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The growth period, phenology, grain yield and gum content of two different guar ecotypes were studied in response to different sowing dates and plant densities. A two-year field experiment was conducted as a split-factorial in a randomized complete block design (RCBD) with three replicates in the research field of Tarbiat Modares University during 2016 and 2017 growing season. Main plots consisted of four sowing dates (May 21, June 4, June 21 and July 5 in 2016 and May 10, May 26, June 10 and June 26 in 2017), and subplots including three plant densities (13, 20 and 40 plants m-2) and two ecotypes (Pakistani and Indian). Based on findings, the phenological traits, plant height, grain yield and harvest index were significantly affected by plant density. The effect of ecotypes was statistically significant (p<0.05) on all traits except harvest index in the first year. Furthermore, the seed sowings on May 21 and May 26 with 13 plants m-2 led to highest grain yield (3004.8 and 2826.10 kg.ha-1 for two consecutive years). The high gum content (33.68 and 33.78% for two consecutive years) was also recorded for Pakistani ecotype while for gravity, Indian ecotype showed higher value in both crop years. By and large, the Pakistani ecotype showed better response compared to the Indian one in both years, especially in 1st and 2nd sowing dates. [ABSTRACT FROM AUTHOR]

Blessed thistle (Cnicus benedictus L.) is an abundant resource with huge phytochemical and agronomic potentials. Their variation in response to agronomic techniques needs to be explored. Field studies were laid out to assess plant density and nitrogen fertilizer (N) effects on blessed thistle plant height, branches number (m-2), vegetative variables and RGR (relative growth rate), CGR (crop growth rate), LAR (leaf area ratio), NAR (net assimilation rate), as growth variables along with blessed thistle essential oil content, yield and compositions in two growing seasons. A three replicated factorial combination of plant densities (5, 10, 15, 20 and 25 plants m-2) and N levels (0, 50, 100 and 150 kg ha-1) in a randomized complete-block design were conducted. Addition of 100 kg N ha-1with 15-20 plants m-2caused a significant increase in vegetative and growth variables. Although the essential oil content declined by 28 and 39 % as N rate level rose from 0 to 150 kg ha-1, essential oil yield peaked at 40-80 kg N ha-1 in both years. The GC and GC/MS analysis showed that eicosane was the dominant component of the essential oil (31-65 %), followed by isopropyl hexadecanoate (5.7-9.2 %), octadecane (3.5-10.5 %) and cryptomerione (3.1-7.1 %) which presented variations across the treatments. Application of N resulted in a decrease in the eicosane and an increase in the proportion of isopropyl hexadecanoate, octadecane and cryptomerione. It can be concluded that optimizing agronomic management techniques could be an effective approach to improve growth, essential oil content and composition of the plant. [ABSTRACT FROM AUTHOR]

To select and introduce the best rapeseed genotypes under withholding irrigation, two field experiments were carried out in seasons 2015–2016 and 2016–2017 in Iran. Factorial arrangement of treatments was set up as RCBD with three replications. The experiment factors were two irrigation treatments (normal irrigation during the growing season and withholding irrigation from silique setting stage until the end of the growing season) and 17 genotypes of rapeseed. Grain yield, oil content and fatty acid contents were measured. The results revealed that oleic acid (62.15%) was the highest followed by linoleic (19.28%), linolenic (5.65%), palmitic (5.24%) and stearic acids (2.44%). ODR (oleic desaturation ratio) and LDR (linoleic desaturation ratio) were significantly affected by genotypes and irrigation treatments. The biosynthetic pathway of fatty acids affected by drought stress. This means that linoleic acid increases under withholding irrigation condition, while linolenic acid decreases in such a water deficit stress condition. The highest performance of qualitative and quantitative was detected in HL3721 genotype due to high values of grain yield (3892.45 kg ha−1), oil content (437.05 g kg−1), unsaturated fatty acids (87.63%) and low values of saturated fatty acids (7.98%), and it could be used under withholding irrigation in arid and semi-arid climates. [ABSTRACT FROM AUTHOR]

