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.

Introduction: Potato production has fourth rank in the world after rice, wheat, and maize with the production of 321 million tons from 19.6 million hectares. In Iran this important crop has third rank after wheat and tomatoes with the production of 4.6 million tons. Potato is a temperate crop, growing and yielding well in cool and humid climates or seasons, but it is also cultivated in tropical to sub-polar climatic regions, and represents a major food crop in many countries. Potato is sensitive to nutrients deficiency especially phosphorus and zinc. At least one-third of the cultivated soils globally are estimated to contain too low amounts of bioavailable zinc for optimal crop production. In Iran more than 70 percent of irrigated soils suffer from zinc deficiency. Many reasons have role in mentioned deficiency such as calcareous and alkaline soils, lower organic carbon and higher application of phosphorus fertilizer. So, evaluation of zinc fertilizers efficiency is essential under different soil phosphorus conditions. …

A factorial completely randomized block design experiment with 3 replications was carried out in the greenhouse to evaluate cereals genotypic variation in phosphorus acquisition and utilization during 2006. Treatments consisted of 8 bread wheat (Triticum aestivum L.), 3 durum wheat (Triticum durum L.), 3 barley (Hordeum vulgare L.), 1 rye (Secale cereale L.), 1 oat (Avena sativa L.) and 1 Triticale (X Triticosecale L.), and two levels of P (0 and 84 mg P/kg soil). Genotypes showed significant differences in number of tillers, shoot P concentration and content, and dry weight. Also, P efficiency (taken as the relative above-ground yield) significantly differed among genotypes and ranged from 0.42 for a barley line (M-80-16) to 0.97 for bread wheat cultivar (Azadi) with the average of 0.71. Application of P significantly increased shoot P concentration and content from 0.19% and 13.24 mg P/pot to 0.47% and 46 mg mg P/pot, respectively. In treatment P0, durum wheat (Yavaroos) with 20.15 mg P/pot and a barley line (M-80-16) with 5.85 mg P/pot had the highest and lowest P uptake, respectively. Oat produced the highest dry weight per unit of P uptake and, hence, was considered to be very efficient in P utilization. Azadi and Yavaroos with 0.45 and 0.43 had the highest relative P uptake, respectively. Therefore, these varieties were efficient in P acquisition. There was no correlation between P efficiency and shoot P concentration of genotypes, but the relationship between P efficiency and shoot P content was highly significant (r=0.66**).

Purpose The increasing demand for phosphorus for the production of mineral fertilizers forces the continuous development of research and new technologies in the field of obtaining it from sources other than phosphate rocks. This paper presents an analysis of optimizing the combustion parameters of chicken manure in the aspect of phosphorus recovery. Methods The combustion process was carried out in different time (3-8 hours) and temperatures (700-900 oC) in laboratory of electric furnace. The content of macro and micronutrients was determined by XRF and ICP-OES analysis. To identify the mineral composition of ashes, the XRD analysis was applied. The content of total phosphorus in ash extracts was determined by photometric method. Results Concentration of P2O5 in ash samples detected by ICP-OES and XRF was comparable, 30. 37 wt. % and 31. 77 wt. % at 900 oC, 26. 27 wt. % and 26. 71 wt. % at 700 oC and 25. 31 wt. % and 25. 00 wt. % at 500 oC, respectively. The mineral composition of ashes showed two phases: crystalline and amorphous. The estimated values of P2O5 content in crystalline phase was 14. 83 wt. % at 500 oC, 20. 96 wt. % at 700 oC and 23. 80 wt. % at 900 oC. The estimated P2O5 content in amorphous phase was 10. 48 wt. % at 500oC and decreased at higher temperature to 5. 31 wt. % at 700 oC and 6. 57 wt. % at 900 oC. Conclusion The chemical composition of ashes from chicken manure depends on the combustion temperature. The highest concentration of phosphorus in their bioavailable forms was determined for samples burned in 500 oC. The results indicate that a valuable source of phosphorus is the amorphous phase.

