Showing 34 results for Production
S Shrifi, H Rahmani, M Motamedi,
Volume 13, Issue 47 (4-2009)
Abstract
In dairy cattle, the increase in milk yield has been accompanied by a more negative energy balance during early lactation and a decrease in fertility. The 167 amino acid protein product of the ob gene was named leptin (derived from the Greek term ‘leptos’ meaning thin). The leptin hormone, as a 16-kDa protein is synthesized mainly by adipose tissue and is involved in regulation of food intake, energy balance, fertility and immune function. The expression and secretion of leptin are correlated with body fat mass and are acutely affected by changes in food intake. The objective of this study was to investigate the fluctuations of leptin concentrations during late pregnancy and early lactation, the effect of parity and BCS on plasma leptin concentration, and to investigate its fluctuation effects on reproductive status. Blood samples of 54 Holstein cows were taken at a fixed time of the day after milking but before feeding, from 2 weeks before calving until 6 weeks after calving. BCS and plasma leptin concentration were measured at 2-wk intervals. Leptin concentrations were affected by parity. Primiparous cows and cows in first parity had higher leptin concentrations compared with multiparous cows (P<0.05). Leptin concentration was not different in late pregnancy and early lactation. BCS was negatively correlated with plasma leptin concentration (P<0.05). Plasma leptin concentration did not influence reproductive traits (days in milk at first breeding, service per conception and open days).
M Kopahi, H Sadat Barikani, M Kavoosi Kelashomi, M Sasoli,
Volume 13, Issue 48 (7-2009)
Abstract
Risk and uncertainty have an important role in determining farmers' goals and their decision making. Risk affects optimal use of inputs and production efficiency. Using production inputs especially new inputs is one of the effective factors in production risk hence, it is necessary to obtain information about inputs use risk in order to find solution to risk management. For investigating effect of inputs use on production risk of rice crop in Gilan province, a quadratic form of production function was applied. Mean production function indicates constant return to scale. Also, risk production function shows increasing acreage and use of fertilizer cause increase in production risk of rice crop. Therefore, consolidating program of rice acreages and policy of paying subsidies to fertilizer input should be managed by considering producers' conditions.
A. Haghverdi, B. Ghahraman, M. Kafi, K. Davari ,
Volume 15, Issue 58 (3-2012)
Abstract
The objective of current study was to perform screening experiment, (phase zero of response surface methodology) the analysis of salinity and water tensions for spring wheat in Mashhad region and derive water production functions. The experiment was performed in the Research Field of Agricultural Faculty of Ferdowsi University of Mashhad in 2009-2010. Two water sources were selected: saline water (10 dS/m) and water without salinity limitation (0.5 dS/m). A single replicate factorial experiment with four variables and water requirements in different growth stages, was done with each variable having two levels, 20% and 100% of water requirements. The central points of experiment area with two replications were added for estimating the curvature in the fitted response surface. The results showed the water requirements in heading and flowering were the most important variables. The fitted water production functions estimated the yield of saline and non saline plots with correlation coefficients equalsing 0.95 and 0.99. In general, the obtained results proved the efficiency of the screening experiment in identifying the relative importance of variables and excluding the ineffective variables
S. Heydari Soreshjani, M. Shayannejad, M. Naderi, B. Haghighati,
Volume 19, Issue 73 (11-2015)
Abstract
In order to investigate the effect of different levels of irrigation on qualitative and quantitative yield and determine the corn's optimum depth of Irrigation in sShahrekord, a randomized complete block design experiment was done with 7 treatments including 40, 55, 70, 85, 100, 115 and 130 percent of soil moisture deficit and three replications in furrow irrigation. Effects of irrigation levels on yield, water use efficiency, weight of dry matter, plant height, stem diameter, median diameter, length and weight of corn were significant. Different levels of irrigation had no significant effect on seed oil and protein content, but their impact on plant fiber content was significant. With increasing depth of irrigation, stem length, grain weight and plant fiber content increased. The minimum and maximum corn yield were related to 40 and 130% of full irrigation with the yield of 43.1 and 88.1 tons per hectare, respectively. The maximum and minimum use efficiencies were 55 and 130% of full irrigation treatments with values of 16.17 and 10.1 Kg per cubic meter, respectively. The result of economic analysis showed that the water consumption is 5/582 mm, equivalent to 86% full irrigation depth.
