نشریه پژوهشهای زراعی ایران
سال نوزدهم شماره 4 (پیاپی 64، زمستان 1400)

Camelina [Camelina sativa (L.) Crantz] oilseed is a low-input crop that grows and yields well in semiarid regions with low-fertility or saline soils in comparison with other crops. Camelina seeds contain 30–40 percent oil. Camelina is an annual plant from the Brassicaceae family that has short and fast growth. Camelina is well adapted to cool temperate and semi-arid climates, it is more tolerant of drought and spring freezing than rapeseed (Brassica napus L.). Also, Resistance to some diseases and pests of other members of Brassicaceae plants is another important features of this plant. Research-based information is lacking to provide basic agronomic recommendations for Camelina. In general, yield and yield components of Camelina seeds depends on nitrogen fertilization, planting time and climatic conditions. Camelina responds differently to fertilizer management and planting date in different climatic and soil conditions. Selection of crop managements such as planting date and fertilization can increase the quantitative and the qualitative yield of this plant.

In order to evaluate the effects of nitrogen fertilizer on agronomic characteristics in Camelina under different planting dates, a study was conducted in split-plot based on randomized complete blocks design with three replications at the research field of Agricultural College, the Shahid Chamran University of Ahvaz, located in the southwest of Ahvaz and the western bank of the Karun River with 31°19׳ʹ N; 48° 41׳ʹ an altitude of 22 meters above sea level during 2018-19 growth season. Experimental factors included planting date in three times (November 6, December 6 and January 5) as the main plots and nitrogen fertilizer at four levels (0, 23, 46 and 69 kg.ha-1) as the subplots. The plant material (seed) of this research was Camelina sativa cultivar Soheil which was prepared from the Biston Shafa Knowledge Foundation Company. Half of the nitrogen fertilizer was spread with phosphorus and potassium in the surface of each experimental unit and mixed with soil before planting. The other half of nitrogen fertilizer used in three sections during three stages of plant phenology included True four leaves, beginning of stem elongation and beginning of silicle emergence.

Analysis of variance of traits showed a significant difference between nitrogen levels at each level of planting date in terms of all traits studied, including grain yield, biological yield, harvest index, plant height, percentage and oil yield, etc. Generally, based on the results of the analysis of variance, in all three planting dates. The highest grain yield (2653.8 kg.ha-1) was obtained from the first planting date and 46 kgN.ha-1 treatment and the highest harvest index in second planting date and 46 kg nitrogen treatment was measured. The highest oil yield (737.9 kg.ha-1) belonged to the first planting date and the level of 23 kgN.ha-1. However, the highest protein percentages (28.53) was obtained in the second planting date and 69 kg nitrogen treatment. Regarding to the other traits, it was observed that the optimal use of nitrogen fertilizer led to the improvement of the studied traits such as the number of sub-branches, silicle per plant, seed per silicle and 1000-grain weight, but delay in planting date caused the mean of these traits decreased significantly.

In general, the results of this study showed a significant response of Camelina to the amount of nitrogen used and planting date, so that in early planting (November 6) was obtained the highest grain yield, yield components, biological yield, oil yield and protein percentage. But in late planting, especially the third planting date, all the studied traits were reduced due to the collision of the plant reproductive stage with the high temperature at the end of Khuzestan growth season and the reduction of the plant growth cycle. Under three planting dates, nitrogen fertilizer application up to 46 kgN.ha-1 increased grain yield, oil yield and some yield components. Based on the results of this experiment, in order to obtain maximum grain and oil yield of Camelina, it is important to consider planting date and optimum nitrogen use.

Medicinal plants in the world are very important and currently the demand for medicinal herbs is on the rise due to higher requirement of products need in the pharmaceutical, health and food industry. Therefore, the assessment of various systems of plant nutrition is one of the important needs of agricultural planning in order to achieve high yield with high quality, especially in medicinal plants. Manure increase soil fertility and improves the growth and yield. This experiment was conducted to investigate the effect of planting density and single or combined application of cow manure (CM) and chemical fertilizers (CF) on growth, yield and pigment content of Isabgol (Plantago ovata Forsk).

