Manure management is an essential component of dairy production. Nutrient-laden, field-applied dairy manure often serves as a fertilizer source, but can also pose environmental threats if not properly managed. The Haa...Manure management is an essential component of dairy production. Nutrient-laden, field-applied dairy manure often serves as a fertilizer source, but can also pose environmental threats if not properly managed. The Haak dairy farm, located in Decatur, Arkansas, was granted a permit by the Arkansas Department of Environmental Quality (ADEQ) to employ a unique method in treating and storing cattle manure generated during the milking process. This method includes minimizing water use in wash water, dry scraping solids to combine with sawdust for composting and pumping effluent underground into a sloped concrete basin that serves as secondary solid separator before transporting the manure effluent into an interception trench and an adjacent grassed field to facilitate manure nutrient uptake and retention. The Arkansas Discovery Farm program (ADF) is conducting research to evaluate the environmental performance of the dairy’s milk center wash water treatment system (MCWW) by statistical analysis, characterization of phosphorus (P) migration in soil downslope from the inception trench, temperature measurements, and nutrient analysis of a stored dry stack manure/sawdust mixture. Goals included determining possible composting effectiveness along with comparisons to untreated dairy manure and quantifying the use of on-farm water. Results from this research demonstrated that: 1) The MCWW was effective at retaining manure-derived nutrients and reducing field nutrient migration as the MCWW interception trench had significantly higher total nitrogen (TN) (804.2 to 4.1), total phosphorus (TP) (135.6 to 1.5), and water extractable phosphorus (WEP) (55.0 to 1.0) concentrations in milligrams per liter (mg⋅L<sup>-1</sup>) than the downhill freshwater pond respectively;2) temperature readings of the manure dry stack indicated heightened levels of microbial and thermal activity, but did not reach a standard composting temperature of 54°C;3) manure dry stack nutrient content was typically higher than untreated dairy manure when measured on a “dry basis” in ppm, but was lower on an “as is basis” in ppm and kg/metric ton;and 4) water meter readings showed that the greatest use of on-farm water was for farm-wide cattle drinking (18.77), followed by water used in the milking center (3.45) and then followed by human usage (0.02) measured in cubic meters per day (m<sup>3</sup>⋅d<sup>-1</sup>). These results demonstrate that practical innovations in agricultural engineering and environmental science, such as the Haak dairy’s manure treatment system, can effectively reduce environmental hazards that accompany the management of manure at this dairy operation.展开更多
Cool, wet conditions in the southern US during the maturing stages of rice in 1998 contributed to outbreaks of false smut caused by Ustilaginoidea virens. Water extracts of false smut galls in Asia have been reported ...Cool, wet conditions in the southern US during the maturing stages of rice in 1998 contributed to outbreaks of false smut caused by Ustilaginoidea virens. Water extracts of false smut galls in Asia have been reported to contain ustiloxin toxins, cyclic peptide antibiotics that interfered with microtubule function and caused “lupinosis”-like lesions in mice. Cell-free extracts from false smut galls on rice grown in Arkansas were fractionated by a published procedure for the purification of ustiloxins. The ustiloxin fraction was phytotoxic to Lemnapausicostata (duckweed) at ≥19 μg/ml, but the host plant, rice, was much less susceptible, exhibiting phytotoxic effects in germinating seeds at ≥1000 μg/ml. The aqueous extract of rice false smut galls showed no cytotoxicity to mammalian cell cultures at 200 μg/ml, but the ustiloxin fractionwas cytotoxic at 10 - 100 μg/ml. However, rice false smut galls were not toxic when fed to mice at 10% of chow, but caused feed refusal at higher concentrations. We conclude that for 1) the U. virens which causes false smut in southern USA differs from Asian isolates in that does not produce detectable ustiloxins;and 2) false smut affects the appearance, but not the food safety of rice in the United States.展开更多
Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people wh...Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people who are allergic to soybean protein. The aim of this research was to assess the variability of the total seed protein content in cowpea. Eleven Arkansas breeding lines were used in this study. Field experiment design was a randomized complete block design (RCBD) with 2 blocks, and conducted in three different locations within Arkansas State (Fayetteville, Alma, and Hope) in 2015. A standard chemical protocol was performed involving an analysis of the total nitrogen by combustion using an Elementar Rapid N III instrument to estimate the protein content. The average protein content was 25.4%, and ranged from 23.7% to 27.4% with a standard deviation of 1.9%. The significant effects of genotype, environment (location), and genotype by environment were observed for the total seed protein content in cowpea. The broad sense heritability (H<sup>2</sup>) for cowpea seed protein was estimated to be 57.8% based on the eleven cowpea genotypes studied. The cowpea lines, “Early Scarlet” and 09-204 had the highest seed protein content with 27.4% and 26.9% dried seed weight, respectively. This study provides valuable information on cowpea protein content for breeders to select and utilize those breeding lines with high seed protein content to develop new high protein cowpea cultivars.展开更多
Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural land.Since the 1990s,agricultural research has been conducted using remote sensing technologies;however...Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural land.Since the 1990s,agricultural research has been conducted using remote sensing technologies;however,few previous reviews have been conducted focused on different conservation management practices.Most of the previous literature has focused on the application of remote sensing in agriculture without focusing exclusively on conservation practices,with some only providing a narrative review,others using biophysical remote sensing for quantitative estimates of the bio-geo-chemical-physical properties of soils and crops,and few others focused on single agricultural management practices.This paper used the preferred reporting items for systematic review(PRISMA)methodology to examine the last 30 years of thematic research,development,and trends associated with remote sensing technologies and methods applied to conservation agriculture research at various spatial and temporal scales.A set of predefined key concepts and keywords were applied in three databases:Scopus,Web of Science,and Google Scholar.A total of 188 articles were compiled for initial examination,where 68 articles were selected for final analysis and grouped into cover crops,crop residue,crop rotation,mulching,and tillage practices.Publications on conservation agriculture research using remote sensing have been increasing since 1991 and peaked at 10 publications in 2020.Among the 68 articles,94%used a pixel-based,while only 6%used an object-based classification method.Prior to 2005,tillage practices were abundantly studied,then crop residue was a focused theme between 2004 and 2012.From 2012 to 2020,the focus shifted again to cover crops.Ten spectral indices were used in 76%of the 68 studies.This examination offered a summary of the new potential and identifies crucial future research needs and directions that could improve the contribution of remote sensing to the provision of long-term operational services for various conservation agriculture applications.展开更多
The modern trend of increasing the number of pigs at production sites led to a noticeable surplus of manure. Separation of manure solids provides an avenue of their utility via thermochemical conversion techniques. Th...The modern trend of increasing the number of pigs at production sites led to a noticeable surplus of manure. Separation of manure solids provides an avenue of their utility via thermochemical conversion techniques. Therefore, the goal of this paper was to assess the physical and thermal properties of solid separated swine manure obtained from two different farms, i.e., farrowing, and growing-finishing, and to determine their pyrolysis kinetic parameters. Swine manure solids were dried and milled prior to assessing their properties. Differential and integral isoconversional methods (Friedman, and Flynn-Wall-Ozawa) were used to determine the apparent activation energy as a function of the conversion ratio. Significant differences were observed in the proximate, ultimate composition between both manure types. The higher heating value (HHV) for the manure solids from farrowing, and growing-finishing farms reached 16.6 MJ/kg and 19.4 MJ/kg, respectively. The apparent activation energy computed using Friedman and FWO methods increased with the increase in the degree of conversion. Between 10% and 40% degrees of conversion, the average activation energies, using Friedman method, were103 and 116 kJ/mol for the farrowing and growing-finishing manure solids, respectively. On the other hand, the same activation energies, calculated from FWO method, were 98 and 104 kJ/mol, for solid manure obtained from farrowing and growing-finishing farms, respectively. The findings in this study will assist in the effort to optimize thermochemical conversion processes to accommodate swine waste. This could, in turn, minimize swine production impacts on the surrounding ecologies and provide sustainable energy and biochar streams.展开更多
The KNOX gene family codes for transcriptional regulators with a variety of functions in plant developmental and physiological processes. In this study, a genome-wide comparative analysis of KNOX genes in Poplar (Popu...The KNOX gene family codes for transcriptional regulators with a variety of functions in plant developmental and physiological processes. In this study, a genome-wide comparative analysis of KNOX genes in Poplar (Populustrichocarpa) and rice (Oryza sativa L. ssp. japonica) was carried out. With comprehensive computational analyses, which take into account the gene structures, phylogeny and conserved motifs, 15 and 13 KNOX genes in Poplar and rice were identified, respectively. These KNOX genes were further divided into 3 groups. The Poplar gene POPTR_0012s04040 and the rice genes LOC_Os03g47042 and LOC_Os03g47022 were classified to a new group of KNOX genes without ahomeobox domain together with KNATM, which were proposed to play potential role in plant development and pluripotency. The identification of KNATM homolog in monocotyledons (rice) provided a strong support for proposing an ancient shuffling of HOMEOBOX gene with MEINOX gene took place in the KNOX phylogeny. Using subcellular location information, GO (gene ontology) and expression profile analysis, KNOX genes in rice and poplar were proposed to function similarly to the members in Arabidopsis. Our observations may lay the foundation for future functional analysis of KNOX genes in rice and poplar to unravel their biological roles in cellular pluripotency.展开更多
