Plant Nutrition, Soil Fertility and Fertilizers
Taleb Nazari; Mojtaba Barani Motlagh; Seyed Omid Rastegar; Mohammad Hosien Sedri
Abstract
Introduction: 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 ...
Read More
Introduction: 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.Results and Discussion: 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. Conclusions: 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
Plant Nutrition, Soil Fertility and Fertilizers
Mehri Bazi abdoli; M Barani; abdolamir Bosatni; Taleb Nazari
Abstract
Introduction: Various biomass sources such as crop residues have been proposed as feedstock for biochar production . Meanwhile, a large quantity of crop residues (rice) is produced as waste and they are either burnt or piled and abandoned at some locations in the fields. Burning of crop residues is resulting ...
Read More
Introduction: Various biomass sources such as crop residues have been proposed as feedstock for biochar production . Meanwhile, a large quantity of crop residues (rice) is produced as waste and they are either burnt or piled and abandoned at some locations in the fields. Burning of crop residues is resulting in substantial loss of nutrients, and may lead to air pollution and human health problems . An alternative approach is to apply crop residues to soil in the form of biochar. Bioavailability of nutrients exclusively micronutrients (Fe, Zn) isa serious problem in soils having high pH which ends in crops yield to decline and ultimately can lead to malnutrition in humans. The biochar modification with acid may increase the solubility of nutrients (P, , Fe, Zn, Cu,,Mn) present in biochar, thereby significant improvement in mineral nutrition of plants grown in calcareous soils. In the other hand, One of the ways to use and exploit saline lands is to use salinity-tolerant cultivars, such as the Quinoa (Chenopodium quinoa) plant. It is known that biochar increases soil pH, which may result in less availability of phosphorus and other micronutrients, such as Fe, Zn, and Mn, in alkaline and calcareous soils. Therefore, modifying biochar with acids can increase the availability of nutrients in biochar for different plants grown in calcareous soils. The objection of this study is to investigate the effect of normal biochar and acid-modified biochar from rice residues on the yield and yield components of quinoa plants (Gizavan number) in a calcareous soil affected by salt.Materials and Methods: The soil used in the study was collected from 0-30 cm depth which passed through via 2-mm sieve after air-drying and its chemical and physical properties were determined. To achieve the aim of this study, the factorial experiment was carried out in a completely randomized design in 4 replications. Factors include 3 types of rice biochar (unmodified, modified by pre-acidic method and modified by post-acidic method) and different levels of biochar (0, 2, and 5% by weight). Then 10 quinoa seeds were planted in each pot at 2 cm depth which after the plant emerging and greening declined to 3 plants in each pot. The pots were randomly moved twice a week during growth to eliminate environmental effects. Irrigation and weeding operations were done by hand. After the end of the growth period (187 days), the plants were harvested. So vegetative growth parameters and yield components including shoots fresh and dry weight, plant height, stem diameter, panicle length, number of leaves, number of lateral branches, and 1000 grain weight were measured and then biological yield and harvest index were determined. The statistical results of the data were analyzed using SAS software (9.4) and the LSD test (at 5% level) was used for comparing the mean values.Results and Discussion: As a result of adding biochar to soil, it becomes alkaline. Chemical modification of biochar using strong acids can reduce soil pH and improve the fertility of calcareous soils and increase vegetative parameters and yield components of quinoa. Based on the obtained results, the interaction effect of different types and levels of biochar on all investigated traits was significant at the level of 1%. The results showed that the highest height, fresh and dry weight, panicle length, number of lateral branches, and stem diameter were related to the 5% post-acidic rice biochar treatment and the lowest value was related to the control treatment. furthermore, the results showed that the highest amount of plant dry weight of 8.82 gr/pot, the height of 77.50 cm, and 1000 seed weight of 17.3 gr/pot was obtained from the treatment of 5% post-acidic rice biochar, compared to the treatment of 5% Unacidified rice biochar had an increase of (81.97), (56.77), (32.17) and (7.06) percent respectively. As a result of the high dry weight of shoots and the 1000 seed weight, the 5% post-acidic rice biochar treatment provided the highest biological yield at 16.05 and harvest index at 45.03.Conclusion: Under the conditions of this study, acid-modified biochars (post-acidic and pre-acidic) enhanced vegetative growth characteristics and yield components of quinoa plants in calcareous soils affected by salt. Therefore, it is recommended to prepare biochar from acidic sources or to modify it with post-acidic and pre- acidic methods.