In order to evaluate the effects of different levels of fertilizer on isabgol (Plantago ovata Forsk) an experiment was arranged as factorial based on a randomized complete block design with three replications at Sarayan Faculty of Agriculture, University of Birjand, during 2017. Experimental factors were included: Fertilization treatments consisted of single (40 ton.ha-1 CM and 40 kg.ha-1 CF from the source of NPK) and combined (40 ton.ha-1 CM + 20 kg.ha-1 CF and 20 ton. CM + 40 kg.ha-1 CF) application of organic and chemical fertilizers along with a control treatment (no-fertilizer) which were evaluated at three levels of density (20, 40 and 60 plants.m2). Measurements of chlorophyll a, b, carotenoid and SPAD: Firstly, 0.1g samples were taken from the collected leaves. Subsequently each sample was extracted by 80% acetone and put in the centrifuges with rotation speed of 6000 per minute for 10 minute. Absorbance using a spectrophotometer at wavelengths of 470, 647, 663 nm was measured. Also, chlorophyll index was measured by manual chlorophyll meter. Measurements of Yield and yield components: In the sampling stage (full flowering stage), 3 plants of cultivation lines were harvested with respect to the elimination of marginal effects. After measuring plant height, the plants were cut from above the soil, immediately weighed (fresh weight) and then the samples were placed in separate bags and after drying in an oven at 72°C for 48 hours, the leaf weight, total dry weight and grain yield of each sample were measured. Finally, Statistical analyses were carried out by ANOVA, with  least significant difference test (LSD) at 5% probability level for subsequent pairwise comparisons.

 The results indicated the significant effect of treatments on plant dry weight, biological yield, seed yield and chlorophyll b content. The highest biological and seed yields (2080 and 806.6 kg.ha-1, respectively), were obtained from planting density of 60 plants m2, while the highest leaf chlorophyll content was gained from 20 plants m2 treatment. The effect of fertilizer resources on all traits (except plant dry weight) and interaction effect of experimental factors on all studied indices were no-significant. The plant showed an appropriate adaptation to low nutritional and its maximum yield was obtained when at least 60 plants.m2 was used.

Based on the obtained results, it could be concluded that isabgol is a low-input medicinal plants in terms of nutrient requirements. Therefore, it seems that the application of fertilizer resources in crops which are located prior to isabgol in a rotation and availability of remaining nutrients can provide the nutritional requirements of this plant. Moreover, consider to open canopy of the plant even when the plant density was 60 plant.m-2, it seems that more densities must be considered in future studies.

Water deficit is one of the factors limiting the growth of plants in the world and is the most common environmental stress. Several studies show decreasing in growth, yield and plant death as a result of unfavorable water or water stress conditions. Management of nutrients consumption along with water consumption management influences the quantitative and qualitative yield of crops and medicinal plants. Although, chemical fertilizers provide plant nutrients for the plants faster and more effective, but to increase the quality of products, especially the medicinal and aromatic plants, the use of organic fertilizers is better than chemical fertilizers. Organic fertilizers cause decreasing in bulk density and increasing water retention in the soil. Manure is one of the organic fertilizer sources which its application is conventional in the sustainable management system of soil. Organic fertilizers, especially manures compare with chemical fertilizers having large amounts of organic materials and counted as a rich source of nutrients especially nitrogen, phosphorus and potassium which provide these elements over the time for the plants.

