نوع مقاله : مقالات پژوهشی
نویسندگان
1 دانشگاه علوم کشاورزی و منابع طبیعی گرگان
2 موسسه تحقیقات پنبه کشور
چکیده
از بین عناصر کم مصرف مورد نیاز گیاهان، آهن محدودیتهای فراوانی را برای محصولات کشاورزی به خصوص در خاکهای آهکی ایجاد کرده است. به منظور بررسی اثر زغالزیستی اشباع شده با آهن در عرضه آهن و رفع کلروز آهن سویا در یک خاک آهکی آزمایشی گلخانهای به صورت فاکتوریل در قالب طرح کاملا تصادفی و با چهار تکرار انجام شد. تیمارها شامل زغالهایزیستی اشباع نشده (زغالزیستی کاهگندم (WB) و زغالزیستی نئوپان (PB) هر کدام 5/2 درصد وزنی)، و زغالهایزیستی اشباع شده (زغالزیستی اشباع شده کاهگندم (Fe-IWB1) 5/2 درصد وزنی، زغالزیستی اشباع شده کاهگندم (Fe-IWB2) 5 درصد وزنی، زغالزیستی نئوپان اشباع شده (Fe-IPB1) 5/2 درصد وزنی و زغالزیستی اشباع شده نئوپان (Fe-IPB2) 5 درصد وزنی)، و کود آهن از منبع سکوسترین آهن (S) و خاک شاهد بدون آهن و زغالزیستی (C) بر روی دو رقم سویا (ویلیامز و سامان) بود. نتایج نشان داد با افزایش میزان مصرف زغالهایزیستی اشباع شده با آهن غلظت آهن فعال خاک، غلظت و جذب آهن فعال و شاخص کلروفیل در برگهای بالایی گیاه افزایش معنادار یافت (05/0 P≤). اما زغالهایزیستی اشباع نشده با آهن غلظت آهن فعال خاک و گیاه و شاخص کلروفیل برگ را نتوانست افزایش معنادار دهد. همچنین همبستگی مثبت معنیداری بین غلظت آهن فعال با شاخص کلروفیل برگ (**88/0r=) و عملکرد ماده خشک سویا (**87/0r=) وجود داشت. بنابراین، زغالزیستی اشباع شده با آهن قادر به عرضه آهن کافی و رفع کلروز آهن سویا در یک خاک آهکی میباشد.
کلیدواژهها
عنوان مقاله [English]
The Ability of Iron-Impregnated Biochar in the Supply of Iron and Correction of Soybean Iron Chlorosis in a Calcareous Soil
نویسندگان [English]
- J. Khallizadeh 1
- E. Dordipour 1
- M. Baranimotlgh 1
- A. Gharanjiki 2
1 Gorgan
2 Gorgan
چکیده [English]
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.
کلیدواژهها [English]
- Biochar
- Chlorosis
- Impregnation
- Iron
- Soybean
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