نشریه روابط خاک و گیاه
پیاپی 28 (زمستان 1395)

Phosphorus (P) is an essential element for plant growth and it is responsible for various functions in the plant. That is why it has been dubbed as the key of plant life. However, its excessive consumption disturbs uptake of micronutrients and reduces plant performance. To investigate the effect of application of P, in calcareous soils containing different amounts of native P, on growth and uptake of micronutrients in cucumber, a greenhouse experiment was carried out as a factorial in a completely randomized design with three replications, at University of Jiroft, Iran. Treatments consisted of five levels of native P (11, 28, 51, 78 and 97.1 mg P/kg soil) and two levels of P fertilizer (0 and 20 mg/kg). Leaf dry weight and concentration of P, Fe, Zn Cu and total uptake of these nutrients by leaves were measured after 6 weeks of plant growth. Results showed that the highest dry weight was related to P fertilizer use, which, as compared to no P-fertilizer application, showed an increase of about 14.61%. Also, treatments which used P fertilizer had the highest concentration of P, and the higher cucumber yield could be justified by P application. On the other hand, micronutrient elements such as Fe, Zn and Cu reached their highest amount in treatments with no use of P fertilizer. However, in case of using P fertilizer, the concentration of these micronutrients in plants was reduced by 25, 16 and 30.41 percent, respectively.

In order to evaluate the effect of different training systems on growth, yield and fruit quality of greenhouse cucumber (Cucumis sativus cv. Gohar) this experiment was set out in a randomized complete block design with three replications. Treatments consisted of four training systems including twin-stem system (V-shape), modified twin-system, high-wire system and horizontal system (single-stem). Results showed that the highest height vine, number of nodes and leaf area were observed in high-wire and horizontal systems. But, different treatments had no significant effect on internode length. The shortest time from flowering to harvesting (14 days) was obtained in V-system. Effects of the training systems on number of fruits and marketable yield per plant in different months were evaluated. The highest number of fruits (25.73) and marketable yield (2626 gr/plant) was observed in high-wire system in April. The highest non-marketable fruit was obtained in modified-twin system. Fruits of high-wire system had the highest length (17.23 cm). Effect of different training systems on dry weight of fruits and chlorophyll content of fruit skin was not significant. Fruits harvested in V-shape system had the highest total soluble solids and potassium content. According to the results and also the importance of yield in greenhouse culture, high-wire system is recommended for low-light intensity conditions and V-shape system for high-light intensity.

Rose is one of the most important flowers in the world, and is ranked first in the market of cutting flowers. An experiment was carried out to study the effects of different planting substrate on the quality and quantity of rose (Rosa hybrida var. Grandgala) flower. In this experiment, one-year-old rooted cuttings of commercial rose cv. Grandgala were transferred into different growing media including: 25% perlite 75% cocopeat, 50% perlite 50% cocopeat, 75% perlite 25% cocopeat, and washed sand, and nourished by one-half Hoagland’s solution, with pH of 6.5, for six months. In this study, effects of different planting media on different characteristics such as vegetative growth, photosynthetic parameters and nutrients were investigated. Results showed that planting media influenced all studied factors and differences between the four medium were clearly visible. Plants grown in medium with 25% perlite 75% cocopeat had the highest increase in growth photosynthetic parameters, and nutrients’ concentration as compared to other treatments. For example, increasing the percentage of cocopeat caused an increase in the number of buds on the plant. Number of buds in 25% perlite 75% cocopeat treatment increased 36% over washed-sand treatment. Also, the highest photochemical quantum yield of PS II photochemistry (Fv/Fm) was observed in 25% perlite 75% cocopeat treatment and the lowest Fv/Fm (0.724) in the plants grown in 75% perlite% cocopeat, respectively. According to the results, mixture of 25% perlite 75% cocopeat substrate was a suitable medium for hydroponic cultivation of rose var. Grandgala.

Soil salinity and compaction are probably the most prevailed limitations for crop growth and production. Their mitigation and control may be important crop management keys that can ensure yield sustainability and optimum use of land and water. This research was performed to investigate the combined effect of soil salinity and soil compaction on some growth characteristics of corn (Zea mays L.) root. For this purpose, a factorial pot experiment on the basis of completely randomized blocks design with three replications was performed. The experimental factors were three levels of soil salinity (electrical conductivity of saturated paste extract of 1.5, 2.5 and 4.5 dS/m) and three levels of soil compaction (bulk density of 1.3, 1.55 and 1.75 g/cm3). For salinity treatments, different amounts of NaCl was dissolved in the required volume of distilled water to have soil water content to 16% and then were added to the soil. For soil compaction treatments, a 4.5 kg solid cylinder was allowed to fall freely from 45 cm height over the soil surface in the pots. During the 3 months of experimental period, the pots were irrigated with distilled water through regular weighing. Results showed that the main effects of soil salinity and compaction at 1% probability level and their combined effects at 5% probability level led to significant reduction in root dry weight, root volume, root length, root mean diameter and ratio of root weight to soil weight. Combined effects of soil salinity and compaction reduced growth characteristics of the corn roots 20% more than their individual effect. Therefore, it can be concluded that soil salinity and compaction intensify their negative effects and suppress growth and development of corn roots.

