provided a cost-effective method for the improvement of the IVGP of corn stover from 164.8 mL/g organic matter (OM) to 246.6 mL/g OM.

Morphological fractions, chemical composition and in vitro digestibility of stover of four common vetch varieties grown on the Tibetan plateau.

This study evaluated the varietal variability and interrelationship of the grain and stover yields, and stover quality characteristics of four common vetch varieties (three improved varieties and one local variety) used on the Tibetan Plateau. Stover quality attributes determined included chemical composition, in vitro true digestibility of dry matter (IVTD) and neutral detergent fibre (dNDF). The improved varieties were superior to the local variety in grain yield, harvest index and potential utility index (PUI). The wide ranges in the proportions of leaf (24.3%-34.6%), pod (22.0%-45.6%) and stem (29.5%-44.7%) fractions were observed. Significant varietal differences (p<.001) were observed for the whole-stover content of crude protein [CP; 78.1-101g/kg dry matter (DM)], neutral detergent fibre (aNDF; 520-564g/kg DM), acid detergent fibre (ADF; 520-564g/kg DM), IVTD (597-658g/kg DM) and dNDF (305-384g/kg aNDF). The leaf fraction had the highest levels of CP, IVTD and dNDF, while the highest contents of aNDF and ADF were observed in the stem fraction. Canonical correlation analysis showed that significant (p<.001) correlations between the quality attributes of whole stover and proportions and quality attributes of stover morphological fractions. Pearson correlation between the grain and stover yield was negative and significant (r=-.295; p=.001), while the correlations between the grain/stover yield and stover quality traits were positive or non-significant. Ranking of the varieties differed when grain yield, PUI and stover quality scores were investigated. Of the varieties tested, Lanjian No.2 has the best potential for use as a ruminant feed, as indicated by PUI and stover quality.

In situ degradation, ruminal fermentation, and the rumen bacterial community of cattle fed corn stover fermented by lignocellulolytic microorganisms

Fifteen ruminally-fistulated Jilin Grassland red cattle (shorthorn ♂ × Mongolia yellow cattle♀ F2; 500 ± 10.0 kg) were used to evaluate the effect of corn stover fermented by lignocellulolytic microorganisms on the in situ degradation, ruminal fermentation, and rumen bacterial community. Among them, three cattle were used to determine the kinetic parameters of dry matter (DM) and neutral detergent fiber (NDF) degradation of fermented corn stover (FCS) and corn stover silage (CSS) ensiled with and without lignocellulolytic microorganisms. Twelve cattle were randomly assigned to two groups: the control group fed CSS, and the treatment group fed FCS. The diets consisted of forage (FCS or CSS) and concentrate (corn-soybean meal diet) in a proportion of 60:40 on a DM basis. The FCS group displayed higher effective degradability of DM (p < 0.01) and NDF (p < 0.1) than the CSS group. After feeding for 21 days, the mean ruminal pH was lower in FCS cattle (p < 0.05), but the NH3–N concentration was higher in the FCS group (p < 0.05). The concentrations of ruminal total volatile fatty acids, acetate and propionate were also significantly higher in the FCS group (p < 0.05). There were no differences in the concentration of butyrate or the ratio of acetate-to-propionate between FCS and CSS cattle. Ruminal bacterial diversity was higher in the FCS group (p < 0.05). All samples were dominated by four phyla; Bacteroidetes, Lentisphaerae, Firmicutes and Fibrobacteres, which together accounted for>77% of the total bacterial abundance. Within Bacteroidetes, the abundance of Prevotella increased by 65.6% and 53.1% from day 0 to day 21 in the FCS and CSS groups, respectively. Fibrobacter abundance decreased by 29.9% in the CSS group but changed much less in the FCS group. This study demonstrated a positive effect of microbial inoculants upon the function of cellulose- and hemicellulose-degrading bacteria. We concluded that improvement in the quality of fermented corn stover increases the absorption of nutrients by cattle. Furthermore, FCS altered rumen fermentation by increasing the abundance of the dominant Prevotella genus, and stabilizing the rumen microbial ecosystem.

