نشریه روابط خاک و گیاه
پیاپی 46 (تابستان 1400)

The aim of this study was to investigate the effect of date kernel biochar and nano-biochar on enzymatic activities of rhizosphere and non-rhizosphere environment of European borage. The date kernel was converted to biochar at 400 and 800 ºC pyrolysis temperatures and mixed with different soils. Four soils with different characteristics including acidic, calcareous, saline-sodic and saline-highly sodic were selected. Biochars were then converted to nano-size materials using the rolling ball method. Also nanoparticles were extracted from date kernel powder by hydrothermal method. The obtained biochars were mixed with soil and transferred to greenhouse pots. European borage was planted and harvested after 60 days. Rhizospheric and non-rhizospheric soils were collected and the activity of acidic and alkaline-phosphomonoesterase, protease and β-glucosidase enzymes were measured. The highest and lowest activities of acid-phosphomonoesterase, protease and β-glucosidase enzymes were found in the acidic and saline-highly sodic soils, respectively. However, the highest alkaline-phosphomonoesterase activity was observed in the saline-highly sodic soil. The activity of enzymes in the rhizosphere soil was greater than in the non-rhizosphere soil. The highest activities of enzymes were found in the control and were reduced by using biochar, nano-biochar and nanoparticle biochars. The conversion of biochar to nano-biochar could not increase the activity of enzymes in the soil.

In order to investigate the effect of nitoxin biofertilizer on black seed (SN) under different levels of water stress, an experiment was conducted in the research farm of Ilam University using a split-split plot arrangement based on a randomized complete block design (RCBD) with three replications in 1398-1399. The main plots were water stress treatment at three levels including no stress, moderate and severe stress based on 100, 50 and 35% of plant water requirement. The sub-plots and sub-sub plots were biofertilizer treatments (at two levels) and four black seed ecotypes (Isfahan, Semirom, Mashhad and Neyshabour), respectively. Based on the results, the highest amounts of chlorophyll a, b and total pigments were 0.711, 0.523 and 1.235 mg g-1 FW from control and the highest levels of anthocyanin (14.69 μmol g-1 FW), catalase (0.0152 U min-1 g-1 P or units per minute per gram of protein) and proline (5.84 micromoles per gram of fresh leaves) were obtained in the severe water stress treatment. Results also showed that the highest amount of proline (0.0152 units per minute per gram of protein) and chlorophyll pigments including chlorophyll a, b and total with 0.711, 0.523 and 1.235 mg per gram of fresh leaves, respectively, were obtained in the control. The use of nitroxin biofertilizer increased the levels of anthocyanin and catalase. Among the tested ecotypes, Semirom had the highest amount of chlorophyll b pigment (0.39 mg g-1 of fresh leaves) and the highest amount of catalase activity (0.0087 U min-1 g-1 P). Neyshabour and Isfahan ecotypes had the highest anthocyanin content (9.21 μmol g-1 fresh leaf) with the highest proline concentration (4.4 μmol g-1 fresh leaf) and total chlorophyll a. Based on the analysis of variance of the data, the triple interaction of water stress × nitroxin × ecotype on all measured physiological traits except catalase activity and chlorophyll a pigment was statistically significant at 5% probability level. Decreased chlorophyll indicates susceptibility to drought stress and increased anthocyanin, catalase and proline indicate plant response to stress. Examining the physiological characteristics of black seed under drought stress indicated that black seed is almost sensitive to drought stress. The results showed that there was a difference between black seed ecotypes in terms of response to dehydration and biofertilizer was able to improve the plantchr('39')s response to stress to some extent.

The supply of mineral elements for plant growth is of great importance in agricultural production. The development of slow-release fertilizers is one of the effective methods for overcoming problems caused by the uncontrolled use of chemical fertilizers in agricultural lands. Biopolymers are among the most suitable natural compounds for the synthesis of slow-release fertilizer systems. In the present research, alginate, rosin gum, and combination of wheat straw and the gum together with zeolite in the mass ratios of 1:2, 1:4, and 1:8 were used to produce slow-release systems of nitrate and potassium. The extents of nitrate and potassium release were measured 1, 3, 5, 10, 15, 20, 25, and 30 days after slow-release fertilizers applications. The highest percentages of potassium and nitrate release were recorded during the first 24 hours. The results showed that the highest percentages of potassium release were recorded for the systems made from wheat straw in combination with gum rosin and zeolite while the lowest release percentages were observed for the 1:8 zeolite:rosin gum system. In general, it may be concluded that the slow-release systems made based on rosin gum:zeolite were suitable candidates for the preparation of slow-release nitrate and potassium fertilizers.

To investigate the effect of biofertilizers application on cherry tomato, a factorial experiment based on a completely randomized design with four replications was carried out under greenhouse conditions. Experimental factors included different concentrations (0, 0.5, 1.0 and 1.5%) of Probiotic biofertilizers (containing Thiobacillus bacteria) and Biofarm (containing Azotobacter and Azosperillium bacteria), and two cherry tomato cultivars (Meeing and Jean ho). Results indicated that combined treatments of Biofarm at both 0.5 or 1% concentrations with Probiotic at 1.5% concentration, caused the highest yield in Meeing cultivar. The highest chlorophyll a and total chlorophyll were observed in Ming cultivar treated with 0.5% of Biofarm. The highest total antioxidant capacity was observed in Ming cultivar by using 1% concentration of Biofarm while the lowest amount was obtained in the application of 1.5% concentration of Probiotic fertilizer in Huang Jinju cultivar. The highest concentrations of lycopene and vitamin C were measured in the plants treated with 1.5% of Probiotic biofertilizer. The highest phenol content of fruits was produced by using 1.5% of Biofarm and 1% Probiotic biofertilizer. In this experiment, Ming cultivar was superior to Huang Jinju for most of the measured traits, especially growth and physiological characteristics. Increasing the concentration of fertilizers, especially Biofarm, the measured quantitative and qualitative traits of cherry tomatoes were improved significantly. Therefore, these biofertilizers could serve as suitable alternatives for chemical fertilizers in cherry tomato production.

