بررسی نقش بیوچار حاصل از پسماند بوته‌های بادمجان و ضایعات میگو بر برخی از ویژگی‌های پایداری خاک

تخریب و فرسایش، از چالش‌ های جدی تهدیدکننده منابع آب‌ و خاک است و یکی از مسائل به‌روز و قابل‌تامل زیست‌محیطی در سطح جهان به شمار می ‌رود. بهبود ویژگی ‌های فیزیکی خاک، یکی از روش‌ های نوین کنترل فرسایش و تخریب مرسوم است که استفاده از اصلاح‌گرهای آلی نقش مهمی در این زمینه دارد. در این تحقیق با توجه به فراوانی ضایعات میگو و بادمجان در استان هرمزگان، استفاده از بیوچار این مواد برای اصلاح خاک قابل ‌توجه قرار گرفت. نمونه‌ های خاک مورد آزمایش، از اراضی کشاورزی اطراف بندرعباس به‌صورت دست‌نخورده با لوله ‌های فشار قوی با ارتفاع 25 و قطر 20 سانتی متر تهیه شد. بیوچارهای تهیه‌شده نیز به‌صورت سوسپانسیون در قالب طرح کاملاً تصادفی در سه غلظت (0، 4 و 8 گرم در لیتر) در سه تکرار به نمونه ‌های خاک اضافه شد و به مدت صد روز در رطوبت بین ظرفیت زراعی تا حدود پنجاه درصد آن در نهالستان نگهداری شد. سپس شاخص‌های mwdwet، mwddry، pad، bd وks اندازه ‌گیری شد. تحلیل آماری و مقایسه میانگین ‌ها در سطح پنج درصد بین تیمارها، بر اساس تجزیه واریانس یک‌طرفه و آزمون دانکن با استفاده از نرم‌افزارspss16 انجام شد. نتایج نشان داد که کاربرد بیوچار به افزایش mwdwet و mwddry و کاهش bd، pad و ks معنی دار در سطح پنج درصد نسبت به شاهد در خاک موردنظر منجر شد. در غلظت‌های 8 و 4 گرم در لیتر بیوچار بادمجان، بیشترین مقدار mwdwetو mwddry مشاهده شد و کمترین مقدار pad مربوط به غلظت 8 گرم در لیتر بیوچار بادمجان بود. کمترین مقدار bd نیز مربوط به غلظت 8 گرم در لیتر هر دو نوع بیوچار (33/1) بود و مقدار ks هم در غلظت 4 گرم در لیتر میگو کمترین مقدار بود.

Investigation of the role of biochar from eggplant plant residues and shrimp waste on some soil stability characteristics

1 IntroductionPhysical properties are one of the most important soil properties that affect other aspects of soil such as erosion and water infiltration into the soil. One way to improve soil properties is to use modifiers. Biochar is one of the modifiers based on organic matter that can play an important role in soil properties and the results of research studies have shown the effect of biochar on the physical and chemical properties of soil. Therefore, the purpose of this study was to investigate the effect of Shrimp and eggplant waste biochar suspension on some soil structure stability indices.2 Methodology In this study, the effect of Shrimp and eggplant waste biochar suspension on soil structure stability indices was investigated and for this purpose sandy soil was selected. The studied soil was sampled from agricultural lands around Bandar Abbas intact areas with polyethylene columns with a height of 25 and a diameter of 20 cm. The experiment was performed in a completely randomized design with 9 treatments and 3 replications. The studied treatments included biochar of eggplant and shrimp wastes suspension separately with concentrations of 0, 4, and 8 g/l which were added to the soil inside the columns according to the weight percentage. They were incubated for 100 days at moisture ranging from field capacity (FC) to 50 % FC in greenhouse conditions. Then some soil physical properties including mean weight diameter of wet sieving (MWDwet), dry sieving (MWDdry) aggregates, percentage of aggregate destruction (PAD), and saturated hydraulic conductivity (Ks) were measured. The analysis of variance for a completely randomized design was performed in order to evaluate the significance of shrimp and eggplant biochar rates on soil physical parameters by using the SPSS16 statistical software. The estimated Means were compared using Duncan rsquo;s test with a P<0.05 level of significance.3 ResultsThe results showed that the addition of shrimp and eggplant waste biochar suspension had a significant (p<0.01) effect on the measured parameters. In addition, the addition of both shrimp and eggplant waste biochar suspension to the soil increased MWDwet and MWDdry and decreased PAD, BD, and Ks, significantly. The maximum values of MWDwet and MWDdry were obtained by application of 8 and 4 g/l eggplant waste biochar suspension, respectively, which showed a significant difference (p<0.05) with the control treatment. The minimum percentage of aggregate destruction (PAD) was obtained by application of 8 g/l eggplant biochar suspension (21.7%), and the minimum of Ks was obtained by application of 4 g/l Shrimp waste biochar suspension (3.7 cm/h).4 Discussion Conclusions The results showed that the addition of different levels of shrimp and eggplant biochar due to the presence of organic nuclei in it can act like cement, causing the mineral particles to stick to the soil and leading to the formation of stable aggregates. Organic biochar carbon in the soil with chemical bonds and the formation of bridges between soil particles as a bonding agent increased the stable bond between soil particles, increased aggregation and the formation of stable aggregates and also increased MWDwet and MWDdry. Therefore, by improving the soil properties by biochar, the percentage of aggregate destruction (PAD) can be reduced. Furthermore, the application of different levels of Shrimp and eggplant waste biochar suspension has reduced bulk density (BD) of sandy soil. It seems that the increase in biowaste of shrimp and eggplant waste biochar, as an organic compound, has affected the amount and distribution of micropores and soil porosity with a sandy texture, therefore, reducing the bulk density of the soil. The application of different concentration levels of shrimp and eggplant waste biochar has reduced the hydraulic conductivity in the studied sandy soil. It seems that the addition of both types of eggplant and shrimp biochar by increasing more stable aggregates in dry and wet conditions and bulk density changes the pore distribution, reduces the number of macropores and increases the micropores in the sandy textures. It can also significantly reduce the saturated hydraulic conductivity compared to the control treatment that lacked any modifiers.According to the results of this research, the application of shrimp and eggplant waste biochar improved the physical properties of soil and reduced the percentage of soil degradation, hydraulic conductivity, and bulk density.