Showing 6 results for Sohrabi
Teymour Sohrabi, Reza Asilmanesh,
Volume 2, Issue 2 (summer 1998)
Abstract
Irrigation systems may or may not be well designed and properly used. Therefore, it is necessary to study these systems to provide direction to management in deciding whether to continue existing practices or to improve upon them. The major objective of this study is to determine the evaluation factors of center-pivot irrigation system and factors which usually affect irrigation performance. A solution. for the improvement of irrigation water use will be presented and design and management problems, will also be mentioned. To achieve the objectives of this study, the characteristics of the soil and the growing plant (seed corn) along with design parameters were determined. The system was designed on the basis of soil and the growing plant characteristics in the 500-ha farm of Ministry of Agriculture (located in the North East of Meshkinabad, Karaj) having a silty loam texture. Then, it was examined with respect to the existing conditions. Four radial rows of catch containers spacing 6 meters were set up and then field data for performance evaluation of system were determined. The evaluation factors were calculated on the basis of field data analysis. The results obtained are as follows: During the growing season, the average PELQ, AELQ and DU for the center-pivot system were about 79, 75.8 and 84 percent, respectively. Analysis of evaluation factors indicated that the system is not efficient DU and PELQ values were not high enough for the system because it was not properly designed for the existing conditions. Al the same time, it seems that the difference between PELQ and AELQ values are meaningful which may indicate management difficulties.
T. Sohrabi, U.a. Khoshkhahesh,
Volume 3, Issue 4 (winter 2000)
Abstract
The purpose of this research is to determine the application efficiency of rice irrigation plots and to analyze the reasons for low efficiency. The study will also try to determine the effective factors which could increase the application efficiency of rice fields. The selection of rice fields was based on climate, soil characteristics, and farmer management. Water application efficiency was determined by field measurements in three modern irrigation networks named Fouman (F), Rasht (G) and Lahidjan (D). In the meantime, a traditional network was included for comparison. In the study areas, the soil texture was heavy with an infiltration rate of less than 3 mm/day. The study was carried out under two different conditions: (1) without return flow and (2) with return flow. In the first case, the average application efficiencies in Fouman (F), Rasht (G) and Lahidjan (D) were about 51.2, 49.0 and 49.4 percent, respectively and the maximum and minimum values were about ((52.6, 49.7)), ((50.7 , 47.3)), and ((50.7 , 48.0)) percent, respectively. In the second case, the average application efficiencies for the above-mentioned regions increased to 73.4, 73.3 and 72.4 percent, respectively and the maximum and minimum values were about ((74.3, 72.4)), ((74.3, 72.1)), and ((73.0, 71.5)) percent, respectively. Runoff ratios in the above-mentioned regions were 30, 33 and 31 percent, respectively. During growing period (from transplanting to harvesting), the average applied irrigation water was about 1130 mm (11300 m3/ha) and the average evapotranspiration was determined to he about 561mm.
T. Sohrabi, A. Hosseini, K.h. Talebi,
Volume 5, Issue 1 (spring 2001)
Abstract
During recent years, worldwide concern has been focused on the potential for contamination of surface waters and ground waters by agrochemicals in runoff and soil water from irrigated fields. Given this perspective, it is very important to correctly evaluate the levels of different agrochemicals in water, both from human toxicological and environmental viewpoints and to develop management strategies for reducing agrochemical loads to acceptable levels in the environment. The main objective of this study was to assess the qualitative changes of tailwater due to the use of agrochemicals and thereby to determine contamination loads. Four farms (A, B, C and D) were chosen in the Foumanat region in the F2 unit in 1996. The areas of these fields ranged from 0.22 to 0.6 ha having a number of unequal successive basins with variable inflow and outflow rates.
A quantitative analysis showed that the tailwater ratio in farms A, B, C and D ranged from 2 to 64% during the irrigation season. The outflow water was classified as C3S1. The changes in qualitative factors were not significant and did not follow any certain pattern during the irrigation season. The changes in SAR, EC, Cu, Zn, B, P, K and DO in the inflow and outflow waters were also insignificant. After fertilizer application, the increase in nitrogen concentration in the outflow was significant. The average pollution loads in the inflow and outflow were about 1618 and 1476 kg/day/ha, respectively. The remaining load in the rice fields was about 142 kg/day/ha, which was meaningful at 1% level. The fifth farm (E) located in Lahidjan was sprayed with diazinon. Water samples were analyzed each day for diazinon residues for 10 days after application. Sample analysis showed that the concentration of the insecticide was 93.08 mg/l immediately after application and gradually reduced to 0.98 mg/l ten days after spraying.
