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Optimizing nitrogen (N) fertilization is critical to ensure high-yield and high-quality wheat (Triticum aestivum L.) production while minimizing its environmental footprint and production costs. A two-yr field trial was conducted in a dryland research farm in Montana with a clay loam soil to evaluate the response of spring bread wheat (cv. Velva) and durum (Triticum durum Defs cv. Joppa) to N rate (45 vs. 90 kg ha−1), N source (urea vs. SuperU®), and application method (broadcast vs. banding). Compared to broadcast application, fertilizer banding reduced plant density by 6% without affecting the final grain yield. Nitrogen rate had a significant effect on grain yield. Neither nitrogen source nor application method affected grain yield when N was applied at 90 kg N ha−1. Grain yield increased from 3171 to 3652 kg ha−1 with increasing N rate from 45 to 90 kg ha−1 in the year with ample rainfall, whereas yield remained unchanged in the drier year. Protein concentration was higher in broadcasting treatment compared to banding at 90 kg N ha−1. However, at 45 kg N ha−1, protein concentration in the grain was not affected by method of application. The source of fertilizer did not show a significant effect on grain protein concentration. Our data indicated no agronomic benefit in using SuperU compared to conventional urea or banding fertilizer vs. broadcasting in this dryland system.
Reza Keshavarz Afshar; Chengci Chen; Huaqin He; Tian Tian; Amir Sadeghpour. Evaluation of nitrogen fertilizer source and application method for dryland wheat. Journal of Plant Nutrition 2021, 44, 1930 -1941.
AMA StyleReza Keshavarz Afshar, Chengci Chen, Huaqin He, Tian Tian, Amir Sadeghpour. Evaluation of nitrogen fertilizer source and application method for dryland wheat. Journal of Plant Nutrition. 2021; 44 (13):1930-1941.
Chicago/Turabian StyleReza Keshavarz Afshar; Chengci Chen; Huaqin He; Tian Tian; Amir Sadeghpour. 2021. "Evaluation of nitrogen fertilizer source and application method for dryland wheat." Journal of Plant Nutrition 44, no. 13: 1930-1941.
BACKGROUND Understanding the relationship between physiological traits with yield and yield components is an essential step toward developing high‐yielding and high‐quality canola (Brassica napus L.) cultivars. This study aimed to explore further the relationship between some physiological features, including RUE, and seed yield in canola. RESULTS Significant differences were found among cultivars regarding maximum leaf area index (LAImax) and required days to achieve maximum LAI (DLAImax). All cultivars obtained the minimum LAI required to intercept 90% of the incident radiation, but at different times. Some cultivars like SW102 and Shirali had the same Fi when LAI was maximal, but SW102 had higher IPAR. This indicated that SW102 was more efficient in irradiation capacity and may have a higher photosynthesis rate when exposed to the high irradiation conditions. The average canola RUE in the current study was 3.80 and 3.63 g MJ‐1 m‐2 in 2014 and 2015, respectively. In general, the crop growth rate was higher in the first year than in the second year due to the fewer cloudy days and more incident radiation. CONCLUSION Results indicated that Duration of growth, crop growth rate (CGR), and harvest index (HI) were crucial for enhancing biomass and seed yield. Also, a relatively high correlation was found between the RUE and DLAImax. The cultivars that reached their maximum leaf area index later demonstrated higher RUE, consequently had higher biological and seed yield. The results obtained can be used to develop an improved canola crop growth model and breeding programs.
Abbas Biabani; Abbas Foroughi; Alli Rahemi Karizaki; Ghorban Ali Rassam; Masoud Hashemi; Reza Keshavarz Afshar. Physiological traits, yield, and yield components relationship in winter and spring canola. Journal of the Science of Food and Agriculture 2021, 101, 3518 -3528.
AMA StyleAbbas Biabani, Abbas Foroughi, Alli Rahemi Karizaki, Ghorban Ali Rassam, Masoud Hashemi, Reza Keshavarz Afshar. Physiological traits, yield, and yield components relationship in winter and spring canola. Journal of the Science of Food and Agriculture. 2021; 101 (8):3518-3528.
Chicago/Turabian StyleAbbas Biabani; Abbas Foroughi; Alli Rahemi Karizaki; Ghorban Ali Rassam; Masoud Hashemi; Reza Keshavarz Afshar. 2021. "Physiological traits, yield, and yield components relationship in winter and spring canola." Journal of the Science of Food and Agriculture 101, no. 8: 3518-3528.
