Document Type : Research Paper
Authors
1
Ph.D. Student Department of Soil Science, College of Agriculture, Lorestan University, Lorestan, Iran.
2
Corresponding Author, Associate Professor, Department of Soil Science, College of Agriculture, Lorestan University, Lorestan, Iran
3
ssistant Professor of Soil and Water research institute, Lorestan Agriculture and Natural Resources Research and Education Center, Agriculture Research Lorestan, Iran
4
Assistant Professor, Department of Soil Science, College of Agriculture, Lorestan, Iran
Abstract
Today, various methods are used to reduce the negative effects of high concentration of heavy metals in the soil. In this regard, the use of biochar is a relatively cost effective and new method to reduce the toxicity and mobility of heavy metals. In this study, in order to investigate the effect of biochar on improving peppermint plant growth in cadmium-contaminated soil, a pot experiment was conducted using a factorial design in the form of a completely randomized design. Treatments included three factors of cadmium (Cd) levels (50 and 100 mg/kg), the type of organic matter (spruce sawdust, sawdust biochar prepared at 300 and 600 °C, wheat straw, wheat straw biochar at 300 and 600 °C) and the amount of organic matter (zero, 2%, and 4 % by weight). Growth characteristics and performance of peppermint plant essential oil were determined. The results showed that with increasing Cd level, there was a reduction in chlorophyll a 37.6%, chlorophyll b 54.9%, total chlorophyll 42.9%, carotenoid level 31.6%, photosynthesis rate 40.5%, essential oil percentage 34.8%, and essential oil content showed 83.3% reduction. The results indicate the positive effects of biochar in reducing the negative effects of Cd. Comparison of Cd treatment alone with Cd treatments along with biochar showed that herbal biochar had a greater ability to reduce the negative effects of Cd than other treatments. In most cases, wheat straw biochar at two temperatures of 300 and 600 degrees at the level of 2% and 4% was superior in improving plant growth and performance. The highest percentage of essential oil belonged to wheat straw biochar at 600 oC and level of 2% and 50 mg/kg of Cd with 86% increase compared to the control, with an increase of 20% in the weight of aerial parts. The amount of N, K, and P absorption in this treatment increased by 100%, 73%, and 76%, respectively, compared to the control. The obtained results show the ability of straw and wheat stubble biochar to increase and improve plant growth compared to other organic materials used in this study.
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