A split plot experiment was carried out in a randomized complete block design with three replications at the research farm of Shahrekord University. Main factor was three levels of irrigation regimes including: full irrigation (control), 75% and 50% of full irrigation while six levels of manure application including: 1) no amended fertilizer (control), 2) 25% urea + 75% manure 3) 50% urea + 50% manure 4) 75% urea + 25% manure 5) 100% urea and 6) 100% manure, were used as subplot. Water need of the other treatments was considered based on the water demand of control. Using the counter, the volume of required water was added to each plot. The period between two irrigations was determined using meteorological data and determining daily water requirement and the moisture regimes (water stress) was applied after the establishment of seedlings at eight leaf stage. Then at full flowering stage, the percentage of leaf water content (LWC), the amount of water to the dry weight (IWC), leaf water-retaining (RWP), water scarcity index of saturation (saturation deficit) (WSD), leaf relative water content (RWC), membrane stability (CMS), moisture retention capacity (MRC), relative water loss (RWL) and dry matter yield (DMY) were studied.

The results showed that the effect of irrigation regime on IWC, WSD, RWC, CMS and RWL was significant. The maximum IWC, RWC, CMS and RWL and the minimum WSD was observed in full water demand and 50% full irrigation treatments, respectively. Different fertilizer levels also showed significant effect on LWC, RWP, WSD, RWC, CMS, MRC, RWL and DMY. The interaction effect between irrigation regime and fertilizer was also significant on IWC, LWC, RWP, MRC, RWL and DMY. In general, in order to maintain the moisture balance of plant, application of 50% urea + 50% manure with supply of full water demand was recommended.

 Based on the results obtained at this experiment, it can be said that the complete water requirement caused increases in IWC, RWC, CMS, RWL and DMY, while the WSD was decreased. Moreover, application of 50% urea + 50% manure could increase LWC, RWP, MRC, RWL, IWC and DMY, reflecting the positive effect of fertilizers combined application. In total, according to the results of this research, in order to maintain the moisture balance of the plant, the combined application of manure and chemical fertilizers for 50% urea + 50% manure and supply of full water demand is recommended.

Potato plays an important role in global food security and it growth and tuber yield are influenced by many biotic and abiotic stresses, such as drought and low or high temperatures. Potato in Khuzestan province is facing unfavorable weather conditions, especially high temperature. Humic acid and amino acid, as well-known biostimulants, can directly or indirectly influence on plant growth and yield and significantly mitigates the injuries caused by abiotic stresses. In some studies, the use of humic acid has been reported increase root length, improve nutrient uptake, and increase chlorophyll synthesis. Amino acids in potato plant increase natural resistance to stresses. It seems that biostimulants and some nutrition elements can be applied as a strategy to reduce the negative effects of high temperatures. Therefore, this study was conducted to evaluate the effect of plant growth biostimulants on growth indices, yield and yield components of potato cultivars in Khuzestan region.

This research was conducted in two studies. First study was carried out as a factorial experiment in a randomized complete block design (RCBD) with two factors including 16 treatments in three replications at Behbahan Agricultural Research Station in 2019-2020. The first factor was application of plant growth biostimulants at eight levels: control (application of chemical fertilizers according to soil test), humic acid, free amino acid (L), amino acid-Zn, amino acid-K, amino acid-Ca, amino acid-K-Ca and application of all studied biostimulants (except free amino acid). The second factor consisted of two potato cultivars: 'Ottawa and Sante'. In the second study, growth analysis was done in a split plot factorial based on RCBD with three replications. Main plot consisted of five sampling periods with 15 days intervals. Sub plot consisted of combination of eight plants growth biostimulants and two cultivars of potato as factorial. Tubers were planted at mid January. One week before harvesting haulms were defoliated and tubers were harvested at mid May. Humic acid was used as fertigation at 10 kg.ha-1 in the early stages of growth. Foliar application of amino acid, amino acid-Zn was done at two stages, tuber initiation and the beginning of tuber bulking. Foliar application of amino acid-K, amino acid-Ca was done at two stages, the beginning and middle of tuber bulking. Amino acid and amino acid-nutritional element were done at a concentration of 0.5 %. Varince analysis were done by MSTATC statistical software and meanes were compared using Duncan’s multiple test range at the 5% level.