• Polyphenol, Caffeic and chlorogenic yield were increased by plant density. • Drought resulted in a decrease in polyphenol, caffeic and chlorogenic yields. • Caffeic and chlorogenic yields were completely influenced by dry matter yield. To study the effects of water stress and plant density on the qualitative and quantitative characteristics of artichoke (Cynara cardunculus var. scolymus), a two-year field experiment was carried out in a semi-arid region in 2016 and 2017. The experimental treatments were arranged as split-plot in a randomized complete block design with three replications. The main plots were three irrigation treatments of 40, 60 and 80% field capacity and sub-plots consisted of four planting densities of 2, 4, 6 and 8 plant m−2. The results showed leaf area, dry matter, and chlorophyll (a, b, and total) concentration decreased by water deficit stress, whereas proline concentration was increased by water deficit stress. Dry matter and LAI were significantly affected by plant density, so that the highest dry matter and LAI in all irrigation treatments were observed at the populations of 6 plants m−2. An increase of plant density decreased concentrations of chlorophyll a and b and total chlorophyll in artichoke leaves. The various irrigation treatments and plant densities influenced total polyphenol and yields of caffeic and chlorogenic acids. Among irrigation treatments, the highest yield of caffeic acid, chlorogenic acid and total polyphenol (5.14, 8.24, and 5.01 g m−2, respectively) belonged to the non-stressed control. In addition, the highest yield of caffeic acid, chlorogenic acids and total polyphenol (5.90, 9.38, and 5.60 g m−2, respectively) were observed at the population of 6 plants m−2. For both of these factors, the yields of these compounds were completely affected by dry matter yield. [ABSTRACT FROM AUTHOR]

Aerial parts of blessed thistle ( Cnicus benedictus L.) contain high amounts of phytochemicals and would be improved through varying agronomic management practices such as N rate and plant density. The objective of this study was to investigate the effect of different N fertilizer rates and plant densities on agronomic performance, photosynthetic capacity, leaf area index, carbon to N ratio (C/N), cnicin content, total phenol and flavonoids, and antioxidant activity in blessed thistle. A two-year field experiment was conducted in a semi-arid region in Iran in 2013 and 2014. The experiment was arranged as a randomized complete block design with a factorial arrangement and three replicates. Treatments consisted of four N rates (0, 50, 100 and 150 kg N ha −1 ) combined with five plant densities (5, 10, 15, 20 and 25 plants m -2 ). Total chlorophyll and straw N contents as well as photosynthesis rate significantly increased by either 50 or 100 kg N ha −1 . The significant reductions of straw N in 2013 and photosynthesis rate in both years were found with increasing plant density. Total phenol, flavonoid contents, C/N ratio and antioxidant activity were decreased as a result of increased N rate. The highest cnicin contents and yields were obtained from high plant densities under low N rates. This response may be attributed to N and plant density compensation effect. The enhancement in secondary metabolites and antioxidant activity were associated with high C/N ratio and low N contents, and accompanied by a decrease in chlorophyll content that showed a positive correlation with photosynthesis and biomass yield. The study demonstrates that increasing plant density (>15 plants m −2 ) with a low N rate (50 kg N ha −1 ) could be suitable for both biomass and phythochemichal production of blessed thistle. Furthermore, this study suggests that blessed thistle has the ability to achieve higher biomass and yield of cnicin in poor soils and unfavorable conditions. [ABSTRACT FROM AUTHOR]

