Due to the importance of zinc in rice plant nutrition, the present study was conducted to determine the effect of waterlogging period on the amount of plant available zinc in acidic and alkaline soils separately based on a completely randomized design. Variation in distribution of different forms of zinc before and after waterlogging was also compared. Soils were submerged for a period of 90 days and then the parameters of Eh, pH and plant available zinc were measured at 0, 7, 15, 30, 45 and 90 days after waterlogging. Different forms of zinc were also determined using sequential extraction method. Generally, the amount of plant available zinc decreased in both acidic and alkaline soils during the waterlogging period. Submergence condition led to a significant decrease in soluble + exchangeable and organic forms of zinc, while at the end of the submergence period, the carbonate form of zinc significantly increased in alkaline soil. In both acidic and alkaline soils, no significant changes were observed in the form of zinc bound to manganese oxide, while the amount of zinc bound to amorphous and crystalline iron oxides increased and the amount of residual zinc significantly decreased. In general, the results showed that the concentration of zinc in waterlogged soils is mainly affected by the changes in various forms of iron. Furthermore, plant available forms of zinc decreased in waterlogged condition which can lead to zinc deficiency in rice plants. Hence, it is recommended that the amount of plant available zinc in soil should be managed via soil or foliare application of zinc fertilizers in a way that its decline during waterlogging period has less negative impact on plant yield.

In recent decade، phytoremediation technology is regarded very important because of its simplicity، inexpensiveness and use of natural resources and solar energy. In this study، we investigated the efficiency of remediation of contaminated soil with Lead and Cadmium by using native plants of Iran. We selected three native plants of Iran (Abutilon theophrasti، Amaranthus retoflexus and Zea maize) for this study. Extraction of soil and plant samples was performed by use of HNO3، HCl and HNO3، HClO4 and H2SO4 respectively. Concentrations of Lead and Cadmium in soil and plants were determined by Perkin-Elmer 603 atomic absorption spectrophotometer. Lead concentration in the roots of plants (Alkaline soil) was more than those in their shoots. In acidic soil (with exception of Zea maize)، concentration of Lead in the shoots was more than its concentration in the roots of the plants. Concentrations of lead in the roots and shoots of Abutilon theophrasti، Amaranths and Zea maize in alkaline soil were (54. 5 and 25. 5 mg/kg)، (69 and 37. 6mg/kg) and (47 and 32mg/kg) respectively، and its respective concentrations in acidic soil were (71. 4 and 92. 5 mg/kg)، (89 and 120. 5mg/kg) and (85 and 66. 7 mg/kg). Cadmium concentrations in alkaline soil were (6. 5 and 4mg/kg)، (8 and 6. 2 mg/kg) and (5. 6 and 3. 4 mg/kg) and in acidic soil were (5. 8 and 4. 5 mg/kg)، (7. 6 and 5. 4mg/ kg) and (6 and 4. 8 mg/kg) respectively. Plants in group 3 produced less biomass than those in control group، group 1 and group 2. Considering the increased rate of absorption of Lead and Cadmium and the amount of biomass produced by Zea maize and Amaranthus retoflexus in the acidic and alkaline soil، use of these native plants is recommended for refining the soil contaminated with heavy metals.

Salt cedar (Tamarix aphylla L. or Tamarix articulata Vahl.) is a rapid growth and salt tolerance species which has been considered as suitable tree for wood production in arid and semi-arid lands of southern Iran in addition to its common usages in desertification and sand fixation programs. In order to study the possibility of development of this tree in saline-alkaline soils of Iran central desert boundaries، this research was carried out on 6 different population of salt cedar from Sistan va Balouchestan (Khash and Zahak townships)، Yazd (Yazd township)، Qom (Qom township)، Isfahan (Kashan township) and Semnan (Garmsar township) provinces at Garmsar research station of desert in CRBD experimental design. Inventory of seedlings was carried out at beginning and end of 2012 and consisted of sprouting، Survival، number of sprouts، collar diameter of thickest sprout، height and crown vitality parameters. Results showed that in contrast with partial advantages of Garmsar and Qom population، there was no significant difference between populations and all of them showed moderate performance. Considering seedlings growth and survival we can conclude that plantation of this tree as suitable species for wood production in saline-alkaline soils of Iran central desert boundaries is possible and in this framework native populations in this region have more priority.