Biomass gasification is a well-developed technology with the potential to convert agricultural residues to value-added products. The availability of on-farm gasifiers that can handle low-density agricultural wastes su...Biomass gasification is a well-developed technology with the potential to convert agricultural residues to value-added products. The availability of on-farm gasifiers that can handle low-density agricultural wastes such as soybean residue, an underutilized feedstock, is limited. Therefore, the goal of this research was to install and assess an allothermal, externally heated, auger gasifier capable of converting agricultural wastes to combustible gas for on-farm grain drying. The system was used to convert soybean residues under different reactor temperature, i.e., 700°C, 750°C, 800°C, and 850°C. The results showed that increasing the reactor temperature from 700°C to 850°C increased the producer gas molar fractions of H2, CO, and CH4, from 1.1% to 1.5%, from 15.0% to 23.8%, and from 5.1% to 7.7%, respectively. The higher heating value of the producer gas reached 6.3 MJ/m3 at reactor temperature of 850°C. Specific gas yield increased from 0.32 to 0.58 m3/kgbiomass while char and particulate yield decreased from 41.7% to 33.6% by increasing the reactor temperature from 700°C to 850°C. Maximum carbon sequestration achieved, in the form of biochar-carbon, was 32% of the raw feedstock carbon. Gasification of collectable soybean residues from 1 acre would be sufficient to dry 1132 kg of soybean seeds (the average yield from one acre)展开更多
The available literature revealed a gap in reporting the rough rice drying kinetics parameters under isothermal conditions, particularly for Arkansas medium- and long-grain varieties. Therefore, medium-grain (RO170112...The available literature revealed a gap in reporting the rough rice drying kinetics parameters under isothermal conditions, particularly for Arkansas medium- and long-grain varieties. Therefore, medium-grain (RO170112 and Titan) and the long-grain (Diamond and Wells) rough rice varieties were dried under isothermal conditions. The drying process occurred under 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C in a system emulating the thermogravimetric analyzer. Drying kinetics models were studied for four well-known models: Page, Newton, Logarithmic, and Henderson & Pabis. The drying kinetics constants were determined for the four studied models. The initial moisture content of rough rice was 28.2% db. Profound moisture reduction was observed during the first three hours of drying, followed by less moisture content reduction. The results showed that at the drying temperature of 100°C and after 6 hours of the drying process, the lowest moisture content reached 13.9% (db) for Titan rough rice. The drying rate of rough rice ranged between 7.41 and 2.01%/h during the first hour of drying under the studied temperature range of 40°C to 100°C. The drying rate was higher with the higher temperature levels during the first three hours. Among all the studied models, the Page, Newton, and Logarithmic models best fit 25%, 25%, and 50% of the twenty-eight studied cases. The challenge that arose from these results led to evolving a mathematical solution by joining the three models in one equation. The combined model showed the best fit for all the studied cases, with R<sup>2</sup> ranging between 0.9999 and 0.9954 for the medium- and long-grain rice varieties. Increasing the drying temperature increased the effective moisture diffusivity values. The highest effective moisture diffusivity of 18.104 × 10<sup>-9</sup> m<sup>2</sup>/s was obtained at the drying temperature of 100°C for medium-grain rice, Titan. The activation energy values ranged between 17.77 and 24.48 kJ/mol for the four rough rice varieties.展开更多
As rice consumption increases,ensuring its safety has become a priority for the food industry.To address this concern,the industry is exploring a single-pass microbial inactivation treatment at the rough rice stage.In...As rice consumption increases,ensuring its safety has become a priority for the food industry.To address this concern,the industry is exploring a single-pass microbial inactivation treatment at the rough rice stage.In this study,a long-grain rice variety,RT7321[21.2%wet basis(WB)and a 20 mm bed thickness]was exposed to microwave radiation(915 MHz frequency)at powers of 16,18,and 20 kW for durations of 1,2,and 3 min.We found that the highest microwave power(20 kW)and the longest exposure duration(3 min)produced the greatest reduction in total aerobic count and total fungal count,reducing them by up to 1.21 and 5.01 log(CFU/g),respectively.Our findings provided insights into the used to high-power,shortduration 915 MHz microwave technology for decontamination purposes in rough rice to help improve the microbial safety of rice.The aim is to develop a single-pass drying approach for microbial inactivation in rice processing facilities while ensuring that the yield and quality is not compromised.展开更多
Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.)can increase soil Cu availability.Brazilian soils have high natural Cu and manganese(Mn)concentrations,increasing the po...Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.)can increase soil Cu availability.Brazilian soils have high natural Cu and manganese(Mn)concentrations,increasing the potential for toxicity to grapevine plants.Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution,especially for the soils grown with young plants.We evaluated the chemical speciation of Cu and Mn in soil solution and young grapevine growth using a contaminated soil with amendment application.Grapevine seedlings of Paulsen 1103rootstock were grown for 12 months on an old vineyard(>30 years of cultivation)soil without(control)and with vermicompost or limestone application.Grapevine dry matter,root morphological characteristics,and plant tissue Cu and Mn concentrations were evaluated.The cation and anion concentrations,dissolved organic carbon,p H,and chemical speciation of Cu and Mn in soil solution from different soil layers were analyzed.Vermicompost application did not reduce Cu and Mn phytotoxicity,and grapevine plants died after winter pruning.High soluble Mn concentration in soil(5.56 mg L-1in 0–45 cm soil layer)and Mn concentration in plant tissue at pruning(380.8 mg kg-1)might be the primary cause of plant death.Limestone application reduced Cu2+and Mn2+chemical species in soil solution,thereby increasing plant growth.The Cu2+and Mn2+species were negatively correlated(P<0.05)with grapevine shoot production at pruning(r=-0.92 and-0.97,respectively)and at the end of the trial(r=-0.73 and-0.51,respectively).Limestone application increased grapevine shoot and root dry matter production by 36%and 41%,respectively,while also presenting the highest root length and volume in the 5–10 cm soil layer.Limestone application is a viable and profitable alternative for reducing soil Cu and Mn availability and their phytotoxic effects.展开更多
