Identifying the constraining factors of production and yield gap is very important. Therefore; this research was performed to identify the production constraining factors of local rice cultivars. All management practices from nursery preparation to harvesting stages for 100 paddy fields of local rice cultivars were recorded through field studies, in Sari, from 2015-2016. In the CPA, the actual and calculated potential yield were 4495 and 5703 kg/ha, respectively and the gap was 1221 kg/ha. The yield gap caused by number of top-dressing variables was 324 kg/ha, equal to 27% of the total yield gap. The yield gap related to previous year of legumes cultivation was 218 kg ha-1, equal to 18% of the total yield variation. Among the 10 variables entered in the CPA model, the effects of top-dress fertilizer application and its application frequency and foliar application were remarkable, which could compensate a significant part of the yield gap (444 kg/ha, 37% of total) in the farmers’ fields by managing these variables. According to boundary line analysis (BLA) finding, actual yield mean on the basis of optimal limit related to 12 variables under study was 5369 kg/ha, with 881 kg/ha yield gap . Mean Relative yield and Relative yield gap for 12 variables (transplanting date, seedling age, number of seedlings per hill, planting density, nitrogen and phosphorous per hectare, nitrogen before transplanting, harvesting date, lodging problem, pest problem, diseases problem and weeds problem) were 83.64 and 16.35 kg/ha, respectively. Based on the finding, it can be stated that the model precision is appropriate and can be applied for both estimation of the quantity of yield gap and determining the portion of each restricting yield variables.

To study the effect of salinity stress on some physiological traits in wheat cultivars (Triticum aestivum L.), a factorial experiment based on randomized complete block design with three replicates was performed at 2017 in the research greenhouse of Agronomy Department, University of Tehran. Salinity treatments at two levels; control (1.2 dS/m) and sodium chloride treatment (16 dS/m) and seven wheat cultivars, Rowshan, Inia-66, Mahdavi, Khazar-1, Karaj-2, Ghods and Shole were the experimental treatments. According to the results, Relative water content, yield and its components and potassium/sodium ratio decreased in all genotypes while Na+ content and remobilization of carbohydrates were increased. Salt resistant varieties, Roshan and Inia-66, had the highest level of Relative water content, remobilization of soluble carbohydrates and number of grains per spike. In addition, Roshan cultivar showed the highest potassium concentration and K+/Na+ in the shoots, while Ghods and Sholeh as sensitive cultivars had the highest sodium concentration in the shoots. Findings showed that the ability of a cultivar to remobilize soluble carbohydrates is one of the traits that determine salt stress tolerance, hence, this trait is suitable for evaluating salt tolerance of wheat cultivars in the future investigations.

In order to investigate the possibility of quinoa producing in Garmsar, Iran, a factorial experiment conducted in randomized complete block design with three replications in 2018-2019 growing season at Garmsar Agricultural Research Station. The factors were planting date at three levels (March 6th, April 1st and April 6th) and the three genotypes of quinoa (Q26, Q29 and Titicaca). Results showed that the effect of planting date was significant for all studied traits except the harvest index. Also, all studied traits were significantly different in all genotypes. Titicaca planted on March 6th had the highest yield (2276 kg.ha-1).The grain yield and yield components decreased with the delaying the planting date. Compared to early plantings, Latest date, April 6th, led to reduction of all traits, especially grain yield (about 50%). The results of simple phenotypic correlation between the studied traits showed that grain yield per hectare had the highest correlation with plant yield (0.877) and then with leaf area index (0.832), panicle weight (0.815) and number of branches per plant (0.745) that was significant at the 1% probability level.

