hamid reza mehrabadi; Ahmad Nezami; Mohammad Kafi; Malihe Ahmadifard
Abstract
Introduction: More plains of Iran are located in arid and semi-arid regions and so agricultural production systems depend heavily on water. Recently, the reduction of water resources has become a serious threat for crop production such as cotton planting. Therefore, application of low irrigation methods ...
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Introduction: More plains of Iran are located in arid and semi-arid regions and so agricultural production systems depend heavily on water. Recently, the reduction of water resources has become a serious threat for crop production such as cotton planting. Therefore, application of low irrigation methods can be an appropriate method to cope with mentioned condition. In addition, it is vital to identify the cotton cultivars reaction to water deficiency. Sensibility of some cotton cultivars is lower than others. Sensitive cultivars seed cotton yield decreases more than tolerant cotton cultivars. Moreover, some of growth stages in cotton plant are more sensitive to water deficiency stress. For example, flowering stage is more sensitive than vegetative growth stage, and boll number per plant is more effective parameter on yield than boll weight. Ulla and et al (2) showed that there are genetic variations for drought stress toleration in cotton plant. Afshar and Mehrabadi (3) indicated that low irrigation on the basis of 50% and 75% of cotton water requirement had no significant effect on vegetative growth of cotton plant. However, it caused the increase of flower and boll shedding per plant. Application of tolerant cultivars compared with sensitive cultivars can increase seed cotton yield under drought stress condition. Consequently, the aim of this study is to survey yield and related morphological traits reactions in sensitive and tolerant cotton cultivars to different water deficiency levels.
Materials and methods: Two tolerant cotton cultivars (Armagan and Varamin) and two sensitive cotton cultivars (Coker349 and Nazili84) as a subplot at three irrigation levels (as a main plot) using split plot design based on complete block design with three replications were carried out at Agricultural Research Station of Kashmar in 2011. Three levels of water consumption based on Penman-Montith method and using cotton KC coefficients were [33% (I33%), 66% (I66%) and 100% (I100% of water requirement)] that it were take placed using drip irrigation method. Yield and yield components traits such as height, the number of boll per plant, boll weight, flower and boll shedding percent, seed cotton yield, biological yield, earliness percent and harvest index were determined at the end of experiment. Data analysis was carried out using Excel and MSTAT-C software.
Results and Discussion: The results showed that although water deficiency stress decreased vegetative components, the amounts of decreasing were higher in tolerant cultivars than sensitive cultivars but, by contrast, the reproductive components of tolerant cultivars indicated lower decreasing than sensitive cultivars under water deficiency stress. For example, Varamin cotton cultivar had more number of bolls per plant than Coker349 as a sensitive cultivar. The results also showed that more retention of boll number per plant was the main factor of cultivars difference as for seed cotton yield. The highest number of boll and flower per plant retention belonged to sensitive cultivars such as Coker349 and Nazili (71.2 and 69 percent, respectively) at 66 percent of water consumption and the lowest number of boll and flower per plant retention were 92.3 percent belonging to Varamin as a tolerant cotton cultivar at full water irrigation treatment. The results indicated that all yield components except boll weight were significantly affected by low irrigation levels. In addition, the results revealed that low shedding of flower and boll and accordingly more retention of boll number per plant and also biomass preservation under drought stress were the main factor in yield of tolerant cultivars in comparison with sensitive cultivars. Biological yield reduction was higher than seed cotton yield under water stress condition. High and significant correlation was observed among yields with boll number per plant, biological yield and harvest index under drought stress. Moreover, there was a significant correlation between yield with plant height and biological yield only in full irrigated treatment. Furthermore, harvest index decreased significantly under drought stress. Harvest index value for Coker349 was significantly lower than other cultivars. Coefficient correlation between harvest index and yield and its components showed that harvest index was more dependent with seed cotton yield to biological yield. Therefore, tolerant cultivars had higher seed cotton yield and also biological yield in comparison with sensitive cultivars. While there was a significant correlation between yield with plant height and biological yield only in full irrigated treatment.
H. Afshar; Hossin Sadrghaen; hamid reza mehrabadi
Abstract
To decree evapotranspiration from soil surface and improving irrigation efficiency and reduce water usage in cotton cultivation , plastic mulch was applied in furrow irrigation. This study was performed as a split plot experiment in capability randomized complete block design, in 3 replications. The ...
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To decree evapotranspiration from soil surface and improving irrigation efficiency and reduce water usage in cotton cultivation , plastic mulch was applied in furrow irrigation. This study was performed as a split plot experiment in capability randomized complete block design, in 3 replications. The experiment was located in Khorasan Razavi –Kashmar- Kashmar agricultural research station and was applied in 2 years, 2004-2005. The treatments were consist of irrigation period at three levels ; 6, 9 and 12 days as main plot and plastic mulch at three levels I-black plastic mulch, II- white plastic mulch and III- control (without plastic mulch)as a subplot on furrow irrigation. Each treatment was irrigated up to field capacity. The results showed that application of plastic mulch used better water usage and black plastic mulch was more effective. Meanwhile The results showed that the use of plastic mulch had significant effect on reducing of weed growth, plant height increasing, yield and water use efficiency in respect with control.
M. Jolaini; H.R. Mehrabadi
Abstract
Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today, process improvement, development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. So this study was conducted to determine ...
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Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today, process improvement, development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. So this study was conducted to determine the impacts of irrigation interval and drip irrigation method and their interactions on yield, water use efficiency and quality characteristic of cotton in Kashmar Agricultural Research Station, Khorasan Razavi Province. The study was carried out during 2006-2008. Experimental design was a completely randomized design with four replications. Treatments were included irrigation intervals (2, 4 and 6 day) and drip irrigation methods (surface and subsurface drip irrigation). The results showed that the irrigation methods had significant effect on Yield and Water Use efficiency (P≤ 0.01). There was significant difference between yield in surface and subsurface drip irrigation that was 3074 and 3988 kg/ha, respectively. Water use efficiency was 0.349 kg/m3 in subsurface drip irrigation that was greater than surface drip irrigation. The highest yield and water use efficiency in drip irrigation and subsurface irrigation 4 days, 4315 kg/ha and 0.375 kg/m3 respectively and the lowest with 2 days 3107 kg/ha and 0.265 kg/m3, respectively. Yields in irrigation intervals of 2, 4 and 6 days were 3491, 3725 and 3364 kg/ha, respectively, with no significance difference. The highest water use efficiency and yield were obtained in subsurface irrigation method with 4 days interval as 4315 kg/ha and 0.375 kg/m3 respectively, while the least water use efficiency and yield was obtained in surface irrigation method with 2 days interval as 3107 kg/ha and 0.265 kg/m3, respectively. Finally, using subsurface drip irrigation with irrigation every 4 days was chosen as the best treatment.