نشریه روابط خاک و گیاه
پیاپی 7 (پاییز 1390)

Plants need adequate nutrients in all stages of growth, which should be available in the growing medium. This study was performed to examine the effect of different substrates on nutrient uptake and quantitative and qualitative yield of greenhouse strawberry. The experiment was carried out in the research greenhouse of Jihad-e- Daneshghahi, West Azarbaijan, using a completely randomized design with 5 treatments and 4 replications. Five different growth media consisted of perlite-cocopeat ratios (v/v) of 100-0, 75-25, 50-50, 25-75 and 0-100. Physical and chemical properties and nutrients concentrations as well as fruit yield were measured. Comparison of the growth media showed that the highest number of flower and fruit was in ratio of 75-25 perlite-cocopeat. The highest fruit yield was obtained from ratios of 75-25 and 50:50 of perlite-cocopeat. Evaluation of qualitative fruit-characteristics indicated that the highest dry matter and total soluble solids were measured in 100-0 ratio of perlite-cocopeat. The highest quantity of fruit N and K was found in 100-0 ratio of perlite-cocopeat. Fruits grown in 0-100 ratio of perlite-cocopeat had the highest calcium and magnesium as compared to other substrates. The general conclusion is that most quantitative and qualitative traits of strawberries grown in hydroponic system depend on the substrate, and the best of these traits were obtained in ratios of 75-25 and 50-50 of perlite-cocopeat.

The objective of this study was economic assessment of greenhouse-cucumber production units in Birjand Township and investigation of factors influencing it. Statistical population of this research consisted of all the greenhouse owners in Birjand (50 units). For economic assessment, the profitability index (TR/TC) and discriminative analysis were used. Based on the TR/TC index and cluster analysis with –K mean method, the considered society was divided into two groups of successful and less-successful units. The median of this index was more than 1.49 in the successful group and less than1.49 in the other group. After dividing the groups by discriminative analysis, the variables distinguishing the groups were determined. Results showed that the most important variables which influence the TR/TC index and distinguish these two groups are amount of applied micronutrients, greenhouse area, number of irrigations, amount of the applied manure, educational-extension films, and visiting other greenhouse-owners’ activities.

Abstract Jiroft area, with upwards of 1250 ha of greenhouses and 250000 ton of yield, is one of the most important areas for production and supply of greenhouse products in Iran. Lettuce is one of the salad vegetable crops that is planted in vast areas in open space and greenhouse conditions. In this study, Great Lakes 118 lettuce variety was planted in a split-plot experiment with factorial design, eight treatments and three frequencies. The studied treatments were planting condition at two levels of greenhouse and open space, planting dates in Oct. 7 and Oct. 22, and 3 and 4 cultivation frequencies in greenhouse and 1 and 2 frequencies in open space. Lettuce plantings were pre-planted in nursery and were transferred after four-leaf process (20-25 days). Planting rows were provided with 6 m length, 70 cm width and 30 cm distance from each other. Shrubs were planted in greenhouse and open space with 8-10 cm distance from the border, 2 rows and 25 cm distance in every plot. Measured factors were: plot yield, total yield per unit area, average head weight and the amount of nitrate accumulation in leaves. On the base of results, total yield of product in greenhouse and open space was 167.9 t/ha and 41.22 t/ha, respectively. Economic analysis showed that the investment in treatment Oct. 22 with four frequencies under greenhouse condition was superior to others and the gross profit of lettuce production in greenhouse condition was more than some other crops.

In this study, effect of spraying nickel sulfate and urea on reproductive growth, yield and some qualitative characteristics of strawberry fruit were investigated. Rooted daughter plants of strawberry, cv. Pajaro, were grown in 3 L pots in greenhouse of College of Agriculture, Shiraz University. The established plants were sprayed, at 4-5-leaf stage, with nickel sulfate at concentrations of 0, 150, 300 and 450 mg/L and urea at concentrations of 0 and 2 g/L. Some traits such as yield, weight of primary, secondary and tertiary fruits, length: diameter ratio, inflorescence number and number of flowers in each inflorescence, vitamin C, total soluble solids and total acid were recorded. Results showed that 300 mg/L nickel sulfate without urea increased significantly the yield, primary and secondary fruits’ weight and inflorescence number as compared to control. Also, the 300 mg/L nickel sulfate treatment with 2 g/L urea had the highest rate of total acid (0.75%). In general, spraying 300 mg/L nickel sulfate with 2 g/L urea is recommended for increasing the strawberry yield.