The Iranian energy sector has recently discovered a great interest in the concept of renewable and clean energy. The interest is motivated primarily by concerns about greenhouse gas (GHG) emissions and global climate change, as well as the desire to find alternative and sustainable energy sources and create potential job opportunities related to these new technologies for future generations of Iranians. This study supports the search for alternative, sustainable energy sources by assessing okra's usability as a biofuel. Okra is an annual, warm season crop that provides a rich source of industrial oil and protein. According to our investigation, the seeds of Iranian okra ecotypes that have an oil content of 20% could produce up to 325 kg/ha oil yield. Our study on Iranian okra seed oil showed that, the most dominant fatty acids of are linoleic acid (C18:2) (38–40%), Palmitic acid (C16:0) (29–30%), and Oleic acid (C18:1) (19–22%). The biodiesel derived from okra via a transesterification reaction using an ultrasonic system could meet ASTM D6751 standards with satisfactory results in methyl ester content (more than 96%), viscosity (2.3–2.4 mm −2 /S, and flash point (155–158 °C)). Because of its high oil yield, quality, and large ecological adaptation window, okra is a strong contender to provide a new source of non-edible oil for biodiesel production in bioenergy farms. [ABSTRACT FROM AUTHOR]

The objective of this study was to study the seed quality aspects of wheat (Triticum aestivum L.) and the extent of weed seed contamination present in wheat seeds produced in different regions of Iran. Four districts (cities), each including 12 fields (six certified seed fields and six farm-saved seed fields), were selected in each regions (provinces). One kilogram of the wheat seed sample was collected from each field for analysis in the laboratory. Wheat seeding was commonly done by farm-saved seed sourced from within the farm due to the high costs of certified seeds purchased from outside sources, followed by the low seed quality. The use of a farm-saved seed resulted in a higher germination rate and a lower mean time to germination compared with another system. The more positive temperatures experienced by mother plants could decrease the number of normal seedling and seedling length vigor index. Generally there was virtually no difference about physiological quality between certified seed and farm-saved seed sector that is related to lower quality of certified seed. The certified produced seeds had the lower number of weed seed, species and genus before and after cleaning. The highest seed purity and 1000 seed weight was obtained from the certified seed production system. The need for cleaning the farm-saved seed samples before sowing is one of the important findings of this survey. [ABSTRACT FROM AUTHOR]

Highlights: [•] Weeds can be a friend of the agroecosystem rather than a foe. [•] First report of corn–pigweed mixture response to different water regimes and N rates. [•] The corn–pigweed mixture was superior to the corn in terms of input use efficiency. [•] The N leaching intensity decreased in the presence of weeds and in response to N. [•] Corn and weed cooperation to produce high quantity and quality forage. [Copyright &y& Elsevier]

• Water deficit stress mitigated by synergistic effect of boron and epibrasinolid. • Boron and 24-epibrasinolid spray improved the oil %. • Polyunsaturated fatty acid content improved by foliar spray. The high oil content and quality of camelina [ Camelina sativa (L.) Crantz] seed oil for various uses, including human nutrition and industry, has encouraged many countries to increase the cultivation of this oilseed crop. Due to the coincidence of initial irrigations of summer crops with the final stages of camelina growth, production of this crop in arid and semi-arid regions depends on tolerance to the late-season water deficit stress. Therefore this two years field experiment focused on boron (B) and 24-epibrassinolide (EBL) foliar spray effect on seed yield, oil content, oil yield and fatty acids profile (FAs) of camelina in a semi-arid area (Iran) during 2018−19 and 2019−20 growing season. Experimental treatments were arranged in a split-plot design based on randomized complete blocks with three replicates. Irrigation regimes based on withholding irrigation (WI): [full irrigation (FI) at 50 % of available soil water (ASW); withholding irrigation with 20 % of ASW from full flowering to silicle formation (WI 1); withholding irrigation with 20 % of ASW from silicle formation to harvesting (WI 2)] were considered as the main plots and ten levels of foliar spray (FS) consisted of control (non foliar spray), distilled water, B (0.5 and 1%) and EBL (0.5 and 1 μM) and their concomitant use (B 0.5 % + EBL 0.5μm , B 0.5 % + EBL 1μm , B 1% + EBL 0.5μm , and B 1% + EBL 1μm) were randomized to the subplot units. Seed and oil yield decreased by 6.7–8.4 % and 10–12 %, respectively in response to the water deficit during the flowering and silicle formation stages. The negative effect of drought stress on the quality of camelina oil was recorded as 3.3–5.3 % increment in erucic acid and significant decrease in the unsaturated fatty acids (UFAs) content, oleic acid (by 4.6–8.5 %), linoleic acid (by 3.5 %), linolenic acid (by 2.5 %) and 1.2–2.8 % for monounsaturated fatty acids (ΣMUFAs) content compared with the control treatment. While foliar spary of B and EBL increased oil content by ranged from 2 to 4% under-withholding irrigation treatments. Also ecosanoic acid and polyunsaturated fatty acids (ΣPUFAs) content significantly increased under combined application of B 0.5 + EBL (0.5 and 1). [ABSTRACT FROM AUTHOR]