M. Naderi, M. Shayannejad, B. Haghighati, S. Karimi, S. Heydari,
Volume 21, Issue 3 (11-2017)
Abstract
Considering water scarcity in Iran, application of deficit irrigation or water stress on some crops is inevitable. We need to provide appropriate design for deficit irrigation. Furrow irrigation management to obtain high efficiency and uniformity is difficult. Therefore, to investigate the variation of the input discharge, the cut-off time and furrow length that are effective on the efficiency and uniformity are very important. The purpose of this research is to provide a method for determining the optimum water use depth and optimizing furrow irrigation design in deficit irrigation conditions and finally comparing design characteristics under full irrigation conditions and deficit irrigation and comparison in different soil tissues. In order to achieve the objectives of this research, an experiment was conducted on forage corn in Shahrekord in a completely randomized block design with 7 treatments of different levels of irrigation in 3 replications. The costs and benefits functions were determined based on design variable and depth of applied water. The software Lingo was used to optimize the design variables (length of the furrow, the input discharge and cut-off time) and depth of applied water in deficit irrigation condition. The results showed that the highest net profit was obtained using 535 mm (equivalent to 79% of full irrigation) and 85 meters, 0.39 liter per second and 188 minutes, respectively, for the length of furrow, input discharge and cut-off time. The results of this design were compared to full irrigation of deferent soil textures. The results showed that an increase in the permeability of the soil caused length of furrow and the cut-off time to decrease, while the flow rate increases and depth of applied water or percent of deficit irrigation were constant.
A. Darzi-Naftchali, S. Rafierad, M. Khoshravesh, A. Asgari, M. R. Babaei, H. Zabardast-Rostami,
Volume 23, Issue 1 (6-2019)
Abstract
Water is a vital source for both human and biological living. Today, water management and conservation, not only both in developing countries but also in and the developed countries ones, has is of great importance. In the traditional economy, water is not considered as a productive factor in the national accounts; however, but in reality, water is the primary factor in many direct and indirect goods and services. To evaluate the effect of growth in the added value of agriculture, industry and electricity sectors on the added value of water sector in the Mazandaran province, coefficients of ARDL model were estimated using the Micro fit software. The extended Dickey-Fuller unit root test was used for the statistical test of variables. The static test of variables showed that all variables were significant at the 95% confidence level and were also consistent with the theory. A 1% increase (decrease) in the added value of industry and electricity resulted in the increase of 0.54 % and 0.39 %, respectively, increase (decrease) in the added value of the water sector, respectively. Also, 1% increase (decrease) in the added value of the agricultural sector caused in a 0.54% increase (decrease) in the added value of the water sector. Industry and electricity sectors affected the added value of water sector more than agriculture. In the long-term, the growth of the added value of the industry sector had the greatest impact on the growth of the added value of water sector. Based on the results, controlling water use in agriculture, industry and electricity sectors increases increased the effects of the added value of these sectors on the added value of the water sector.
A. R. Alipour, S. H. Mosavi, A. Arjomandi,
Volume 23, Issue 2 (9-2019)
Abstract
Increasing the productivity and conservation of limited water resources in the agricultural sector, especially in the agricultural sub-sectors, is closely related to the revision of the traditional approaches of production system in the agricultural sector of developing countries. The aim of this study was to develop the optimal combination of crop production in Varamin Agricultural and Animal Husbandry Complex as one of the leading agricultural units in the agricultural sector of Varamin County with the emphasis on increasing water use efficiency. For this purpose, the statistical data and information of the 2015-2016 crop year of the complex were used in the framework of the multi-criteria decision making model. The results showed that in the optimum crop pattern in this unit, the priorities of maximizing net energy production and the annual profit as the economic goals would be significantly aggregated with the goal of increasing water use efficiency. Accordingly, in the optimum condition, net energy production was increased by 10%, gross profit was improved by 4%, and water use efficiency was promoted by 15%. Therefore, according to the results, it is suggested that, in order to achieve the economic aspirations and increase water use efficiency in Varamin Agricultural and Animal Husbandry Complex, wheat, alfalfa, silage and maize corn, based on the values calculated in this study, constitute the main combination of the crop production pattern.
A. Ghorbani, E. Hassanzadeh Kuhsareh2, M. Moameri, K. Hashemi Majd, A. Pournemati,
Volume 23, Issue 3 (12-2019)
Abstract
In this study, the effect of some soil parameters on the life forms and total aboveground net primary production (ANPP) in meadow rangelands in Fandoghlou region of Namin county in Ardabil Province were investigated. ANPP in 180 plots of 12 by harvesting and weighting method were measured. Eighteen soil samples were collected along transects. Some physical and chemical attributes of the soil were measured by standard methods. The relationship between these parameters and ANPP was performed using multivariate regression (enter) method. To determine the effects of important soil parameters on ANPP variation, principal component analysis (PCA) was used. The results of regression analysis showed that electrical conductivity (EC), magnesium (Mg), spreadable clay (WDC), volumetric moisture content (VM), organic carbon (OC), soluble potassium (KS), exchangeable potassium (Kexch), sodium (Na) and phosphorus (P) were the effective parameters on the life forms and total ANPP (p<0.01). The accuracy of obtained equations for grasses, forbs and total ANPP were calculated 79, 76 and 70%, respectively. Moreover, results of PCA showed that soil parameters justify 84.52 percent of total ANPP variation and in comparison, with regression results with 28% it provides better results.
