نشریه مدیریت خاک و تولید پایدار
سال یازدهم شماره 2 (پیاپی 36، تابستان 1400)

Soil, as an important component of terrestrial ecosystems, plant growth media, and a habitat of diverse living organisms commonly encounters a variety of abiotic stresses. Soil microorganisms play an important role in maintaining soil quality and functioning, since they are responsible for the decomposition of dead organic material, nutrient cycling and degradation of hazardous organic pollutants. Metal toxicity and salinity are the major abiotic stresses affecting soil microbial activity and community structure in many areas of the world, in particular arid regions. Salinity may prompt the negative influences of soil pollution on soil microbial activity. On the other hands, application of organic amendments to saline soils or toxic metal-polluted soils may alleviate the negative consequences of these two abiotic stresses on soil microbial activity and population.

This study was conducted under controlled laboratory conditions at Shahrekord University. The main aim of this study was to investigate the effects of salinity and plant residue as an organic amendment on concentrations of soluble elements, enzyme activity and substrate-induced respirations (SIR) in a calcareous soil polluted with cadmium (Cd) over a three-month incubation experiment. A factorial experiment with two levels of cadmium (0 and 30 mg kg-1), three levels of salinity (1.35, 7.5 and 15 dS m-1) and plant residue treatments (with and without alfalfa residue) was conducted using a completely randomized design with four replications. Using cadmium chloride salt, the soil was contaminated, and subsequently amended with alfalfa residue (1%, w/w). After thorough mixing of soil and plant residue, salinity treatments were applied using NaCl salt. To reactivate the microbial population and for the aging effect, soil moisture was set at 70% of field capacity, and containers were pre-incubated at room temperature for 4 weeks. The samples were then incubated at 25±1 oC for 98 days.

Increasing salinity levels resulted in an increase in soluble Na concentration, a reduction in soil enzyme activity and SIR, and a decline in the concentrations of soluble Ca, Mg and K. The harmful impact of soil salinity on microbial properties was much greater in Cd-polluted soils than unpolluted soils.

Results indicated that addition of plant residue reduced the negative impacts of salinity and Cd pollution stresses on soil microbial and enzyme activity, and that resulted in increases in the concentrations of water soluble elements.The findings of the current study confirmed that application of adequate organic amendments can decrease Cd toxicity, enhance substrate availability and maintain soil microbial and enzyme activity in saline and polluted soils with substrate limitation.

In drought stress, in addition to inhibiting water uptake, the availability and uptake of various nutrients is also limited. Proper soil nutrition through the use of organic and inorganic modifiers is known as one of the soil management methods under various environmental stresses.the main objective of this research is to test the performance of concurrent application of amendents in field under qinoa.

In order to investigate the changes in the concentration of nutrients (phosphorus, potassium, copper, iron, manganese, zinc) in soil by application of organic amendments (rice straw biochar, municipal waste compost) and mineral amendments (bentonite and zeolite) under drought stress, a factorial experiment was conducted based on randomized complete block design with three replications in research greenhouse of faculty of agricultural, University of Tarbiat Modares in 2019. Organic amendments (biochar, compost) in 2 levels (0.4 and 0.8%) and mineral amendments (bentonite and zeolite) in 2 levels (0.75 aand 1.5%) were used and drought stress in 4 levels (discharge of 25 % available water (control), 40%, 55% and 70% (servere stress) was applied to the soil, which was a total of 108 pots. Soil sampling was done in three stages four-leaf stage, flowering and harvesting of quinoa.

The results showed that organic and mineral amendments under different levels of drought affected significantly on the P concentration (in four-leaf stage and flowering stage), K (in each three stages), Cu (in each three stages), Fe in four-leaf stage and available Zn in four-leaf stage and flowering stages of quinoa. With increasing drought levels, Application of organic and mineral amendments increased P, K, Cu, Fe, Mn and Zn in all three sampling stages .While the concentration of these elements in the first stage of sampling (four-leaf stage) was more than others.

