Introduction Phosphorus (P) is the second nutrient and plays a key role in plant growth. The availability of P in the soil depends on the P fractions, which influence the primary productivity of agricultural ecosystems. Having sufficient and accurate information about soil mineral phosphorus is very important for the development of sustainable agriculture in arid regions. Awareness of phosphorus deformation in different soils is also very important for phosphorus fertilizer recommendation. When phosphorus is used in its soluble forms, it is rapidly converted into unusable forms for the plant. Native soil phosphorus is often in unusable form for the plant. Therefore, having enough information about phosphorus deformation in different soils is very important to recommend phosphorus fertilizer. The objective of this study was to find out the effects of long-term use of different sources of phosphorus on available P for pistachio plants in southeast Iran.Materials and Methods The aim of this study was to find the effects of long-term use of different sources of phosphorus fertilizers that can be used for pistachio plants. For that, 168 different soil samples from 63000 ha of Sirjan pistachio orchards of Kerman province. Jiang and Gu method was used to isolate and determine the mineral forms of phosphorus in the soil. Each P fraction was extracted as follows: 1g (oven-dry weight) of sample soil weighed out into a 50 mL polyethylene centrifuge tube. A volume of 40 mL of the first extractant, NaHCO3 (Table 1) was added and placed in an automated mechanical shaker at 25° C with 110 rpm for 1 h to allow time for the solution top equilibrate. The tubes were then centrifuged at 6000 × g for 15 min and the supernatant was carefully filtered through Whatman No. 42 with minimum loss of soil. Reactive P in the supernatant was determined using the ascorbic acid method at 882 nm. This method separates phosphorus in the forms of di calcium phosphate, octa calcium phosphate, aluminum phosphates, iron phosphates, occluded phosphates and apatite. The data showed that Ca10-P was the most abundant P forms in the soils tested. Results and Discussion Results showed that the total P was high in these soil samples and the abundance of P fractions was in order to Ca10-P type≥ Al-P >Ca2-P type> Occluded P ≥ Fe-P > Ca8-P type in two depths. These results suggested that continuous P application leads to plant available P convert into unavailable P forms such as Ca10-P. results indicate that NaOH-extractable P has resulted from active Fe oxides. Also, by comparing two depths of soil in the study area, it can be concluded that the occupied phosphorus in the surface layer is more than the deep layer. Finally, it can be concluded that by increasing the stability of various forms of phosphorus, their contribution to other forms of phosphorus increases, so that the concentration of apatite is much higher than phosphate-calcium phosphate. Results showed the amount of available phosphorus (Ca2-P) in the surface layer is more than the deep layer, which can be attributed to surface application of Phosphorus fertilizers. However, there are sections where phosphorus in the surface layer and the bottom is almost equal. Amount of this form of P is less than Al-P and Fe-P. It may be due to increase in Al and Fe contents in in calcareous soils.Conclusion High amounts of total P clarifies that by optimally managing the use of phosphorus fertilizers and soil conditions, the required P of the plant can be provided without additional use. From the results reported in this study, it appears that in the calcareous soils tested, the abundance of different forms of P was in order Ca10-P type≥ Al-P >Ca2-P type> Occluded P ≥ Fe-P > Ca8-P. furthermore, it observed that Fe-P, Al-P and Oc-P are important forms of P and on average constitute 30% of the sum of inorganic P forms. These findings demonstrate that the ability of NaOH to extract Al-P will be reduced with an increase in Al-P content and that NaOH is unable to remove Al-P completely. Therefore, it seems that more research is needed to find some light on whether NH4F can be omitted from the regular P fractionation schemes in the highly calcareous soils of Iran.

Objective Root structure modification is associated with the efficient water uptake and the nutrient utilization. It also provides structural support for the anchoring in soil. Genetic engineering for the improvement of plant root structure may help to maintain higher yields under drought conditions. The aim of this study was to modify the root structure of rice in order to improve drought tolerance and the efficiency of nutrient uptake. For this purpose, simultaneous transformation of Deeper Rooting1 or OsDRO1 gene, which is involved in the regulation of growth angle of the root in order to adapt to drought conditions, and Phosphorus-Starvation Tolerance1 or OsPSTOL1 gene, which is effective in increasing phosphorus uptake and improving root structure, were considered for rice root structure modification. Materials and methods The OsDRO1 and OsPSTOL1 genes derived from the wild rice cultivars were cloned together in a single construct under the control of the root specific and the ubiquitin promoters, respectively. The resulting construct, pUhrDroPstol is transformed into the Agrobacterium tumefactions strain EHA105 and used for the gene transformation into Hashemi cultivar. Putative transgenic plants, survived on 50 mg/L Hygromycin during tissue culture steps, are transplanted into the Yoshida solution and then into the pots until they set seeds. Construct specific and gene specific PCR analysis are used to confirm the transgenic plants. Results In this study, 12 putative transgenic rice events were obtained, of which 10 showed the presence of both OsDRO1 and OsPSTOL1 genes in the PCR analysis. Transgenic plants show stronger root structure compared to the non-transgenic ones. Molecular analysis in the T1 and T2 generations determined the homozygous events. Conclusions In this study, two candidate genes affecting root structure, nutrient uptake and drought tolerance were transferred to the Hashemi rice using genetic engineering. So far, simultaneous transfer of these two candidate genes have not been reported. Transgenic plants present better root system compared to the control plants. The mentioned construct can be used for the transformation of other crops to improve their root structure, nutrient uptake and their drought tolerance. It is hoped that the production of the transgenic rice with modified root structure and efficient phosphorus uptake increases its drought tolerance and reduce water consumption in rice cultivation.