The effects of waterlogging, sewage sludge and animal manure on the concentrations of DTPA extractable copper, iron, manganese and zinc were investigated in two different types of soil. A factorial experiment based upon a completely randomized design of two replications containing duration of waterlogging at six levels (0, 1, 3, 7, 15, 30 days), source of organic fertilizer at three levels (control, animal manure, sewage sludge) and soil type at two levels (one alkaline loamy sand soil and one acidic clay soil) was carried out under laboratory conditions. Equal quantities of animal manure and sewage sludge, at a rate of 30 grams per kilogram of soil, were added. During waterlogging period, the water level was maintained 3 cm above the soil surface. The results showed that by increase in the duration of soil waterlogging, the DTPA extractable Fe and Mn in both soils and for all treatments increased significantly with the degree of increase in acidic clay soil being more than that in alkaline loamy sand soil. Following waterlogging, manganese reduction rate was more than iron in acid clay soil for all treatments except control. By increasing the duration of soil waterlogging, the DTPA extractable Cu and Zn for both soils and in all treatments decreased significantly with the level of decrease in acidic clay soil being higher than that in the alkaline loamy sand soil. By application of sewage sludge and animal manure, the DTPA extractable Cu, Fe, Mn, and Zn in both soils increased significantly with the level of increase being dependent on the duration of soil waterlogging. There existed significant regression equations between the duration of soil waterlogging and concentrations of DTPA extractable Cu, Fe, Mn, and Zn in both soils and for all treatments. Following waterlogging, the pH in an alkaline soil increased for all the treatments. The pH in an alkaline soil increased following the application of animal manure while being decreased following application of sewage sludge.

This research has focused on isolation and characterization of a strain of Bacillus sp. from alkaline soil, which was able to produce extracellular alkaline protease at pHs ranging from 8 to 11 and temperatures of 20 to 50C. Also the impact of different carbon and nitrogen sources were investigated. The yield and fold of enzyme purification was 24% and 50 times, respectively. Molecular weight of purified enzyme was measured by SDS-PAGE as 24.7 kDa. The alkaline protease produced by Bacillus sp. 2 - 5 showed the most caseinolytic activity (without any gelatinolytic activity) at pH>10.

This study was carried out to investigate the effect of crown canopy of Ziziphus spina-christi on seed bank characteristics (density and similarity with above ground flora) in two sites with saline-alkaline and alkaline soils. In each soil، forty plots were established، half in and half outside of Z. spina-christi cover. In each plot، soil sampling was done from 0-5 and 5-10 cm depths. Paired and un-paired t-test were used to compare soil seed bank characteristics between the depths، between two different soils and between in- and outside the tree canopy. The results showed that the density of seed bank in 0-5 cm depths was significantly higher than 5-10 cm depths in both soils. The density of seed in both depths was significantly higher in saline-alkaline than alkaline soils. The similarity coefficient between soil seed bank and above-ground was significantly different between under tree canopy of two soils in 0-5 cm. Soil seed density was highest under crown cover in both soils. The crown canopy of trees in dry rangelands can play an important role in reservation of soil seed bank. Therefore، the conservation of individual trees in these areas should be concerned of the managers.

Zinc (Zn) is an essential element for plants growth at low concentrations and at high concentrations, it acts as a heavy metal and soil pollutant. Biochar is used to improve soil quality, plant growth and also to reduce the availability of heavy metals in contaminated soils. The biochar behavior in soil and its effect on Zn availability rely on the feedstock nature and pyrolysis temperature. This study aimed to investigate the effects of produced biochars on Zn bioavaiability in two acidic and alkaline soils with different levels of applied Zn, during one year-long incubation.