Quantitative trait loci mapping of forage stover quality traits in six mapping populations derived from European elite maize germplasm

AbstractFour forage maize stover quality traits were analysed including in vitro digestibility of organic matter (IVDOM), neutral detergent fibre (NDF), water‐soluble carbohydrates (WSC) and digestibility of NDF (DNDF). We mapped quantitative trait loci (QTL) in three DH (doubled haploid) populations (totally 250–720 DH lines): one RIL population (358 lines) and two testcross (TC) populations, based on field phenotyping at multiple locations and years for each. High phenotypic and genotypic correlations were found for all traits and significant (p &lt; .01) at two locations, and NDF was negatively correlated with the other traits. QTL analyses were conducted by composite interval mapping. A total of 33, 23, 32 and 25 QTL were identified for IVDOM, NDF, WSC and DNDF, respectively, with three, four, five and two major QTL for each. Few consistent QTL for IVDOM, WSC and DNDF were detected in more than two populations. This study contributed to the identification of key QTL associated with forage maize digestibility traits and is beneficial for marker‐assisted breeding and fine mapping of candidate genes associated with forage maize quality.

The Effect of Organic Phosphorus and Nitrogen Enriched Manure on Nutritive Value of Sweet Corn Stover

The experiment aimed to evaluate the effect of some manure enriched with phosphorus (P) and nitrogen (N) organic (‘manure plus’) on crude protein and mineral production of sweet corn (Zea mays saccharata)and quality of fermented stover as livestock feed. A field experiment was conducted on a vertisol soil (low pH, nitrogen and low available Bray II extractable P). Randomized block design with 9 treatments in 3 replicates was used in this experiment. The treatments were T1(TSP), T2 (SA), T3 (TSP+SA), T4 (manure), T5 (manure+PR), T6 (manure+guano), T7 (manure+N-legume), T8 (manure+PR+N-legume), T9 (manure +guano+N-legume). Data were analyzed using analysis of variance (ANOVA) and the differences between treatment means were examined by Duncan Multiple Range Test (DMRT). Results of the experiment showed that the treatment significantly affected to the crude protein and calcium production of stover and nutrient concentration of fermented stover, but it is not affected to P production of stover. The result of DMRT showed that the effect of ‘manure plus’ was not significantly different on CP and Ca production of stover, mineral concentration, in vitro DMD and OMD of fermented stover, compared to inorganic fertilization. Conclusion, manure enriched with organic NP, resulted in similar on CP and Ca production of stover and nutrient concentration of fermented stover compared to inorganic fertilizer. Thus, organic-NP enriched manure could be an alternative and viable technology to utilize low grade of phosphate rock, guano and Gliricidea sepium to produce sweet corn in vertisol soil.

Effects of Formic or Acetic Acid on the Storage Quality of Mixed Air-Dried Corn Stover and Cabbage Waste, and Microbial Community Analysis.

A mixture of air-dried corn stover and cabbage waste was ensiled to preserve lignocellulosic biomass for use as biofuel. Furthermore, the effects of different fresh mass fractions (0.3 and 0.6%) of formic or acetic acid on the mixed silage quality were evaluated to guarantee its quality. The application of formic or acetic acid prior to mixing the silage led to higher water-soluble carbohydrate fractions than the negative control, indicating that both acids contributed to preservation of water-soluble carbohydrates during storage for 170 days. The dry matter content was also increased after storage from 90 to 170 days. It was found that the content of neutral and acid detergent fibre, cellulose and holocellulose (the sum of cellulose and hemicellulose) in mixed silage treated with formic or acetic acid was significantly lower than that obtained in the negative control. The pH and the ratio of ammoniacal nitrogen to total nitrogen in mixed silage treated with acetic acid also significantly decreased. Furthermore, the addition of formic or acetic acid significantly weakened the fermentation intensity of lactic acid, depending on the ratio of lactic to acetic acid, as well as the ratio of lactic acid to total organic acids. The number of bacterial species and their relative abundance shifted during silage mixing, wherein microbial communities at phylum level mainly consisted of Proteobacteria and Firmicutes. The dominant bacteria were also observed to shift from Lactobacillus and Enterobacter in presilage biomass to Lactobacillus and Paralactobacillus. Specifically, Enterobacter disappeared after 130 days of storage. In conclusion, the addition of a low dose of acetic acid to fresh mass (0.3%) could effectively improve the fermentation quality and is conducive to the preservation of the organic components.