Corn (Zea mays L.) grain is a major commodity crop in Illinois and its production largely relies on timely application of nitrogen (N) fertilizers. Currently, growers in Illinois and other neighboring states in the U.S. Midwest use the maximum return to N (MRTN) decision support system to predict corn N requirements. However, the current tool does not factor in implications of integrating cover crops into the rotation, which has recently gained attention among growers due to several ecosystem services associated with cover cropping. A two-year field trail was conducted at the Agronomy Research Center in Carbondale, IL in 2018 and 2019 to evaluate whether split N application affects nitrogen use efficiency (NUE) of corn with and without a wheat (Triticum aestivum L.) cover crop. A randomized complete block design with split plot arrangements and four replicates was used. Main plots were cover crop treatments (no cover crop (control) compared to a wheat cover crop) and subplots were N timing applications to the corn: (1) 168 kg N ha−1 at planting; (2) 56 kg N ha−1 at planting + 112 kg N ha−1 at sidedress; (3) 112 kg N ha−1 at planting + 56 kg N ha−1 at sidedress; and (4) 168 kg N ha−1 at sidedress along with a zero-N control as check plot. Corn yield was higher in 2018 than 2019 reflecting more timely precipitation in that year. In 2018, grain yield declined by 12.6% following the wheat cover crop compared to no cover crop control, indicating a yield penalty when corn was preceded with a wheat cover crop. In 2018, a year with timely and sufficient rainfall, there were no yield differences among N treatments and N balances were near zero. In 2019, delaying the N application improved NUE and corn grain yield due to excessive rainfall early in the season reflecting on N losses which was confirmed by lower N balances in sidedressed treatments. Overall, our findings suggest including N credit for cereals in MRTN prediction model could help with improved N management in the Midwestern United States.
Oladapo Adeyemi; Reza Keshavarz-Afshar; Emad Jahanzad; Martin Leonardo Battaglia; Yuan Luo; Amir Sadeghpour. Effect of Wheat Cover Crop and Split Nitrogen Application on Corn Yield and Nitrogen Use Efficiency. Agronomy 2020, 10, 1081 .
AMA StyleOladapo Adeyemi, Reza Keshavarz-Afshar, Emad Jahanzad, Martin Leonardo Battaglia, Yuan Luo, Amir Sadeghpour. Effect of Wheat Cover Crop and Split Nitrogen Application on Corn Yield and Nitrogen Use Efficiency. Agronomy. 2020; 10 (8):1081.
Chicago/Turabian StyleOladapo Adeyemi; Reza Keshavarz-Afshar; Emad Jahanzad; Martin Leonardo Battaglia; Yuan Luo; Amir Sadeghpour. 2020. "Effect of Wheat Cover Crop and Split Nitrogen Application on Corn Yield and Nitrogen Use Efficiency." Agronomy 10, no. 8: 1081.
Zinc (Zn) deficiency is a common micronutrient deficiency in human population, especially in regions where grain cereals are the primary supply of daily calorie intake. Zinc also performs an important role in plant growth and its deficiency limits crop yield and quality. A 3‐yr field study was conducted to determine response of wheat cultivars to foliar application of Zn. Zinc sulfate was sprayed on plant canopy at a rate of 1.12 kg Zn ha−1 once (at heading) or twice (at heading and flowering). One application of Zn at heading increased grain Zn concentration by a range of 5.8 to 9.5 mg kg−1 corresponding to 17‐ 47% increase over the unfertilized control in various years. With the application of Zn at both heading and flowering grain Zn concentration reached 44.3 and 52.4 mg kg−1 (in year 2 and 3), implying an increase of 35‐ 93% compared to the untreated control. The second application of Zn at flowering was necessary to produce grains with Zn concentration above the target level of 40 mg kg−1 to have a nutritional impact. Zinc application also marginally increased grain yield. This yield increase, however, was not adequate to offset additional production costs associated with Zn fertilization. The economic analysis revealed that the net return from the first and second Zn application was ‐1 and +13 USD ha−1, respectively. Therefore, it is unlikely that farmers will be motivated to adopt this system unless a price incentive or government payments are provided for farmers for producing Zn‐enriched grains. This article is protected by copyright. All rights reserved
Reza Keshavarz Afshar; Chengci Chen; Shuang Zhou; Fatemeh Etemadi; Huaqin He; Zhaowei Li. Agronomic and economic response of bread wheat to foliar zinc application. Agronomy Journal 2020, 112, 4045 -4056.
AMA StyleReza Keshavarz Afshar, Chengci Chen, Shuang Zhou, Fatemeh Etemadi, Huaqin He, Zhaowei Li. Agronomic and economic response of bread wheat to foliar zinc application. Agronomy Journal. 2020; 112 (5):4045-4056.
Chicago/Turabian StyleReza Keshavarz Afshar; Chengci Chen; Shuang Zhou; Fatemeh Etemadi; Huaqin He; Zhaowei Li. 2020. "Agronomic and economic response of bread wheat to foliar zinc application." Agronomy Journal 112, no. 5: 4045-4056.
Chengci Chen; Reza Keshavarz Afshar; Yesuf Mohammed. Intensified Dryland Cropping Systems for Food and Biofuel Feedstock Production. The 4th World Congress on New Technologies 2018, 1 .