M. Mokari, H. Dehghan, M. Taherian,
Volume 23, Issue 4 (12-2019)
Abstract
In order to investigate the effect of new deficit irrigation strategies on the quantitative characteristics and water productivity of two field grown corn cultivars, a split plot experiment was conducted as a randomized design in three replications. The irrigation treatments included full irrigation treatment (FI), static deficit irrigation (SDI), dynamic deficit irrigation (DDI), static partial root zone drying irrigation (SPRD), which received 75% of ET during the growth period, dynamic partial root zone drying irrigation (DPRD), which received 90% of ET in the first one- third of the growth period, 75% of ET in the second one- third of growth period, and 50% of ET in the last one- third of the growth period. The results showed that there were significant differences between irrigation strategies. The SDI, DDI, SPRD and DPRD irrigation treatments decreased the corn yield by 18%, 27%, 49% and 53%, as compared to FI, respectively. The results also showed that there were no significant differences between cultivars. Compared to FI, the SDI increased WP by 14%, but DDI, SPRD and DPRD decreased WP by 3%, 19% and 44%, respectively. According to economic analysis, irrigation optimum depth for the maximum net profit was obtained to be 858.5 mm. In general, the SDI strategy is recommended in the study area.
S. Jamali, H. Banejad, A. Safarizadehsani, B. Hadi,
Volume 26, Issue 1 (5-2022)
Abstract
This research was conducted to study the effect of deficit irrigation and saline water on yield and yield components of Peppermint in the experimental research greenhouse of Ferdowsi University of Mashhad from 2018 to 2019. This research was performed as a factorial experiment based on the randomized complete design with three replications. In this research, irrigation levels consist of 4 levels (100 (I1), 80 (I2), 70 (I3), and 55 (I4) percent of FC) and saline water factors consist of 4 levels (0.9 (EC1), 1.9 (EC2), 2.5 (EC3), and 3.4 dSm-1 (EC4)). The result showed that a decrease of the water to 15, 30, and 45 percent have resulted in the reduction of shoot fresh weights (to 15.8, 28.4, and 30.1 percent), shoot dry weights (to 7.1, 11.5, and 11.5 percent), and root dry weights (to 4.6, 9.2, and 9.2 percent), respectively. Also, results showed that irrigation with EC2, EC3, and EC4 has resulted in a decrease in shoot fresh weights (to 12.7, 28.5, and 34.0 percent), shoot dry weights (to 3.6, 11.6, and 11.6 percent), and root dry weights (to 6.7, 12.4, and 14.6 percent), respectively. The result indicated that interaction effects of salinity and water stress decreased peppermint water productivity, as the highest and lowest peppermint water productivity with 3.54 and 2.06 Kgm-3 were in the EC1I4 and EC3I1 treatments, respectively. Results revoluted that maximum dry yield and peppermint water productivity were in the EC1I4, so this treatment was recommended for irrigation of peppermint.
A. Keshavarz, R. Modarres, S.a.r. Gohari,
Volume 28, Issue 4 (12-2024)
Abstract
This study was conducted to present rangeland bioclimatic zoning for Iran based on the changes in the power spectrum of the average monthly Net Primary Production (NPP) of the rangelands of Iran. Fluctuations of the mean monthly power spectrum of the NPP signal of rangelands of Iran from 2000 to 2022 were analyzed using the Power Spectrum Density (PSD) method in the frequency band between 0-100 Hz. In 24 bioclimatic subzones, there are four common periods in all sites at frequencies of 0 (no change is repeated), 8.34 (3.59 days), 16.66 (1.80 days), and 25 (1.2 days) Hz observed, which shows that the major data changes occur in those periods and that the NPP changes of Iranian rangeland are more influenced by global and regional effects than local effects. The maximum power of these spectra is concentrated in high time scales. Therefore, cycles with lower frequency (higher time scale) are more important than cycles with higher frequency (shorter time scale) and show that the changes of NPP in Iranian rangelands have long-duration cycles under climate fluctuations. In the present research, Iran was classified into 5+1 rangeland bioclimatic zones using the results of the monthly mean power spectrum of the NPP signal of rangelands, the Wards clustering method, and the Euclidean square distance. It seems that this method provides a proper match between biological boundaries and climate. Pearson correlation coefficient was used to investigate the coherence of rangeland bioclimatic regions within each homogeneous group. Correlation results showed a significant spectral density similarity within groups at the significance level of 0.01% between rangeland bioclimatic regions, especially in the second and fifth clusters.
