J. Khallizadeh; E. Dordipour; M. Baranimotlgh; A. Gharanjiki
Abstract
Introduction: Iron deficiency is one of the most important nutritional disorders in plants, particularly in calcareous soils and deeply affects the yield and quality of the product. Due to the major role of iron in the synthesis of chlorophyll, chlorosis occurs in young leaves in deficiency conditions. ...
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Introduction: Iron deficiency is one of the most important nutritional disorders in plants, particularly in calcareous soils and deeply affects the yield and quality of the product. Due to the major role of iron in the synthesis of chlorophyll, chlorosis occurs in young leaves in deficiency conditions. In such condition, biochar can help to increase OM, soil fertility level, and iron use efficiency and, to reduce iron chlorosis. The aim of this study was to investigate the effect of iron- impregnated biochar on the availability of iron and the elimination of soybean iron chlorosis in a calcareous soil.
Materials and Methods: Calcareous soil with iron deficiency (0-30 cm) was collected from the east of Golestan province and prepared for cultivation. Two types of biochar were produced from wheat straw and particleboard through slow pyrolysis (increasing 5 °C/min) at 300 °C for 2 hours under restricted oxygen conditions in an electric furnace, and then impregnated with iron sulfate solution. FTIR spectra and SEM images of biochars surfaces were also provided. A pot experiment was conducted as a factorial based on a completely randomized design with four replications. Factors were biochars (wheat straw biochar (WB) and particleboard biochars (PB) each one with 2.5% w/w), iron impregnated biochars (Fe impregnated wheat straw biochar 2.5% w/w (Fe- IWB1) and 5% w/w (Fe-IWB2), 2.5% w/w (Fe-IPB1) and 5% w/w (Fe-IPB2) Fe impregnated particleboards, Fe- Sequestrene (S) and control without Fe and biochar (C), and two soybean cultivars (Williams and Saman). The sown pots were maintained near the field capacity for 12 weeks. Then, SPAD numbers, concentration and uptake of active iron in young and senile leaves and active iron content in soil were determined after harvest.
Results and Discussion: With increasing application of iron impregnated biochar, active iron content increased in the soil. SPAD numbers of the upper leaves of both soybean cultivars in Fe impregnated biochars were significantly higher than those of non-impregnated biochars and control treatments (P ≤ 0.05). Iron chlorosis symptoms in soybeans decreased following the increased application of Fe impregnated biochars, consequently, there were no iron chlorosis symptoms in 5% Fe impregnated biochar treatments. Also, the active iron concentration of the upper leaves and the amount of leaf active iron uptake significantly increased as a result of Fe impregnated biochars application in both soybean cultivars compared to control and non-impregnated biochars (P ≤ 0.05). The highest concentration of active iron in upper leaves was observed in 5% w/w Fe impregnated biochars treatments, but its value for cultivar Williams in Fe impregnated wheat biochar was higher than that in Fe impregnated particleboard biochar. The results of the SEM images indicated that wheat biochar had more quantity of and fine pores (also CEC) than that of the particleboard biochar, and the surface areas of both biochars were rough and dark after impregnation with iron, indicating the adsorption or accumulation of iron at their surfaces. Also, there was a significant positive correlation between the active iron concentration with SPAD numbers in the upper leaves (r = 0.88 **) and dry weight of soybean shoots (r = 0.87 **). Cultivars responses to Fe impregnated biochars showed that iron uptake and active iron concentration in the upper leaves of Williams variety were significantly less than those of Saman variety at both levels of Fe impregnated biochars (P ≤ 0.05), which indicates that cultivar Williams is more susceptible to the iron chlorosis. The results of this experiment and reports from other studies show that the application of impregnated biochars from nutrients besides increasing SOM, permeability and soil moisture, CEC and soil fertility level, also increases the acquisition and use efficiency of iron in the plant.
Conclusion: The results of this study showed that due to the strong adsorption of soil iron, non-impregnated biochar application in the level of 2.5% had no significant effect on the concentration and uptake of active iron and spad numbers of the plant. However, using Fe impregnated biochar and increasing their application in calcareous soils with iron chlorosis resulted in a significant increase of active soil iron content, concentration and uptake of active iron and SPAD numbers of the plant, and, conversely, a decrease of leaf chlorosis. Therefore, besides improving the physical, chemical and biological properties of the soil, the application of Fe impregnated biochar can also be a promising approach to eliminate iron chlorosis in sensitive plants, particularly soybeans in calcareous soils.
M. Esmaeili; Bahman Farhadi Bansouleh; M. Ghobadi
Abstract
Introduction: Expansion of the area of oilseed crops such as soybean is one of the policies of Iranian agricultural policy makers as Iran is one of the major oilseed importers in the world. However, the area of this crop in Kermanshah province is negligible, but it could be cultivated in most parts ...
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Introduction: Expansion of the area of oilseed crops such as soybean is one of the policies of Iranian agricultural policy makers as Iran is one of the major oilseed importers in the world. However, the area of this crop in Kermanshah province is negligible, but it could be cultivated in most parts of this province. The quantity and quality of the produced grain could be affected by environmental factors such as weather parameters and water availability. The aim of the current study was to investigate the effects of levels of deficit irrigation on the quantity and quality of soybean crop yield in Kermanshah, Iran.