The results showed that in two cultivars, application of all studied biostimulants (except free amino acid) significantly increased tuber yield compared with control. In Sante cultivar, the highest yield was dedicated in the treatment of combined, and the yield of this treatment was significantly higher than the yield of  alone application of these substances. In Ottawa cultivar, the highest yield was achieved by application of combined biostimulants, but the differences of tuber yield among this treatment and treatments of amino acid-K, amino acid-Ca and amino acid-K-Ca and humic acid were not significant. The results of growth analysis showed, in the most sampling periods, the highest tuber and crop growth rate were recorded in the combined treatment. Therefore the highest tuber yield was observed in this treatment. In the first and second sampling periods, application of humic acid or amino acid-Zn were more effective than other treatments. But, in the third and fourth sampling periods, treatments of amino acid-K, amino acid-Ca were more effective in comparision to alone of these substances. In different sampling periods, tuber and crop growth rate in Ottawa cultivar was significantly higher than Sante cultivar.

According to results, in Sante cultivar, the combined treatment of plant growth biostimulants produced the highest yield in comparision to any individuals of these substances. Therefore, use of humic acid as fertigation in the early stages of growth and foliar application of amino acid- Zn at two stages tuber initiation and the beginning of tuber growth and amino acid-K-Ca at two stages the beginning and middle of tuber growth, are recommended. In Ottawa cultivar, the differences of tuber yield among treatment of combined application of growth biostimulants, amino acid-K, amino acid-Ca and amino acid-K-Ca and humic acid were not significant. Therefore, based on the finding of the present study, it could be concluded that treatments of amino acid-K, amino acid-Ca or humic acid may be an effective growth biostimulants for improving yield of Ottawa cultivar.

Quinoa (Chenopodium quinoa Willd) is a dicotyledonous plant that belongs to family Amaranthaceae and subfamily Chenopodiaceae, native to the Andes of the Americas. Due to the climatic diversity of Iran, one of the notable cases is the study of planting history as the most important factor in adapting and increasing plant yield; therefore, this study was conducted to determine the optimum sowing date of quinoa in Kavar (city of Fars province). In that experiment, the yield response and the yield components of different cultivars of quinoa were examined in relation to the different sowing dates in spring cultivation.

In order to study and determine the most suitable genotype and sowing date of Quinoa, a factorial experiment was conducted with three replications in Kavar, Fars, Iran. Experimental treatments included five quinoa genotypes (Q29, Q26, Red Carina, Titicaca, and Giza1) on the three dates of February 10 and 20, and March 1, in the two years of 2018 and 2019.Each experimental plot consisted of five rows, five m in length and 30 cm apart. Seeds were sown at a density of 67 seeds.m-2. Plants in the three center rows (three m long) in each plot were used for the measurements of the yield of the grain and its components. To determine the number of panicles per unit area, before the final harvest, count half a meter in each experimental plot, specific quadrants was used to count the number of panicles. To calculate the weight: each thousand seeds (1000 seeds) of the seeded seeds were randomly counted with each seed counting machine and weighed with an electric scale (with an accuracy of one thousandth of a gram), And from the division of grain yield to biological yield, the harvest index was calculated. To measure the height of the plant from each experimental plot, 10 plants were randomly selected and the necessary measurements were performed. Water use efficiency (WUE) in the plant was calculated from the division of grain yield to amount of water used. The growth and Efficiency and contribution of materials remobilization were measured too.

The present results showed that sowing date and genotype had a significant effect on grain yield, plant height, and 1000 grain weight, biomass and number of panicles. The most plant height belonged to the Titicaca genotype on the second and third sowing dates. Q26 had the highest 1000 grain weight among the studied genotypes and was obtained on February 10 sowing date. The relationship between WUE and yield was linear regression in different genotypes positively and significantly (r2= 0.715) and the highest WUE belonged to Giza1 genotype on February 10 (1.4 kg.m-3). The effect of sowing date and genotype on dry matter accumulation rate, remobilization contribution and remobilization efficiency of photosynthetic materials were significant. Q29 genotype had the highest rate of dry matter accumulation (6.1 g.m-2.day-1). The highest remobilization contribution of stored materials and their efficiency belonged to the sowing of quinoa on February 10. The highest grain yield was obtained in Q26 genotype on February 10 of 4080kg.ha-1. Delayed sowing reduced yields in all genotypes.