AMA StyleChengci Chen, Reza Keshavarz Afshar, Yesuf Mohammed. Intensified Dryland Cropping Systems for Food and Biofuel Feedstock Production. The 4th World Congress on New Technologies. 2018; ():1.
Chicago/Turabian StyleChengci Chen; Reza Keshavarz Afshar; Yesuf Mohammed. 2018. "Intensified Dryland Cropping Systems for Food and Biofuel Feedstock Production." The 4th World Congress on New Technologies , no. : 1.
Lack of crop rotation diversity and extensive tillage leaves the soil in many sugarbeet-based production systems vulnerable to wind erosion. Intercropping sugarbeet (Beta vulgaris L.) with a living mulch is a practice that aims to protect sugarbeet seedlings from blowing soil and provide ecosystem services such as enhancing soil organic matter, reducing sedimentation in surface-irrigated farms, and improving soil biological activity. If managed improperly, nevertheless, the living mulch can compete with sugarbeet and reduce its production. Selection of an appropriate crop species along with timely termination are the two critical points that need to be researched in order to minimize the impact of living mulch on sugarbeet performance while still offering ecosystem services. A 4-yr field experiment was conducted to evaluate the effect of living mulch and its termination time on sugarbeet population, root yield, and purity. Over four years of the study, living mulch terminated at sugarbeet V2 growth stage had no significant effect on sugarbeet yield and quality. However, when living mulch termination was delayed to V4 and V6 growth stages, root yield declined by 17 and 14 Mg ha−1, respectively, compared to 66.4 Mg ha−1 yield in the control. Living mulch had a positive impact on root quality traits by increasing sucrose concentration and decreasing root impurities (sodium, potassium, and amino-N concentration in the beet). The results indicated that planting sugarbeet with a living mulch can offer ecosystem services without negatively impacting sugarbeet productivity (recoverable sucrose yield) if terminated no later than V2 growth stage.
Reza Keshavarz Afshar; Chengci Chen; Joyce Eckhoff; Charles Flynn. Impact of a living mulch cover crop on sugarbeet establishment, root yield and sucrose purity. Field Crops Research 2018, 223, 150 -154.
AMA StyleReza Keshavarz Afshar, Chengci Chen, Joyce Eckhoff, Charles Flynn. Impact of a living mulch cover crop on sugarbeet establishment, root yield and sucrose purity. Field Crops Research. 2018; 223 ():150-154.
Chicago/Turabian StyleReza Keshavarz Afshar; Chengci Chen; Joyce Eckhoff; Charles Flynn. 2018. "Impact of a living mulch cover crop on sugarbeet establishment, root yield and sucrose purity." Field Crops Research 223, no. : 150-154.
Reza Keshavarz Afshar; Ruiyu Lin; Yesuf Assen Mohammed; Chengci Chen. Agronomic effects of urease and nitrification inhibitors on ammonia volatilization and nitrogen utilization in a dryland farming system: Field and laboratory investigation. Journal of Cleaner Production 2018, 172, 4130 -4139.
AMA StyleReza Keshavarz Afshar, Ruiyu Lin, Yesuf Assen Mohammed, Chengci Chen. Agronomic effects of urease and nitrification inhibitors on ammonia volatilization and nitrogen utilization in a dryland farming system: Field and laboratory investigation. Journal of Cleaner Production. 2018; 172 ():4130-4139.
Chicago/Turabian StyleReza Keshavarz Afshar; Ruiyu Lin; Yesuf Assen Mohammed; Chengci Chen. 2018. "Agronomic effects of urease and nitrification inhibitors on ammonia volatilization and nitrogen utilization in a dryland farming system: Field and laboratory investigation." Journal of Cleaner Production 172, no. : 4130-4139.
Pea (Pisum sativum L.) has long been an important component of the human diet, providing an excellent source of protein. In addition to its protein, pea starch, especially resistant starch (RS), has received an extensive attention in food industries in recent years. We evaluated nine pea cultivars varying in cotyledon color, grain weight, maturity group, and phenology planted at five locations with diverse climatic conditions across Montana in 2013 and 2014 to assess genetic and environmental factors affecting their yield, protein, RS, and total starch (TS). Grain yield varied from 982 to 5951 kg ha–1, RS content ranged from 5 to 53 g kg–1, and protein from 159 to 251 g kg–1. Statistical analysis showed that environment was the most important driving factor in grain yield, protein, and TS determination whereas RS content was mainly determined by cultivar. Drought at all phenological stages reduced pea yield and different cultivars tended to respond differently. Yield was positively correlated with protein, implying a potential to select/breed a cultivar with higher yield and protein. Protein was negatively correlated with TS, thus protein- or starch-type cultivars may be bred for different end users. Compared to other cultivars tested, DS Admiral was the most promising one with above average yield, protein, and RS. Copyright © 2017. . Copyright © 2017 by the American Society of Agronomy, Inc.
