leila saberpour; Saeid Soufizadeh; Abdolmajid Mahdavi Damghani; Jafar Kambouzia; Ghorban Ghorbani Nasrabad
Abstract
Introduction: Cotton is one of the most important fiber plants in Iran which needs more production for national fiber sufficiency goal. Its cropping area in Iran is now about 140,000 ha in which 95.3% is irrigated; rainfed cotton is growing only in Khorasan, Golestan and Mazandaran. Planting date and ...
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Introduction: Cotton is one of the most important fiber plants in Iran which needs more production for national fiber sufficiency goal. Its cropping area in Iran is now about 140,000 ha in which 95.3% is irrigated; rainfed cotton is growing only in Khorasan, Golestan and Mazandaran. Planting date and nutrition management and their interactions are amongst the most important determinants of crop yield.Material and methods: Field experiment in 2016 in the fields of Cotton Research Center of Golestan province in Hashem Abad split plot factorial in a randomized complete block design was conducted. Treatments include the planting date as the main factor, cultivar (Latif and Golestan) and nitrogen (three levels: desirable, a third desirable and without fertilizer) as sub plots. The first planting date in the traits (TDM, LAI, CGR and RGR) was superior to the second planting date. Among the cultivars, Golestan cultivar showed a better response to Latif cultivar at zero fertilizer level and 160 kg ha-1 nitrogen fertilizer.Results and discussion: TDM variation and LAI of cotton cultivars during the growing season were three stages. The first stage, the phase of presentation, in which the TDM variations continued up to 55 and 61 days after planting and the rate of changes in the LAI, respectively, was 55 and 43 days after planting in the first and second planting dates. TDM accumulation changes up to 109 and 96 days, the LAI was about 88 and 96 days, the RGR was 55 and 61 days, and the CGR was 88 and 96 days after planting in the first and second plantings increased linearly. Maximum RGR and CGR were observed at cultivar Golestan cultivar at zero and 160 kg ha-1 in first planting date.Conclusion: In general, first planting date (29 June) in comparison with the second planting date (12 July) caused higher DM production, LAI, RGR and vegetative growth and Golestan cultivar had better performance than Latif cultivar at 0 and 160 khNha-1. The maximum RGR at these two-fertilizer level in Golestan cultivar was recorded at the first planting date which caused a significant difference for the time reaching maximum LAI.
Tayyebeh Zare-Zadeh Mehrizi; Korus Khoshbakht; Abdolmajid Mahdavi Damghani; Jafar Kambouzia
Volume 8, Issue 4 , July 2011
Abstract
Ignorance to the principals of sustainable development has affected mangrove forests due to development projects. In order to study the effects of reduction in tidal flooding on vegetative structure of mangrove forests in Nayband coastal national park, a survey was conducted using linear transect method. ...
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Ignorance to the principals of sustainable development has affected mangrove forests due to development projects. In order to study the effects of reduction in tidal flooding on vegetative structure of mangrove forests in Nayband coastal national park, a survey was conducted using linear transect method. By comparing the structure of mangroves in the Nayband area with Mound protected area the amount of destruction in this area was studied. Linear transact was used to determine the structure of the mangrove forests in this area. 5 Stations were considered. From that four stations were located in Nayband national park and the last one was situated in Mound protected area as control. A quadrate sample plot with 100 m2 in each transect has been used as the measuring unit with random–systematic distribution. In each plot, the height and steed diameter of trees as well as the height and diameter of crowns were measured. Furthermore, 1 m2 micro plots were used to measure the quantity and height of aerial roots as well as number of seedlings. Results showed that the road construction in this protected area resulting in decrease of water streams in some parts which are the main factor for destruction of this worthy ecosystem. Increase of the number of dried trees, reduction of canopy and the number of aerial roots are main evidences to prove these claim. The green density of mangroves was reduced to 60 and 40 % in the stations 1 and 4 respectively. The canopy in these stations was 40 and 52% respectively; that makes a spare canopy of mangroves forests. There was no seedling in station 1. Therefore, more efforts are need to improve the mangrove vegetation in these stations with strengthening of tidal fluctuations.
Maryam Atapour; Saeid Moharramipour; Jafar Kambouzia
Volume 4, Issue 4 , July 2007
Abstract
The rice stem borer, Chilo suppressalis Walker, is the most important rice pest in north parts of Iran and survives the winter as diapausing mature larvae in rice stubble and weeds. To determine the strategy of hibernation and changes of cold hardiness, overwintering larvae were collected from a paddy ...
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The rice stem borer, Chilo suppressalis Walker, is the most important rice pest in north parts of Iran and survives the winter as diapausing mature larvae in rice stubble and weeds. To determine the strategy of hibernation and changes of cold hardiness, overwintering larvae were collected from a paddy field at Rice Research Institute in Rasht from October 2004 to March 2005. Because of hard winter in 2004 and snowfall about 2m on February no sampling was done on this month. The supercooling points (SCPs) of whole body of the larvae collected on October was -18.8∞C but it significantly increased to -12.4∞C on November and did not change until snowfall on February. Thereafter, SCPs was raised to -8.2∞C on March. There was more than 90% survival in the larvae collected from October to March, 24h after exposure to -10 and -15∞C but the survival was increased from 30% on October to 80% on November and the following months, 24h after exposure at –20∞C. Because of the increase of supercooling point in winter and endurance of temperaure below this point it is suggested that this pest to be a freezing tolerant insect in Iran and entered diapause from late November in the year of study.