In order to study the effects of nano-fertile fertilizer containing humic acid on uptake of nutrients of two lettuce (Lactuca sativa L.) cultivars in a nutrient film technique (NFT) system, a factorial experiment based on completely randomized design with four replications was conducted. The experiment consisted of two factors, the nano-fertile fertilizer (0, 500 and 1000 mg/L) and cultivar (Great Lake and Super salad). In this experiment, nutrient elements (K, P, Ca, Mg, Fe, Zn, Mn and Cu) concentration in plant shoots and roots were measured. Results showed that concentration of 1000 mg/L of nano-fertile fertilizer increased concentration of these nutrient elements in shoots and roots of the lettuce plants. But, in the treatment of 500 mg/L nano-fertile fertilizer, only Zn, K and Mg in shoots and Zn, K and Ca in roots were higher compared to control. Great Lake cultivar was better than Super salad cultivar in the uptake of Zn in shoots and Ca, Fe, Mn, Zn and Cu in roots. According to results of this experiment, concentration of 1000 mg/L of nano-fertile fertilizer containing 75% humic substances can have positive effects on improving uptake of nutrient elements in treated plants.

Fragrant tuberose is the most important scented cut flower of Iran, which rank 4th among other cut flowers, based on the cultivation area and production. Due to the scarcity of water resources, soil constraints, and the aim of comparison and possible substitution of soil cultivation with soilless cultivation of tuberose, a pot experiment was conducted as factorial, based on completely randomized design with four replications, on two cultivars of tuberose (‘Mahallati’ and ‘Dezfuli’), in two greenhouse production systems, with soil and soilless medium. Based on the ANOVA results, photosynthetic capacity [number of leaves and leaf area, stomatal conductance and photosynthetic pigments content (chlorophyll a, b and total)], flower-stem height, number of florets, diameter of florets, nutrients uptake and flower vase life were significantly (P≤0.01) affected by culture system. Soilless system increased the flower-stem height and vase life (as the main quality indices of cut flowers) by 50% and 35%, respectively, as compared with soil cultivation. In addition, peroxidase activity, calcium, and potassium uptake were significantly (P≤0.05) affected by cultivar. Analysis of variance indicated that interaction of cultivar and cultivation system had significant effects on calcium uptake and number of leaves per plant. According to the results, soilless culture improved photosynthetic capacity and mineral uptake and subsequently increased quality and vase life of cut tuberose. This culture system showed high ability and potential to replace soil cultivation of tuberose.

Earthworms are considered as one of the soil quality and health indicators. In order to evaluate the effects of earthworms activity on some soil biological quality indicators, an experiment was carried out in greenhouse conditions with different organic materials including trees’ pruning waste compost (PWC), wheat straw (WS), herbal extracts waste (HEW), trees’ pruning waste (PW) in a pot experiment, with growing corn plants, for evaluating soil rhizosphere properties. At the end of growing period, some soil biological properties including basal respiration (BR), substrate-induced respiration (SIR), microbial biomass carbon (MBC) and microbial population were measured in rhizosphere and non-rhizospheric soils. Results showed that WS treatment had the most impact on basal respiration and substrate induced respiration content (2 and 2.4 fold) compared to control treatment (without organic matter), respectively. Also, microbial biomass carbon in PWC treatment (in rhizosphere soil) increased 59.2% as compared to non-rhizosphere soil. Microbial population in PWC, HEW, PW and WS treatments was 1.5, 2.6, 2.7 and 1.9 times more than control, respectively. Therefore, application of different organic matter in the presence of earthworms led to improve soil biological properties compared to when no earthworms were added.

