P. Daneshpazhoh; A. R. Ghasemi; Mohamad reza Nori Emamzadeie; R. Barzegar
Abstract
Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways ...
Read More
Introduction: Optimal water utilization is one of the most important challenges of the present century. Due to limited water resources and the existence of alternate droughts in the country, optimal use of it is necessary. The deficit irrigation technique is one of the most effective and practical ways in which it can determine and justify the minimum water consumption with acceptable economic performance. Its use in reducing water consumption for biomass production and for irrigation of annual and perennial crops. To effectively apply water deficit management, an understanding of the effects of irrigation at different stages of vine growth is required. Partial Root-zone Drying (PRD) is also one of the new irrigation techniques over the past years. The results of many studies indicate that water use efficiency has increased and there is no significant reduction in the yield in this irrigation method. In this technique, only half of the roots are irrigated at each turn and the remaining half remains dry. On the other hand, in recent years, the use of natural minerals has improved in order to improve the physical and chemical composition of the soil, which leads to an increase in water holding capacity in the soil. One of the methods for increasing the water use efficiency is the application of water absorbent materials in soil. Super absorbent polymer increases the water saving in soil and decreases the amount of water used for irrigation. Zeolite is one of these minerals that increases the soil water holding capacity. So far, many studies have been carried out on the use of PRD, as well as the use of zeolite, but none has examined the effect of these two simultaneously. Therefore, in the present study, the efficiency of both above method and deficit irrigation on yield and water use efficiency of sweet pepper were investigated.
Materials and Methods: This research was carried out in a completely randomized design with 9 treatments and 4 replications in a greenhouse in Shahrekord University. This study was carried out at three levels of irrigation of 100%, 75% and 50% of the water requirement of the plant by Partial Root-zone Drying and zeolite in two levels of 2 and 4% by weight in the soil, in one and two sides of the pots with a height of 30 and diameter 28 cm. After preparing the culture medium, the F1 type Lummus seedlings were transferred to the pots. During the transfer of transplants into the pot, careful attention was paid to the fact that the roots were developed on both sides. Physiological parameters such as leaf area, total fresh and dry weight of the whole organ, total fresh weight of fruit, diameter and number of fruits and chemical indices including vitamin C, pH, total soluble solids and chlorophyll a, b and total chlorophyll with water use efficiency were measured and evaluated. In order to analyze the results, SAS software (version 1/9) was used. Mean comparison was also performed by LSD test.
Results and Discussion: The results of this study showed that there was a significant difference in the 1% level for fresh and dry weight, fresh weight of fruit and chemical indices of vitamin C, pH and soluble solids, and a significant difference at 5% for diameter fruit and chlorophyll. The results of comparing the meanings showed that fresh weight and fruit diameter were significantly decreased in all treatments than control. The number of fruits in severe irrigation (50%) and in both levels of zeolite showed a significant decrease compared to control. Vitamin C value as an important indicator of fruit quality in all treatments was significantly higher than control, in other words water stress causes an increase in the amount of vitamin C in the fruit, and the amount of pH in the most treatments has decreased significantly compared to the control treatment.
Conclusion: Given that all important processes such as photosynthesis, nutrition, opening and closing of stomatal and plant growth and development are under the influence of water, most of the studied traits in this research (except chlorophyll) in zeolite-containing treatments, showed a significant advantage over non-consumption of zeolite. The results also showed that application of PRD method with zeolite in deficit irrigation resulted in significant increase in water use efficiency in all treatments.
Marjan Nekokhoo; Seyfollah Fallah; Rahim Barzegar
Abstract
Introduction: Water resources are very limited for agricultural production. Therefore, optimal use of available water resources and increased water use efficiency in agriculture are necessary. Application of poly ethylene mulch is one of the approaches that can be effective in increasing water use efficiency. ...