Beneficial utilization of industrial byproducts such as papermill biosolids (PB) provides a unique opportunity to reduce the overall production cost and increase environmental sustainability. Pelletization of a byprod...Beneficial utilization of industrial byproducts such as papermill biosolids (PB) provides a unique opportunity to reduce the overall production cost and increase environmental sustainability. Pelletization of a byproduct enhances its marketability by improving the transportation and application. This greenhouse study was conducted to gain a better understanding of the properties and effects of, a recently developed pelletized papermill biosolids (PPB), on corn (Zea mays L.) and soil. Urea and PPB were each applied at four total N rates equivalent to 45, 90, 135, and 180 kg⋅ha−1 and an additional control treatments of 0 was also included. The PPB contained 379 and 14 g⋅kg−1 total N and C and its C:N ratio was 27. Nitrogen treatment significantly (P ⋅plant−1 where application of 180 kg⋅ha−1 of PPB-N produced the smallest plant biomass. Numerically the dry biomass of corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea was 38.3, 26.9 - 41.1 and 38.1 - 40.92 g⋅plant−1 respectively. Nitrogen concentration in corn plants ranged 6.2 - 11.5 g⋅kg−1. Nitrogen concentration in corn that did not receive any urea or corn that received urea was 8.7 - 11.5 g⋅kg−1 and was significantly more than corn treated with any PPB. Total N uptake (removed from soil) by the corn plant was 166 - 455 mg⋅plant−1. Total N uptake by corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea were 327, 166 - 278, and 379 - 455 mg⋅plant−1 respectively. The data suggest that the high C/N ratio (27.2) of PPB resulted in immobilization of PPB-N. Thus the next step will be to research the optimal rates of inorganic N that should be incorporated into this PPB to reduce its C:N to make it an effective high organic matter content N fertilizer. Nitrogen treatment significantly (P g⋅kg−1. The SOM of the treatments fertilized with 90 and 180 kg⋅ha−1 of PPB-N was 19.4 - 19.7 g⋅kg−1 and was significantly higher than soil that did not receive any N. The application of PPB significantly increased the soil total C which was 36.0 and 23.6 g⋅kg−1 in the soil amended with 180 kg⋅ha−1 of PPB-N and the control respectively. The observed increase in SOM and total C in PPB treated soil points to the potential soil health and C sequestration benefits of PPB provided that its C/N ratio can be increased by incorporating inorganic N into it.展开更多
The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity o...The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity on seedcotton yield and Mehlich-3 soil-test K concentrations. The cotton cultivars “Stoneville 4892” and “Stoneville 5599” represented long-season cultivars while “Paymaster 1218” and “Deltapine 444” represented early-season cultivars. The same K fertilizer treatments were applied to the same plots during the three years of the study. Higher order interactions of cropping year, cotton cultivar and K-fertilization rates were not significant (P ≥ 0.50), indicating the two cultivars of slightly different maturity respond similarly to K-fertilization. Cropping year and K-fertilizer application rates significantly affected seedcotton yield (P P ≤ 0.0074), as well as 3-year average, and total seedcotton yields (P ≤ 0.0006). Seedcotton yields ranged from 3418 to 4127 kg·ha-1 and 2980 to 3487 kg·ha-1 in the second and third year respectively while 3-year average and total seedcotton yields were 2943 to 3443 and 8832 to 10,330 kg·ha-1. The relation between annual, 3-year average, and total K application rates and seedcotton yield was linear (R2 ≥ 0.82, P ≤ 0.0125). Potassium fertilization significantly increased post-harvest (fall) Mehlich-3 extractable soil K in all three years (P ≤ 0.0002). This study indicated that, in a representative Mississippi River Delta silt loam soil, when Mehlich-3 extractable K was -1, K fertilization was needed to increase seedcotton yield and prevent soil K depletion. This supports the current University of Arkansas fertilizer recommendations for irrigated cotton production, where application of 56 kg of K ha-1 is recommended to optimize seedcotton yield and prevent soil K reserve depletion when Mehlich-3 extractable soil test K is medium (91 - 130 mg/kg).展开更多
Exploitative harvesting can lower stand quality in the short term and diminish forest productivity over the long term. In 2003, a rehabilitation experiment was installed in a southern hardwood stand on a bottomland te...Exploitative harvesting can lower stand quality in the short term and diminish forest productivity over the long term. In 2003, a rehabilitation experiment was installed in a southern hardwood stand on a bottomland terrace site, degraded by periodic exploitative cutting, to test the effectiveness of overstory removal and oak enrichment planting for improving stand quality and composition. Overstory removal treatments included clearcutting, stand improvement partial cutting, and an uncut control. Overstory treatment units were either planted with Nuttall oak (Quercus texana) seedlings or not planted. We revisited this study in 2017 to assess the outcome of oak enrichment planting across levels of overstory removal. Results in year 14 indicated poor survival of planted oaks under all overstory removal treatments (14% - 24%) and minimal height growth (0.3 m in 13 years) in areas treated with partial cutting and in uncut areas. Growth performance of planted oaks was significantly enhanced by clearcutting (p < 0.01). However, the overwhelming response of natural oak regeneration initiated by clearcutting trumped the contribution from enrichment planting on this low quality bottomland terrace site. Enrichment planting of Nuttall oak did not increase oak regeneration success in our study. The ineffectiveness of enrichment planting in this study was likely related to the shady understory of partially cut stands and intense competition in clearcuts. Additional treatments, such as pre-planting site preparation and post-planting release may be necessary for enhancing and maintaining competitiveness of planted red oak seedlings on similar sites.展开更多