Aifen Tao; Reza Keshavarz Afshar; Jinwen Huang; Yesuf Assen Mohammed; Matthew Espe; Chengci Chen. Variation in Yield, Starch, and Protein of Dry Pea Grown Across Montana. Agronomy Journal 2017, 109, 1491 -1501.
AMA StyleAifen Tao, Reza Keshavarz Afshar, Jinwen Huang, Yesuf Assen Mohammed, Matthew Espe, Chengci Chen. Variation in Yield, Starch, and Protein of Dry Pea Grown Across Montana. Agronomy Journal. 2017; 109 (4):1491-1501.
Chicago/Turabian StyleAifen Tao; Reza Keshavarz Afshar; Jinwen Huang; Yesuf Assen Mohammed; Matthew Espe; Chengci Chen. 2017. "Variation in Yield, Starch, and Protein of Dry Pea Grown Across Montana." Agronomy Journal 109, no. 4: 1491-1501.
Chengci Chen; Reza Keshavarz Afshar. Conservation Tillage and Nitrogen Management for Sugarbeet Production. The 3rd World Congress on New Technologies 2017, 1 .
AMA StyleChengci Chen, Reza Keshavarz Afshar. Conservation Tillage and Nitrogen Management for Sugarbeet Production. The 3rd World Congress on New Technologies. 2017; ():1.
Chicago/Turabian StyleChengci Chen; Reza Keshavarz Afshar. 2017. "Conservation Tillage and Nitrogen Management for Sugarbeet Production." The 3rd World Congress on New Technologies , no. : 1.
Recent interest in renewable energy sources and the need to diversify cropping systems have triggered research interest in camelina ( L. Crantz). Camelina is well adapted to the temperate dryland climates and can be used as an energy crop. But information on agronomic evaluation of camelina cultivars for biodiesel feedstock are limited. The objective of this study was to evaluate six spring camelina cultivars (cv. Blaine Creek, Calena, Ligena, Pronghorn, Shoshone, and Suneson) on seed yield, oil concentration, and oil yield. The study was carried out from 2013 to 2015 at three locations (Havre, Moccasin, and Pendroy, MT). Over locations and years, mean seed yield differences among cultivars were significant ( < 0.05). The mean seed yield for cultivars ranging from 1295 kg ha (Suneson) to 1420 kg ha (Ligena). Ligena and Calena showed a combination of good seed yield performance and stability across environments. Environmental means for seed yield differences were substantial compared with cultivar means. The location Havre produced 45 and 32% more mean seed yield than Pendroy and Moccasin, respectively. There was no significant difference among cultivars in oil concentration and oil yield. The absence of variations in oil concentration and oil yield differences among these cultivars could indicate the need for further research to improve these qualities essential for biodiesel.
Yesuf Assen Mohammed; Chengci Chen; Peggy Lamb; Reza Keshavarz Afshar. Agronomic Evaluation of Camelina (Camelina sativa L. Crantz) Cultivars for Biodiesel Feedstock. BioEnergy Research 2017, 10, 792 -799.
AMA StyleYesuf Assen Mohammed, Chengci Chen, Peggy Lamb, Reza Keshavarz Afshar. Agronomic Evaluation of Camelina (Camelina sativa L. Crantz) Cultivars for Biodiesel Feedstock. BioEnergy Research. 2017; 10 (3):792-799.
Chicago/Turabian StyleYesuf Assen Mohammed; Chengci Chen; Peggy Lamb; Reza Keshavarz Afshar. 2017. "Agronomic Evaluation of Camelina (Camelina sativa L. Crantz) Cultivars for Biodiesel Feedstock." BioEnergy Research 10, no. 3: 792-799.
Uncertainties exist about the importance of rhizobia inoculant and starter nitrogen (N) application in dry pea (Pisum sativum L.) production. Three field experiments were conducted to evaluate how rhizobia inoculant and starter N fertilizer affect pea seed yield and protein concentration in a semi-arid environment in central Montana. Commercial rhizobia inoculant was mixed with seed prior to planting at the manufacturer’s recommended rate. Starter N fertilizers were applied into the same furrow as seed at 0, 22, 44 and 88 kg ha−1 as urea, slow-release polymer-coated N fertilizer (ESN), and a combination of both. The application of rhizobia inoculant had no or a very small beneficial effect on pea yield in lands with a previous history of peas. In a land without pea history, application of rhizobia increased pea seed yield by 16%. The positive effect of starter N was only pronounced when initial soil N was low (≤ 10 kg ha−1 nitrate-nitrogen), which increased net return by up to US$ 42 ha−1. In this condition, application of slow-release N outperformed urea. However, application of starter N (especially with urea) had a negative effect on pea establishment, vigor and seed yield when soil initial N was high (≥ 44 kg ha−1 NO3-N). The results indicate that the rate, placement and form of the starter N must be optimized to benefit pea yield and protein without detrimental effects on germination and nodulation. Moreover, application of starter N must be guided by the soil nitrate content.