Variation in carbohydrate and protein fractions, energy, digestibility and mineral concentrations in stover of sorghum cultivars

The nutritional attributes of stover from 11 sorghum cultivars ( SP 18005A x 220-2,3,6,7; PC-5; GGUB44 x SSG-59-3; ICSV-700; CSV-17; NRF-526; FM-1; SPV-1616; PVK-809; UPMC-503; and HC-308 ), selected on the basis of their diverse genetic backgrounds and use, were evaluated to aid in selecting parents superior in protein concentration and digestibility for use in sorghum breeding programs. Samples of stovers were collected after grain harvesting and analyzed. The CP concentrations in different cultivars differed (3.7‒6.7%; P<0.05) as did NDF, ADF, cellulose and lignin concentrations (P<0.05). Total carbohydrate, non-structural carbohydrate and structural carbohydrate concentrations differed (P<0.05) amongst cultivars as did carbohydrate fractions (C A , C B1 , C B2 , C C ; P<0.05). Protein fractions (P B1 , P B2 , P B3 and P C ) except P A differed (P<0.05). Concentrations of stover protein fractions P A and P B3 were lower than P B1 , P B2 and P C . Unavailable protein fraction P C was highest (P<0.05) in stover of SPV-1616 (36.8% CP) and lowest in ICSV-700 (20.4% CP). Concentrations of gross energy (GE), digestible energy (DE), metabolizable energy (ME) and total digestible nutrients (TDN) varied (P<0.05) and ICSV-700 had highest concentrations of DE, ME and TDN (2.60 kcal/g DM, 2.13 kcal/g DM and 59.0%, respectively). Energetic efficiency for maintenance (NE M ), lactation (NE L ) and growth (NE G ) differed (P<0.05) with ranges of 1.13‒1.42, 0.41‒0.70 and 0.95‒1.33 kcal/g DM, respectively. Values for estimated DM intake, estimated digestible DM and relative feed value for stovers also varied (P<0.05) with ranges of 1.76‒2.19%, 55.3‒61.4% and 75.4‒104.1%, respectively. In vitro dry matter digestibility was highest (P<0.05) for cultivars PVK-809 (55.7%) and ICSV-700 (54.3%). Macro- and micro-mineral concentrations also differed (P<0.05) across cultivar stovers. The wide genetic variability for nutritional attributes in stovers of sorghum cultivars indicates significant potential for improvement of stover quality through sorghum improvement programs, but care needs to be taken that grain and stover yields do not suffer. Keywords : Energy values, nutritive value, sorghum stover, yields. DOI: 10.17138/TGFT(6)42-52

Living Mulch for Sustainable Maize Stover Biomass Harvest

The Renewable Fuels Standard mandate provides enhanced opportunity for maize (Zea mays L.) stover use as a bioenergy feedstock. Living mulch (LM) offers a possible solution for the natural resources constraints associated with maize stover biomass harvest. A two‐site‐year study was conducted near Boone and Kanawha, IA, in both maize following maize (MM) and maize following soybean [Glycine max (L.) Merr.] (SM) sequences to evaluate the impact of established and chemically suppressed Kentucky bluegrass (Poa pratensis L.) ‘Ridgeline’, ‘Wild Horse’, ‘Oasis’, and ‘Mallard’ blend and creeping red fescue (Festuca rubra L.) ‘Boreal’ as LM on three maize hybrids (population sensitive, population insensitive, and yield stable). Maize grain yield for the no LM treatments in the MM and SM sequences was 12.0 and 13.2 Mg ha−1, respectively, at Boone and 12.8 and 14.8 Mg ha−1, respectively, at Kanawha, 23 to 73% greater than the LM treatment. Ethanol yield (L ha−1) was 12 to 119% greater, protein concentration was ≤9% greater, and starch concentration was ≤1% lower in the no LM treatment maize than in LM treatment maize. Maize hybrid by cover interaction was significant for parameters including total aboveground biomass and protein concentration at Boone, with inconsistent maize hybrid responses to the LM system. Stover yield, stover quality, stover C and N, leaf area index, maize plant density, maize maturity, and sequence year in the MM sequence were also evaluated. Results emphasize the need for maize hybrid and LM system compatibility, as well as effective LM suppression techniques.

Uncertainties in corn stover feedstock supply logistics cost and life-cycle greenhouse gas emissions for butanol production