The results showed that the application of four soil amendments increased the concentration of macro and micronutrient compared to control in drought stress status , but municipal waste compost at 0.8% level and then biochar at 0.8% level could provide the most suitable nutritional conditions in loam soil. Therefore, according to the results obtained in this experiment, Based on the findings of this study, in drought stress conditions, the use of municipal waste compost and biochar compared to zeolite and bentonite is recommended to improve soil nutritional status.Key words: Biochar, Bentonite, Drought Stress, Zeolite, Compost.

Potassium, such as nitrogen and phosphorus, is a macronutrient that plays an important role in plant growth. Large amounts of potassium in the soils comes from the silicate minerals such as phyllosilicate minerals. Potassium in the structure of silicate minerals is not available for plants. Inoculation of potassium solubilizing bacteria as biofertilizers is one of the most important biological approaches to provide potassium for plants. The study aimed to isolate, select, and identify the most efficient potassium solubilizing bacteria and their effect on the availability of potassium in a soil amended with biotite.

In the present study, 15 isolates of bacteria from rhizosphere of five different plants (wheat, tomato, alfalfa, corn and basil) were isolated and purified. The determination of potassium solubility of isolates was performed in two separate parts. In the first part, the solubility of potassium by bacterial isolates in liquid Alexandrove culture medium was performed in a completely randomized design with the factorial arrangement in three replications. Experimental factors included 15 bacterial isolates and 3 incubation times (7, 14 and 21 days). The second part of the study was conducted in a completely randomized design to evaluate the effect of selective isolates of potassium-solubilizing bacteria on the growth of single cross cultivar 640 maize in a soil with sandy loam texture class. Experimental treatments included positive control (potassium sulfate fertilizer (SK)), negative control (soil without fertilizer (S)), 2500 mg/kg biotite (SM1), 5000 mg/kg biotite (SM2), B5 isolate + SM1 (SM1B5), B11 isolate + SM1 (SM1B11), B13 isolate + SM1 (SM1B13), B5 isolate + SM2 (SM2B5), B11 isolate + SM2 (SM2B11), and B13 isolate + SM2 (SM2B13). Data analysis was performed using JMP 8 software and the comparison of means was performed using the Tukey test at a probability level of 5% and graphs were drawn with Excel software.

The results of the first part showed that the highest potassium content (16.4 mg / l) and the lowest pH (3.04) belonged to B11 isolates after 21 days of incubation. The results of the second part showed that The highest potassium concentration of shoot (2.81%) and root (0.956%) was observed in potassium sulfate fertilizer treatment (SK) and SM2B11 treatments, respectively. Plant height, green index, and dry weight were higher in the bacterial treatments compare to the negative control. Based on this, the B11 isolate was selected as the superior isolate. Finally, the superior isolate was identified using 16SrRNA gene sequencing and 99.37% was similar to Paenibacillus stellifer.

This study showed that potassium solubilizing bacteria can release potassium from the mineral biotite in both laboratory and greenhouse. In both experiments, B11 (Paenibacillus stellifer) isolate had the greatest effect on the release of mineral potassium from the mineral biotite. Therefore, its use as a biofertilizer is recommended.

One of the ways to use and exploit saline water and lands is to use salinity tolerant cultivars such as quinoa. Management of nutrients such as nitrogen in saline soils can have negative effects of salinity on growth and yield. Cut plants. The aim of this study was to investigate the effect of different levels of urea fertilizer under irrigation conditions of sugarcane fields on some chemical properties of soil and quinoa seeds during a growing season.