Materials and Methods: For this purpose, a field study was conducted as randomized complete block design with four replications and four irrigation treatments at the research farm of Razi University, Kermanshah in 2012. The size of each plot was 4 * 4 m. Irrigation treatments consisted of four irrigation levels: 20% over irrigation (T4), full irrigation (T3 as control), 20% less irrigation (T2) and 40% less irrigation (T1). The reason to choose T4 treatment was the lack of confidence in estimated crop evapotranspiration as there was no local calibration of crop coefficient (Kc) for this crop. The required water for T3 treatment was calculated based on daily weather data using FAO-Penman-Montith equation. Daily weather data was recorded in a weather station which was located in the research farm and is available in the www.fieldclimate.com. As there was no rainfall during the crop season, all of the required water was supplied through irrigation. The required water for treatments of T1, T2 and T4 was considered as 60%, 80% and 120% of T3 treatment. The required water was applied using a hose connected to a volumetric flow meter with a liter precision. Total amount of applied water during the crop season was 4399, 5865, 7331 and 8797 m3.ha-1 in the treatments. Fertilizers were applied based on the recommendations of soil fertility experts. Weeds were controlled manually. Finally, the area of two square meters in the middle of each plot was harvested in order to determine crop yield in terms of grain, biomass, stem, pod, seed protein content and fat percentage and also water productivity index. Dry weights of the samples were measured after drying samples in the oven for48hours at 70° C. The percentage of fat and protein in the grains are also measured in the laboratory. Water productivity index was calculated for each treatment by dividing crop yield (in terms of grain, biomass, protein and fat) over seasonal water use. Statistical analysis of the results is also done using MSTATC software.
Results and Discussion: The highest and lowest crop yields were measured respectively in the treatments T4 and T1.The mean value of grain yield was 1084, 1367, 1716 and 1940 kg.ha-1,respectively in the treatments T1, T2, T3 and T4. These results showed a 36% decrease in the grain yield by decreasing 40% in the amount of supplied water. However, biological yield was decreasedby the level of irrigation, but the rate of reduction was lower than that of grain yield. By reducing irrigation application, thepercentage of grain protein content increased while the percentage of fat in the grain decreased. Considering simultaneous reduction in grain yield and fat content in the grain, severe reductions in fat yield (oil content) were observed under water stress conditions. Crop yield in terms of fat was reduced by 26.2 and 50.1 %, respectively in treatments T2 and T1 in comparison with T3 (control treatment). The maximum and minimum percentages of protein in the treatments were 31% and 27%, respectively in the treatments T1 and T4. Maximum water productivity in terms of grain, biomass and protein was achieved in T1 treatment respectively with the amounts of 0.24, 0.81 and 0.077 kg.m-3. Maximum and minimum fat percentage was 0.052 and 0.040 kg.m-3, respectively in the T4 and T1 treatments. In addition,the results indicated that water productivity index in terms of grain, biomass and protein increased while they decreased in terms of fat yield.The results of statistical analysis indicated that water productivity index in all terms except protein had significant differences (at 5%) with T3 treatment.
Conclusion: Crop yield and water productivity (except in terms of fat) was increased by increasing applied water. Considering all indices of treatment T2 (20% deficit irrigation), itwas suggested as the best treatment.
A. Hassanoghli
Abstract
Produced sludge from wastewater treatment plants is a source of macro and micro nutrients and organic matters which is needed for agriculture. On the other hand, application of sludge with no criterion may cause some health risks and also, soil and surface water and ground water resources pollution may ...
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Produced sludge from wastewater treatment plants is a source of macro and micro nutrients and organic matters which is needed for agriculture. On the other hand, application of sludge with no criterion may cause some health risks and also, soil and surface water and ground water resources pollution may be followed. In this regards, the effect of different amounts of sewage sludge used as organic fertilizer in compare with chemical fertilizers on transport of minerals below the root zone and yield and yield components in soybean cultivation were studied. Therefore, 15 cylindrical plastic soil culomns with a height of 100 cm and 60 cm diameter were constructed and drainage PVC pipes with geotextile filter were installed for all of them. The sludge of Ekbatan housing complex wastewater treatment plant after processing and digestion was taken place and used. The culomns were filled by a Clay Loam textured soil and Soybean (Williams variety) was planted. Treatments include three levels of wastewater sludge fertilizer (10, 25 and 50 ton/ha), chemical fertilizers (150 kg/ha ammonium phosphate and 50 kg/ha urea) and control without using fertilizer in three replications. According to the results, the highest mean amount of nitrate in drainage water of culomns (base on split plot through time as statistical completely randomized design) was 57.17 mg/lit in the early season and treatment related to the use of sludge was 50 ton/ha. The lowest mean value of nitrate obtained from the control in the end of cultivation season and was 3.51 mg/lit. The most yield of Soybean was 277.85 gr grains per culomn which obtained from use of 50 ton/ha of manure sludge. The greatest weight of 1000 grains and the number of pods with values of 127.42 gr and 856 in number, measured in this treatment too. Application of 25 ton/ha sludge, chemical fertilizers and 10 ton/ha sludge were after it, respectively. So, the highest use of sewage sludge on soybean cultivation (at the rate of 50 ton/ha), transfer the highest amount of nitrate below the root zone and led to the best yield indicators