Jinwen Huang; Reza Keshavarz Afshar; Aifen Tao; Chengci Chen. Efficacy of starter N fertilizer and rhizobia inoculant in dry pea (Pisum sativum Linn.) production in a semi-arid temperate environment. Soil Science and Plant Nutrition 2017, 1 -6.
AMA StyleJinwen Huang, Reza Keshavarz Afshar, Aifen Tao, Chengci Chen. Efficacy of starter N fertilizer and rhizobia inoculant in dry pea (Pisum sativum Linn.) production in a semi-arid temperate environment. Soil Science and Plant Nutrition. 2017; ():1-6.
Chicago/Turabian StyleJinwen Huang; Reza Keshavarz Afshar; Aifen Tao; Chengci Chen. 2017. "Efficacy of starter N fertilizer and rhizobia inoculant in dry pea (Pisum sativum Linn.) production in a semi-arid temperate environment." Soil Science and Plant Nutrition , no. : 1-6.
Genetic mapping and quantitative trait locus (QTL) detection are powerful methodologies in plant improvement and breeding. White jute (Corchorus capsularis L.) is an important industrial raw material fiber crop because of its elite characteristics. However, construction of a high-density genetic map and identification of QTLs has been limited in white jute due to a lack of sufficient molecular markers. The specific locus amplified fragment sequencing (SLAF-seq) strategy combines locus-specific amplification and high-throughput sequencing to carry out de novo single nuclear polymorphism (SNP) discovery and large-scale genotyping. In this study, SLAF-seq was employed to obtain sufficient markers to construct a high-density genetic map for white jute. Moreover, with the development of abundant markers, genetic dissection of fiber yield traits such as plant height was also possible. Here, we present QTLs associated with plant height that were identified using our newly constructed genetic linkage groups. An F8 population consisting of 100 lines was developed. In total, 69,446 high-quality SLAFs were detected of which 5,074 SLAFs were polymorphic; 913 polymorphic markers were used for the construction of a genetic map. The average coverage for each SLAF marker was 43-fold in the parents, and 9.8-fold in each F8 individual. A linkage map was constructed that contained 913 SLAFs on 11 linkage groups (LGs) covering 1621.4 cM with an average density of 1.61 cM per locus. Among the 11 LGs, LG1 was the largest with 210 markers, a length of 406.34 cM, and an average distance of 1.93 cM between adjacent markers. LG11 was the smallest with only 25 markers, a length of 29.66 cM, and an average distance of 1.19 cM between adjacent markers. 'SNP_only' markers accounted for 85.54% and were the predominant markers on the map. QTL mapping based on the F8 phenotypes detected 11 plant height QTLs including one major effect QTL across two cultivation locations, with each QTL accounting for 4.14-15.63% of the phenotypic variance. To our knowledge, the linkage map constructed here is the densest one available to date for white jute. This analysis also identified the first QTL in white jute. The results will provide an important platform for gene/QTL mapping, sequence assembly, genome comparisons, and marker-assisted selection breeding for white jute.
Aifen Tao; Long Huang; Guifen Wu; Reza Keshavarz Afshar; Jianmin Qi; Jiantang Xu; Pingping Fang; Lihui Lin; Liwu Zhang; Peiqing Lin. High-density genetic map construction and QTLs identification for plant height in white jute (Corchorus capsularis L.) using specific locus amplified fragment (SLAF) sequencing. BMC Genomics 2017, 18, 355 .
AMA StyleAifen Tao, Long Huang, Guifen Wu, Reza Keshavarz Afshar, Jianmin Qi, Jiantang Xu, Pingping Fang, Lihui Lin, Liwu Zhang, Peiqing Lin. High-density genetic map construction and QTLs identification for plant height in white jute (Corchorus capsularis L.) using specific locus amplified fragment (SLAF) sequencing. BMC Genomics. 2017; 18 (1):355.
Chicago/Turabian StyleAifen Tao; Long Huang; Guifen Wu; Reza Keshavarz Afshar; Jianmin Qi; Jiantang Xu; Pingping Fang; Lihui Lin; Liwu Zhang; Peiqing Lin. 2017. "High-density genetic map construction and QTLs identification for plant height in white jute (Corchorus capsularis L.) using specific locus amplified fragment (SLAF) sequencing." BMC Genomics 18, no. 1: 355.
