Iran Agricultural Research
Volume:41 Issue: 1, Winter and Spring 2022

To studies a suggested method for estimating fractional green canopy cover (FGCC or CC) from normalized difference vegetation index (NDVI) in Iran, a research project was carried out on four wheat farms in the large-scale region, in Fars and Khuzestan provinces during four growing seasons from 2015 to 2019. Two different image classification methods were used to provide the CCs of farms. In both methods, R2s were greater than 0.95 and NRMSEs were less than 0.15. A simple regression equation was constructed between CC and NDVI of 64 Landsat 8-Oli images with high accuracy from 2015 to 2018. The R2s of CC-NDVI equations were 0.84, 0.85, 0.88, 0.80 and 0.76 in Dezful, Omidieh, Darab, Zarghan and all sites together. The simple regression equation was used to simulate CC in 2018-2019 for validating the equation and had a good agreement with the measurements, especially in using the general equation of all sites. The p-values of the four equations were less than 0.03. As a suggested method, the CC-NDVI equation can be used to predict CC from NDVI as a low-cost and less time-consuming method in the study area to use in crop growth studies, crop growth models and crop growth management.

Biochar, as a soil amendment, improves soil fertility and enhances crops productivity under water or salinity stresses. This study aimed to investigate the effects of biochar application rates (zero, 40, and 80 Mg ha-1) under three irrigation regimes (50, 75, and 100% of plant water requirement) and salinity levels (0.6, 6, and 12 dS m-1) on physiological parameters, evapotranspiration, and growth of wheat grown under greenhouse condition. The experiment was performed in a complete randomized design with a factorial arrangement in four replications. Application of a high level of salinity (12 dS m-1) declined wheat grain yield by 28%, 57%, and 75% in comparison with that at 0.6 dS m-1 under zero, 40, and 80 Mg ha-1 biochar application, respectively. The results showed that application of 80 Mg ha-1 biochar decreased wheat evapotranspiration by 24.4% in comparison with that at no biochar application. In addition, the application of biochar improved wheat stomatal conductance and canopy temperature under both abiotic stress conditions. Salinity (12 dS m-1) and deficit irrigation (50 %), respectively declined wheat evapotranspiration by 19% and 15% in comparison with that at 0.6 dS m-1 and full irrigation. Also, the application of biochar and salinity both declined the root length density due to the accumulation of salt around the root. It is concluded that 40 Mg ha-1 of biochar can be applied as a soil amendment to improve wheat yield and reduce evapotranspiration under applied deficit irrigation and salinity stress.

In recent decades, the application of biochar to improve soil fertility and soil physical property and also enhance crop tolerance to abiotic stress has been proposed by researchers. Therefore, the effect of three levels of biochar (zero, 40, and 80 Mg ha-1) produced from wheat straw, irrigation water salinity (0.6, 6, and 12 dS m-1), and three irrigation regimes (50, 75, and 100% of crop water requirement) on wheat grain ions and soil ions concentration as well as some soil physical properties after wheat harvest were investigated under greenhouse conditions. The results showed that the Na+ and K+ concentration in soil significantly increased by application of biochar and also salinity, while application of 50% deficit irrigation significantly declined the Na+ and K+ concentration in soil. Also, the soil ECe of the highest level of biochar and salinity increased 2.1 and 1.59 times that of without biochar and salinity, respectively, while application of deficit irrigation significantly declined the soil ECe due to lower application of saline water and lower accumulation of salt. Considering the main effects of treatments, application of the highest level of biochar (80 Mg ha-1) increased the K+ concentration in grain, while application of saline water (6 and 12 dS m-1) and deficit irrigation (75% and 50 %) both declined the K+ concentration in grain. The application of biochar enhanced the soil water holding capacity. In conclusion, it is recommended to apply wheat straw biochar to increase soil fertility and increased water storage capacity in the soil. Finally, the application of non-saline biochar is suggested to prevent salinization and the destruction of agricultural soil.

The bending behavior analysis of boxwood stalk, including bending force, bending strength, and Young’s modulus, were carried out at different loading rates and internode positions as a function of applied force direction to design a new hedge trimmer machine. Given that the cross-section of the stalk is oval, the stalk specimens were examined in a quasi-static process at four loading rates of 5, 10, 15, and 20 mm min-1, three internode positions of fifth, tenth, and fifteenth, and two directions of the applied force of the oval major (x-direction) and minor (y-direction) diameters. The results showed that the loading rate of 20 mm min-1 had 20–30% and 15–20% lower values for the bending force and bending strength than the loading rate of 5 mm min-1 for all stalk regions and both directions of applied force. Also, the loading rate of 20 mm min-1 had 50–70% and 35–40% lower values for Young’s modulus than the loading rate of 5 mm min-1 in the x and y directions of applied force, respectively, for all stalk regions. The fifth internode had 40–48% and 35–37% lower values for bending force and bending strength than that of the fifteenth internode position for all loading rates and both applying force directions. Also, the fifteenth internode position had 50–80% and 40–60% lower values for Young’s modulus than the fifth internode position in the x and y directions of applied force, respectively, for all stalk regions.