A field experiment was conducted in the year 2018 in the form of split plots in a randomized complete block design with three replications in Mirza Kuchak Khan Sugarcane Cultivation and Industry Company in the southwest of Khuzestan province. In this experiment, four levels of urea fertilizer (0, 75, 150, 225 kg/ha) as the main factor and three levels of sugarcane drainage including control (Karun water with salinity of 2.5 dS-Siemens per meter) and irrigation one in between ( Karun - sugarcane drainage) and sugarcane drainage irrigation (with salinity of 7.5 dS / m) were considered as sub-factors. Seed sowing was done in the form of barley and ridges with a distance of 7-10 cm between two plants and a distance of 65 cm between the lines by hand. Irrigation treatments were applied at the seedling establishment stage. Before irrigation, soil moisture samples were taken and irrigation was done to reach the moisture content of the field capacity. For irrigation with drainage, saline water of agricultural and industrial drains was used. Soil samples were taken at the end of the quinoa cultivation period from a depth of 0-50 cm per experimental plot. At the end of quinoa growth period, quinoa seeds were chemically analyzed separately for each treatment.

The results of the present study showed that the interaction effect of treatments on mean soil salinity, soil soluble potassium and nitrogen, potassium and sodium concentrations of quinoa seeds was statistically significant but had a significant effect on soil acidity and sodium concentration, phosphorus and grain iron concentrations. Quinoa not observed. Soil salinity decreased at the end of Quinoa crop season compared to the beginning of the season in plots with Karun irrigation and increased in intermediate and drainage irrigation treatments. The highest average quinoa nitrogen (2.94%) was obtained from the level of 150 kg N / ha with one irrigation, which resulted in an increase of 56%. With increasing application of urea fertilizer in soil, a gradual increase in total nitrogen content of quinoa was observed. At all salinity levels, increasing urea fertilizer decreased the quinoa sodium content. Urea fertilizer was able to improve the absorption of potassium, which is reduced in saline conditions due to sodium toxicity.

The results of this study showed that sufficient nitrogen can be a suitable physiological solution to increase tolerance to the harmful effects of salinity in quinoa and due to the salinity nature of quinoa, in moderate irrigation management, increasing soil salinity to moderate Morphological growth conditions and grain quality of quinoa. It is recommended to replace Karun irrigation with intermittent irrigation in order to make optimal use of Karun water and achieve high quinoa yield.

Apples are the world's largest commercial fruit orchard. According to the World Food Agriculture Organization in 2017, Iran is one of the top three apple producers in the world. Nutrition is one of the important factors that affect the quality and quantity of fruit. This study was conducted to evaluate and compare different fertilizer management on the nutritional status of apple trees in 1397-1398 at Razi University of Kermanshah (34◦ 19′ N and 47◦ and 7′ E).

This research was conducted to a complete randomized block design in a four-year-old high-density apple orchard with Gala cultivar based on M9. Different managements included mineral, organic, and integrated systems. In the chemical management, 65 g urea, 38 g triple superphosphate, and 60 g KCl per tree plus the foliar application of ferrous, zinc, and calcium were used. Inorganic management 5 kg compost, 0.5 kg farmyard manure (cow), and 5 kg biochar per tree were used. The integrated management included chemical fertilizers +biochar, chemical fertilizers +compost, chemical fertilizers + farmyard manure, and compost + biochar. The balance of nutrients in apple leaf nutrients was investigated using the compositional nutrient diagnosis (CND) method.

The coefficient of determination (R2) of the third-order equation model for all elements was in the range of 0.79-0.89. The cutoff points of the curves (-b/3a) for nitrogen 7.98, phosphorus 7.64, potassium 7.12, calcium 7.82, magnesium 8.00, ferrous 7.87, zinc 7.98, copper 7.79, manganese 7.41 and residual value (R9) 8.11 kg were obtained. In general, the average fruit yield for different elements are so closed and ranged from 7.12 to 8.11 (on average of 7.77± 0.31) related to potassium and R9, respectively. According to the Cate-Nelson method, fruit yield equals 8.75 kg was chosen as critical fruit yield to grouping the groups into high- and low- fruit yield subgroups. The control, farmyard manure, and compost treatments belonged to a low- fruit yield subgroup. While integrated treatments as well as chemical fertilizers and biochar treatments grouped in the high- fruit yield subgroup. The results indicated that in the high-fruit yield subgroup the average of compositional nutrient diagnosis norms (V*(x)) were positive for nitrogen, potassium, calcium, and magnesium besides negative for phosphorus, ferrous, copper, and manganese. The balance index (r2) indicated the imbalances of nutrients under different fertilizer management. After the application of different fertilizers, some indices were changed from the most negative amounts to the most positive amounts. These changes were found for the ferrous index in chemical management, calcium index in organic management, and nitrogen and phosphorus indices in integrated management (in comparison with the application of only chemical fertilizers). In integrated management calcium, magnesium, and ferrous indices were increased from -0.17, -0.42, and -1.24 in untreated trees to 0.15, 0.07, and 0.15, respectively