The experiment was conducted as a factorial split arrangement in a completely randomized design in two acidic and alkaline soils, with two factors including biochar types at 9 levels and extraction times at 12 levels with two replications. Four types of biochar were produced from rice straw (RB) and apple wood waste (WB) biomasses at two pyrolysis temperatures (300 and 600 °C). Two acidic (pH=5.8) and alkaline (pH=8.1) soils were collected and treated with 3 levels of Zn (0, 10, and 200 mg kg-1) from zinc sulfate (ZnSO4.7H2O) source. Biochars were added to soils in two doses (1 and 4 % w/w) and incubated at around FC moisture condition for 360 days at 25±2◦C. The pH, EC, moisture content and DTPA extractable-Zn were measured in the studied soils at 12 designated extraction times (0.25, 1, 3, 5, 15, 30, 60, 90, 120, 180, 270 and 360 day).

In acidic soil and Zn level of 200 mg kg-1, levels of 1 and 4 % biochars caused the significant decrease in DTPA-Zn concentration and the elapsing of time had a significant effect on the reduction of DTPA-Zn concentration and maximum decrease (48 %) was observed in the treatment of 4% RB600 and 360th day (p<0.05). At the Zn levels of 0 and 10 mg kg-1, in acidic soil, DTPA-Zn concentration was significantly increased in 4% RB300, 1% RB600, and 4% RB600 treatments, and passage of time had a decreasing effect on it and DTPA-Zn concentration significantly reduced with time in 4% WB300 treatment compared to the control (without biochar). A significant increase of pH in acidic soil was observed in 4% RB600 and 4% WB600 treatments during the 360 days of incubation while the significant decrease was showed in 4% WB300 treatment. In alkaline soil and under Zn=0, the maximum increment of DTPA-Zn concentration compared to the control (without biochar) was obtained in 4% RB600 treatment but the elapsing of time had a significant reduction effect on it. In alkaline soil at Zn level of 10 mg kg-1, only the 4% WB300 treatment could significantly decrease the concentration of DTPA-Zn over time, but in the same soil at the level Zn of 200 mg kg-1, the significant decrease of DTPA-Zn concentration was observed at the 4% RB300, 1% RB600, 4% RB600 and WB300 4% treatments. A significant decrease in alkaline soil pH was observed in the 4% RB300 and 4% WB300 treatments and an increase in electrical conductivity (EC) in both acidic and alkaline soils was observed in rice straw-derived biochars treatments.

Although the application of rice straw derived biochar (pyrolysis at 600 °C) decreased the availability of Zn in both acid and alkaline soils with the high level of Zn (200 mg kg-1), it did not have a negative effect on Zn availability in normal levels of Zn (0 and 10 mg kg-1) and even increased the concentration of DTPA-Zn in both acidic and alkaline soils under without Zn application conditions.

A comparative study was carried out on the production of alkaline protease using wheat straw as substrate in solid-state fermentation (SSF) and submerged fermentation (SMF). A strain of bacillus. spp was isolated from Guilan alkaline soils and after screening for enzyme production enzyme activity was assayed in SSF and SmF simultaneously. The best result were obtain at 100% initial moisture content, 40% inoculums size, temperature 37◦c and initial PH 9.4 in SSF. In the same condition enzyme production in SSF (4025u/gr) was 1.9 fold of SmF (2100u/ml).

Chemical immobilization is an operative approach to reduce detrimental effects of heavy metals in soils. The present study was conducted to test the usefulness of this procedure to decrease soluble and DTPA-extractable Zn in two Zn-spiked (addition of 200 mg Zn kg–1soil from zinc sulfate and incubation for two weeks at 25±1ºC) acid and alkaline soils. In order to study the effect of submergence، two Zn-spiked acid and alkaline soils under two moisture conditions (field capacity [FC] and submergence [S]، with and without 50 g cow manure/kg soil [M]) were incubated for one month. Results showed that S+M treatment caused a markedly decrease in soluble and DTPA-extractable Zn in both alkaline (97 and 75%، respectively) and acid (85 and 78%، respectively) soils. To evaluate the effect of phosphate amendments، 5 g P/kg soil from various sources (Ca(H2PO4) 2. H20، Ca3 (PO4) 2، H3PO4، K2HPO4 and KH2PO4) was added to the Zn-spiked acid soil. Results showed that the K2HPO4 treatment caused a markedly decrease in soluble Zn (88%). Neverthless DTPA-extractable Zn decreased (12. 5%) in Ca3 (PO4) 2 treatment. In another experiment the addition of calcium carbonate to acid soil (10 g CaCO3 kg-1 soil) caused a markedly decrease in soluble and DTPA-extractable Zn (97 and 43%، respectively).