文摘Manure management is an essential component of dairy production. Nutrient-laden, field-applied dairy manure often serves as a fertilizer source, but can also pose environmental threats if not properly managed. The Haak dairy farm, located in Decatur, Arkansas, was granted a permit by the Arkansas Department of Environmental Quality (ADEQ) to employ a unique method in treating and storing cattle manure generated during the milking process. This method includes minimizing water use in wash water, dry scraping solids to combine with sawdust for composting and pumping effluent underground into a sloped concrete basin that serves as secondary solid separator before transporting the manure effluent into an interception trench and an adjacent grassed field to facilitate manure nutrient uptake and retention. The Arkansas Discovery Farm program (ADF) is conducting research to evaluate the environmental performance of the dairy’s milk center wash water treatment system (MCWW) by statistical analysis, characterization of phosphorus (P) migration in soil downslope from the inception trench, temperature measurements, and nutrient analysis of a stored dry stack manure/sawdust mixture. Goals included determining possible composting effectiveness along with comparisons to untreated dairy manure and quantifying the use of on-farm water. Results from this research demonstrated that: 1) The MCWW was effective at retaining manure-derived nutrients and reducing field nutrient migration as the MCWW interception trench had significantly higher total nitrogen (TN) (804.2 to 4.1), total phosphorus (TP) (135.6 to 1.5), and water extractable phosphorus (WEP) (55.0 to 1.0) concentrations in milligrams per liter (mg⋅L<sup>-1</sup>) than the downhill freshwater pond respectively;2) temperature readings of the manure dry stack indicated heightened levels of microbial and thermal activity, but did not reach a standard composting temperature of 54°C;3) manure dry stack nutrient content was typically higher than untreated dairy manure when measured on a “dry basis” in ppm, but was lower on an “as is basis” in ppm and kg/metric ton;and 4) water meter readings showed that the greatest use of on-farm water was for farm-wide cattle drinking (18.77), followed by water used in the milking center (3.45) and then followed by human usage (0.02) measured in cubic meters per day (m<sup>3</sup>⋅d<sup>-1</sup>). These results demonstrate that practical innovations in agricultural engineering and environmental science, such as the Haak dairy’s manure treatment system, can effectively reduce environmental hazards that accompany the management of manure at this dairy operation.
文摘Cool, wet conditions in the southern US during the maturing stages of rice in 1998 contributed to outbreaks of false smut caused by Ustilaginoidea virens. Water extracts of false smut galls in Asia have been reported to contain ustiloxin toxins, cyclic peptide antibiotics that interfered with microtubule function and caused “lupinosis”-like lesions in mice. Cell-free extracts from false smut galls on rice grown in Arkansas were fractionated by a published procedure for the purification of ustiloxins. The ustiloxin fraction was phytotoxic to Lemnapausicostata (duckweed) at ≥19 μg/ml, but the host plant, rice, was much less susceptible, exhibiting phytotoxic effects in germinating seeds at ≥1000 μg/ml. The aqueous extract of rice false smut galls showed no cytotoxicity to mammalian cell cultures at 200 μg/ml, but the ustiloxin fractionwas cytotoxic at 10 - 100 μg/ml. However, rice false smut galls were not toxic when fed to mice at 10% of chow, but caused feed refusal at higher concentrations. We conclude that for 1) the U. virens which causes false smut in southern USA differs from Asian isolates in that does not produce detectable ustiloxins;and 2) false smut affects the appearance, but not the food safety of rice in the United States.
文摘Cowpea is cultivated on more than 11 million hectares with a worldwide production of 5.4 million tons of dried seeds. Cowpea is an affordable source of protein, which is used as an alternative to soybean for people who are allergic to soybean protein. The aim of this research was to assess the variability of the total seed protein content in cowpea. Eleven Arkansas breeding lines were used in this study. Field experiment design was a randomized complete block design (RCBD) with 2 blocks, and conducted in three different locations within Arkansas State (Fayetteville, Alma, and Hope) in 2015. A standard chemical protocol was performed involving an analysis of the total nitrogen by combustion using an Elementar Rapid N III instrument to estimate the protein content. The average protein content was 25.4%, and ranged from 23.7% to 27.4% with a standard deviation of 1.9%. The significant effects of genotype, environment (location), and genotype by environment were observed for the total seed protein content in cowpea. The broad sense heritability (H<sup>2</sup>) for cowpea seed protein was estimated to be 57.8% based on the eleven cowpea genotypes studied. The cowpea lines, “Early Scarlet” and 09-204 had the highest seed protein content with 27.4% and 26.9% dried seed weight, respectively. This study provides valuable information on cowpea protein content for breeders to select and utilize those breeding lines with high seed protein content to develop new high protein cowpea cultivars.
基金This research is based upon funding supported by the Natural Resources Conservation Service(NRCS)-U.S.Department of Agriculture(USDA),under agreement number NR1871003XXXXC054.