Background: Feverfew (Tanacetum parthenium L.) is a herbal plant that has anti- septic, anti-microbial, anti-parasitic and anti-inflammatory effects. The main objective of this study is to evaluate the antimicrobial effect of shoot essential oil (essential oil of the aerial parts of the plant) of the feverfew on a number of microorganisms including gram-negative and gram-positive bacteria, filamentous fungi and yeasts. Materials and Methods: In this empirical study, plant samples were collected at the full blooming stage. Shoot essential oil was extracted using hydro-distillation technique and Clevenger apparatus. Components of the extract were identified using GC and GC/MS apparatus and its antimicrobial properties were evaluated using diffusion in Agar method (disk diffusion) and dilution in the well (Micro-broth dilution)6T. Results: Among 35 compounds identified in the essential oil of the feverfew, camphor (45%), 8Tchrysanthenyl acetate8T (21.5) and camphene (9.6%), were the main components respectively. Essential oil showed very good antifungal effect which was stronger than its antibacterial effect. Gram-negative bacteria were less sensitive to the essential oil than gram-positive bacteria. The mean diameter of inhibition zone, in the bio-assessment of the effect of feverfew essential oil on gram-positive bacteria and fungi was respectively more than the effect of vancomycin and amphotericin B and this effect on gram-negative bacteria was less than the effect of gentamicin. This effect is attributed to the high value of camphor, chrysanthenyl acetate and camphene found in the essential oil. Conclusion: Feverfew essential oil could be utilized as a sound and harmless substitute for the antibiotics. [ABSTRACT FROM AUTHOR]

Abstract: Descurainia sophia (flixweed) is an annual weed widely distributed in cultivated crops, forage and rangelands throughout the world. This weed, in particular its seed, is used for food, medicinal and industrial purposes. The objective of this study was to investigate the effects of irrigation management and different application rates of nitrogen on morphological traits and yield components of this weed as a means of enhancing production and economic returns. A two-year field experiment was conducted in a semi-arid region in Iran during the 2009–2010 and 2010–2011 growing seasons. The experiment was a split plot in a randomized complete block design with three replicates, with irrigation treatments as main plots and nitrogen rates as sub plots. The three irrigation regimes consisted of 0.1 maximum allowable depletion or deficiency (MAD) of available soil water (ASW), 0.2 MAD of ASW, 0.4 MAD of ASW in 2010 and 0.2 MAD of ASW, 0.4 MAD of ASW and 0.8 MAD of ASW in 2011. The plants were grown at three nitrogen rates of 0, 200, and 300kgNha−1. Generally there were significant increases in seed yield, biomass, straw yield, harvest index, number of siliques (pods) per plant, seed weight, plant height, time to maturity, water use efficiency, protein concentration in seed, straw N concentration, nitrogen uptakes and nitrogen harvest index each growing season by applying nitrogen at all irrigation treatments. There was a decreasing trend in number of plants per m2, nitrogen utilization efficiency and oil concentration with increasing nitrogen application under all the irrigation treatments. Seed yield response to irrigation treatments and N rates seemed to be more related to number of plants per m2 and number of siliques per plant. The highest seed yield was obtained at the plant population of 686plantsperm2. The results obtained here suggest that nitrogen application can improve the seed yield and seed quality of D. sophia grown under different irrigation regimes. Averaged over both years, the application of 300kgNha−1 under 0.2 MAD of ASW resulted in the highest revenue; 200kgNha−1 was not significantly different to 300kgNha−1. [Copyright &y& Elsevier]