Scallion (Allium fistulosum) is one of the essential edible vegetables with various medicinal uses. The seeds of this plant have low germination power, which may disappear due to storage conditions. In this study, the germination characteristics of scallion seeds were experimented with a factorial arrangement based on a completely randomized design with three replications in the physiology laboratory of Khorasan Razavi Agricultural and Natural Resources Research and Education Center in 2019. The first factor was indole-3-butyric acid (IBA) at 0 (or control), 100, and 200 ppm, and the second factor was gibberellin (GA3) at the same concentrations. The results showed that the maximum germination percentage was obtained by 200 ppm of gibberellin without using IBA. The maximum rootlet dry weight (7.02 mg) was recorded with 100 ppm of GA3 and IBA. The maximum allometric coefficient was obtained using 100 ppm IBA and 200 ppm GA3. The maximum seed vigor index was observed at 100 and 200 ppm of GA3 with 0 ppm of IBA (2.18 and 2.33, respectively). The maximum seedling vigor length index (0.799) and seedling vigor weight index (6.77 ) were obtained when 200 ppm of GA3 was applied with 0 ppm of IBA. In general, the results showed that the use of different concentrations of gibberellin has a significant effect on increasing germination and vigor index in scallion seeds.

Efficiency is the first step towards accomplishing sustainable agriculture. To provide a comprehensive image of the status of potato-producing provinces in Iran, this research was conducted to rank potato-producing provinces in Iran using the DEA ranking models, including cross-efficiency, super efficiency, best and worst relative efficiency, and distance to the ideal hyperplane. Then to provide a more comprehensive image of their status, the results were integrated using the TOPSIS technique for 2018. In this regard, the research considered yield and gross profit as indicators of production and profitability. The results showed that considering yield as an output shows higher efficiency than when profit is considered. Higher yield efficiency than profit efficiency means that producers care more about increasing production as an objective output than increasing profitability. The rankings of the provinces revealed that different ranking models do not provide similar results, so they need to be integrated to give a more precise assessment. The integration of these indicators by the TOPSIS method shows that the provinces of Mazandaran, Kerman and West Azerbaijan, which have good ranks in yield and profit efficiency, can be good patterns for other provinces. Furthermore, profit and yield efficiency are negatively related to seed, K-fertilizer, and pesticide, so the management of biofertilizers, as well as biological control and integrated pest management, are recommended for the improvement of the efficiency of potato-producing provinces.

This study aimed to study the mutual effects of grafting and Arbuscular mycorrhiza on cucumber. The experimental design was a factorial experiment based on a randomized block design. Accordingly, treatments were mycorrhiza inoculation including non-inoculation mycorrhiza (AM1) as the control, mycorrhiza with 2400 spores per pot (AM2); and grafting, in which cucumbers (Cucumis sativus var. super daminos) were grafted on Lagenaria siceraria (R2) and non-grafted cucumbers (R1), and the salinity concentration included the control (C), without adding NaCl, medium salinity equal to 30 mM NaCl and high salinity equal to 60 mM NaCl with three replications. The results showed that growth parameters such as the number of male and female flowers, time of appearance of the first male and female flower, the node number of the first female flower, stem length, the number of nodes and leaves, shoot and root fresh weights, were decreased with salinity stress. Grafting also affected the time of appearance of the first male flower and in the node, the number of the first female flower appearance at high and moderate NaCl concentrations. The appearance of the first female flower was postponed under the high concentration of NaCl. Photosynthetic reduction detected in cucumbers subjected to salinity was associated with a decrease in their chlorophyll and mesophyll conductance. In addition to reducing the photosynthesis rate, chlorophyll fluorescence was also affected by moderate and high salinity stress. Generally, grafting and mycorrhiza application decreased the harmful effect of salinity, especially in moderate salinity.

This study was carried out in order to determine the cost and benefit of investment, cost price, margin safety ratio, gross margin, benefit-cost ratio, and economic value of the wheat seed losses in processing lines of domestic systems of  Ar-Mashin, Arvin-Sanat, Ramsanat Bhareh, and Azaran Boojar lines, located in Fars, Khorasan Razavi, Khouzestan and Golestan provinces, respectively in 2018. In this case, profitability analysis and engineering economic indicators were considered to achieve the research objectives. According to results, the average cost price of wheat seed (per kg) in target processing lines and provinces was estimated to be 19633.9 Iranian Rials, which was lower than selling price in most of the provinces. Average gross margins for processing lines in Jovein Cultivation and Industry, Fars Thousand Khoosheh Talayehdaran, Amiran Zagros Taha, Army Sample, Sabz Dasht Sorkheh, and Razmandegan Companies in target provinces were positive and was 11.2 billion Iranian Rials, but, this gross margins in Marvdasht Rural Cooperative Company, Rural Cooperative Company of Gonbad, and Zarrin Daneh Benvar Company in Khouzestan were negative. Average benefit-cost ratio in domestic processing lines was 1.05 during the analysis period. Also, average useful waste separated from the seed processing line was 20.2%, and the value of lost seeds was 958.6 million Iranian Rials. Therefore, it is recommended that profitable companies continue their activities by increasing the amount of purchased inbound seeds to minimize losses and receive positive economic benefits.