Camelina (Camelina sativa L. Crantz) shows potential to provide an alternative renewable energy source and enhance crop diversification in temperate semiarid regions. Information on the effect of N, P, K, and S on yield and quality of camelina for biodiesel feedstock in the northern Great Plains (NGP) of the United States is limited. The objective of this experiment was to determine the effects of the above nutrients on seed and oil yields, test weight, oil concentration and agronomic nitrogen use efficiency (ANUE) of camelina on a clay loam soil in central Montana. Results showed that fertilizer treatments significantly affected seed yield, oil concentration and oil yield of camelina. The seed and oil yields ranged from 677 to 1306 kg ha–1 and from 234 to 445 kg ha–1, respectively. Although the highest seed and oil yields were obtained from the application of 134–22–22–28 kg ha–1 N–P2O5–K2O–S, they were statistically in the same group with yields achieved from the application of only 45 kg ha–1 N. Application of P and S fertilizers increased camelina seed yield compared with the control treatment. There was no response to K fertilization. Simultaneous application of N and S did not show synergistic effects in enhancing ANUE. The ANUE reduced with increasing N application rates. From trend analysis, application of 60 kg ha–1 N produced agronomic maximum seed and oil yields. Therefore, optimizing camelina seed and oil yields production with regard to nutrient management using current variety should focus on N fertilization. Copyright © 2016. . Copyright © 2016 by the American Society of Agronomy, Inc.
Yesuf Assen Mohammed; Chengci Chen; Reza Keshavarz Afshar. Nutrient Requirements of Camelina for Biodiesel Feedstock in Central Montana. Agronomy Journal 2017, 109, 309 -316.
AMA StyleYesuf Assen Mohammed, Chengci Chen, Reza Keshavarz Afshar. Nutrient Requirements of Camelina for Biodiesel Feedstock in Central Montana. Agronomy Journal. 2017; 109 (1):309-316.
Chicago/Turabian StyleYesuf Assen Mohammed; Chengci Chen; Reza Keshavarz Afshar. 2017. "Nutrient Requirements of Camelina for Biodiesel Feedstock in Central Montana." Agronomy Journal 109, no. 1: 309-316.
Shortage of fresh water and drought stress are important factors limiting crop productivity in semi-arid and arid regions. Irrigation management needs to be optimised to improve irrigation water-use efficiency (IWUE), and thus, agricultural sustainability in these climates. A field experiment was conducted at two semi-arid locations in Iran to evaluate the impact of irrigation regime (applied after crop evapotranspiration of 70 mm (I70), 100 mm (I100) or 130 mm (I130)) and irrigation method (applied to every furrow (EFI) or variable alternate furrow (AFI)) on yield and IWUE of maize (Zea mays L.). Yield response to irrigation rate was quadratic. Kernel yield was 8476 kg ha–1 under I70, and this reduced by 12.3% under I100 and 27.7% under I130. Yield reduction due to water stress was attributed to decline in both kernel number and kernel weight. Implementation of AFI resulted in a significant saving in irrigation water. At I70, 31% less water was used with AFI than with EFI. Irrigation water saving was even greater under I100 and I130 when AFI was implemented. Regardless of irrigation regime, IWUE under AFI was always greater than under EFI (1.32 vs 1.03 kg m–3 for grain and 3.30 vs 2.47 kg m–3 for biomass production). In addition, plants were shorter with a longer root system under AFI, and the role of carbohydrate remobilisation in kernel filling was greater under AFI consistently among irrigation regimes. The results indicated good potential of AFI for development of water-saving strategies for maize production in semi-arid climates.
Farid Golzardi; Amirsaleh Baghdadi; Reza Keshavarz Afshar. Alternate furrow irrigation affects yield and water-use efficiency of maize under deficit irrigation. Crop and Pasture Science 2017, 68, 726 -734.
AMA StyleFarid Golzardi, Amirsaleh Baghdadi, Reza Keshavarz Afshar. Alternate furrow irrigation affects yield and water-use efficiency of maize under deficit irrigation. Crop and Pasture Science. 2017; 68 (8):726-734.
Chicago/Turabian StyleFarid Golzardi; Amirsaleh Baghdadi; Reza Keshavarz Afshar. 2017. "Alternate furrow irrigation affects yield and water-use efficiency of maize under deficit irrigation." Crop and Pasture Science 68, no. 8: 726-734.
Reza Keshavarz Afshar; Yesuf Assen Mohammed; Chengci Chen. Enhanced efficiency nitrogen fertilizer effect on camelina production under conventional and conservation tillage practices. Industrial Crops and Products 2016, 94, 783 -789.
AMA StyleReza Keshavarz Afshar, Yesuf Assen Mohammed, Chengci Chen. Enhanced efficiency nitrogen fertilizer effect on camelina production under conventional and conservation tillage practices. Industrial Crops and Products. 2016; 94 ():783-789.
Chicago/Turabian StyleReza Keshavarz Afshar; Yesuf Assen Mohammed; Chengci Chen. 2016. "Enhanced efficiency nitrogen fertilizer effect on camelina production under conventional and conservation tillage practices." Industrial Crops and Products 94, no. : 783-789.