With regard to the low cation-exchange capacity and large saturated hydraulic conductivity of sandy soils, a field experiment was carried out in 2006–2007 to determine the impact of zeolite on nitrogen leaching and canola production. Four nitrogen (N) rates (0, 90, 180, and 270 kg ha–1) and three zeolite amounts (3, 6 and 9 t ha−1) were included as treatments. The results demonstrated that the highest growth parameters and seed yield were attained with 270 kg N ha−1 and 9 t zeolite ha−1. However, the highest and the lowest seed protein percentage and oil content were obtained with 270 kg N ha−1 accompanied by 9 t zeolite ha−1, respectively. Nitrate concentration in drained water was affected by nitrogen and zeolite. The lowest and highest leached nitrate values were found in control without N and zeolite (N0Z0) and in treatments with the highest N supply without zeolite (N270Z0), respectively. In general, nitrogen-use efficiency decreased with an increase in N supply. Application of 9 t zeolite ha−1 showed higher nitrogen use efficiency than other zeolite amounts. Also, application of more N fertilizer in soil reduced nitrogen uptake efficiency. In total, application of 270 kg N ha−1 and 9 t zeolite ha−1 could be suggested as superior treatment. [ABSTRACT FROM AUTHOR]

A field experiment was carried out in a semi-arid region of Iran during the 2006–2007 growing season to investigate canola seed yield as affected by nitrogen (N) and natural zeolite (Z) rates. This experiment studied N efficiency and N leaching loss in a sandy soil. Experimental treatments consisted of a factorial combination of three N levels (90, 180, and 270 kg N ha−1) and four zeolite rates (0, 3, 6, and 9 t zeolite ha−1). The result showed that the greatest seed yield (2452.3 kg ha−1) was obtained from the N270Z9 treatment whereas the control treatment (N0Z0) produced the lowest seed yield (1038.3 kg ha−1). Moreover, use of 270 kg N ha−1 without zeolite (N270Z0) led to the greatest amount of N leaching loss (144.23 kg ha−1). Zeolite application clearly reduced N leaching loss in all N rates. This justified low N-use efficiency in high N applications. More N uptake and more canola seed yield is attributed to zeolite application. [ABSTRACT FROM AUTHOR]

In the present study, the possibility of enhancing cold stress tolerance of young soybean plants (Glycine max [L.] Merr) by exogenous application of 5-aminolevulinic acid (ALA) was investigated. ALA was applied at various concentrations (0, 0.3, 0.6 and 0.9 mM) by seed priming and foliar application method. After ALA treatment, the plants were subjected to cold stress at 10 ± 0.5 °C for 72 h. Cold stress significantly decreased plant growth, relative water content, chlorophyll, photosynthesis and stomatal conductivity, while it increased electrolyte leakage and proline accumulation. ALA at low concentrations (0.3 mM) protected plants against cold stress, enhancing plant height, shoot fresh and dry weight, chlorophyll content, photosynthesis, stomatal conductivity as well as relative water content. Increase of electrolyte leakage was also prevented by 0.6 mM ALA. ALA also enhanced superoxide dismutase and catalase activities at 0.6 mM concentration especially under cold stress conditions. Proline increased with increasing in ALA concentration under both temperature conditions. In most cases, application of ALA by spraying method was better than seed priming method. Results showed that ALA, which is considered as an endogenous plant growth regulator, can be used effectively to protect soybean plants from the damaging effects of cold stress, by enhancing the activity of antioxidative enzymes, protecting cell membrane against reactive oxygen species and finally by promoting chlorophyll synthesis, leading to more intense photosynthesis and more carbon fixation, without any adverse effect on the plant growth. [ABSTRACT FROM AUTHOR]