it is necessary to consider micronutrients’ deficiency in the future fertilizer management of the studied apple orchard. Among macronutrients calcium, phosphorus, magnesium, and potassium in mineral fertilizer management should be considered. The potassium deficiency was one of the limiting factors to produce apple fruit in organic and integrated fertilizer management. Based on the fruit yield, the application of chemical fertilizers or biochar was recommended. For the integrated management, chemical fertilizer +biochar, chemical fertilizer + farmyard manure, and chemical fertilizer +compost were suggested regarding the available fertilizers.

Date palm cultivation has played a valuable role in sustainability and life improvement of poor communities in rural and remote areas for a long time. Iran is the second largest producer of dates in the world with Minab regions of southern province of Hormozgan being the main producer. Cultivation of this crop is the main source of income for the majority of Minab’s farmers; to maintain this industry profitable, orchard management practices such as application of right amounts of fertilizers are required. Annually with each harvest, nutritional elements are removed from orchard soil at various amounts. On average, in one hectare orchard of 121 palms, 42 kg nitrogen (N) and 11 kg phosphorus (P) are taken away with annual harvest. If not replaced, this depletion could negatively affect the following crop loads and fruit quality. Therefore, in this experiment, with the aim of replenishing the soil nutrients, effect of application of different levels of N and P on fruit quality and crop load of Mordaseng, a cv. widely under cultivation in Minab, was assessed over successive fruiting cycles

This study was conducted as a factorial experiment in a randomized complete block design in three replicates using six-year-old trees of Mordaseng cv. at Minab Agricultural Research Station over six successive years. The aim of the experiment was to investigate the effect of N and P nutrients on yield and some characteristics of Mordaseng date palm cultivar. The independent variables were various levels of N (0.0, 150, 200 and 250 (g tree-1)) sourced from urea and pure P (P2O5) (0.0, 66 and 88 (g tree-1)) sourced from triple superphosphate, and the dependent variables were fruit yield and quality characteristics. The following amounts were yearly added to each level of N and P as trees grew older: 0.0, 60, 120 and 180 g for N, and 0.0, 20 and 40 for P.

The yield for N4P2 treatment gained the highest place in statistical group while for N1P1 treatment (excluding N and P) gained the lowest one. The highest fruit flesh weight (FW) and total soluble sugar (TSSu) were obtained for N4P1 treatment whereas the highest total soluble solid (TSS) was obtained from N2P3 treatment.

Application of N and P resulted in a significant increase in the yield comparing to control. Using the highest level of N (250 (g tree-1)) gave the highest fruit FW and TSSu percentage along the highest yield. Application of the highest level of P (88 (g tree-1)) produced the highest TSS percentage. Overall, these results revealed that the application of N and P significantly improved fruit yield and some quality criteria of Mordaseng cv. under the environmental condition of Minab region.

Reducing wheat production due to salinity stress is one of the most important food security challenges worldwide. Plant rhizosphere bacteria reduce the effect of salinity stress on plants, including wheat, by mechanisms such as modulating plant hormones, making nutrients available to the plant, and combating pathogens. This study was designed and performed with the aim of increasing the salinity resistance of wheat (var. Ghods) using salinity-resistant growth-promoting bacteria isolated from the rhizosphere of several halophyte plants in Yazd province.