The success and sustainable operation of a commercial cellulosic biorefinery are highly dependent on price, quality, and availability of feedstocks. Currently, corn stover is a primary feedstock choice for cellulosic ethanol production and the same feedstock can be used for butanol production, which is a potential alternative biofuel. However, butanol production requires different levels of feedstock and logistical resources when compared to ethanol due to about 20% lower theoretical yield. A thorough analysis of cost, life-cycle energy use and life-cycle greenhouse gas emissions associated with a feedstock supply logistics system for butanol production is yet to be done. Additionally, quality standards for corn stover feedstock are yet to be determined, which could determine cost of the feedstock for commercial applications. Thus, this study aimed to fulfill these research gaps using techno-economic analysis and life-cycle assessment methodologies. Variability in logistical resources and other input parameters gathered from recent literature were used for analyses in this study. Average corn stover supply logistics cost ($/metric ton(t), dry), life-cycle energy use (MJ/t, dry) and life-cycle greenhouse gas emissions (kg CO2e/t, dry) were 86.9, 1073.7 and 83.8, which could increase at 95% certainty to 159–504, 1672–3817 and 138–271, respectively, depending on the types of probability distributions of the input parameters. However, the mode value of logistics cost ($/t, dry), life-cycle energy use (MJ/t, dry) and life-cycle greenhouse gas emissions (kg CO2e/t, dry) of 80–120, 913–1231 and 79–120, respectively, closely represents the results of the static model. The average estimated feedstock cost for butanol production was about 1.3 times and the minimum 95% certainty value is about 2 times more than the targeted feedstock cost ($/metric ton, dry) of 66.4, excluding preprocessing. Overall, the location of the biorefinery, quality of corn stover, sustainable agricultural practices, and optimum utilization of transportation resources were key factors that enable a sustainable feedstock supply logistics system.

Amonificación de la Panca de Maíz (Zea mays L) con Tres Niveles de Urea para la Mejora de su Digestibilidad

El objetivo del presente estudio fue evaluar el efecto de la urea (46% de N) sobre la calidad nutricional de la panca de maíz proveniente de las zonas de Chilampa, La Villa, Miramar y La Querencia, de la Asociación de Ganaderos de la Irrigación San Felipe, situada en la provincia de Huaura, Lima (Perú). Se trabajó con tres niveles de urea (0, 3 y 6%) en forma de solución acuosa sobre la panca de maíz almacenada herméticamente en bolsas plásticas durante un periodo de 14 días. Se evaluaron las siguientes variables: proteína cruda (PC%), fibra detergente neutro (FDN%), digestibilidad in vitro de la materia seca (DIVMS%), digestibilidad in vitro de la fibra detergente neutro (DIVFDN%), ingesta potencial de materia seca (%PV en MS) y valor relativo del forraje (VRF), con un diseño de bloques completamente al azar con tres repeticiones. Los resultados para los tratamientos 0, 3 y 6% de urea fueron: 84.66, 70.01 y 67.78% de MS; 5.08, 8.02 y 12.92% de PC; 77.31, 76.89 y 74.84% de FDN; 59.90, 61.17 y 66.59% de DIVMS; 48.15; 50.97 y 55.41% de DIVFDN; 1.55, 1.56 y 1.60% de ingesta potencial de materia seca; y 72.09, 74.03 y 82.81 de VRF, respectivamente. No se encontró diferencias significativas entre las procedencias de la panca de maíz ni para la DIVFDN entre los niveles de urea aplicado; sin embargo, hubo diferencia significativa (p&amp;lt;0.05) para el contenido de PC, FDN, DIVMS, ingesta potencial de materia y VRF entre los niveles de urea.

Post‐Flowering Drought Tolerance Using Managed Stress Trials, Adjustment to Flowering, and Mini Core Collection in Sorghum

Sorghum [Sorghum bicolor (L.) Moench] crop in the semiarid tropics often suffers from post‐flowering drought stress, which causes substantial losses in grain yield and stover quality. This research was aimed at studying the yield response of sorghum mini core accessions to post‐flowering drought stress to identify drought‐tolerant sources for sorghum improvement. Mini core accessions were grouped based on days to 50% flowering (extra early, early, medium, late, and extra late) and evaluated in two post‐rainy seasons under managed drought stress and optimally irrigated conditions. Drought tolerance index (DTI), as a standard residual after removing the known contributory effects of flowering time and grain yield under optimum irrigation (yield potential) from the grain yield under drought, was used to segregate the genotypic responses to drought stress. The residual (or restricted) maximum likelihood analysis of data revealed significant genotypic variance (σ2g) for days to 50% flowering, grain yield, and DTI (except in the extra late flowering group), in both the seasons and significant genotype × environment interactions for DTI in extra early to late flowering groups. On the basis of DTI, seven accessions, i.e., ‘IS 14779’, ‘IS 23891’, ‘IS 31714’, ‘IS 4515’, ‘IS 5094’, ‘IS 9108’, and ‘IS 15466’, were identified as drought tolerant and five accessions were sensitive to drought in both of the post‐rainy seasons. The tolerant accessions belonging to durra, caudatum, or durra‐caudatum races were of diverse geographical origins, and most yielded at par with or greater than the extensively grown cultivar ‘IS 33844’. These accessions can be employed to investigate the physiological and molecular basis of drought adaptation and to breed for drought tolerance in sorghum.