Information regarding the evaluation of priming treatments on germination traits of Dracocephalum moldavica L. varieties is not available. Therefore, this assay was conducted during 2013 in Islamic Azad University of Sanandaj located in Kurdistan province of Iran. Twelve treatments resulted from a factorial combination of six priming method (factor A) and two varieties of moldavian dragonhead (factor B), arranged in a completely randomized design replicated three times. Factor A included 50 mg L-1 Salicylic acid (SA), 100 mg L-1 SA, 50 mg L-1 Ascorbic acid (AsA), 100 mg L-1 AsA, hydro-priming and control. Factor B included Kurdish landrace and SZK1 cultivar. Results showed that the highest and lowest emergence percentages were 90.1% in Kurdish SA50 and 52.8% in SZK1 AsA100 treatments, respectively. Hydro priming treatment increased the emergence rate index more than 100 mg L-1 SA, 100 mg L-1 AsA and control treatments. The highest shoot weight was 9.41 mg for Kurdish SA50 treatment and the lowest length, 1.24 mg was attributed to SZK1 control treatment. The highest (6.56 mg) and lowest (1.74 mg) radicle weight were observed in Kurdish-hydro-priming and SZK1-AsA100 treatments. The Kurdish landrace showed a favorable germination condition compared to SZK1 cultivar. [ABSTRACT FROM AUTHOR]

The high vulnerability of sweet corn (Zea mays L. var. saccharata) to weed competition and the urgent reduction of the dependence on chemical herbicides are major challenges facing the agricultural community. To investigate the effects of plastic mulches on weed control and yields in sweet corn under different sowing dates, a 2-year experiment was conducted at Varamin, Iran, in 2010 and 2011. The mulch treatments included black plastic mulch, semitransparent biodegradable mulch, an unmulched weeded control, and an unmulched unweeded control. The sowing dates were 5 June, 20 June, and 6 July. Results revealed that delayed sowing (6 July) reduced weed dry weight by 51% and 41% compared with the 5 June sowing date in 2010 and 2011, respectively, without reducing crop yield. The black plastic mulch treatment had the lowest weed biomass. The sowing date x mulch interactions on kernel number per ear, length of ear, percentage of unfilled ear tip, and yield of sweet corn were statistically significant (P < 0.01) in both years. The maximum kernel number per ear (535) and the highest fresh ear yield (24,684 kg-ha-1) in 2010 were obtained on the 6 July sowing date under biodegradable mulch. The plants sown on 6 July produced the highest fresh kernel yield with the black plastic mulch (12,893 kg-ha-1) and unmulched weeded control (11,777 kg-ha-1) in 2010 and 2011, respectively. The highest percentage of unfilled ear tips in both years was observed in the unmulched unweeded plots sown on 5 June. According to our findings, to suppress the weeds and avoid the sweet corn yield loss in such a hot summer that we had, using the black plastic mulch and delayed sowing are recommended. [ABSTRACT FROM AUTHOR]

Nitrate leaching from agricultural soils represents substantial losses of N from fertilizer. Nitrogen leaching in sandy soil decreases fertilizer efficiency and can depress crop production. Materials with high cation-exchange capacity are hypothesized to reduce N leaching and increase N uptake in sandy soils. This randomized complete-block design study evaluated the influence of chemical, organic, and integrated fertilizer treatments and natural zeolite on growth, yield, and grain mineral content of wheat (Triticum aestivum L.) grown on sandy soils. Supply of N by urea and composted cattle manure amended with 10% (w/w) zeolite increased wheat growth, yield, and yield components. Similar results were obtained when zeolite was applied directly to soil. The highest grain Zn, Fe, and Mn contents were achieved in plots treated only with organic fertilizers. Chemical plots produced the highest N and protein content. Integrated fertilizer treatments amended with zeolite are an effective and environmentally sound method to improve wheat yield. [ABSTRACT FROM PUBLISHER]