文摘Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural land.Since the 1990s,agricultural research has been conducted using remote sensing technologies;however,few previous reviews have been conducted focused on different conservation management practices.Most of the previous literature has focused on the application of remote sensing in agriculture without focusing exclusively on conservation practices,with some only providing a narrative review,others using biophysical remote sensing for quantitative estimates of the bio-geo-chemical-physical properties of soils and crops,and few others focused on single agricultural management practices.This paper used the preferred reporting items for systematic review(PRISMA)methodology to examine the last 30 years of thematic research,development,and trends associated with remote sensing technologies and methods applied to conservation agriculture research at various spatial and temporal scales.A set of predefined key concepts and keywords were applied in three databases:Scopus,Web of Science,and Google Scholar.A total of 188 articles were compiled for initial examination,where 68 articles were selected for final analysis and grouped into cover crops,crop residue,crop rotation,mulching,and tillage practices.Publications on conservation agriculture research using remote sensing have been increasing since 1991 and peaked at 10 publications in 2020.Among the 68 articles,94%used a pixel-based,while only 6%used an object-based classification method.Prior to 2005,tillage practices were abundantly studied,then crop residue was a focused theme between 2004 and 2012.From 2012 to 2020,the focus shifted again to cover crops.Ten spectral indices were used in 76%of the 68 studies.This examination offered a summary of the new potential and identifies crucial future research needs and directions that could improve the contribution of remote sensing to the provision of long-term operational services for various conservation agriculture applications.
文摘The modern trend of increasing the number of pigs at production sites led to a noticeable surplus of manure. Separation of manure solids provides an avenue of their utility via thermochemical conversion techniques. Therefore, the goal of this paper was to assess the physical and thermal properties of solid separated swine manure obtained from two different farms, i.e., farrowing, and growing-finishing, and to determine their pyrolysis kinetic parameters. Swine manure solids were dried and milled prior to assessing their properties. Differential and integral isoconversional methods (Friedman, and Flynn-Wall-Ozawa) were used to determine the apparent activation energy as a function of the conversion ratio. Significant differences were observed in the proximate, ultimate composition between both manure types. The higher heating value (HHV) for the manure solids from farrowing, and growing-finishing farms reached 16.6 MJ/kg and 19.4 MJ/kg, respectively. The apparent activation energy computed using Friedman and FWO methods increased with the increase in the degree of conversion. Between 10% and 40% degrees of conversion, the average activation energies, using Friedman method, were103 and 116 kJ/mol for the farrowing and growing-finishing manure solids, respectively. On the other hand, the same activation energies, calculated from FWO method, were 98 and 104 kJ/mol, for solid manure obtained from farrowing and growing-finishing farms, respectively. The findings in this study will assist in the effort to optimize thermochemical conversion processes to accommodate swine waste. This could, in turn, minimize swine production impacts on the surrounding ecologies and provide sustainable energy and biochar streams.
文摘The KNOX gene family codes for transcriptional regulators with a variety of functions in plant developmental and physiological processes. In this study, a genome-wide comparative analysis of KNOX genes in Poplar (Populustrichocarpa) and rice (Oryza sativa L. ssp. japonica) was carried out. With comprehensive computational analyses, which take into account the gene structures, phylogeny and conserved motifs, 15 and 13 KNOX genes in Poplar and rice were identified, respectively. These KNOX genes were further divided into 3 groups. The Poplar gene POPTR_0012s04040 and the rice genes LOC_Os03g47042 and LOC_Os03g47022 were classified to a new group of KNOX genes without ahomeobox domain together with KNATM, which were proposed to play potential role in plant development and pluripotency. The identification of KNATM homolog in monocotyledons (rice) provided a strong support for proposing an ancient shuffling of HOMEOBOX gene with MEINOX gene took place in the KNOX phylogeny. Using subcellular location information, GO (gene ontology) and expression profile analysis, KNOX genes in rice and poplar were proposed to function similarly to the members in Arabidopsis. Our observations may lay the foundation for future functional analysis of KNOX genes in rice and poplar to unravel their biological roles in cellular pluripotency.