The highest yields were obtained from Q29 and Q26 genotypes. The highest yield of these genotypes was on February 10. Also, the delay in sowing seed yield was reduced. The results of this study showed that the genotypes studied in the spring cultivation conditions had different with yield potential. Accordingly, the most optimum sowing date in terms of grain yield under climatic conditions of Kavar region in this study was planting at tenth and twentieth of February.

Wheat is the most important staple food crop in the world as well as in Iran. About 63% of the wheat cultivation areas and 40% of its production is under dryland conditions in Iran. Water and nitrogen are the two most important limiting factors for wheat production in dryland conditions. However, the role of water is about 2.3 to 3.9 times the nitrogen because the water deficiency limits the absorption of the nutrients especially nitrogen. Nitrogen deficiency is very critical than the other nutrients for plant growth in the arid and semi-arid region. Therefore, applying supplemental irrigation (wherever it is possible) at the critical crop growth stages along with nitrogen fertilizer will increase wheat production by increasing the greenness and photosynthetic activity of the plant. In this regard, the cereal department of Dryland Agricultural Research Institute (DARI) has introduced different new wheat cultivars for supplementary irrigation conditions in the last decade. Hence, evaluating the response of bread wheat genotypes to different rates of nitrogen under supplementary conditions, determining the relationship between nitrogen requirement and water status of varieties as well as the relationship between these factors with yield components and effective traits to improve the quantity and quality of the crop, are the key factors for wheat production in dryland areas.

A field experiment was conducted to evaluate the response of dryland wheat (Triticum aestivum L.) genotypes to different rates and timing of nitrogen application under supplemental irrigation in 2018-2020 cropping seasons at DARI, Maragheh, Iran. The experimental design was a randomized complete block with three replicates based on split-split-split plot arrangement consisting of two irrigation treatments (50 mm in planting time and 50 mm in planting time + 30 mm at booting stage) in the main plot; nitrogen application time (fall application and split 2/3 in planting time + 1/3 in booting stage) in the sub-plot; four nitrogen rates (0, 40, 80 and 120 kg.ha−1) in the sub-sub-plot and three genotypes (Takab, Hoor and Griset-16 (sup-96-18) in the sub-sub-sub plots. The soil samples were collected from 0-25 cm depth before the sowing and were determined soil texture (loam to silty clay), pH, EC, Organic carbon, P (Olsen method), K (Sodium bicarbonate method), micronutrients (Fe, Mn, Zn, and Cu) by DTPA method. Because all these elements were more than critical levels (P: 10 mg.kg-1; K: 250 mg.kg-1; Fe: 5 mg.kg-1; Mn: 11 mg.kg-1; Zn: mg.kg-1 and Cu: 1.4 mg.kg-1) in the soil, only nitrogen rates were used in the experiment (Feiziasl et al., 2004; Feiziasl et al., 2009). The data was collected for biological and grain yield, yield components, plant height, spike length, nitrogen use efficiency (NUE), water use efficiency (WUE), and seed quality (Seed protein, Number of Zeleny Grain hardness, Grain starch). The GenStat14 software was used to combined analysis of variance and mean comparison of traits by Duncan's Multiple Range Test. The CurveExpert 2.6.3 software was used to fit equations, Excel to draw charts and Xlstat2016 software to do principal component analysis.