Physiological responses of Hairy vetch (Vicia vilosa Roth) to biological, chemical and organic fertilizers were investigated in a completely randomized blocks design with three replicates. Fertilizer treatments consisted of three biological fertilizers and their combinations as well as incorporated with vermicompost and chemical fertilizer, resulting in 6 experimental treatments: 1- Mycorrhizae (Glomus moseae sp., 320 g/m2), 2- Mycorrhizae vermicompost (400 g/m2), 3- Mycorrhizae Nitroxin (Azospirillum sp. and Azotobacter sp.), 4- Mycorrhizae Rhizobium sp., 5- Mycorrhizae chemical fertilizer (NPK), and 6- control. Dry matter (DM), crop growth rate (CGR), net assimilation rate (NAR), leaf area index (LAI) and relative growth rate (RGR) were measured. Results showed that the effects of experimental treatments were significant for total DM, RGR, LAI and NAR, and not for RGR. The highest values of DM (83.3 g/m2), CGR (12.18 g/m2.day) and LAI (3.26) were observed in Mycorrhizae Rhizobium treatment. Based on the results of this experiment, a combination of Mycorrhizae Rhizobium fertilizer is suggested for highest performance of the Vicia vilosa Roth.

Artichoke (Cynara scolymus) is peculiar among the vegetables due to its medicinal properties. Previous studies have been shown that Ultraviolet (UV) radiation stimulates the production of some secondary metabolites in the plants. In the present study, the effects of UV-A (360 nm) radiation on total phenolic content, total flavonoid content, antioxidant capacity, cynarin content and some morphophysiological properties of Artichoke leaves were investigated. The greenhouse experiment was carried out on one cultivated type from Isfahan and two varieties from USA (Green Globe) and Italy (White Giant), with four treatments of UV-A radiation (0, 1, 2 and 4 hours per day). Radiation treatments were applied once every 2 hours during the 16 hours of daylight. Results showed that exposure to UV-A increased the fresh and dry weight of plants. Chlorophyll a, b and total chlorophyll contents decreased under the UV-A radiation. Maximum and minimum contents of chlorophyll a were observed in White Giant cultivar (control treatment) and 4 hours per day treatment, respectively. UV-A radiation had a significant effect on total phenolic content, total flavonoids content and antioxidant capacity of the three cultivars of Artichoke. The highest and the lowest total phenolic content were observed in White Giant cultivar (4 hours per day treatment) and control, respectively. The highest and the lowest amounts of antioxidant capacity were recorded for Green Globe variety and Isfahan cultivar, respectively. However, the results showed that the leaf cynarin content was decreased by increasing the UV-A radiation. Due to the increase in total phenolics and flavonoids in the mentioned conditions, the amount of other phenolic compounds may have increased in the leaves.

Although silicon (Si) is a non-essential element for most crops, but has shown beneficial roles in growth of crop plants. Therefore, evaluation of nutritional role of Si and nano Si components in crop production is necessary. For this purpose, a factorial experiment, based on randomized complete blocks design with three replications, was conducted at the Research Greenhouse of College of Agriculture, Ferdowsi University of Mashhad, in 2013. Treatments included size of the sodium silicate particles (nano and micro) and foliar application of Si [zero (without foliar application), distilled water, 100, 200, 300 and 400 mg/L]. Results showed that Si had beneficial effects on chlorophyll index, maximum chlorophyll fluorescence, quantum yield of photosystem II, photosynthesis, water use efficiency and mesophyll conductance of potato (cultivar Agria) leaves. Conversely, stomatal conductance, transpiration and intercellular CO2 decreased with application of Si. In most traits, effect of nanoparticles of sodium silicate showed a higher performance than micro particles, and 400 mg/L of nano-Si had maximum effects. Overall, nano-Si particles showed the highest efficiency compared to micro-Si. Therefore, using nanoparticles of sodium silicate at optimum level improves plant photosynthetic traits.

Aphis gossypii Glover (Hem.: Aphididae) is an important pest of vegetables and ornamental plants in greenhouses. Continued use of chemical pesticides for control of this pest has caused several problems and it is necessary to use other management methods, such as biological control. Coccinula elegantula weise (Col.: Coccinellidae) is one the natural enemies of cotton aphid with effective role in control of this pest. In this study, the effect of temperature was investigated on functional response and predation potential of this coccinellid with respect to different densities of the aphid. Based on the results, the predator exhibited type II functional response at three tested temperatures (18, 25 and 32 °C). By increasing the temperature from 18 to 25 °C, handling time of C. elegantula was significantly increased and searching efficiency was decreased; but these parameters didn’t change when the temperature increased from 25 to 32 °C. According to the results of the present study, in which the high searching rate and short handling time of C. elegantula were found to be at 25 and 32 °C and the fact that optimum temperature range for A. gossypii development over cucumber is 22.5 to 30 °C, and more importantly if we can overcome the obstacles of mass rearing, this predator could be a valuable and potential species in biological control of cotton aphid

