سوپر فسفات تریپل

The recovery of phosphorus as struvite from treatment plants has attracted researchers' attention due to its potential as a phosphorus fertilizer. Struvite is a white crystalline substance consisting of magnesium, ammonium and phosphorus in equal molar concentrations (MgNH4P04.6H2O). The low water solubility of struvite is thought to limit its agronomic utility as a phosphorus (P) fertilizer compared with highly soluble P fertilizers (triple superphosphate). Because limited studies have been done regarding the effect of struvite on the availability of phosphorus in calcareous soils. Therefore, this study examines the effect of struvite replacement with triple superphosphate fertilizer on phosphorus availability in wheat plants in calcareous soils deficient in phosphorus.Methods and Materials: Soil with phosphorus deficiency was collected from 0-30 cm depth under arable lands of Hajjiabad-e Seyyedeh located in Ghorveh township, Kurdistan Province, Iran. The soil was air-dried and ground to pass through a 2-mm sieve, followed by laboratory analysis to determine its physico-chemical properties. Struvite used in the research was obtained by optimizing the three main factors of sulfuric acid concentration, solid-to-liquid ratio, and time for the leaching process, and the three key factors of Mg/P ratio, N/P ratio and pH for the precipitation process by Response Surface Methodology. To achieve the aim of this study The factorial experiment was carried out in the form of a completely randomized design in 3 replications. The factors include the application of different proportions of struvite replaced with triple superphosphate in 6 levels (S0:P0, S0:P100, S25:P75, S50:P50, S75:P25 and S100:P0) and 3 levels of phosphorus (50, 100 and 150 kg/ha) and a total of 54 pots. The application rate for struvite was calculated based on total phosphorus (P2O5) of triple superphosphate. Then 10 wheat seeds were planted in each pot at 2-cm depth which after plant emerging and greening declined to 4 plants in each pot. The pots were randomly moved twice a week during the growth period to eliminate environmental effects. Irrigation and weeding operations were done by hand. Plants (shoots and roots) were harvested 60 days after planting (beginning of flowering), washed with distilled water and dry with tissue paper. The samples were air-dried and then oven dried at 70˚C to a constant weight in a forced air-driven oven. Phosphorus concentrations in plant extracts by the molybdenum vanadate or yellow method and Nitrogen concentration in plant was measured by the Kjeldahl method. After harvesting the plants, the soil was immediately air-dried and passed through a 2mm sieve. Then, the amount of phosphorus was determined by Olsen method. The statistical results of the data were analyzed using SAS software and LSD test (at 5% level) was used for comparing the mean values.

Based on the obtained results, all of the investigated treatments and their interactions were significant at the probability level of one percent (P < 0.01). The comparison of the average effects of different struvite treatments showed that by replacing struvite instead of triple super phosphate fertilizer in all three levels of fertilizer, the highest shoot fresh weight (with an average of 7.79 gr/pot), shoot dry weight (with an average of 1.13 gr/pot) shoot Nitrogen concentration (with an average of 4.82%) and its uptake (with an average of 5.44 gr/pot) was obtained from the application of S75:P25 150 kg/h superphosphate fertilizer. Also, the results showed that the highest amount of phosphorus concentration and uptake, respectively, with an average of 0.174% and 0.197 gr/pot, was obtained from the application of the S75:P25 treatment with 150 kg TSP/ha, which is compared to the application of the S75:P25 treatment of 50 and 100 kg TSP/ha had an increase equivalent to 26.43, 59.89, 11.49 and 43.14% respectively. The results also showed that the highest amount of soil phosphorus after harvesting the plant with an average of 18.95 mg/kg was obtained from the S100:P0 treatment with 150 kg TSP/ha, which compared to the S100:P0 treatment with 100 and 50 kg TSP/ha with an average of 13.29 and 12.56 mg/kg had an increase equivalent to 29.86 and 33.72%, respectively.

In spite of its low solubility, struvite is as effective as highly soluble phosphorus fertilizers for plants. There is still a lack of clarity regarding the mechanisms of struvite dissolution as well as the reasons behind this apparent dichotomy. Therefore, more accurate measurements of pH and EC in substrates, analysis of soil properties and fractionation of phosphorus in soil will enhance our understanding of the use of struvite. Therefore, it is recommended to optimize the timing and application rate of struvite in relation to the demand for different agricultural and garden crops

In order to study the effect of phosphorus fertilizer and less irrigation on grain yield of the forage Millet، an experiment was carried out in 2010. The experimenta design was the split plot based on a randomized complete block with three replications. The main factor was two varieties of forage millet (Bastan - Pishahang)، three levels of less-irrigation as sub plot (non-stress conditions، water cut stage BBCH 55 and cut the water stage BBCH 65) and sub-sub plots with three levels of super phosphate fertilizer of Triple before planting (no Triple superphosphate fertilizer، superphosphate fertilizer Triple as 100 kg/ha and superphosphate of triple as 200 kg/ha). The results showed that the amount of carbohydrates and sodium in millet shoots under was influenced by millet varieties and less irrigation، respectively، and it was it was statistically significant at 1 and 5 per cent levels. Also the percentage of dry weight was affected by cultivar and less irrigation was significant at 1% level. Also the plant dried weight under the influence of triple superphosphate was significantly different at 1% level. Generally، maximum amount of carbohydrates، percentage of plant dried weight، and the amount of sodium in the bastan variety (23. 71%، 57. 79% and 4. 75 PPM) and at BBCH 55، respectively (22. 69&، 62. 58% and PPM 4. 58) compared to the Pishahang and other stress treatments were observed. The highest of crude fiber content under less irrigation was observed at the BBCH 65 to 25. 87%، respectively. Whereas the maximum amount of ash in shoots was observed in non stress condition and the highest level of crude protein was observed in Pishahang equal to 13. 9%. In addition، the highest dry weight of triple superphosphate fertilizer at the rate of 200 kilograms per hectare، was equal to 397. 24 mg was compared to other fertilizer treatments.

In order to study the effects of phosphate biofertilizer Barvar 2 and triple super phosphate fertilizer on yield, quality and nutrient uptake in Medicago scutellata, cv. Robinson, a field research work was done in the Research Field of Agricultural College, Shahed University, located in Tehran, Qom highway in 2006. The treatments included phosphate biofertilizer Barvar 2 at two levels including control and triple super phosphate fertilizer at the levels of control, 75, 150, and 225 kg/ha. The experiment was carried out as a factorial on the basis of randomized complete block design with three replications. After sampling, yield, protein, fiber, phosphorous (P), potassium (K), calcium (Ca), nitrogen (N), and sodium (Na) uptake were determined in the plant samples. The results showed that the amounts of yield, protein, fiber and nutrients including P, K, Ca, and N was the highest with the application of biofertilizer and chemical fertilizer at 75 kg/ha, The lowest level of yield, protein, fiber and nutrient uptake was related to the control treatments of biofertilizer and triple super phosphate.