The first year of the experiment produced a significantly higher yield (P≤0.05) due to higher precipitations. Two stages of supplementary irrigation significantly increased biological yield, grain yield, and straw yield by 2975, 895, and 2069 kg ha-1, respectively. Although fall and split application of nitrogen had no significant effect on yield and yield components, fall application increased grain yield, NUE, and WUE by 195 kg.ha-1, 1.97 kg.kg-1, and 0.5 kg.ha-1.mm-1, respectively. Nitrogen application increased grain yield components for which the number of spikes per square meter was increased more than the two others. The nitrogen requirement of dryland wheat was determined 70 kg.ha-1 under single irrigation at planting time by fertilizer placement method while it was determined 90 kg.ha-1 for two stages supplementary irrigation for which 2/3 of it was applied at fall (planting time) and 1/3 at booting stage with supplementary irrigation.

 Although the interactions of irrigation, nitrogen rates, application times, and genotypes factors on grain yield were not significant, supplemental irrigation and nitrogen application could increase the yield production of dryland wheat genotypes.

One approach for medicinal plants cultivation expansion is to sow them in rainfed areas. In recent years, the study of valuable types of medicinal plants, development of cultivation and meeting the needs of the pharmaceutical industry has been one of the goals of scientific and research centers. Savory is a valuable medicinal species in the world. The aerial parts and volatile constituents of Satureja species are commonly used as a medicinal herb and flavoring agents. They can be used as antioxidant, antiseptic, antispasmolidic and as a condiment in food industry. Two of the most important species of savory grow wildly in Iran are S. sahendica and S. spicigera. Both of them are native species to semi-arid zones of Iran, and considered as aromatic and medicinal plant. Wheat straw and cow manure are the two most common soil amendments which have been using for improving soil structure and soil fertility. Limited studies have been performed on rainfed cultivation of medicinal species, especially savory. This study was conducted to evaluate the effects of planting bed on vegetative characteristics and yield of two savory species in rainfed conditions.

Experiment was carried out for three years (2018-2020) as split plots based on a randomized complete block design with three replications. The experiment was conducted at the Fereidoonshar (32°56’N, 50°06’E and an altitude of 2491 m). Planting bed as main plot consisted of cow manure (30 ton.ha-1), wheat straw (10 ton.ha-1) and control (without manure and straw); species as subplot consisted of S. sahendica and S. spicigera. Morphological traits including plant height, crown diameter, canopy area per plant, canopy area per square meter, and number of stems per plant; and yield traits including total dry weight, leaf dry weight and stem dry weight were thetraits which were measured over the study. The recorded data were subjected to analysis of variance (ANOVA) and least significant difference (LSD) on 0.05 probability level for comparison of means using SAS (ver. 8.2) software.

The results of analysis of variance showed that the effects of planting bed, year and their interactions on the measured traits were significant in many cases. Results showed that the highest values of plant height (46 cm), crown diameter (35 cm), canopy area (3980 cm2) and number of stems per plant (23) were seen in S. spicigera. Also, the highest rates of total dry weight and leaf dry weight were seen in S. spicigera, 695 and 470 kg.ha-1, respectively. Wheat straw treatment reduced aerial parts dry weight in two species in the first year, but in the second year it caused an increase. Cow manure made a slight increase in two species growth only in the first year. The highest values of all measured traits in two species were achieved in the last year of measurements, as the values of leaf dry weight for S. spicigera and S. sahendica were 1018 and 855 kg.ha-1, respectively. The highest values of leaf area index and harvest index were observed in the first year of the experiment including 4.59 and 72, respectively.

Cow manure was able to significantly increase the yield of the two species in the first and second years, especially for S. spicigera. Although the use of wheat straw reduced the rates of morphological and yield treatments of the two species of savory in the first year, but increased them in the second year, so It is recommended to cultivate savory after decomposition of wheat straw. The role of increasing vegetative growth and plant yield under the influence of increasing plant age was quite obvious. On the whole, in order to produce savory under dryland conditions similar to this research, cultivation of S. spicigera withouth usng manure or straw could be recommended, although incorporation of these amendments into the lower depth of the soil could be more effective on this species growth and yield.