文摘Biomass gasification is a well-developed technology with the potential to convert agricultural residues to value-added products. The availability of on-farm gasifiers that can handle low-density agricultural wastes such as soybean residue, an underutilized feedstock, is limited. Therefore, the goal of this research was to install and assess an allothermal, externally heated, auger gasifier capable of converting agricultural wastes to combustible gas for on-farm grain drying. The system was used to convert soybean residues under different reactor temperature, i.e., 700°C, 750°C, 800°C, and 850°C. The results showed that increasing the reactor temperature from 700°C to 850°C increased the producer gas molar fractions of H2, CO, and CH4, from 1.1% to 1.5%, from 15.0% to 23.8%, and from 5.1% to 7.7%, respectively. The higher heating value of the producer gas reached 6.3 MJ/m3 at reactor temperature of 850°C. Specific gas yield increased from 0.32 to 0.58 m3/kgbiomass while char and particulate yield decreased from 41.7% to 33.6% by increasing the reactor temperature from 700°C to 850°C. Maximum carbon sequestration achieved, in the form of biochar-carbon, was 32% of the raw feedstock carbon. Gasification of collectable soybean residues from 1 acre would be sufficient to dry 1132 kg of soybean seeds (the average yield from one acre)
文摘The available literature revealed a gap in reporting the rough rice drying kinetics parameters under isothermal conditions, particularly for Arkansas medium- and long-grain varieties. Therefore, medium-grain (RO170112 and Titan) and the long-grain (Diamond and Wells) rough rice varieties were dried under isothermal conditions. The drying process occurred under 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C in a system emulating the thermogravimetric analyzer. Drying kinetics models were studied for four well-known models: Page, Newton, Logarithmic, and Henderson & Pabis. The drying kinetics constants were determined for the four studied models. The initial moisture content of rough rice was 28.2% db. Profound moisture reduction was observed during the first three hours of drying, followed by less moisture content reduction. The results showed that at the drying temperature of 100°C and after 6 hours of the drying process, the lowest moisture content reached 13.9% (db) for Titan rough rice. The drying rate of rough rice ranged between 7.41 and 2.01%/h during the first hour of drying under the studied temperature range of 40°C to 100°C. The drying rate was higher with the higher temperature levels during the first three hours. Among all the studied models, the Page, Newton, and Logarithmic models best fit 25%, 25%, and 50% of the twenty-eight studied cases. The challenge that arose from these results led to evolving a mathematical solution by joining the three models in one equation. The combined model showed the best fit for all the studied cases, with R<sup>2</sup> ranging between 0.9999 and 0.9954 for the medium- and long-grain rice varieties. Increasing the drying temperature increased the effective moisture diffusivity values. The highest effective moisture diffusivity of 18.104 × 10<sup>-9</sup> m<sup>2</sup>/s was obtained at the drying temperature of 100°C for medium-grain rice, Titan. The activation energy values ranged between 17.77 and 24.48 kJ/mol for the four rough rice varieties.
基金supported, in part, by the United States Department of Agriculture National Institute of Food and Agriculture Hatch Act Fundingthe University of Arkansas Grain and Rice Processing Program, USA
文摘As rice consumption increases,ensuring its safety has become a priority for the food industry.To address this concern,the industry is exploring a single-pass microbial inactivation treatment at the rough rice stage.In this study,a long-grain rice variety,RT7321[21.2%wet basis(WB)and a 20 mm bed thickness]was exposed to microwave radiation(915 MHz frequency)at powers of 16,18,and 20 kW for durations of 1,2,and 3 min.We found that the highest microwave power(20 kW)and the longest exposure duration(3 min)produced the greatest reduction in total aerobic count and total fungal count,reducing them by up to 1.21 and 5.01 log(CFU/g),respectively.Our findings provided insights into the used to high-power,shortduration 915 MHz microwave technology for decontamination purposes in rough rice to help improve the microbial safety of rice.The aim is to develop a single-pass drying approach for microbial inactivation in rice processing facilities while ensuring that the yield and quality is not compromised.
基金the Conselho Nacional de Desenvolvimento Científico e Tecnológico(Brazilian National Council for Scientific and Technological Development,e CNPq)(No.408318/2018)Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES,Brazilian Federal Agency for Support and Evaluation of Graduate Education)+1 种基金Fundacao de Amparo à Pesquisa do Estado do Rio Grande do Sul(Foundation for Research Support of the State of Rio Grande do Sul,Brazil)FAPERGS(No.17/2551-0000925-8)for the scholarships provided and the financial resources made available for this study。
文摘Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.)can increase soil Cu availability.Brazilian soils have high natural Cu and manganese(Mn)concentrations,increasing the potential for toxicity to grapevine plants.Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution,especially for the soils grown with young plants.We evaluated the chemical speciation of Cu and Mn in soil solution and young grapevine growth using a contaminated soil with amendment application.Grapevine seedlings of Paulsen 1103rootstock were grown for 12 months on an old vineyard(>30 years of cultivation)soil without(control)and with vermicompost or limestone application.Grapevine dry matter,root morphological characteristics,and plant tissue Cu and Mn concentrations were evaluated.The cation and anion concentrations,dissolved organic carbon,p H,and chemical speciation of Cu and Mn in soil solution from different soil layers were analyzed.Vermicompost application did not reduce Cu and Mn phytotoxicity,and grapevine plants died after winter pruning.High soluble Mn concentration in soil(5.56 mg L-1in 0–45 cm soil layer)and Mn concentration in plant tissue at pruning(380.8 mg kg-1)might be the primary cause of plant death.Limestone application reduced Cu2+and Mn2+chemical species in soil solution,thereby increasing plant growth.The Cu2+and Mn2+species were negatively correlated(P<0.05)with grapevine shoot production at pruning(r=-0.92 and-0.97,respectively)and at the end of the trial(r=-0.73 and-0.51,respectively).Limestone application increased grapevine shoot and root dry matter production by 36%and 41%,respectively,while also presenting the highest root length and volume in the 5–10 cm soil layer.Limestone application is a viable and profitable alternative for reducing soil Cu and Mn availability and their phytotoxic effects.