Clipping fall-sown cereals provides a good source of high-quality forage during late winter. Farmers usually use more inputs, including fertilizers and seed, in dual-purpose systems compared with grain-only systems. A 2-yr field study was conducted in Karaj, Iran, to evaluate the effects of nitrogen (N) rates (0, 50, 100, 150 kg N ha−1) and seeding rates (400, 600, 800 seed m−2) on forage and grain yields of two barley (Hordeum vulgare L.) cultivars (Fasih and CB 744) in grain-only and dual-purpose systems. Fasih and CB 744 grain yields in the grain-only system were 2996 and 3250 kg ha−1, respectively (averaged over experimental treatments). Forage removal in the dual-purpose system resulted in 25% grain yield penalty. Despite the lower grain yield, the economic return of the dual-purpose system was considerably greater due to the high price of forage during late winter in the region. Grain yield response to N was linear in the grain-only system, but the trend was not significant in the dual-purpose system. In both production systems, grain yield response to seeding rate was quadratic, and the highest yields of both cultivars (2534 and 3192 kg ha−1 for Fasih and CB 744, respectively) were obtained from 600 seed m−2. In both production systems, 600 seed m−2 and 100 kg N ha−1 were optimum for grain and forage production. Our results showed considerably higher revenue in the dual-purpose system compared with the grain-only system in this region. Moreover, no additional inputs of N and seed are required for dual-purpose barley than those usually used in a grain-only system. Copyright © 2016. . Copyright © 2016 by the American Society of Agronomy, Inc.
S. Hajighasemi; R. Keshavarz-Afshar; M. R. Chaichi. Nitrogen Fertilizer and Seeding Rate Influence on Grain and Forage Yield of Dual-Purpose Barley. Agronomy Journal 2016, 108, 1486 -1494.
AMA StyleS. Hajighasemi, R. Keshavarz-Afshar, M. R. Chaichi. Nitrogen Fertilizer and Seeding Rate Influence on Grain and Forage Yield of Dual-Purpose Barley. Agronomy Journal. 2016; 108 (4):1486-1494.
Chicago/Turabian StyleS. Hajighasemi; R. Keshavarz-Afshar; M. R. Chaichi. 2016. "Nitrogen Fertilizer and Seeding Rate Influence on Grain and Forage Yield of Dual-Purpose Barley." Agronomy Journal 108, no. 4: 1486-1494.
Soil amending with biochar has been viewed as a sustainable way to improve soil moisture holding capacity. The potential of biochar application to improve water status of crops under drought stress has not been extensively evaluated. In this study, we evaluated the impact of biochar application (0%, 1%, and 2% w/w soil) on some important physiological traits of milk thistle (Silybum marianum L. Gaertn) under moderate and severe drought stress conditions in a controlled environment. Although, the application of biochar at the higher rate slightly improved soil moisture holding capacity, the magnitude of its effect was not sufficient to influence plant performance under drought stress. To get the positive effects of biochar application on milk thistle performance under drought stress, application with higher rates is probably necessary.
R. Keshavarz Afshar; M. Hashemi; M. Dacosta; J. Spargo; A. Sadeghpour. Biochar Application and Drought Stress Effects on Physiological Characteristics ofSilybum marianum. Communications in Soil Science and Plant Analysis 2016, 47, 743 -752.
AMA StyleR. Keshavarz Afshar, M. Hashemi, M. Dacosta, J. Spargo, A. Sadeghpour. Biochar Application and Drought Stress Effects on Physiological Characteristics ofSilybum marianum. Communications in Soil Science and Plant Analysis. 2016; 47 (6):743-752.
Chicago/Turabian StyleR. Keshavarz Afshar; M. Hashemi; M. Dacosta; J. Spargo; A. Sadeghpour. 2016. "Biochar Application and Drought Stress Effects on Physiological Characteristics ofSilybum marianum." Communications in Soil Science and Plant Analysis 47, no. 6: 743-752.
Fenugreek (Trigonella foenum-graecum L.) is an annual leguminous crop, widely cultivated as a medicinal plant, a high quality forage crop, or a nitrogen (N) fixing cover crop around the world. There is a lack of information about the effect of irrigation and fertilization on growth and yield of this crop, especially in regions with limited water availability. In this study, we evaluated the effects of moderate (I75: 25% saving in irrigation water) and severe deficit irrigation (I50: 50% saving in irrigation water) regimes on forage, seed, and trigonelin yield of fenugreek in a semi-arid environment (Karaj, Iran). We also examined if application of bio-fertilizers (seed inoculation with Azotobacter chroococcum and Peudomoance fluorescence) could substitute the need for chemical N, phosphorus (P), and potassium (K) fertilizer in whole or in part. The field experiment was conducted in 2012 and 2013 in a split plot arrangement based on a randomized complete block design with three replications. Forage yield, seed yield, and trigonelline concentration were significantly influenced by deficit irrigation. Implementation of I75 and I50 resulted in 40 and 65% lower forage yield compared with full irrigation (I100). Averaged over fertilizer treatments and two years, fenugreek seed yield in I100 was 839 kg ha−1 which declined by 27 and 42% under I75 and I50 treatments, respectively. Accumulation of trigonelline in fenugreek seeds was elevated from 2.9 g kg−1 in I100 to 3.1 g kg−1 in I50. Fenugreek forage and seed yield, both were significantly improved when integrated fertilizers (biofertilizer + chemical fertilizer) were applied. Among the biological, chemical and integrated fertilizers, fenugreek forage and seed yield best responded to bio + 50% chemical fertilizer. The advantage of the integrated fertilizer over chemical fertilizer was even more pronounced when deficit irrigation was practiced. Fertilization had no significant effect on trigonelline concentration According to the results of this study, integration of biofertilizer + 50% chemical fertilizer could be successfully used for fenugreek production in this region toward minimizing the consumption of chemical fertilizers and improving fenugreek yield, especially under deficit irrigation regimes.
