نشریه روابط خاک و گیاه
پیاپی 42 (تابستان 1399)

Organic substrate can increase crop productivity. This experiment aimed to improve the yield and growth parameters of sweet pepper (Capsicum annuum L. cv. ‘Gold flame’) by using three levels of modified Johnson’s nutrient solution (JNS), including full JNS as the control (NSc), 75% JNS (NS1) and 50% JNS (NS2) as well as three types of substrates that were based on three levels of vermicompost: vermicompost:perlite:cocopeat (1:1:1 v/v; V1) as the control, vermicompost:perlite:cocopeat (1:1:2 v/v; V2) and vermicompost:perlite:cocopeat (2:1:1 v/v; V3). Fruit fresh weight (86.18%) and dry weight (43.03%), root dry weight (68.63%) and root volume (43.67%), fruit diameter (12.39%) and yield (59.30%) increased significantly in V3 treatment. The application of vermicompost increased photosynthesis rate, respiration, nitrogen, phosphorus, and potassium concentrations more than Johnson’s nutrient solution. Fruit fresh and dry weights, root fresh and dry weights, root volume, fruit diameter and yield decreased in NS2 and NS1 and application of V3 improves the fresh weight of fruit in NS1. The highest fruit yield was observed in NSc treatment in combination with V3. Photosynthetic rate, and P and K concentrations increased with vermicompost application in all nutrient solution. The N and P concentrations decreased in NS1 and NS2 while respiration was stimulated by V2 and V3 in combination with NS1. The P decreased in NS1 and NS2 but was stimulated by both V2 and V3 treatments. The N level was reduced in NS1 and NS2 but V3 enhanced the level of N when combined with NS1. Overall, plant growth, yield, photosynthesis and nutrient N, P, K concentrations can be increased in sweet pepper by the addition of vermicompost and nutrient solution.

In this research, the ability of a fuzzy logic control (FLC) system in providing optimal temperature and humidity inside greenhouse and the effect of FLC on the growth parameters of basil plant were aimed. At first, the FLC algorithm was implemented in Fuzzy Tech software. Second, two small, separated and isolated spaces were prepared as model and control greenhouses. Then, the FLC equipment were installed inside model greenhouse, including temperature, humidity and soil moisture sensors along with a fan, a heater, a fogger system and electric valves as actuators. During 40 days experiments, temperature and humidity changes inside and outside of the greenhouse were recorded. Finally, the basil plants were harvested and some growth parameters of the crop were measured. The results showed that the FLC greenhouse was more capable than the control greenhouse in providing the plantchr('39')s growth conditions. The root mean square errors (RMSE) of temperature were 1.33 and 5.71 oC, and of humidity were 2.29 and 19.45% in FLC and control greenhouses, respectively, which indicates better performance of FLC than On/Off control for providing optimum temperature and humidity for plant’s growth. Both greenhouses had the same performance at germination percentage, but the FLC greenhouse had better performance at other growth parameters. The measured values for dry and fresh weights of basil plant in the FLC greenhouse showed 50 and 35% increase in the yield, respectively, compared to the control greenhouse. In general, the results of this study showed that the fuzzy control method is able to optimally control the environmental conditions of greenhouses; so it is recommended for use in new greenhouses.

The aim of this study is to determine the energy efficiency of greenhouse cucumber production using Data Envelopment Analysis (DEA) method and to assess its main determinants in central region of Isfahan province, Iran. Data were collected through structured questionnaire and via face-to-face interview with 81 greenhouse farmers in 2016. The results showed that the higher level of farmer’s education played a positive role in improving energy efficiency, while long years of farming experience and using more family labor force had a negative effect. Among the farmer’s communication channels, visiting other greenhouses and consulting with agricultural input suppliers had the most positive effect on greenhouse energy conservation. Designing a process for visiting and following energy-efficient greenhouses can lead to less energy consumption. Due to the close relationship of the greenhouse farmers with the agricultural input vendors, mutual connection of outreach experts with agricultural input vendors plays a role in linking farmers and scientific and research centers and facilitates the exchange of problems and information, and knowledge and technology transition.

Organic amendments not only promote soil quality but also indirectly facilitate the establishment of bacteria. A greenhouse experiment was conducted to investigate the effects of organic substrates and plant growth promoting rhizobacteria inoculation on morphological characteristics of lettuce (Lactuca sativa L. Cv Rabicon.) in a factorial arrangement based on completely randomized design with four replications. Experimental treatments included organic fertilizers (vermicompost 20% v/v, spent mushroom 10% v/v and soil) and seed priming with promoting growth regulating bacteria (Pseudomonas putida P10, Pseudomonas fluorescence R159 and R150 and non-inoculated). At the end of growth stage, morphological traits (plant height, leaf number, crown diameter, leaf area, root length and volume, shoot fresh and dry weight), photosynthesis pigments (chlorophyll a, b, total and carotenoid), vitamin C, phenol, flavonoid and nitrate concentration were measured. The results indicated that the simple effects of substrate and bacterial strains inoculation were significant on traits including plant height, crown diameter, leaf area, root length and volume, shoot dry and fresh weights, chlorophyll a, b, total and carotenoid, vitamin C, phenol and flavonoid. Interaction of both factors had significant effects on leaf area, root length and volume, chlorophyll a and phenol. However, plants treated with vermicompost and Pseudomonas fluorescence R159 had higher values for both fresh and dry weight, phenol content and chlorophyll. Although some traits were higher in plants treated with compost and Pseudomonas putida P10 or vermicompost and Pseudomonas putida P10, but finally it seems that Pseudomonas fluorescence R159 has played a higher role in the final quantity and quality of lettuce.

