Journal of Soil and Plant Interactions

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Given the increasing growth of the population, soil and water limitations and the decrease of the foodstuff, plantation in greenhouses could be one of the solutions for efficient use of natural resources. As for the 10 times increase of the outcome compared with the plantation in open air, the agricultural experts believe that greenhouse plantation is appropriate for maintaining the nutrition security. Nevertheless, people with entrepreneurship motivations are required for developing the greenhouse plantation units because entrepreneurship is to convert a new idea to a new product or new services. This entails such privileges as facilitating products marketing, job creation, rising productivity, economic self-reliance, and growth in agricultural products. The present research studied the impact of entrepreneurship on the greenhouse products of West Azerbaijan via time series data of 241 greenhouses. The Cronbach alpha coefficient was calculated as 0.85, which shows the appropriate reliability of the research tools. The content validity of the questionnaire was confirmed through the experts and the teachers dealing with the subject. The results showed that the entrepreneurship has a negative impact on the quantity of consumable elements. In other words, the entrepreneurship decreases the quantity of consumable elements. It must be noted that the risk-avoidance affects the consumable elements negatively.

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In order to determine the most appropriate nutrient solution spraying interval and effects of light quality in the root zone on anthurium in aeroponic system, a split plot experiment, with completely randomized design, was carried out in a greenhouse located in the city of Karaj, Iran. In this study, time between the sprays was the main plot and consisted of two levels (2 minutes spray and 30 minutes without spray, and 2 minutes spray and 45 minutes without spray) and color of the containers was the sub plot at three levels (black, blue and red). Results showed that 2 minutes spay and 45 minutes without spay increased number of leaves and shoot fresh weight much higher than 2 minutes spray and 30 minutes without spray. Study of light quality in the root zone showed that black color of the containers, by increasing total leaf area and shoot dry and fresh weight, was the best color treatment. Blue color in the root zone had the most influence on final root length but was not able to increase root dry and fresh weight, because of higher number of roots in other color treatments. In general, spraying nutrient solution for two minutes, and 45 minutes without spray, along with black color containers in the root zone was the best treatment for most growth characteristics of the anthurium plant.

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Poinsettia (Euphorbia pulcherrima) is a pot plant, which its colorful bracts form in short days. In order to increase the marketability of this plant, effect of spraying different concentrations of 2-chloroethyl-N, N, N-trimethyl-ammonium chloride (cycocle) growth retardant on the vegetative growth and flowering characteristics of poinsettia was investigated. The experiment was arranged in a completely randomized blocks design with three replications. Poinsettia plants were sprayed with different concentrations of cycocle (0, 500, 1000, 1500 and 2000 mg/L). At the harvest time, the vegetative characteristics, fresh and dry weight of aerial parts and roots, chlorophyll index and mineral elements’ concentration were measured. The results revealed that quality and quantity characteristics of poinsettia was significantly (P≤0.01) affected by various cycocle levels. Spraying the cycocle at 2000 mg/L increased chlorophyll content of the leaves. In 1500 mg/L chloromequat treatment, plant height was decreased while number and area of bracts increased significantly as compared to the control. Also, effect of cycocle treatment on fresh and dry weight of leaf, stem, and roots was meaningful. Therefore, based on the obtained results, it seems that spraying of cycocle at 1500 mg/L level, made improving in the production characteristics of poinsettia.

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To evaluate the effect of limited application of phosphorus (P) on height and performance quality of geranium (Pelargonium hortorum cv. Bulles Eye), an experiment was conducted in the greenhouse environment, based on completely randomized blocks design, during 2011-2012. Geranium seedlings were cultivated in the pots filled with peat-based substrate (80% peat + 20% garden loam soil (v/v)). Treatments were applied as four levels of nutrient solution (0.2 (control), 0.15, 0.1 and 0.05 mM P). At the end of the experiment, traits such as plant height, number and length of shoots, number of inflorescences, number of flowers in each inflorescence, pedicle length, fresh and dry weight of shoots and roots, number of leaves, leaf area, chlorophyll content of leaves, and leaf anthocyanin content were measured. According to the results, although the application of 0.05 mM P reduced plant height and length of the pedicles, but negatively affected fresh and dry weight of shoots and roots, chlorophyll content of leaves, and leaf number and leaf area, and the produced plants were not marketable. While, reducing the concentration of P in the nutrient solution from 0.2 to 0.1 mM, other than reduction of plant height, did not affect negatively other qualitative traits. Therefore, to achieve proper qualitative traits and reduce the consumption of P by geranium, limiting the application of P up to 0.1 mM is recommended

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Effects of nutrient solutions on quantitative and qualitative indices of tulip (Tulipa gesneriana cv. Apricot parrot) were studied in a completely randomized design with 5 nutrient solutions, 4 experimental units and 3 replications. Plants were fed with five nutrient solutions (S₁, S₂, S₃, S₄ and S₅) having NH₄⁺-N/total N ratios of 0, 0.038, 0.074, 0.11 and 0.14, respectively. All nutrient solutions had similar concentrations of mineral elements. The five treatments consisted of 2.5 meq/L total N, and concentration of all the nutrients was 8.4 meq/L. Based on the results, increasing the ammonium level in nutrient solutions decreased N and total protein storage in the bulbs, but increased N concentration in the shoots. The ammonium level had no significant effect on potassium concentration of shoots, but increased phosphorus concentration in the shoots. Maximum calcium and magnesium concentration in shoots, wet weight and length and diameter of flowering stem were obtained in plants fed with S₂ solution. Increasing the ammonium level increased number of bulblets, but decreased their size. Increasing the ammonium level decreased time to flowering of bulbs. The highest longevity of cut flowers was observed in plants fed with S₂ solution. In general, based on the results of this research, with increasing the ammonium level in the nutrients solution, the qualitative traits of tulip, such as length and diameter of flowering stem, were increased, but longevity of cut flowers and number of produced bulblets were decreased.

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