Plant species differ in their ability to grow at low available P soils in other words, plant species differ in P use efficiency at low P supply. This ability can be investigated by comparing P uptake efficiency of plants and relative effective factors. A pot experiment was carried out in the growth chamber and sugar beet, maize and groundnut were grown in a low available P soil in a completely randomized design with three P fertilizer levels of low, medium and high. Three harvests were performed at two different growth periods. The results showed that at low P supply, sugar beet was the most efficient plant among three species as it showed the highest relative yield. The higher P use efficiency of sugar beet was due to a higher P uptake efficiency. Phosphorus uptake for sugar beet was 29 mg P plant-1 while those for maize and groundnut were 19 and 0.8 mg P plant-1, respectively. The main reason for higher P uptake efficiency of sugar beet was its higher P influx as compared to maize and groundnut. Under low P supply during the first growing period, P influx of sugar beet was higher than that of maize and groundnut by factor 4 and 22, respectively. Finally, the higher P use efficiency of sugar beet was due to a higher P uptake efficiency which in turn was due to a high P influx.

In order to determine the efficiency of different safflower (Carthamus tinctorius L. ) cultivars in terms of their uptake and response to phosphorus fertilizer application, a 2-year (2016-2018) experiment was conducted in a randomized complete block design as 2 x 5 factorial with three replications at the Arak Agricultural Research Center Station. Treatments included two cultivars of Sina and Padideh and five levels of phosphorus (0, 25, 50, 75 and 100 kg. ha-1 ) as triple superphosphate. The results of analysis of variance showed that grain yield, number of bolls, 1000-seed weight, phosphorus, nitrogen, and potassium uptake, and total phosphorus yield were affected by the effect of cultivar and phosphorus levels. Apart from the total dry matter weight and phosphorus concentration, other studied characteristics were affected by the year. Plant height and nitrogen concentration were affected only by cultivar, while total dry matter weight and phosphorus concentration were affected by phosphorus levels. Comparison of the mean effect of phosphorus levels on grain yield showed that the maximum grain yield in both cultivars was obtained in treatment of 25 kg P/ha. In terms of total phosphorus efficiency, the level of 50 and in terms of phosphorus grain uptake efficiency and phosphorus-stress factor the level of 25 kg P/ha were optimal. Phosphorus efficiency indices did not differ significantly between the two cultivars, but Sina cultivar showed higher phosphorus uptake than Padideh.

In order to determine the efficiency of different safflower (Carthamus tinctorius L. ) cultivars in terms of their uptake and response to phosphorus fertilizer application, a 2-year (2016-2018) experiment was conducted in a randomized complete block design as 2 x 5 factorial with three replications at the Arak Agricultural Research Center Station. Treatments included two cultivars of Sina and Padideh and five levels of phosphorus (0, 25, 50, 75 and 100 kg. ha-1) as triple superphosphate. The results of analysis of variance showed that grain yield, number of bolls, 1000-seed weight, phosphorus, nitrogen, and potassium uptake, and total phosphorus yield were affected by the effect of cultivar and phosphorus levels. Apart from the total dry matter weight and phosphorus concentration, other studied characteristics were affected by the year. Plant height and nitrogen concentration were affected only by cultivar, while total dry matter weight and phosphorus concentration were affected by phosphorus levels. Comparison of the mean effect of phosphorus levels on grain yield showed that the maximum grain yield in both cultivars was obtained in treatment of 25 kg P/ha. In terms of total phosphorus efficiency, the level of 50 and in terms of phosphorus grain uptake efficiency and phosphorus-stress factor the level of 25 kg P/ha were optimal. Phosphorus efficiency indices did not differ significantly between the two cultivars, but Sina cultivar showed higher phosphorus uptake than Padideh.