L. Moradi, A. َsiosemardeh, Y. Sohrabi, B. Bahramnejad, ّf. Hosseinpanahi,
Volume 11, Issue 3 (11-2021)
Abstract
Accumulation of nitrogen in vegetative organs and its translocation to grain of wheat are important processes that determine the yield and quality. In order to investigate the effect of supplemental irrigation nitrogen fertilizer on dry matter remobilization, yield and yield components of three wheat cultivars a split-split plot experiment was conducted based on randomized complete block design with 3 replications at Research Field of Kurdistan University, Sanandaj, west of Iran, during 2016-2017. Treatments were two levels of Irrigation (rainfed and irrigation at the booting stage) as main-plots, three rainfed cultivars (Sardari, Azar2, and Rejaw) as subplot and three rates of nitrogen (50 kg/ha N (N1), 100 kg/ha N (N2) and 100 kg/ha N plus 20 kg/ha N (N3) foliar application in Heading stage) as sub-subplot. The results showed that supplementary irrigation increased the concentration of leaf chlorophyll a, chlorophyll b, proline, and glycine betaine and decreased the electrolyte leakage. Supplemental irrigation also increased leaf nitrogen, chaff and total nitrogen content at flowering stage. Rejaw cultivar had the highest leaf nitrogen remobilization efficiency and the lowest total nitrogen remobilization efficiency. N1 fertilizer treatment led to the lowest concentration of leaf chlorophyll a and b, proline, glycine betaine, and nitrogen, and stem, chaff and total nitrogen in both flowering and maturity stages. Nitrogen remobilization was affected by supplementary irrigation and different rates of nitrogen fertilizer. It seems that supplementary irrigation in the booting stage leads to an increase in nitrogen content in the vegetative organs, which is transferred to the grain during the seed filling stage.
F. Sadeghi, Y. Sohrabi, A. Sio-Se Mardeh,
Volume 12, Issue 3 (11-2022)
Abstract
Adverse environmental conditions cause stress in plants, and some plant growth regulators (PGR’s) improve plant tolerance to these undesirable conditions. In order to study the effect of gibberellin, cytokinin and cycocle on some physiological traits of two wheat cultivars under different irrigation regimes, a study was conducted as a split-split plot experiment based on a randomized complete block design with three replications at the Agricultural Research Station of Kurdistan University, Sanandaj, Iran in 2016. Irrigation at four levels: rainfed, irrigation at booting stage, irrigation at booting + flowering and irrigation at booting + flowering + grain filling stages as the main plots, two wheat cultivars (Sirvan and Homa) as sub-plots and levels of plant growth regulators foliar application including control (no-PGR), gibberellin (100 µm), cytokinin (100 µm) and cycocel (3 g l-1) at the wheat stem elongation and grain filling stages as the sub-sub plots were examined. The results showed that soluble carbohydrates concentration was higher in rainfed conditions, compared to the other levels of irrigation. Relative water content, rate of water loss and maximum quantum yield of photosystem II (Fv/Fm) increased due to irrigation, relative to the rainfed condition. A higher chlorophyll a and total chlorophyll concentration was observed with cytokinin spray in the presence of the three irrigation treatments. The results also indicate that, at the stem elongation and grain filling stages, foliar application of gibberellin reduced the rate of leaf water loss. Application of cytokinin and cycocel increased the concent of carotenoids, application of gibberellin and cycocel increased the Fv/Fm and the use of all three PGR’s increased soluble carbohydrates concentration compared to the no-PGR condition. The highest grain yield was obtained with cytokinin and cycocel spray at the wheat stem elongation and with the application of cycocel at grain filling stages under the condition of irrigation at booting + flowering + grain filling stages. Homa cultivar produced a higher grain yield compared to Sirvan. It may be concluded that the application of cytokinin and cycocel is beneficial to some physiological attributes and hence increasing the grain yield of wheat.
Mrs T. Sohrabi, Dr M. Movahhedi Dehnavi, Dr A. Salehi, Dr H. R. Balouchi,
Volume 12, Issue 4 (1-2023)
Abstract
In order to investigate the effect of chemical and biological nitrogen fertilizer on canola, a field experiment was conducted as a split plot based on a randomized complete block design with three replications at the research station of the Faculty of Agriculture, Yasouj University, located in Deshtrum region, in 2019. The main factor consisted of nitrogen fertilizer (zero, 25, 50, 75, 100 and 125 kg/ha of pure nitrogen from urea source) and the secondary factor consisted of nitroxin biofertilizer contained Azotobacter and Azospirillium bacteria (use and non-use). The results showed that nitrogen fertilizer and nitroxin had a significant effect on all investigated traits. Nitrogen fertilizer significantly increased plant height, number of lateral branches, chlorophyll index and oil yield. The highest grain (8790.60 kg/ha) and biological (23910.93 kg/ha) yield were obtained in 125 kg/ha of nitrogen and the use of nitroxin. With the consumption of 125 kg/ha of nitrogen and nitroxin, the lowest percentage of seed oil, and contrastingly the highest percentage of seed protein (36.65%) was obtained. In general, combined application of biofertilizer with chemical nitrogen increased grain, biological and oil yield. Nitroxin bio-fertilizer could reduce the consumption of chemical nitrogen fertilizer. The results showed that there was no significant difference between the application of 50 kg/ha of nitrogen + bacteria and the application of higher levels of nitrogen (75, 100 and 125 kg/ha) alone in most of the investigated traits.