Growth-promoting traits and salinity resistance of bacteria isolated from rhizosphere of plants Atriplex lentiformis (Torr.) S. Watson، Tamarix ramosissima Ledeb. Seidlitzia rosmarinus Ehrenb. ex Bois and Halostachys belangeriana (Moq.) Botsch. were investigated. Wheat seeds were inoculated with superior bacteria in terms of growth-promoting traits and salinity resistance, including Bacillus safensis, Bacillus pumilus and Zhihengliuella halotolerans. During the growth period, physiological parameters of chlorophyll a, chlorophyll b and total chlorophyll, proline, enzymatic activity of antioxidants, phenol and total soluble sugars in the leaves were measured.

All three bacteria were able to produce auxin. The highest amount of auxin production was measured in B. safensis (29.72 μg / ml). All three bacteria were able to produce hydrogen cyanide and the highest amount of hydrogen cyanide production was observed in Z. halotolerans with grade 5 (very high). All three bacteria were able to produce siderophore. ACC deaminase production was observed in all three bacteria and the highest amount was measured in B. pumilus at 8 μg / ml. Ability to dissolve phosphate in Z. halotolerans was more than twice that of B. safensis. The results of wheat leaf analysis showed that with increasing salinity, (without bacteria inouculation) chlorophyll content in all treatments decreased, instead the amount of proline, antioxidant activity, the amount of phenol and the amount of soluble sugars decreased compared to the control (0.2 ds/m). The use of bacteria increases chlorophyll a, chlorophyll b, total chlorophyll, proline, total phenol, total antioxidants and total soluble sugar compared to without bacteria inoculation treatment.

The growth-promoting bacteria under study with a set of growth-promoting mechanisms significantly improved the resistance of wheat to salinity stress. Therefore, the bacteria studied in this experiment can be used to reduce the effects of salinity on wheat var Qhods under saline irrigation. B. safensis, in salinity of 8 ds/m, more than the other two bacteria, improved the physiological indices of salinity resistance of Qods wheat. Since this experiment was performed under greenhouse conditions, it is recommended that this experiment be performed in field conditions to complete the findings.

Organic fertilizers are considerd as valuable sources for plant nutritions in agricultural ecosystems, because in addition to providing nutrients, they can also help to increase soil organic matter levels, which can compensate the deficiency of soil organic matter of arid and semi-arid regions. On the other hand, the use of organic fertilizers in the medicinal plants cropping has a higher priority due to the limited cultivation area of these plants and also the reduction of reliance on chemical fertilizers. Therefore, in this experiment, the effects of organic and inorganic fertilizers were investigated on growth, yield and essential oil of Hyssopus officinalis L.

The experiment was conducted as a randomized complete block design with three replications at the model cultivation site of medicinal plants of Koohrang Agriculture-Jahad (average rainfall of 1357 mm and minimum and maximum temperatures of 2.8 and 16.2 Celsius), in 2018 and 2019. The experimental treatments were 33 plots and includeed poultry manure with three levels of nitrogen uptake efficiency (100, 70 and 40%; PM100, PM70, PM40, respectively), sheep manure with three levels of nitrogen uptake efficiency (100, 70 and 40% SM100, SM70, SM40, respectively), cattle manure with three levels of nitrogen uptake efficiency (100, 70 and 40%; CM100, CM70, CM40, respectively), as well as two levels of control treatment (positive and negative; chemical fertilizer:100 kg N/ha + 100 P/ha and without fertilizer, respectively.The traits that assessed were included photosynthetic pigments, leaf area index, arial biomass, essential oil content and essential oil yield. Data analysis was performed by SAS software and means were compared by (least significant differences) LSD test.