Salinity and water-deficit stress reduce yield in agricultural crops. On the other hand, seed germination is critical in seedling establishment and subsequent plant growth. Therefore, the present investigation was carried out to evaluate the effects of chitosan (Ch) concentrations (0% [control], 0.05%, 0.1%, 0.2%, 0.4%, 0.5%, 1%, 2%, and 3%) on the tolerance of safflower (Carthamus tinctorius L.) to different osmotic potentials (0, −0.4, −0.8, and −1.2 MPa). Induced osmotic potential significantly decreased germination percentage, germination index and rate, length and weight of root and shoot, and protein content. Proline content, malondialdehyde content (MDA), and catalase (CAT) and peroxidase (POX) activity increased when osmotic potential was increased to −0.8 MPa. Under unstressed conditions (0 MPa), there were no significant differences in germination percentage among different concentrations of chitosan, whereas MDA content, CAT, and POX activity were increased by low concentrations of chitosan (0.05%–0.4%). With increasing water-deficit stress, low concentrations of chitosan increased germination percentage but decreased MDA and proline contents and CAT and POX activity. Thus, it could be concluded that low concentrations of chitosan exhibited positive effects on water-deficit alleviation through the reduction of enzyme activity. Therefore, chitosan should be an effective biostimulator to enhance seedling growth and plant tolerance to oxidative stress conditions, especially under conditions of drought stress. [ABSTRACT FROM PUBLISHER]

A comparative field experiment has been conducted in order to study the effect of chemical, organic and integrated nitrogen suppliment on micro and macro nutrient residue after wheat harvesting, at Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. The treatments consisted in three groups that are chemical, organically and integrated of them. Nitrogen was supplied in different proportion from chemical and organic sources. Also, zeolite was applied in two ways: mixed with soil and mixed with cattle manure during composting. Before sowing and after wheat harvesting, macro and micro nutrient availability in the soil were examined. The results showed that, among treatments supplying with 100% nitrogen required from composted cattle manure amended with 10% (w/w) zeolite had the best effect on nutrition residue after wheat production because zeolite decreased nitrogen leaching during the manure composting. Crop yield was not sratistically different between fertilizer treatments but the highest seed yield was achieved from supplying 50% nitrogen required from cattle manure compost and 50% by urea amended with 10% (w/w) zeolite. This study demonstrated that composted cattle. manure amended with zeolite improves soil fertility after wheat production compared with chemical fertilization. [ABSTRACT FROM AUTHOR]

Water deficit is the main reason for sugar yield losses in semi-arid areas. Triazole derivatives may mitigate the harmful impacts of water stress. Therefore, this study aimed to assess the effect of tebuconazole (TEB) application on antioxidants, root quality traits, and sugar yield under drought stress conditions. The treatments included three levels of irrigation set according to crop evapotranspiration (ET C): 100%, 75%, and 50% ET C , as well as three levels of TEB (0, 25, and 50 mg L−1). While significantly increasing antioxidant and alpha-amino-nitrogen (α-amino-N) contents, limited irrigation decreased total chlorophyll content, net photosynthesis rate, leaf relative water content, the weight of roots, and sugar yield. In contrast, TEB treatment resulted in a marked rise in all biological and physiological traits as well as enzymatic antioxidants. Our findings indicated that the decline in α-amino-N content might be linked to increased NR activity in response to the TEB application. Our results also showed that the stress-ameliorating role of TEB cannot be associated with the increase of flavonols (quercetin and rutin). Overall, the results demonstrated that TEB has a high potential for ameliorating the negative impacts of limited irrigation. [Display omitted] • TEB-treated plants exhibited an improved activity of antioxidant enzymes under limited irrigation. • The stress-ameliorating role of TEB cannot be associated with the increase of flavonols in TEB-treated plants. • Improved nitrate reductase activity may be responsible for increasing white sugar yield under severe water stress. • Spraying of TEB substantially decreased alpha-amino-N in sugar beet taproot under limited irrigation. [ABSTRACT FROM AUTHOR]