M. Dadrasan; M.R. Chaichi; A.A. Pourbabaee; D. Yazdani; R. Keshavarz-Afshar. Deficit irrigation and biological fertilizer influence on yield and trigonelline production of fenugreek. Industrial Crops and Products 2015, 77, 156 -162.
AMA StyleM. Dadrasan, M.R. Chaichi, A.A. Pourbabaee, D. Yazdani, R. Keshavarz-Afshar. Deficit irrigation and biological fertilizer influence on yield and trigonelline production of fenugreek. Industrial Crops and Products. 2015; 77 ():156-162.
Chicago/Turabian StyleM. Dadrasan; M.R. Chaichi; A.A. Pourbabaee; D. Yazdani; R. Keshavarz-Afshar. 2015. "Deficit irrigation and biological fertilizer influence on yield and trigonelline production of fenugreek." Industrial Crops and Products 77, no. : 156-162.
Emad Jahanzad; Amir Sadeghpour; Mohammad B. Hoseini; Allen V. Barker; Masoud Hashemi; Reza Keshavarz Afshar. Competition, Nitrogen Use Efficiency, and Productivity of Millet-Soybean Intercropping in Semiarid Conditions. Crop Science 2015, 55, 2842 -2851.
AMA StyleEmad Jahanzad, Amir Sadeghpour, Mohammad B. Hoseini, Allen V. Barker, Masoud Hashemi, Reza Keshavarz Afshar. Competition, Nitrogen Use Efficiency, and Productivity of Millet-Soybean Intercropping in Semiarid Conditions. Crop Science. 2015; 55 (6):2842-2851.
Chicago/Turabian StyleEmad Jahanzad; Amir Sadeghpour; Mohammad B. Hoseini; Allen V. Barker; Masoud Hashemi; Reza Keshavarz Afshar. 2015. "Competition, Nitrogen Use Efficiency, and Productivity of Millet-Soybean Intercropping in Semiarid Conditions." Crop Science 55, no. 6: 2842-2851.
Highlights•Camelina produced 14,945 MJ ha−1 of net energy in this study.•No tillage operation reduced 5% energy input and 8% greenhouse gas emission.•Nitrogen fertilizer was the most energy-intensive input in camelina production. AbstractDespite the great potential of camelina (Camelina sativa L. Crantz) as a promising biofuel feedstock, in-farm energy flow of the crop and its associated environmental impacts has not received sufficient attention from researchers. In order to assess net energy gain and to identify energy saving and environmental friendly production operations, a two year study was conducted at central Montana. We investigated the effects of tillage method (CT (conventional tillage) vs. NT (no-tillage)) and N (nitrogen) fertilizer rate (0, 45, 90 kg N ha−1) on energy balance and GHG (greenhouse gas emission) of dryland camelina production. Results indicated that energy input and GHG emission were 5 and 8% lower in NT than in CT. Application of 45 and 90 kg N ha−1 increased camelina energy input by 186 and 365%, while increased energy output by only 21 and 64%, respectively. There was no significant difference in net energy gain in response to N fertilization, but lower energy efficiency in response to higher N inputs. Averaged across tillage systems, the GHG emission was 32.0 kg C eq ha−1 with 0 N applied, and the GHG emission increased by 206 and 389% when 45 and 90 kg N ha−1 was applied. Overall, N fertilizer had the biggest share in total energy input. Averaged over all experimental treatments, 14,945 MJ ha−1 net energy was obtained from camelina crop in this study which shows the potential of this crop as a bioenergy feedstock. Our result showed that implementation of NT is strongly recommendable for camelina production in this region. Moreover, improvement of N use efficiency has the highest priority to improve energy performance and reduce GHG emissions in camelina production.
Reza Keshavarz-Afshar; Yesuf Assen Mohammed; Chengci Chen. Energy balance and greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen. Energy 2015, 91, 1057 -1063.
AMA StyleReza Keshavarz-Afshar, Yesuf Assen Mohammed, Chengci Chen. Energy balance and greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen. Energy. 2015; 91 ():1057-1063.
Chicago/Turabian StyleReza Keshavarz-Afshar; Yesuf Assen Mohammed; Chengci Chen. 2015. "Energy balance and greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen." Energy 91, no. : 1057-1063.