Read More
Introduction: Water resources are very limited for agricultural production. Therefore, optimal use of available water resources and increased water use efficiency in agriculture are necessary. Application of poly ethylene mulch is one of the approaches that can be effective in increasing water use efficiency. The water deficient trend is increasing in agricultural lands of the Iran and, on the other hand, the yield components of hull-less seed pumpkin are sensitive to drought stress. Therefore, the aim of this study was to determine the effect of transparent polyethylene mulch on the performance and water use efficiency of hull-less seed pumpkin under different irrigation rates.
Materials and Methods: This experiment was carried out in the central part of Isfahan, Northern Baraan (320 and 32/N, 510 and 52/ E, and 1534 m above sea level) in a randomized complete block design with three replications, during 2016. Treatments consisted of full irrigation+ poly ethylene mulch (M+FW), 0.75% full irrigation+ poly ethylene mulch (M+0.75FW), 0.50% full irrigation+ poly ethylene mulch (M+0.5 FW), and full irrigation without mulch (FW). In April, the cultivation operations include mechanical planting, mulch were done. The spacing of the rows was 150 cm and the spacing between plants was 70 cm. The irrigation was applied until the plant was fully established and then drought stress was begun based on above irrigation treatments. The studied traits were number of fruits per plant, average fruit weight (kg), fruit yield (ton ha-1), number of seeds per fruit, fruit diameter (cm), 1000 grains weight (g), grain yield (kg ha-1), water use efficiency (kg m-3), oil content (%) and oil yield (kg ha-1). Statistical analysis was performed using SAS software and comparisons of the means were made using the least significant difference (LSD) test at the 5% probability level.
Results and Discussion: The highest number of fruits per plant belonged to M+FW treatment (with an average of 3.22) and the lowest was recorded in M+0.5FW treatment (with an average of 2.44). This difference between treatment FW and M+0.75FW can be due to the high moisture under the poly ethylene mulch. The highest fruit weight (3.60 kg) was obtained in M+FW treatments, which had a significant difference with other treatments. The difference weight of fruit in M + FW treatment was 14% compared to FW irrigation treatments. The highest fruit yield (95.72 ton ha-1) belonged to M+FW treatment and the lowest one (79.78) belonged to M+0.5FW treatment. The difference in fruit yield in M+0.75FW compared to FW treatment was 6%, but it was not significant. The number of seeds per fruit in M+0.75FW compared to FW and M+0.5FW treatments showed a difference of 13% and 17%, respectively which they were significant only with M+0.5FW treatment. With increasing drought stress, the amount of photosynthetic assimilate decreased, which reduced the number of seeds per fruit. The highest 1000 grains weight (173.13 g) belonged to M+FW treatment and the lowest one belonged to M+0.5FW (156.18 g). 1000 seeds weight in FW treatment was not significant compared to M+0.75FW treatment. Drought stress during plant development decreased the leaf area index in the plant. Application of plastic mulch reduces the effect of drought stress on leaf growth and its photosynthesis by decreasing water loss by evapotranspiration and transpiration. The difference grain yield between two treatments M+0.75FW with FW was 7% and this difference was not significant. Only significant difference was observed among M+0.5FW treatment with other treatments. The effect of different levels of moisture on water use efficiency was significant at 1% probability level. The highest water use efficiency was recorded in M+0.5FW treatment and the lowest was recorded in FW treatment. The difference in water use efficiency between M+0.75FW with full irrigation (FW) was 0.99 kg m-3, which was significant. Difference in water use efficiency between M+FW and FW was not significant for water use efficiency. The use of plastic mulch reduced water loss throughout the plant growth period and significantly increased water use efficiency. There was a significant difference among M+FW, M+0.75FW and FW for oil content. The highest and lowest oil contents belonged to M+FW and M+0.5FW, respectively. The maximum oil yield (558 kg ha-1) belonged to M+FW and the lowest one (412 kg ha-1) was obtained in M+0.5FW.
Conclusion: Transparent plastic mulch under water stress conditions can reduce the effect of drought stress on hull-less seed pumpkin by preserving water and other beneficial effects, including weeds reduction. Therefore, the use of this type of mulch is recommended for the cultivation of hull-less seed pumpkin in the central areas of the country facing the water crisis.