Davood Akbari Nodehi; Mohammad Zanguei; Fazl Shirdel Shahmiri
Abstract
Introduction: Water is one of the most important factors limiting plant growth and agricultural productivity in many areas of the world. Decreasing water losses and irrigation times are one of the basic countermeasures for agriculture development and minimizing the stress to plants. Correct management ...
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Introduction: Water is one of the most important factors limiting plant growth and agricultural productivity in many areas of the world. Decreasing water losses and irrigation times are one of the basic countermeasures for agriculture development and minimizing the stress to plants. Correct management and applying improved techniques for saving and conserving the humidity of soil and increasing the soil water holding capacity is among the activities for productivity increasing and consequently exploiting limited water resources. New method in science of soil and water is using super absorbent materials as reservoirs and prevention from water wastage and increase of irrigation efficiency.
Materials and Methods: In order to evaluate the application effects of different levels of superabsorbent polymer on growth of strawberry plants under drought stress condition, a research was conducted in the Mazandaran province in loamy soil during 2010. Experiment was carried out as factorial based on randomized complete block design with three replications and three plants for each replication. Dryness stress treatments (30%, 50% and 70% of Maximum allowable depletion of soil moisture; MAD) and superabsorbent polymer (0, 0.25, 0.5, 0.75 and 1 % of soil weight) were allocated to main and sub-plots, respectively. In this research the superabsorbent polymer TawaratA200 is used that is produced by the research center of petrochemical and polymer of Iran. Before planting, super absorbent polymer was added to the soil of pots in deepness of root development. For stress application, the pots were weighted every day. During the experiment, the physicomorpholigic characteristics such as number and length of stolones, number of leaves, plant length, biomass, fresh and dry weight, fruit diameter, number and weight of fruit were estimated.
Results and Discussion: The results showed, superabsorbent and drought stress and their interaction effects effected on all factors. In vegetative characteristics, number and length of stolones in treatment of 1% superabsorbent and 30%of MAD (maximum allowable depletion) has been maximum. By increasing stress, number and length of stolones declined. The lowest amount was obtained in the treatment of non-superabsorbent and 70% of MAD. With increasing stress, the number of leaves decreased and with increased superabsorbent, leaf number was increased. Strawberry leaves in treatment of one percent superabsorbent and 30%of MAD has a maximum value and in treatment of non-absorbent and 70% of MAD was minimal. Root length, fresh and dry weight were affected by the water stress. 70% of MAD and 30% of MAD has been the minimum and maximum amount, respectively. The plant length, biomass, fresh and dry weight, by reducing stress and increasing superabsorbent has increased and maximum values were obtained in the treatment of 30%of MAD and one percent of superabsorbent. In reproductive characteristics, fruit diameter reduction, occurred with increase stress. Fruit diameter was increased by adding superabsorbent and reducing stress. In the treatment of 1% superabsorbent and 30%MAD the maximum diameter of the fruit was obtained. Increased water stress has been causes weight reduction. In treatment 30%of MAD, the weight of fruit was obtained 4.17 g, with the increase of water stress, the fruit weight was reduced to 1.99 g. The use of superabsorbent increases the yield. With an increase of 0.25%superabsorbent, fruit weight was increased from 4.17 to 8.14 g. In the interaction of stress and superabsorbent, the maximum weight of the fruit with 18.99 g was obtained in treatment of 1% superabsorbent and 30% MAD. the maximum number of fruits was obtained, in treatment with 1% superabsorbent and 30% MAD with the number of 19.67.
Conclusion: Super absorbent polymer plays an important role in enhancement of absorption capacity and retention of water in soil, fighting against water shortage and decreasing harmful effects of drought stress. The above mentioned rates of polymer have the best effect to all characteristics of strawberry in all levels of water stress treatment. The findings strongly suggest that the irrigation period of strawberry cultivation can be increased by application of polymer.