Trichoderma species are significant biocontrol agents against fungal plant pathogens. Some species produce a wide diversity of metabolites, antibiotics, as well as the toxins. Because of the intimate relationship between species of Trichoderma and human activity, there is a great need for the accurate identification of Trichoderma species. Accurate species identification is possible only through a combination of morphological and molecular methods. For identification of new Trichoderma species, most authors have used the combination of ITS and tef1. Many studies have been done on the taxonomy of this genus in the world. Nevertheless, the information about the diversity of Trichoderma/Hypocrea in Iran is scarce. Due to this, in discussing the use of antagonistic agents in biological control, the establishment of biocontrol agents seems to be the first and most important step. Thus, identifying effective native biocontrol agents to be used against plant pathogen agents in an area is of considerable importance. There are no reports for the biodiversity of Trichoderma species on saline and alkaline soils of pistachio orchards in Iran and the world. Because of the alkaline and saline nature of Iranian pistachio soils and the importance and applications of Trichoderma species in biological control of plant pathogens, the objective of the present study was to evaluate the occurrence and species diversity of Trichoderma isolates recovered from alkaline soils of pistachio orchards based on morphological and molecular analysis.
Soil samples were collected from a depth of 0 – 60 cm the rhizosphere of pistachio trees in Kerman province during 2010 – 2012. The samples were then transferred to the laboratory. Trichoderma species were isolated from soil samples using a selective Trichoderma medium (TSMC). The pH and electrical conductivity EC of each soil sample were measured. The morphological identification of Trichoderma isolates was performed based on macro- micromorphological observation, including rate growth and colony formation, presence or absence of pustules, pigmentation and sporulation, as well as conidiophores shape and branching, size and shape of phialid, conidia and chlamydospores on PDA and CMD media using valid Trichoderma keys. Then, the Trichoderma isolates were grouped in the preliminary experiment based on morphological characteristics and the resulted data from RAPD molecular marker using the primer A-5. The molecular identification of selected Trichoderma isolates was performed based on determination of the complete sequences of ribosomal DNA internal transcribed spacer regions using the primer set ITS1F-ITS4 and identified by submission to GenBank and the BLAST interface in TrichoKEY 2.0 to BLAST homology search.
In our present study, 194 soil samples were collected from pistachio orchards. The soils were near neutral to alkaline with an optimal pH range of 7.0 to 8.3 and the EC ranged from 1.5 to12.3 dSm–1. A total of 117 isolates of Trichoderma were obtained and purified. Isolates were identified to species level by a combination of morphological and genotypic characters. Before molecular identification, the Trichoderma isolates were grouped according to an examination of their morphology on PDA and CMD, using the following macroscopic and microscopic characteristics. Also, all isolates of each group were analyzed by RAPD molecular marker using the primer A-5. The RAPD-PCR profile analysis showed 16 different band patterns. The representative isolates of each profile was selected for DNA sequencing. As a result the isolates were identified as four species including T. harzianum, T. virens, T. brevicompactum and T. longibrachiatum. The results showed that more than 50% of the isolates belonged to T. harzianum and introduced as the dominant species in soil of pistachio orchards in Kerman province. Based on logistic regression analysis, although there was no relationship between the soil properties (pH, EC) and the presence of Trichoderma (R2=0.25, Pr=0.74, 0.26>0.05) but decreasing in numbers and diversity of Thrichoderma species in testing soils could be a result of alkaline conditions. To our knowledge, this study was the first report of identification and diversity of Trichoderma species in alkaline soils and pistachio trees.
A low degree of biodiversity of Trichoderma isolates was found in soils of pistachio orchards. In fact, acidity and alkaline conditions as well as environmental parameters such as soil temperature, moisture, pH, organic matter (OM) and nutrient content are factors that could affect on Trichoderma population, such as its presence, density, longevity as well as production of enzymes.