T. Nazari; M. Baranimotlgh; E. Dordipour; R. Ghorbani nasrabadi; S. Sefidgar Shahkolaee
Abstract
Introduction One of the most important needs in crop planning is the evaluation of different systems of plant nutrition. plant nutrition in a correct way can preserve the environment and increase efficiency of agricultural inputs. Humic acid contains many nutrients that increase the soil fertility and ...
Read More
Introduction One of the most important needs in crop planning is the evaluation of different systems of plant nutrition. plant nutrition in a correct way can preserve the environment and increase efficiency of agricultural inputs. Humic acid contains many nutrients that increase the soil fertility and soil organic matter content and thus affect plant growth and yield. In the present study, the effect of soil and foliar application as well as fertigation application of humic acid on iron and phosphorous availability of canola (Hyola 308) was evaluated. Materials and Methods The soil was air-dried and ground to pass through a 2-mm sieve and then was analyzed to determine soil physical and chemical properties using standard methods. A greenhouse experiment was carried out with 10 treatments in four replications. Treatments include humic acid soil application at three levels (1, 2 and 4 g.kg-1 soil), foliar application at three levels (0.1, 0.2 and 0.4%) and three fertigation levels (1000, 2000 and 4000 mg L-1) and control). Soil application in the form of humic acid powder and in cropping time based on the soil weight of the pots and for spraying and use along with irrigation water, each of the spraying and together with irrigation water levels is divided into three equal parts and in three stages (plant establishment, stem elongation and flowering). At the end of growth period (for 139 days), vegetative growth indices were determined and then plants were harvested and stem and leaves were separated. Phosphorous content in plant extracts was measured by molybdate vanadate method (yellow method) and iron concentration in the samples was determined by atomic absorption (AAS-Unicam-919). Statistical analysis was conducted via SAS software and mean comparisons carried out by LSD test at 5% probability level. Results and Discussion Results show that the application methods and the different levels of humic acid had significant impacts (p < 0.01) on the all parameters but they had no significant effects on the numbers of leaves. The maximum leaf fresh weight was 4.34 gr per plant which obtained water irrigated treatments with 2000 mg/lit. However, there was no significant difference between water irrigation with 4000 and 2000 mg/lit humic acid concentrations. Besides, maximum leaf dry weight was 0.37 gr in the plant that was water irrigated with 4000 mg/lit, however there was no significant difference between water irrigation with 4000 and 2000 mg/lit humic acid concentrations. Also, the maximum stem dry and fresh weight was 5.92 and 1.53 gr which observed in water irrigated with 2000 mg/lit. The application methods and the different levels of humic acid had significant impact (p<0.01) on the content and absorption of Fe and P excluding the Fe content in the root. The maximum Fe content in stem and seed were 321.25 and 85 mg/kg was observed in the treatment of humic acid with water irrigation of 2000 mg/lit. Also, in the treatment of spraying with 0.4 % of humic acid, the maximum of Fe concentration (245.46 mg/kg) was obtained. The humic acid molecules can pass from the cell membranes and cause iron reduction in the Apoplast and increase the availability of Fe. Because of the reduction effect of humic acid on the availability and accumulation of Fe in the plant tissue, increasing in the Fe absorption with humic acid treatment is observed. The increase in the accumulation of Fe by humic material might be due to the releasing phenolic material in the root rhizosphere. The maximum P concentration in the leaf, stem and seed were 0.40, 0.72 and 0.897 respectively that was observed in the treatment of water irrigation with 2000 mg/lit with humic acid. Due to the availability of phosphorus and other nutrients for wheat, humic acid increases the plant yield in the reproductive stage of seeding. Conclusion Results of the study show that humic acid can ameliorate the negative effect of a large amount of phosphorus on iron availability. In fact, humic acid, due to providing nutritional balance for the plant, prevents negative effects caused by the high amounts of specific elements such as phosphorus. Also, the results showed that all three humic acid application methods increased vegetative growth parameters, and iron and phosphate availability for canola plant compared to control. But in general, 2000 mg/L acid humic with irrigation water was more effective than two methods of soil and foliar application.