In order to evaluate the effect of various irrigation regimes and different fertilizer combinations on some morphological and physiological traits of Mentha piperita, a greenhouse experiment was carried out at the research greenhouse of Ferdowsi University of  Mashhad, during growing season 2017-2018. The experiment was conducted in factorial experiment based on completely randomized design with three replicates. Factors were consisted of different irrigation regimes levels: 100% FC, 75% FC and 50% FC, and different biological and chemical fertilizers combinations including:1-biochemical bacterial NPK + NPP, 2- NPP bio-fertilizer, 3-NPK, 4-micronutrient fertilizer (MIC), 5-MIC + amino acid fertilizer (AP). The results showed that interaction of irrigation regimes and different biofertilizers on leaf area, height, branch number and stomatal conductance and RWC had different significant at 1% and 5% level respectively. The highest leaf area (1353 centimeters square), Maximum height (42 cm) and the highest number of branches (37) were obtained in irrigation of 100% FC and NPK + NPP combination fertilizer treatments and the highest stomatal conductance (99 mmoles per second) and the highest RWC (82.6%) were obtained in 100% FC irrigation and NPP fertilizer treatments. Also, the results of variance analysis showed that the main effects of irrigation regimes and fertilizer types on dry weight, electrolyte leakage, spade number and essential oil percentage were significant at 1% level, but their interactions were not significant. The highest dry weight (17.7 g) and spade (49.8) were observed in FC 100% irrigation and NPK + NPP combination treatment, the highest electrolyte leakage (70.2%) and percentage of essential oil (2.9%) were observed in irrigation of 50% FC and NPK + NPP combination fertilizer treatments. The results of this study showed that the use of bacterial and chemical fertilizers in the complete irrigation regime increased morphological and physiological traits. Also, the results showed that the use of biofertilizers less increased the amount of electrolyte leakage under drought stress compared to other fertilizer treatments.

Intercropping in compared to monoculture can increase yield sustainability. Deficit irrigation as a limiting factor for growth, affects the plantchr('39')s yield characteristics. Therefore, The aim of this study was to investigate the effect of cultivation type: monoculture tomato (T), monoculture basil (B) and intercropping (50T:50B), and different moisture levels including four irrigation periods based on soil field capacity (FC): irrigation without water stress in the root zone 0.85‒1FC, and deficit irrigation levels of 0.7‒0.85FC, 0.5‒0.7FC and 0.3‒0.5FC, with a factorial arrangement (with two factors) in a completely randomized design and a total of 12 treatments in three replications. Plant characteristics including greenness index, stomatal conductance, leaf area index, leaf temperature and fresh and dry weights were measured. Based on the results, the highest fresh and dry weights of aerial part of the tomato were obtained in 0.7‒0.85FC treatment with intercropping (349.73 and 69.42 g per plant) and their lowest values were obtained in the irrigation level 0.3‒0.5FC with monoculture (204.66 and 40.42 g per plant). Tomato leaf area index was not significantly decreased up to water stress level of 0.5‒0.7FC. For basil, the highest fresh and dry weights of the plant (91.71 and 16.39 g per plant) and leaf area index (1845.99 cm2 per plant) were obtained in monoculture, and at non-stress level and 0.7‒0.85FC, respectively. Tomato was dominant in intra-specific competition with basil and significantly influenced basil yield. Finally, according to the results of this study intercropping of basil and tomato and water level up to 50% of field capacity resulted in reduction of water loss and increased fruit yield of two plants by considering consumed water.

Factors such as suitable substrate and packaging may increase the shelf life of greenhouse bell pepper. In this study, the greenhouse bell pepper plants grown in the substrates containing 0, 25, 50, 75 and 100% compost tea in hydroponic culture were packaged in two types of film using the modified atmosphere method. Firmness of fruit texture, total soluble solids, pH, titratable acidity, vitamin C, and respiration were measured immediately after harvesting and during storage time with three replications. Then, the data obtained from the above tests were analyzed in a completely randomized design with factorial arrangement (three factors: substrates containing different amounts of compost tea, type of packing material, and storage time). Although the results showed that characteristics of the bell peppers grown on the substrates containing different amounts of compost tea were significantly different (p<0.05) from the substrate without compost, no significant result was obtained as to which percentage of compost tea had the most impact. With regard to storage time, most of the tested characteristics had a decreasing trend, but still laid within the standard ranges. In terms of the type of film, with a slight difference, nanofilm was superior to polyethylene film. As a conclusion, the bell peppers grown on the substrates containing compost tea and packaged in the nanofilms with the modified atmosphere method had acceptable shelf lifes more than one month.