To investigate the effect of weed interference and weed-free periods on Balangu (Lallemantia royleana Benth. in Wall) and to evaluate the critical period of weed control (CPWC) in this oilseed crop, an experiment was conducted as a randomized complete block design with three replications in Naghadeh region in 2018. Experimental consisted of two groups of treatments; weed infestation treatments (infestation for 144.2, 345.9, 574, 848.2, 1147.6 and 1451.3 growing degree day (GDD) after transplanting and then plots were remained weed-free the rest of the growing season) and weed-free treatments (weeding for 144.2, 345.9, 574, 848.2, 1147.6 and 1451.3 GDD after transplanting and then plots were remained infested until harvesting time). In each block, one weed free and weed infested control was for all the growing season. Results indicated that the density and dry biomass of weeds were increased as weed removal was delayed. In contrast, density and dry biomass of weeds were decreased as weeds establishment was delayed. Height, tetrachenes fruits, ripened achenes, 1000-seed weight and biological, seed and Relative yields of Balangu were decreased and increased as the duration of weed-infested and weed-free period increased, respectively. Also, logistic and Gompertz curves fitted to data showed that the beginning and end of the CPWC based on a 10% yield loss of Relative yield, was estimated to be from 11 to 108 days after transplanting (97 days weed-free period) in order to prevent a noticeable yield loss.

Harvest time, in olive, is an important key to achieve high quality and quantity of oil with a desired and balanced fatty acid (high oleic acid and low palmitic and linoleic acid) composition. Appropriate harvesting time varies in different locations depending on climatic and agronomic situations and identifying the right time for harvesting may bring about a high quality oil. Thus, the current study was carried out to determine the best harvesting time for two Iranian (Mari and Shenge) and two foreign (Kroniki and Arbequina) cultivars in the region of Tarom, Zanjan, (north of Iran). The results obtained indicated that palmitic, oleic and stearic acid contents decreased and linoleic and palmitic acid contents increased with the progress of ripening. In addition, oil percentage increased with the progress of fruit growth and development. Based on the amount of desired fatty acids, the best harvesting time for the Mari, Kroniki and Arbeqina cultivars, was 180 days after full bloom. It was revealed that the cultivar Shenge is not suitable for oil extraction, due to the low percentage of oleic acids. Therefore, Shenge could be cultivated for producing olive cans rather than olive oil and the best harvesting time for Shenge is 120 days after full bloom.

Due to the importance of Tabriz in various historical periods after the Mongol’s invasion to the end of the Qajar period, as continuously being the capital city or the residence city of the prince, entrance to this city has been reflected in various reports. Most of the foreigners who entered Iran from European countries came from Caucasus Road to Tabriz and reported many buildings on their way. Moreover, this road was one of the most significant roadways for Caravans on the Silk Road, where various residential buildings have been constructed. Alaki caravansarai is one of the most important roadside accommodations in Northwest Iran, and so many reports about it and the quality of its façade decorations can be traced in the travelogues of foreigners who traveled to Iran. Its vastitude and elegant entrance gate nevertheless, this building has unfortunately been neglected and was about to be ruined in the 19th century and afterward. However, the beauty of its entrance gate has gained the attention of many people and has been reported in many sources. Based on the ornaments used, recent sources in the history of architecture have estimated its date to the 12th century and Ilkhanid Abū Saʿīd Bahādor Khan and the Timurid period. These sources based their estimation only on the type of ornaments used on its entrance gate and its probable that the existence of dated artworks of the Ilkhanid period nearby, such as the Mihrab of Marand’s Jame Mosque, has influenced this speculation. This article aims to meticulously study this building in various travelogues, al-Wqafīyya al-Rashīdīyya, and other sources in the history of architecture and discusses the ornament types used and their history. The detailed study of the documents and sources indicated that this building could belong to the presidency period of Ḵᵛāja Rašid-al-Din Fażl-Allāh, and based on his emphasis to establish this building, can be dated 1297-1309. The ornaments, moreover, indicate the transient period from brickwork to tilework which happened in the late 13th and early 14th centuries

To increase yield of sunflower, it is essential to determine proper sowing dates for its cultivars. A factorial experiment was carried out with 2 factors in RCBD with 3 replications at the Agricultural and Natural Rresources Research Station of Khoy, Iran, during 2007-2008. Results showed that sowing date had significant effects on the plant height, stem diameter, percentage of empty achenes and harvest index. Latest planting date reduced all of the parameters under study (except empty achenes percentage). Delaying planting date reduced seed yield. The yield of Azar-gol, due to its greater head diameter, seed number per head and heavy seeds, was higher than the others. Highest seed yield was obtained from Azar-gol at second sowing date. Cultivars producing over 3000 kg seeds per hectare at latest sowing date in this regions, would be promising ones to be used in double cropping system and thus increase farmers income.