This research was carried out to investigate the effects of different commercial nutrient solutions on growth and yield of gerbera (Gerbera jamesonii L.) cut flowers in open soilless culture system. The experiment was set up in a completely randomized factorial design with three nutrient solutions (S1: Schreurs, S2: Florist and S3: Research Station for Floriculture and Greenhouse Vegetables, RSFGV) and two gerbera cultivars (Red “Stanza” and Yellow “Double Dutch”). Results showed that minimum days to the first flower bud appearance (38.2 days) and days to the first flower harvest (58.5 days) were obtained from Red cultivar supplied with the S3 nutrient solution. The highest number of leaves (12.3 leaves/plant), stalk length (52.2 cm), stalk fresh weight (38.4 g) and number of flowers (291 stalks/m2.yr) were obtained from Red cultivar supplied with the S3 solution, while maximum vase life (11.4 days) was obtained from Yellow cultivar supplied with the Schreurs nutrient solution. Based on the results, RSFGV nutrient solution (S3) can be recommended as a basic nutrient solution for commercial gerbera cut flower production in hydroponic.

Calcareous soils with high pH in Jiroft region have caused difficulties in uptake of micronutrients, particularly iron (Fe), by strawberry plant. In the present greenhouse research, treatments consist of combination of different sources, application method and amount of iron application. Results showed that soil application of 10.5 kg/ha chelated iron (Fe-EDDHA) had the highest fruit yield, average fruit weight and vitamin C content. Based on the orthogonal comparison, in general, applying iron with any method of application and combination significantly affected most of the measured plant traits (with the exception of fruit acidity and vitamin C content). Therefore, regardless of the type and method of iron application, its application is necessary to increase yield and other quality parameters of the strawberry under greenhouses conditions in Jiroft region. Economic evaluation of the treatments showed that spraying iron sulfate and Fe-HEEDTA is not economically justified due to the costs imposed on greenhouse owner. Generally, soil application of Sequestrene-138-Fe is economically valuable, compared with spraying of iron sulfate and Fe-HEEDTA. Using 4.5 kg/ha Sequestrene-138-Fe has higher economic justification and higher profitability rate (1979.95% in comparison with 1345 and 1176.89%, respectively) compared to 7.5 and 10.5 kg/ha. Thus, soil application of 4.5 kg/ha Sequestrene-138-Fe (Fe-EDDHA) for greenhouse production of strawberry in Jiroft region, which have similar conditions to the present experiment, is recommended.

Because of increasing trend in salinization of water sources, and inevitable using non-traditional water, a research was planned to determine the tolerance range of strawberry cv. Paros to salinity and possible role of salicylic acid (SA) in ameliorating its adverse effect on plant growth. In this research, effect of different salinity levels (0, 20 and 40 mM in nutrient solution) and SA (0, 100, 200 and 300 mg/L as foliar spray) on this plant was investigated. Rooted plants of strawberry were cultivated in 3 L plastic pots, filled with 1:1 ratio of perlite and cocopeat under greenhouse conditions. Day and night temperatures were 23±3 and 15±3 oC and relative humidity was about 60 to 70%. After establishment of plants, salinity treatments were carried out. Results indicated that salt stress had adverse influence on most of the parameters and caused reduction in shoot and root fresh and dry weight, and also decreased vitamin C concentration of fruits. Foliar application of SA solution at 200 mg/L caused an increase in tolerance level of plants and improved such characteristics as leaf area, shoot and root fresh and dry weight and yield. This ameliorative effect of SA decreased along with increase in salinity concentration to 40 mM. In general, SA could mitigate the detrimental effect of saline conditions on growth of strawberry plants, especially at 200 mg/L concentration.

One of the most important limiting factors in cultivation of strawberry in greenhouses during winter season is short day-length. An experiment was conducted to evaluate the effect of end-of-day red light on growth characteristics, yield and fruit quality of strawberry (cv. Queen Elisa) in a completely randomized design with 4 treatments in winter of 2013. Strawberry plants were exposed to red light (660 nm, 12 µmol/m.s) for 2, 4 and 8 hours, using LED light source, from 6 pm, and were compared with control (plants without red light treatment). Results showed that 8 hours of red light radiation caused a significant increase in number of leaves, petiole length, leaf length and width and leaf area of the plants. Fresh and dry weight of plants, as well as weight and length of Queen Elisa strawberry fruits were increased in red-light treatments. Also, soluble-solids content of fruits in radiated treatments, especially in 8 hours red light treatment, was increased. But, fruit’s titratable acidity and pH were not significantly affected by the red light. Results clearly demonstrated that end-of-day red light, emitted from LED source, improved morphological characteristics, growth, yield and fruit quality of strawberry cv. Queen Elisa.