In the first cutting (June 24), the results showed that the maximum contents of chlorophyll a and b were observed under PM40 and CF feeding conditions, respectively. PM40, PM70, PM100 and CF treatments had the maximum arial biomass (3760, 3672, 3632 and 3576 kg/ha, respectively) and were placed in a statistical group without significant. The highest essential oil content was obtained in PM40, CF and PM70 % treatments, with average of 1.49%, 1.33% and 1.3, respectively. However, the highest essential oil yield was observed in PM40, PM70, CF and PM100 fertilizer treatments (56.3, 47.8, 47.3 and 43.8 kg/ha, respectively). In the second cutting (September 5), PM40, CF, CM40 and SM40 treatments had the highest chlorophyll a (7.6, 7.2, 7.1 and 6.9 μg/ml, respectively), and CF, PM40 and PM70 had the highest chlorophyll b (6.8, 6.7 and 6.5 μg/ml, respectively). The maximum arial biomass was observed in conditions of feeding with PM40 and PM70, with average of 2801 and 2746 kg/ha, respectively. The amount of essential oil obtained from feeded plants was not significantly differed from control treatment. However, PM40 and PM70 treatments had the maximum essential oil yield with average of 50.7 and 43.6 kg/ha, respectively.

In this study, considering the maximum production of plant biomass in different levels of poultry manure and also the superiority of essential oil yield of these levels during the first cutting and PM40 and PM70 in the second cutting, it can be concluded that an average level of poultry manure is appropriate for hyssop regarding to its growth and essential oil production. Therefore, poultry manure can be used as an alternative source of chemical fertilizer in order to hyssop production in a similar climatic conditions to Koohrang.

Erwinia carotovora is a pathogen of many important plant species and infects a large number of ornamental and agricultural plants such as corn, rice, tomatoes, onions, sugar beets and vegetables. This bacterium is one of the most important factors that greatly reduces crop yields by causing soft rot in the stems and tubers of potatoes before and after harvest. Although the disease has been reported in most potato-growing areas of the country, no environmentally friendly control measure has been taken to prevent this disease. Therefore, identifying the biological factors effective in controlling soft rot disease, especially in agricultural hotspots such as Golestan province, seems to be essential. This study aimed to isolate and identify rhizosphere and endophytic bacteria with antagonistic activity against E. carotovora in potato fields of Marzankola and Fazelabad villages of Gorgan city located in Golestan province.

Soil, root, leaf and stem samples of potatoes were cultured on nutrient agar medium and after incubating at 26°C for 3 -5 days the grown colonies were morphologically examined. After purification of the colonies, the initial identification of the isolates was performed by Gram staining and the ability to produce spores. The antagonistic activity of the isolates was determined by agar well diffusion method. In this method, the plates were incubated at room temperature for 3-5 days and the growth inhibition zone was measured around the wells. Chloroform test was used to evaluate the production of antimicrobial agent by antagonist isolates. Catalase and protease sensitivity tests were used to determine the nature of the antimicrobial agent. Then, the thermal stability of the antimicrobial agent and the effect of pH on its inhibitory activity were measured. Isolates with more antagonistic activity were identified based on 16S rRNA sequencing.

A total of 42 bacterial strains were isolated from roots (13), leaves (7), stems (5) and rhizosphere soil (17). Among the isolates, 33 isolates were Gram-positive and 9 isolates were Gram-negative. Based on the results of antagonistic activity of isolates, the 8 isolates showed antagonistic activity against E. carotovora, all of which were Gram-positive spore-forming bacilli and belonged to the genus Bacillus. The inhibitory activity of the isolates was consistent with the results obtained from the chloroform test. That is, compared to the control, the isolate with a greater amount of antimicrobial agent had the larger growth inhibition zone. In the catalase test, it was found that the antimicrobial substance produced by the isolates is of a nature other than hydrogen peroxide and it was inactivated after treatment with proteases, indicating their protein nature. The inhibitory activity of the supernatant of these isolates was lost at 100 ° C and had the best inhibitory effect at pH 7 to 8. The isolates that had the highest inhibitory activity against E. carotovora were identified based on the sequence of 16 S rRNA gene. After sequencing, these isolates were found to be more than 90% similar to Bacillus subtilis strain ZWQ-1 and Bacillus Mycoides strain 29B-B9, respectively.

Considering that in the present study, the isolates with the best inhibitory effect against E. carotovora belonged to the genus Bacillus, it seems that the antagonistic potential of these bacteria can be used for biological control of plant diseases, of course, to better judge about their performance, it is necessary to conduct further experiments in greenhouse and field conditions.