Precipitation and temperature are two main climatic factors that influence crop productivity in arid and semi-arid areas. Study of the variability in these variables is thus important especially under dryland farming. In the present study, we evaluated the relationship between minimum, maximum, and mean temperatures; precipitation; and dryland wheat yield in northwest of Iran. The association between long-term weather data and dryland wheat yield for the time period bracketing 1990 and 2004 was investigated in seven stations (Ahar, Tabriz, Maragheh, Myaneh, Urmia, Khoy, and Makou) homogenously distributed over the study region. Aridity index (AI) was also calculated and its relationship with wheat yield was studied. Results showed that AI significantly decreased in the whole region (except for Urmia) with the highest variation in Maragheh and Myaneh. Increase in temperature was the major contributing factor to the increasing AI. Association between weather variables and dryland wheat yield at annual, seasonal, and monthly scales showed different results. At seasonal scale, spring was the main season affecting wheat yield. Also, at monthly scale, January, April, and May had more important role in wheat yield variation compared to the other months. The association between dryland wheat yield and weather variables was stronger in Maragheh and Myaneh. At the end, it was concluded that wheat yield was more affected by the variability in the climate in East Azerbaijan compared to that in West Azerbaijan. [ABSTRACT FROM AUTHOR]

Climate variability adversely impacts crop production and imposes a major constraint on farming planning, mostly under rainfed conditions, across the world. Considering the recent advances in climate science, many studies are trying to provide a reliable basis for climate, and subsequently agricultural production, forecasts. The El Niño-Southern Oscillation phenomenon (ENSO) is one of the principle sources of interannual climatic variability. In Iran, primarily in the northeast, rainfed cereal yield shows a high annual variability. This study investigated the role played by precipitation, temperature and three climate indices [Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and NINO 3.4] in historically observed rainfed crop yields (1983-2005) of both barley and wheat in the northeast of Iran. The results revealed differences in the association between crop yield and climatic factors at different locations. The south of the study area is a very hot location, and the maximum temperature proved to be the limiting and determining factor for crop yields; temperature variability resulted in crop yield variability. For the north of the study area, NINO 3.4 exhibited a clear association trend with crop yields. In central locations, NAO provided a solid basis for the relationship between crop yields and climate factors. [ABSTRACT FROM AUTHOR]

Screening new alternative vegetable oil sources as biodiesel feedstocks has attracted worldwide attention as world oil reserves decline and environmental concerns increase. Blessed thistle (Cnicus benedictus L.) has recently been identified as a multipurpose crop with optimal economic yield in poor soils. Blessed thistle was seeded into three different site soil conditions (site 1: silt clay loam, site 2: sandy loam, site 3: saline sandy loam) in eastern North Dakota, USA to evaluate agronomic performance and seed properties as well as biodiesel potential. The highest biomass and plant heights were obtained from the sandy loam soil, while plants grown in saline sandy loam soil had similar seed and oil yield, and similar oil content as plants grown in other site soil conditions. Biodiesel obtained from blessed thistle oil in the saline site was an excellent substitute for fossil fuels. The saline soil did not influence the blessed thistle oil yield; however, the saline soil did affect the fatty acid composition and biodiesel properties with some improvement in biodiesel quality. Results showed that blessed thistle was a promising species for biodiesel feedstock, especially for marginal soils such as the saline soil conditions in North Dakota. • Site soil conditions caused a slight variation in blessed thistle productivity. • Blessed thistle is a salt-tolerant promising plant to grow in marginal lands. • Blessed thistle is a potential feedstock for biofuels production. • Saline soil induced lipids are suitable for biodiesel production. [ABSTRACT FROM AUTHOR]