Production, carbon and nitrogen in stover fractions of corn ( Zea mays L.) in response to cultivar development

ABSTRACT Changes in quantity and quality of corn crop stover can have a large impact on soil conservation and soil carbon (C) sequestration over large areas. The aim of this study was to evaluate changes in production, concentration and amount of C and nitrogen (N) in corn stover fractions due to cultivar development. Two field experiments were conducted in the city of Rolândia (Paraná State, Brazil) using ten cultivars representing five technological levels: single cross hybrids, double or triple hybrids, commercial varieties, and creole cultivars. Plant heights and stalk, leaf, cob, husk and tassel weights were determined at final harvest. Elemental C and N analyses were performed in triplicate for each stover fraction. In general, the creole cultivars had greater height, more dry matter (kg ha-1) and C content (kg ha-1) in husks, leaves, tassels and stalks, particularly when compared to single cross hybrids or others hybrids. There was a direct relationship between C/N ratio and corn selection for husks in both years and for the others fractions in one study year. This was due to the combined effects of increasing C and decreasing N due to crop selection. Large differences were observed within the same technological levels for the evaluated properties, suggesting a wide variation in genetic background. The quantity and quality of stover fractions vary among cultivars and may affect their use for soil cover, animal feed, biomass energy and other applications.

Performance assessment of dilute-acid leaching to improve corn stover quality for thermochemical conversion

Lignocellulosic biomass is a sustainable energy source that can help meet the demand for biofuels in the United States. However, the quality and availability of such feedstocks greatly affect their suitability for downstream conversion. This work reports the effects of dilute-acid leaching at various aqueous loadings, temperatures and catalyst loadings (sulfuric acid) on the quality of a traditional biochemical feedstock, corn stover, as a potential feedstock for thermochemical conversions.At 95wt% aqueous, dilute-acid leaching was observed to effectively remove 97.3% of the alkali metals and alkaline earth metals that can negatively affect degradation pathways during pyrolysis and result in greater yield of non-condensable gases. In addition, up to 98.4% of the chlorine and 88.8% of the phosphorus, which can cause equipment corrosion and foul upgrading catalysts, respectively, were removed. At 25°C in the absence of the acid catalyst, only 6.8% of the alkali metals and alkaline earth metals were removed; however, 88.0% of chloride was still removed.The ratio of alkaline/acidic ash species has been suggested to proportionately relate to slagging in combustion applications. The initial alkali/acid ratio of the ash species present in the untreated corn stover was 0.38 (significant slagging risk). At 95wt% aqueous, this ratio was decreased to 0.18 (moderate slagging risk). At 0wt% catalyst and 90°C, the ratio was decreased to 0.07, 0.08 and 0.06 at 0.5wt% catalyst at 25°C, 50°C and 90°C, respectively (low slagging risk). Increasing the catalyst loading to 1.0% slightly decreased the measured alkali/acid ratio of remaining ash.The results presented here show that a water wash or a dilute-acid preprocessing step can improve corn stover quality for pyrolysis, hydrothermal liquefaction and combustion.

Corn stover ethanol yield as affected by grain yield, Bt trait, and environment

Literature values for glucose release from corn stover are highly variable which would likely result in tremendous variability in bio-refinery ethanol yield from corn stover feedstock. A relatively recent change in United States corn genetics is the inclusion of the Bacillus thuringiensis (Bt) trait, which now accounts for three-fourths of all US planted corn acreage. The objective of this study was to evaluate the effect of corn grain yield, inclusion of the Bt trait, and location environment on corn stover quality for subsequent ethanol conversion. Two hybrid pairs (each having a Bt and non-Bt near-isoline) were analyzed giving a total of 4 hybrids. In 2010 and 2011, field plots were located in Michigan at four latitudinal differing locations in four replicated plots at each location. Stover composition and enzymatic digestibility was analyzed and estimated ethanol yield (g g−1) was calculated based on hydrolyzable glucan and xylan levels. Analysis showed that there were no significant differences in total glucose or xylose levels nor in enzymatically hydrolyzable glucan and xylan concentrations between Bt corn stover and the non-Bt stover isolines. Regression analyses between corn grain yield (Mg ha−1) and corn stover ethanol yield (g g−1) showed an inverse relationship indicative of a photosynthate source-sink relationship. Nevertheless, the quantity of stover produced was found to be more critical than the quality of stover produced in maximizing potential stover ethanol yield on a land area basis.