In order to investigate the effect of nutrient solution type and concentration on physiological and morphological characteristics of strawberry cultivar ‘Parus’ in hydroponic culture (75% volumetric perlite + 25% volumetric cocopeat), an experiment using a completely randomized design with three replications was conducted. The growth media included Full-Strength Morgan (FSM), Double Strength Morgan (DSM), Half-Strength Morgan (HSM), Full-Strength Hoagland (FSH), and Half-Strength Hoagland (HSH). The results showed that nutrient solution type had significant effects on plant growth characteristics and quality of strawberry fruit, so that the highest number of leaves (7.16 per plant), shoot height (28.62 cm), fresh weight (11.70 g per plant) and dry weight (2.66 g per plant) of the shoot were related to the HSH treatment. But, the highest fresh weight (15.15 g per plant) and dry weight (1.40 g per plant) of roots were obtained in DSM and FSM treatments, respectively. Fruits of plants treated with FSM nutrient solution had the highest amount of vitamin C (83.4 mg/100 ml of extract) and total soluble solids (5.7%), while HSM produced the highest titrable acidity (0.17%). Nutrient solutions had no significant effect on crown diameter, and pH, firmness and color of the fruits. Therefore, HSH treatment is recommended for vegetative phase because it improves the growing conditions with less water and nutrients used. With FSM and HSM treatments, fruits with higher quality were obtained. Also because MFS nutrient solution produced more vitamin C (as a powerful antioxidant) and soluble solids (as a flavoring agent), this nutrient solution is recommended for the reproductive growth phase.

Sequestrene 138 Fe (Fe-EDDHA), one of the most common fertilizers, is used as a source of iron (Fe) in soilless cultures, but its high price leads to increased production costs. This experiment was conducted to investigate the effect of nano iron chelate (consisting of Fe, Zn and Mn) in comparison with Fe-EDDHA on the micronutrients concentration, leaf photosynthetic pigments and yield of two lettuce (Lactuca sativa L.) cultivars in soilless culture. A factorial experiment using completely randomized design was carried out with two factors of iron fertilizers and lettuce cultivars (Teresa and California) and three replications at Shahrekord University. Lettuce plants were nourished with 20 and 40 μmol L-1 of Fe in nutrient solution from sources of Fe-EDDHA and nano iron chelate (provided that this fertilizer can supply or is not able to supply Zn and Mn required for the plant). The results indicated no significant difference between the application of 40 μmol L-1 of Fe from either nano iron chelate (provided that this fertilizer can supply Zn and Mn required for the plant) or Fe-EDDHA fertilizers in respect to leaf chlorophyll and carotenoid contents, root and shoot fresh weights, and shoot Fe concentrations of the studied lettuce cultivars. Although the highest shoot fresh weight (436 g plant-1) was obtained in 40 μmol L-1 of Fe as Fe-EDDHA, it was not significantly different with shoot fresh weight (387 g plant-1) gained by application of 40 μmol L-1 of Fe as nano iron chelate. Based on the results, nano iron chelate might be an ideal substitution for the Fe-EDDHA in soilless culture of lettuce, however further research is still required to completely evaluate its potential risks to the environment and food safety.

Due to high production and good economic income, greenhouse cultures are growing. Therefore, it is necessary to find methods that increase yield and water use efficiency in greenhouse conditions. Use of mycorrhiza fungi and hydrogel can be suggested in this regard. A factorial experiment was conducted in a completely randomized design with 3 replications in the greenhouse of Payame Noor University of Zahedan center in 2017-2018. The first experimental factor included irrigation at three levels of low, moderate and normal with 540, 790 and 1040 liters of water per square meter, respectively. The second factor consisted of mycorrhizal fungus at two levels of inoculation and no inoculation. Hydrogel treatment at two levels was considered as the third factor. The results showed that under normal irrigation conditions and combined application of fungus and hydrogel, the highest plant height, number of fruits per plant, final fruit yield, dry weight of shoot and root, relative leaf water content and water use efficiency were obtained. For the above traits, no significant difference was observed between this treatment and treatment of normal irrigation and fungal inoculation and without hydrogel application. At moderate irrigation condition, the highest values of the mentioned traits were obtained from the combined treatment of fungus and hydrogel and the yield obtained from this treatment was not significantly different from the one at normal irrigation condition without the use of fungus and hydrogel. At low irrigation condition, the highest values of the studied traits were obtained from combined treatment fungus and hydrogel and also application of hydrogel without the use of fungus. The lowest values of the studied traits in this experiment were obtained at low irrigation treatment without the use of fungus and hydrogel. At low irrigation condition, there was no significant difference between the two treatments of fungal application without the use of hydrogel and lack of fungal application which indicates that the fungus is not effective at low irrigation condition.