Introduction: Due to the compatibility of canola with different conditions, economic value, its price and importance of rotation with cereals, it has the highest level of cultivation area among the oilseed crops in Iran. Phosphorus (P) deficiency is a widespread macronutrient deficiency and is one of the major limiting constraints for canola production. Despite its importance, it limits crop yield on more than 40% of the world’ s arable land and 70. 2% in Iran. Moreover, global P reserves are being depleted at a higher rate and according to some estimates, there will be no economic P reserve by the year 2050. This is a potential threat to sustainable canola production. Most of the P applied in the form of fertilizers may be adsorbed by the soil, and would not be available for plants lacking specific adaptations. It is widely accepted that the most realistic solution to the problem of P deficiency is to develop new plant cultivars that adapt to P-deficient soils. Phosphorus efficiency is a term that generally describes the ability of crop species/genotypes to give higher yield under P-limiting condition. Plant species as well as genotypes within the same species may differ in P efficiency. This study was conducted to determine the effect of phosphorus fertilization on the grain yield and phosphorus efficiency indices in different canola cultivars. Materials and Methods: The present study was carried out at the research farm of the Mahidasht Agricultural Research Station located 20 km away from Kermanshah (with elevation of 1265 m). This experiment was conducted as factorial in a randomized complete block design with three replications with 2 factors including canola varieties and different amounts of phosphorus fertilizer. The first factor consisted of five triple superphosphate (TSP) levels (0, 16, 32, 49, and 61 kg per ha) and the second factor consisted of three cultivars (Okapi, Opera and Zarfam). This research was conducted on soil where the amount of available phosphorus was lower than the critical level required for canola (15 mg kg-1). Prior to sowing, all phosphorus treatments with 30 kg ha-1 of zinc sulfate fertilizer as well as one-third of nitrogen fertilizer (100 kg ha-1 urea) were applied during planting and mixed thoroughly with the soil. The remaining urea fertilizer was applied at two stages of stem growth (120 kg ha-1) and early flowering (100 kg ha-1). Each experimental plot had an area of 12 m2. Irrigation method was sprinkler. Grain and straw yield were determined after the harvest and seed samples (harvesting stage) were taken and rinsed with distilled water, oven dried at 70 ° C, ground, digested and analyzed for determining the P concentration. Analysis of variance was performed using SAS software and mean comparisons performed by Duncan’ s multiple range tests (P ≤ 0. 05). Results and Discussion: The results showed that the interaction effects of phosphorus fertilizer rate and canola cultivars on leaf P concentration, grain and straw yield, grain P concentration and uptake, and P efficiency indices were significant. In average of the two-years, the highest grain and straw yields (3203 and 4613 kg ha-1, respectively) were obtained from 300 kg ha-1 P fertilizer rate for Okapi cultivar. Under the P deficiency condition, no significant difference was observed between cultivars in terms of grain yield. Significant differences were observed among three cultivars in terms of P efficiency. Opera cultivar was efficient in absorption (0. 84) and Zarfam cultivar was efficient in phosphorus utilization (152 kg grain / kg fertilizer), but Opera was phosphorus efficient. With application of phosphorus fertilizer, phosphorus use efficiency decreased and the highest amount was found for the control treatment which produced 169 kg seeds per kg of phosphorus. The lowest amount of this characteristic was obtained for 300 kg phosphorus fertilizer treatment. Considering the correlation between phosphorus stress factor and P uptake efficiency, it seems that P efficiency was dependent on P uptake (R2 = 0. 477 **) rather than P utilization (R2 = 0. 076 ns). Conclusion: Phosphorus uptake efficiency can be used for selecting P efficient cultivars of canola under farm condition. Application of Opera and Okapi cultivars with 80 kg of fertilizer per ha in similar conditions of this experiment would be advisable and excess phosphorus fertilizer application would not significantly increase grain yield. Selecting suitable varieties could decrease application of chemical fertilizers in the soil.

Uptake and use efficiencies of phosphorus and some other nutrients affected by rate of phosphorus fertilizer and bio-fertilizers application. This experiment carried out to evaluate the effect of chemical and biological phosphorus fertilizers on the phosphorus uptake and use efficiency in rapeseed in a factorial based on a randomized complete block design with three replications at the research station of the Faculty of Agriculture, Yasouj University, in 2019. The first factor included zero, 25, 50, 75, 100, and 125 kg ha-1 of phosphorus and the second factor included phosphorus biofertilizer containing Pseudomonas and its non-use. Phosphorous increased the uptake of nitrogen, phosphorus, and potassium. The highest yield was obtained from 125 kg of phosphorus and phosphorus biofertilizer. With the consumption of 125 kg of phosphorus and biofertilizer, the highest phosphorus use efficiency and remobilization was achieved. The highest phosphorus harvest index was obtained from the applying 50 kg of phosphorus and no biofertilizer, and the highest phosphorus utilization efficiency was obtained from the applying 50 kg of phosphorus along with biofertilizer. Generally, using biofertilizer with phosphorus increased nutrients uptake and seed yield. In traits such as grain yield, grain and shoot phosphorus content, there was no significant difference between the application of 50 kg of phosphorus + bacteria with the application of higher levels of phosphorus fertilizer alone, therefore, biological fertilizer can be substituted a significant part of chemical phosphorus fertilizer.