Drought stress is one of the major limitations in crop production worldwide. Genotype mixture has been evaluated as a new way to increase yield in different crops. In this study, different genotype mix systems in durum wheat (Triticum durum Desf.) as impacted by drought stress were investigated. The experiments were conducted under normal and water-stressed conditions in the form of randomized complete block designs, each with three replicates,  in the research farm of the College of Agriculture and Natural Resources of Darab, Shiraz University for two years (2016-2017 and 2017 - 2018). Monocultures of four durum wheat genotypes including Shabrang and Behrang cultivars and DW-92-4, DW-94-14 lines and their binary and quadruple mixing combinations were used in the cropping systems. Drought tolerance indices, including stability tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI), yield stability index (YSI) and a new criterion designated as SIIG (Selection Index of Ideal Genotype) were used and evaluated to identify the best cropping system. Behrang+DW-94-14 cropping system showed the highest GMP, STI and MP values of drought indices, while the highest value (0.890) of SIIG index was identified in the Shabrang+DW-94-14 cropping system. Positive correlations were found among GMP, STI, and MP with YP. Moreover, biplot analysis of these indices using principle component analysis revealed strong positive correlations among GMP, STI and MP while SIIG index was closely related to YSI index. GMP, MP, and STI indices were identified as the best criteria to identify cropping systems in water-stressed conditions. In both normal and water-stressed circumstances, quadruple genotype culture yielded better yields than monoculture and most binary cultures. However, the highest seed yield was obtained in the normal and water-stressed treatments in the Behrang + DW-94-14 cultivation system with an average of 8815 and 7342 kg ha-1, respectively.

In the present study, the application feasibility of an air-assisted centralized metering device equipped with a fluted feed roller was investigated. The performance of the proposed metering device for rapeseed planting was evaluated in the laboratory. For this purpose, effects of rotational speed (n) of the metering device shaft (at levels of 46.5, 48, 79, and 96 rpm), active roller length, L, (at levels of 1/6, 1/4, and 1/3 of the total length of the fluted roller), and number (N) of seed delivery tubes (at levels of 16, 24, and 32 outlets) on the seed weight delivery coefficient of variation (CV) and seeding rate (SR, kg ha-1) were investigated. A factorial experiment arranged as a completely randomized design with three replications was used to perform the laboratory experiments. Results showed that the effects of all treatments (n, L, and N) on both SR and CV were significant. The interactions of N×L and L×n were also significant on both SR and CV. The interaction of N×n was significant only on the SR. The interaction of N×L×n was also significant on the SR. Results of mean comparisons revealed that the CV decreased as n and L increased; whereas, it increased as N increased. However, the opposite pattern was observed for the SR with changing the mentioned factors. Minimum SR value (6.1 kg ha-1 – in the recommended SR range for rapeseed planting) was obtained at 46.5 rpm and L1 (1/6 of the total length of the fluted roller) with 32- outlet seed delivery tube.

In the sorghum plant, prussic acid and nitrate are the main anti-nutritional compounds that can harm animals if the permitted levels are exceeded. This study aimed to determine the effect of cutting sequentially on prussic acid and nitrate content in eighteen varieties of sorghum forage including four Iranian domestic and fourteen imported varieties. All varieties under the same irrigation, fertilization, light, and temperature conditions were planted. The first and second cuttings were conducted at the flowering stage, and 50 days later, respectively. According to the results, the foreign variety of FS one BMR had the highest amount of prussic acid in both cuttings but this compound level reduced from 481 ppm in the first cutting to 397 ppm in the second one. While the lowest content of prussic acid was detected in the Titan variety (163 and 37 ppm in the first and second cuttings, respectively). In the second cutting, nitrate contents were also significantly lower than those in the first one. Moreover, two varieties of Juicy sweet 2 and Juicy Sweet BMR SSH.1 recorded the maximum nitrate content (2417, and 2089 ppm, respectively) in the first cutting. By contrast, the minimum nitrate found in KFS-2 and FGCSI09 varieties by 127 and 143 ppm, respectively at the same time. Regarding the second harvesting, HFS1 and PFS-21 varieties recorded the highest nitrate content (162 and 150 ppm, respectively) whereas FGCSI12 and PHFS-27 varieties had the minimum amounts of 14 and 64 ppm, respectively. As compared with the recommended tolerable levels of prussic acid and nitrate in animal feed, the  studied varieties were not toxic in the first cutting, and both compounds decreased significantly in the second cutting.