H. Ramezani Etedali, S. Koohi,
Volume 29, Issue 1 (4-2025)
Abstract
Agriculture, as a crucial economic and social sector in Iran, has always been significantly influenced by weather conditions, water availability, and farm management practices. Enhancing productivity and optimizing resource management in crop production are essential to achieving sustainable agricultural development and ensuring food security. This research aimed to investigate how much wheat, barley, and corn production, separately from irrigated and rainfed crops, will be affected by the severity of climatic drought (based on the CMIP6) in Iran. This research was carried out using the amount of wheat, barley, and corn production in all the provinces, which was provided by the Agricultural Jihad Organization during the years 1371 to 1402. Climate data was obtained from the NEX-GDDP database, and the De Martonne aridity index was calculated to investigate changes in aridity under climate scenarios. The results indicated that during the baseline period, the production of rainfed wheat, barley, and corn under semi-arid to very arid climatic conditions was approximately 2,076, 434, and 15 thousand tons per year, respectively. With the intensification of arid conditions across the country, these production levels are projected to increase to 3,333, 693, and 16 thousand tons under the SSP2 scenario and further rise to 3,558, 842, and 16 thousand tons under the SSP5 scenario. Additionally, the production of irrigated wheat, barley, and corn in semi-arid to very arid climatic conditions during the baseline period stands at approximately 6,240, 1,683, and 5,842 thousand tons, respectively. Under the SSP2 climate scenario, the production is expected to reach about 7,126, 1,757, and 6,253 thousand tons, while in the SSP5 scenario, the estimated production is approximately 7,348, 1,780, and 6,324 thousand tons. The findings revealed notable spatial differences in crop production across the country, highlighting that the climatic conditions, particularly in the central, southern, southeastern, and southwestern regions, are becoming increasingly arid. It is crucial to implement smart planning and policies, adopt advanced technologies, and improve the management of water and soil resources to mitigate the adverse impacts of these changes and better adapt to evolving conditions. Addressing these challenges and implementing effective measures are essential steps toward achieving sustainability in the agriculture and natural resources sectors.
H. Ramezani Etedali, M. Ahmadi,
Volume 29, Issue 2 (7-2025)
Abstract
change, accurately predicting wheat production is essential for developing precision agriculture. Remote sensing enables the indirect prediction of crop production before harvest. This research investigates the application of the random forest method and support vector regression for simulating wheat production across ten selected farms in Qazvin Plain from 2019 to 2020, employing NDVI, MSAVI, and EVI vegetation indices. Sentinel 2 satellite data was utilized for the vegetation indices. Production data for the ten wheat fields was obtained from the Agricultural Jihad Organization of Qazvin Province. Evaluation of support vector regression and random forest to assess both the observed and simulated wheat production data was conducted using R2, MBE, RMSE, and MAE statistics. To explore the simulation of wheat production using vegetation indices, seven methods were defined: methods 1 to 3 examine each index separately; methods 4 to 6 focus on binary combinations of the indices; and method 7 considers the combined effects of all three indices. The support vector regression model provided good estimates of wheat production in all methods, except methods one and four, in the test phase, with a coefficient of determination of more than 0.98 and a low RMSE. The random forest model showed significant results in all methods except methods two and six during the test phase, achieving a 95% probability (P-value=0.00) with a coefficient of determination greater than 0.8. Overall, this research highlights the importance and potential of machine learning techniques for timely crop production prediction as a strong foundation for regional food security.
S. Yousefi, S.n. Emami, M. Nekooeimehr, S. Mardanian,
Volume 29, Issue 2 (7-2025)
Abstract
In the present study, the Road Sediment Delivery Model (SEDMODL) and Geographic Information System (GIS) were utilized to estimate the average annual sedimentation caused by the forest road network in the oak forests in the west of Iran, Chaharmahal and Bakhtiari Provinces (Nazi forest road with a length of 5171 meters). Sedimentation from the study forest road network was estimated based on three basic factors in the model. Also, 30 erosion benchmarks were installed to measure the erosion and sedimentation rate at different distances from the road and in different parts of the study road and changes were measured during a year. The results showed that the average soil erosion at different distances from the Nazi road based on erosion benchmarks is 5.7 mm per year. In addition, the estimated erosion and sedimentation rate of the entire study road network based on the SEDMODL model is 2875 and 570 tons per year per kilometer, respectively. Model evaluation using erosion benchmarks showed that SEDMODL is a suitable model for estimating soil erosion on forest roads in the west of Iran (R2=0.78 and RMSE=0.73). It should be noted that statistical analysis of erosion hot-spot analysis showed that 39 percent of forest roads in Nazi showed very high erosion. Based on the results of the present study, it is suggested that conservative, protective, and road maintenance measures in areas with high erosion risk should be prioritized by decision-makers.