To investigate the effects of water deficit and chemical phosphorus (P) application methods on yield and phosphorus recovery efficiency of two rapeseed cultivars, a field experiment was conducted at Agriculture College and Natural Resources of Darab, Shiraz University during 2013-2014. The experimental design was a split split-plot based on randomized complete block design with three replications. Treatments including irrigation regimes (common irrigation, cutting off irrigation at midflowering and mid-silique formation stages), P application methods (without P, broadcast and band) and rapeseed cultivars (Sarigol and RGS) were assigned in main plots, sub plots and sub sub plots, respectively. Results showed that cutting of irrigation at common irrigation with 25. 31 seed numbers per silique had significant differences with mid-flowering with 22. 25 seed numbers per silique and cutting of irrigation at mid-silique formation with 22. 94 seed numbers per silique. In cutting of irrigation at midflowering and band application of P, RGS had the highest biological yield (12435 hg/ha). Common irrigation had the highest (11. 02 kg/ha) and cutting of irrigation at mid-flowering had the lowest (5. 95 kg/ha) P absorption amount. Overall, P recovery efficiency in broadcast and band application methods of P was 1. 09% and 1. 38%, respectively. RGS cultivar compared to Sarigol had maximum grain yield under cutting of irrigation at mid-flowering (3830 kg/ha) and mid-silique formation conditions (5428 kg/ha). RGS had the highest rate of assimilate remobilization under cutting off irrigation at mid-flowering and band application of P and it can prevent a further reduction in grain yield when exposed to late season water shortage.

Phosphorus (P) and iron (Fe) are essential nutrients for plants. Iron availability is low in calcareous soils of Iran due to the excessive amounts of CaCO3 and high pH. Over-fertilization of P fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effect of P and Fe on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH2PO4) and Fe rates (0, 2.5, 5 and 10mg kg-1 as Fe EDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, classified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts).Results showed that P application up to 80 mg kg-1 increased corn top dry matter. Corn P concentration and total uptake increased by P application but decreased by Fe application. Application of Fe up to 5 mg kg-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Zinc and copper concentrations decreased significantly when P was added. Manganese concentration increased at 40 mg P kg-1 but decreased at higher rates. Iron application decreased zinc and manganese concentrations but had no effect on copper.

The use of bio-fertilizers is a global approach to reduce chemical inputs pollution to increase the quantity and quality of plant products in line with sustainable agriculture. In this study in order to compare the effects of biological and chemical phosphorus fertilizer on phosphorus uptake and yield of ornamental calendula, a factorial experiment with two factors: 1 - Application of biological phosphorus fertilizer at four levels: M1 (without using biological phosphorus manure), M2 (inoculated seed with biological phosphorus fertilizer), M3 (inoculated roots with biological phosphorus fertilizer), M4 (inoculated seed and roots with biological phosphorus fertilizer) and (2) the amount of phosphorus in the form of triple superphosphate at four levels P1 (zero), P2 (100), P3 (200), P4 (300 mgl-1), based on a randomized complete block design with 16 treatments and 5 replicates with 5 pot per treatment was performed. The results showed that of the biological phosphate fertilizer application methods, M4 to most of the traits such plant height (35.53 cm), flower diameter (66.58 mm), flower number (9.15), number of leaves per plant (64.25), shoot fresh weight (29.9 g) and shoot P (% 3.45) was effective and efficient and phosphorus fertilizer consumption has reduced. Whereas in most of the characteristics M4P3 treatment had no significant difference with M4P4 treatment. Therefore, it is advisable to reduce consumption of chemical phosphorus fertilizer.

To evaluate the efficiency of phosphorus solubilizing bacteria and phosphorus chemical fertilizer on yield and yield components of barley cultivar (Karoon Dar Kavir) an experiment was conducted in experimental farm of college of Agriculture of University of Tehran during 2005-2006 growing season. The treatments were arranged as split plots and were evaluated in a complete randomized block design with thee replications. The phosphorus chemical fertilizer level of P0 (control), P1 (30 Kg/ha), P2 (60 Kg/ha), P3 (90 Kg/ha) and P4 (120 Kg/ha) of super phosphate triple were allocated to the main plots. While the different bacteria strains of S0 (control), S1 (strain No.9) , S2( strain No.10) were allocated to the sub plots. The results of the experiment indicated that the highest forage dry matter yield of 83750.2 Kg/ha was obtained with application of 60 Kg/ha of phosphorus fertilizer accompanied with S3 bacteria (strain No.41 yield). The S3 (strain No.41) demonstrated an acceptable efficiency in forage and grain product in of barley with no chemical phosphorus fertilizer application. This result indicated that in organic farming systems, this bacterium could be used as a source of phosphorus requirements in barley production.