Knowing crop evapotranspiration at any time is very important in management of irrigation systems for greenhouse. Changes in evapotranspiration during the crop growth period are described by crop coefficient (Kc), which is defined as the ratio between crop evapotranspiration and reference evapotranspiration. This study was conducted to determine the evapotranspiration of cucumber, tomato and pepper at Isfahan University of Technology greenhouse using micro-lysimeters for 7 months. Gravimetric method was used to determine the water balance of soil in micro-lysimeters. Simultaneously, reference crop evapotranspiration was estimated using drained lysimeters. Results indicated total reference evapotranspiration during the 7 months of the study in greenhouse was 824 mm. Total evapotranspiration for cucumber in 3.5 months of growth period was 202 mm, for tomato in 6 months was 524 mm and for pepper in 7 months was 667 mm. Weekly changes in crop coefficients of different crops in the growth period were variable. The average crop coefficients for cucumber at the initial, development, midseason and late season were obtained as 0.41, 0.69, 0.98 and 0.77, respectively. For the tomato, these values were 0.44, 0.68, 1.15 and 0.68, and for pepper were 0.25, 0.53, 1.03 and 0.75, respectively. To find the relationship between climatic data of greenhouse and crop evapotranspiration, the SPSS software was used to model the evapotranspiration process. Results indicated that the best proposed model is a nonlinear regression equation, based on the average daily air temperature, solar radiation and crop height.

Short vase life and low quality of cut rose flowers are the main problems of most rose greenhouses in Iran. Calcium is one of the most important nutrients that plays a major role in vase life of cut rose flowers. In this study, a factorial experiment was conducted based on completely randomized blocks design to elucidate the effects of foliar application of calcium rates and sources on yield and quality of rose flowers cv. Illona. Rose plants were sprayed by three rates of 0, 0.3 and 0.6 g/L calcium in combination with two sources of calcium nitrate (Ca(NO3)2.4H2O) and calcium chelate (Ca-EDTA) before the harvest. The experiment was conducted in 3 replications during 2005-2007 in Safi Abad Agricultural Research Center, Dezful. The results revealed that rose yield and flower quality indices at harvest time consisting of flowering stem fresh weight and length and length and diameter of buds were not affected by different rates and sources of calcium. But, vase life of cut rose flowers was increased significantly by 2.7 and 2.9 days in 0.3 and 0.6 g/L treatments, respectively (P<0.01). This was due to increased Ca concentration in the rose leaves and petals. There was no significant difference between the calcium nitrate and calcium chelate in supplying calcium and increasing vase life of cut rose flowers. According to the results of the present study, pre-harvest foliar application of calcium nitrate or calcium chelate at the rate of 0.3 g/L is recommended to improve vase life of cut rose flowers in north Khuzestan under greenhouse conditions.

Abstract In order to determine the actual evapotranspiration of tomato in the greenhouse, crop and soil-water stress coefficients were surveyed. To compare the actual evapotranspiration at different irrigation intervals (1, 2, 4, 6 and 8-day), a completely randomized blocks design with four replications was performed. The present study was carried out in a greenhouse covered by 4 mm thick glass. Maximum and minimum temperatures and solar radiation were measured inside the greenhouse once in 24 h. Relative humidity was measured in the greenhouse once in 2 h. Microclimate data were measured in a metrological station, 100 m from the greenhouse, simultaneously, at outside the greenhouse. Reference crop evapotranspiration was calculated by FAO Penman-Monteith method for inside and outside of the greenhouse. Results indicated that the reference evapotranspiration in the inside of the greenhouse was 73% of outside the greenhouse. The actual evapotranspiration of tomato for inside of the greenhouse was determined by using the water balance method. By using the pergeometer and albidometer data, the crop coefficient for inside the greenhouse at three different stages (development, mid, and end) of growth was determined as 0.85, 1.0 and 0.77, respectively. Soil-water stress coefficient, with readily available coefficient of 0.7, was determined to be in the range of 0.53 to 0.98 for all the treatments. This coefficient was 0.88 for water-stressed 4-day treatment, and reduced to 0.72 for 8-day treatment.

Serpentine leaf miner is one of the serious pests of vegetable crops in greenhouse and open fields، especially on cucumber and tomato. Reduction of synthetic insecticides’ use in order to minimize pesticide residues on these crops is an important basis of food safety. Application of bio-insecticides، especially neem products’ oil، is a very important alternative. Investigation on the efficacy of the commercial neem extract formulation with different concentrations was experimented on cucumber under greenhouse conditions. In the first year، experiments were performed in a completely randomized blocks design with six treatments and three replications. Five treatments included various concentrations of NeemAzal-T/S including 0. 25، 0. 5، 0. 75، 1 and 1. 5 ml/m2 and the sixth one was control without any chemicals. The results showed that on the third and seventh day of the treatment with concentrations of 0. 75، 1 and 1. 5 ml/m2، more than 80% mortality was observed، which shows a significant difference with 0. 25 and 0. 5 ml/m2 treatments. In the second year، the efficiency of two concentrations (1 and 1. 5 ml/m2) of NeemAzal-T/S was evaluated in comparison with chlorpyrifos، abamectin and permethrin. Results revealed that efficiency of the two neem concentrations had no significant difference compared with chlorpirophos and abamectin. Therefore، it could be concluded that NeemAzal-T/S could be successfully recommended to replace the chemical insecticides.