Currently deficiency of raw materials and initiative resources caused an increasing need of cellulose industries to new lingo cellulose products and resources. kenaf as a fibrous plant is considered along with the other plant sources that their bast has suitable fiber. This experiment was carried out in split–plot form with 4 replication in order to evaluation effect of harvest time and genotype on hemp production in Research Farm of Gorgan University of Agriculture Sciences and Natural Resources in 2007. Experiment factors were six genotypes consisting of cubana, Neiger, 9277, Cubana 2032 and 7551, and three harvest times consisting of  85, 105  and 135 days after swing. Result showed that yield, bast, pith, and stem yield were affected by harvest time. Bast to pith in second harvest time and leaf to stem in first harvest time was more than the other times. In addition, interaction between genotype and harvest time was not significant. Genotype Neiger was the best genotype for yield, bast, pith and leaf yield also Cubana 2032 and Cubana with 40.41 and 40.00 percent were the best genotypes for bast to pith ratio. Third harvest time was the best for most factors except leaf to stem ratio results of this study showed that increase in length of period of growing could be result in more production of fiber in kenaf.

Soil is one of the main treasures of each country that serious measures must be done for its protection, preservation and restoration. The first step in planning for the soil conservation and erosion control programs comprises the familiarity with the erosion condition, determining the Relative importance of sediment sources, and identification of critical zones within the watershed. The main objective of this study is to determine the Relative sediment yield potential of each lithological units of the Vartavan catchment by comparing the color of sediment grains median diameter with the grains color of each lithological unit. The results show that the soil particles of each sediment source unit almost were formed of a dominant color while the sediment samples were formed of the composition of different colors. Independent T-test between the mean values of the observed pigments and expected pigments indicate that the lithological units have different sediment yield from the expected amounts. The results has also show that the Relative sediment yield potential in the lithological units with black pigment (black shale containing coal horizons), white and red (plagioclase tuff and red mudstone), green (sandstone), gray (andesine) and finally brown (orbitolina limestone, Shale Limestone, red sandstone and tuff) is reduced, respectively. In general, the source fingerprinting method using the sediment grain color is a valuable method for determining the Relative power of different lithological units.

In recent decades, drastic land use changes in Golestan province caused to reduce a substantial amount of Hyrcanian forest. To investigate the changes, land cover maps produced using Landsat satellite imagery classification of sensors TM from 1984, 2012 and 2016 respectively used as input data in Land Change Modeler (LCM) to predict land cover changes in 2030. In order to assess the accuracy of modeling, statistics of Relative performance characteristic (ROC), ratio Hits/False Alarms and figure of merit was used. In continue to investigate the role of land use changes in water yield as one of ecosystem services was discussed. The results show the accuracy of artificial neural network with the ROC equal to 0. 949, the ratio Hits/False Alarms equal to 57 percent and the figure of merit is equal to 11 percent. Land use change modeling results showed that from 1984 to 2012, The most prominent changes were related to reduction of forest cover. This process modeling using artificial neural network showed, from 2016 to 2030 forest cover will be reduced about 30361 hectares. The results of water yield study showed that runoff in the area, particularly in the East and North East area has increased. This increase in the amount of runoff occurred as a result of land use change on forest ecosystems to agriculture. Results of this study improve our understanding of hydrological consequences of land-use changes, and provide needed knowledge for effectively developing and managing land-use for sustainability and productivity in the Gorgan-rood watershed.