基金supported by USDA-ARS National Program NP301 project "Response of Diverse Rice Germplasm to Biotic and Abiotic Stresses Project No. 6225-21000-008-00D"
文摘Beneficial utilization of industrial byproducts such as papermill biosolids (PB) provides a unique opportunity to reduce the overall production cost and increase environmental sustainability. Pelletization of a byproduct enhances its marketability by improving the transportation and application. This greenhouse study was conducted to gain a better understanding of the properties and effects of, a recently developed pelletized papermill biosolids (PPB), on corn (Zea mays L.) and soil. Urea and PPB were each applied at four total N rates equivalent to 45, 90, 135, and 180 kg⋅ha−1 and an additional control treatments of 0 was also included. The PPB contained 379 and 14 g⋅kg−1 total N and C and its C:N ratio was 27. Nitrogen treatment significantly (P ⋅plant−1 where application of 180 kg⋅ha−1 of PPB-N produced the smallest plant biomass. Numerically the dry biomass of corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea was 38.3, 26.9 - 41.1 and 38.1 - 40.92 g⋅plant−1 respectively. Nitrogen concentration in corn plants ranged 6.2 - 11.5 g⋅kg−1. Nitrogen concentration in corn that did not receive any urea or corn that received urea was 8.7 - 11.5 g⋅kg−1 and was significantly more than corn treated with any PPB. Total N uptake (removed from soil) by the corn plant was 166 - 455 mg⋅plant−1. Total N uptake by corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea were 327, 166 - 278, and 379 - 455 mg⋅plant−1 respectively. The data suggest that the high C/N ratio (27.2) of PPB resulted in immobilization of PPB-N. Thus the next step will be to research the optimal rates of inorganic N that should be incorporated into this PPB to reduce its C:N to make it an effective high organic matter content N fertilizer. Nitrogen treatment significantly (P g⋅kg−1. The SOM of the treatments fertilized with 90 and 180 kg⋅ha−1 of PPB-N was 19.4 - 19.7 g⋅kg−1 and was significantly higher than soil that did not receive any N. The application of PPB significantly increased the soil total C which was 36.0 and 23.6 g⋅kg−1 in the soil amended with 180 kg⋅ha−1 of PPB-N and the control respectively. The observed increase in SOM and total C in PPB treated soil points to the potential soil health and C sequestration benefits of PPB provided that its C/N ratio can be increased by incorporating inorganic N into it.
文摘The objective of this study was to evaluate the effect of potassium (K) fertilization rate (0, 27.9, 56.4, 84.7, 112.9, and 141.1 kg K/ha) and cotton (Gossypium hirsutumn L.) cultivars of slightly differing maturity on seedcotton yield and Mehlich-3 soil-test K concentrations. The cotton cultivars “Stoneville 4892” and “Stoneville 5599” represented long-season cultivars while “Paymaster 1218” and “Deltapine 444” represented early-season cultivars. The same K fertilizer treatments were applied to the same plots during the three years of the study. Higher order interactions of cropping year, cotton cultivar and K-fertilization rates were not significant (P ≥ 0.50), indicating the two cultivars of slightly different maturity respond similarly to K-fertilization. Cropping year and K-fertilizer application rates significantly affected seedcotton yield (P P ≤ 0.0074), as well as 3-year average, and total seedcotton yields (P ≤ 0.0006). Seedcotton yields ranged from 3418 to 4127 kg·ha-1 and 2980 to 3487 kg·ha-1 in the second and third year respectively while 3-year average and total seedcotton yields were 2943 to 3443 and 8832 to 10,330 kg·ha-1. The relation between annual, 3-year average, and total K application rates and seedcotton yield was linear (R2 ≥ 0.82, P ≤ 0.0125). Potassium fertilization significantly increased post-harvest (fall) Mehlich-3 extractable soil K in all three years (P ≤ 0.0002). This study indicated that, in a representative Mississippi River Delta silt loam soil, when Mehlich-3 extractable K was -1, K fertilization was needed to increase seedcotton yield and prevent soil K depletion. This supports the current University of Arkansas fertilizer recommendations for irrigated cotton production, where application of 56 kg of K ha-1 is recommended to optimize seedcotton yield and prevent soil K reserve depletion when Mehlich-3 extractable soil test K is medium (91 - 130 mg/kg).
文摘Exploitative harvesting can lower stand quality in the short term and diminish forest productivity over the long term. In 2003, a rehabilitation experiment was installed in a southern hardwood stand on a bottomland terrace site, degraded by periodic exploitative cutting, to test the effectiveness of overstory removal and oak enrichment planting for improving stand quality and composition. Overstory removal treatments included clearcutting, stand improvement partial cutting, and an uncut control. Overstory treatment units were either planted with Nuttall oak (Quercus texana) seedlings or not planted. We revisited this study in 2017 to assess the outcome of oak enrichment planting across levels of overstory removal. Results in year 14 indicated poor survival of planted oaks under all overstory removal treatments (14% - 24%) and minimal height growth (0.3 m in 13 years) in areas treated with partial cutting and in uncut areas. Growth performance of planted oaks was significantly enhanced by clearcutting (p < 0.01). However, the overwhelming response of natural oak regeneration initiated by clearcutting trumped the contribution from enrichment planting on this low quality bottomland terrace site. Enrichment planting of Nuttall oak did not increase oak regeneration success in our study. The ineffectiveness of enrichment planting in this study was likely related to the shady understory of partially cut stands and intense competition in clearcuts. Additional treatments, such as pre-planting site preparation and post-planting release may be necessary for enhancing and maintaining competitiveness of planted red oak seedlings on similar sites.