To investigate the effects of water deficit stress and bio and non-bio fertilizers on Thymus Vulgaris, a split plot experiment was conducted based on randomized complete block design with three replications in 2017 in Asgarya agricultural field in Yazd. The treatments included water tension: W1=7 (Control), W2=12 and W3=17 days irrigation intervals as the main factor and bio and non - bio fertilizers at five levels including B1= control (without fertilizer), B2= endo mycorrhiza (Glomus), B3= Azospirillum bacteria, B4= Pseudomonas bacteria and B5= chemical fertilizer (NPK) a sub – factors. Results showed that the highest flowering branches yield, a, b, and total chlorophylls and nitrogen and phosphorus elements were observed in 17 days of irrigation (W3). 12 days of irrigation treatment (W2) showed the highest potassium element rate. The highest a, b and chlorophylls and nitrogen were observed in Azospirillum treatment (B3). The highest total chlorophyll, phosphorus element, carotenoids and flavonoids were observed in Pseudomonas treatment (B4); the highest potassium element rate were obtained in mycorrhiza treatment (B2); the highest flowering branches yield were observed in NPK treatment (B5) and control (B1) treatment resulted in the highest anthocyanin

Red phosphorus (RP) is one of the most important allotropes of phosphorus with extensive military and civil pyrotechnics applications. During maintenance of red phosphorus, its decomposition generates phosphorus acid family and poisonous phosphine gas. One of the conventional method for evaluation of chemical stability of red phosphorus munitions is evolved phosphine measurement. In the present study, four samples of coated red phosphorus with ethyl cellulose, nitrocellulose and their combination with hydroxyl-terminated poly-butadiene (HTPB) were prepared. Then, the stability of all samples were characterized via water absorption measurment (as an effective parameter for chemical stability of red phosphorus) and evolved phosphine estimation(as ml of NaOH consumption in titration). Ethyl cellulose-HTPB coated sample exhibited best water absorption (37 and 38. 8% reduction in water absorption at 24 and 48 hours compared to blank sample) and phosphine generation results (70% reduction in phosphine generation compared to blank sample) during chemical stability test compared to other samples. Then the aging process of this sample was evaluated and compared in a month with blank red phosphorus. Finally two pyrotechnic formulations containing blank and coated red phosphorus have been evaluated for phosphine release and thermal analysis(for calculation kinetic parameters according to Kissinger and Starink equations). The peak temperatures for both formulations containing red phosphorus appear in the range of 304 to 321, depending on the heating rate.

Micronutrients availability including that of Zn is critical for optimum growth of plants. Zinc availability in calcareous soils of Iran is relatively low due to the presence of a large amount of CaCO3 and high pH levels. Over application of phosphorus to soils may also cause P-induced Zn deficiency. The objective of this experiment was to evaluate the effect of phosphorus and zinc application on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial combination of 5 levels of P (0, 25, 50, 100 and 200 μg P/g soil as KH2PO4) and 3 levels of Zn ( 0, 5 and 10 μg Zn/g soil as ZnSO4. 7H2O) in a completely randomized design with 3 replications. Plants were allowed to grow for 60 days and then cut at the soil surface. Results showed that P and Zn applications increased top dry weight. Applied P increased P concentration and total uptake in plants, but decreased Zn concentration and had no effect on Zn uptake. Zinc application decreased P concentration of corn but increased Zn uptake and concentration. The P: Zn ratio in plants increased with P application but decreased with Zn addition. Application of P and Zn increased Fe concentration in plant but decreased Mn concentration and had no effect on Cu concentration. Prior to making any fertilizer recommendations, more research is required to precisely evaluate the response of corn to P and Zn applications under field conditions.    

To survey the effects of chemical and biological phosphorus on the yield and essential oil of Satureja hortensis L. as an important medicinal plant, factorial experiment was conducted based on randomized complete block design with three replicates at Research Station of Faculty of Agriculture, Urmia University in 2011. The treatments were chemical phosphorus fertilizer with four levels (0, 50, 100 and 150 kg/ha P as triple supper phosphate) and biological phosphorus fertilizer with four levels (0, 100, 200 and 300 g/ha Pseudomonas putida Strain P13 and Bacillus lentus Strain P5). The results of ANOVA showed the significant interaction effect between chemical and biological phosphorus on the yield of fresh weight, biological yield, stem dry weight, and the yield of drug and essential oil. There was non-significant effect of chemical and biological phosphorus on the essential oil percent, harvest index of drug and harvest index of essential oil. The highest amounts of total fresh weight (23327 kg/ha), biological yield (5282 kg/ha), stem dry weight (2523 kg/ha) and yield of drug (2759 kg/ha) and essential oil (79 kg/ha) were obtained from 200 g/ha of biological phosphorus without chemical fertilizer. The minimum amounts of total fresh weight, biological yield, stem dry weight, the yield of drug and essential oil were observed in higher than 200 g/ha of biological phosphorus.