Calcium-Rich Biochar Stimulates Salt Resistance in Pearl Millet (Pennisetum glaucum L.) Plants by Improving Soil Quality and Enhancing the Antioxidant Defense

Abstract

Shrimp waste is rich in organic compounds and essential plant nutrients, e.g., calcium (Ca), and converting these wastes to organic fertilizer is important for environmental preservation and to achieve sustainable agricultural management. In the current study, Ca-rich biochar was prepared from shrimp wastes (SWB) by pyrolysis at 300 °C. We hypothesized that the Ca-rich biochar will help in solving the problem of plant growth in saline soil by reducing sodium (Na) uptake and mitigating oxidative stress. The current study aimed to investigate the effect of SWB on the quality of saline sandy soil and the mechanism of salt resistance in pearl millet (Pennisetum glaucum L.). Pearl millet plants were planted in saline sandy soil (10 dS m−1) in wooden boxes (1.3 × 0.8 m size and 0.4 m height), and 5 doses (0, 1.0, 1.5, 2.0, and 2.5% (w/w)) of SWB were added. SWB application increased the soil quality and nutrient uptake by pearl millet plants. The highest rate of SWB increased the soil microbial biomass carbon and the activity of dehydrogenase enzyme by 43 and 47% compared to the control soil. SWB application reduced the uptake of sodium (Na+) and chloride (Cl−) and increased the K/Na ratio in the leaf tissues. SWB addition significantly increased the activity of antioxidant enzymes, e.g., ascorbate peroxidase (APX), polyphenol oxidase (PPO), and pyrogallol peroxidases (PPX). The application of 2.5% SWB to the saline soil increased the soluble carbohydrates and proline in plant leaves by 75 and 60%, respectively, and reduced the malondialdehyde (MDA) by 32% compared to the control. SWB enhanced the antioxidant defense and mitigated oxidative stress by improving the synthesis of osmoprotectants, e.g., soluble carbohydrates and proline. Sandy saline soils in arid and semiarid areas suffer greatly from low organic matter contents, which reduces the soil quality and increases the risk of salt during plant growth. The high organic matter and calcium content (30%) in the shrimp waste-derived biochar improved the quality of the saline sandy soil, reduced the uptake of toxic salts, and increased the quality of the forage material. The addition of recycled shrimp waste to saline low-fertility soils improves soil productivity and is safe for soil health.

Response of saline irrigated quinoa (Chenopodium quinoa Wild) grown on coarse texture soils to organic manure

“…Under the current study, increasing the water salinity reduced the uptake of N, P, and K by quinoa plants. These negative impacts of salt stress on nutrients uptake are also confirmed by other studies e. g., Ding et al (2020), Li et al (2021), Liu et al (2021), and Abo-Elyousr et al, 2022. The results obtained proved the ability of organic matter to reduce the negative effects of salt on the growth of quinoa and to improve the absorption of nutrients, especially P and K. The addition of organic matter affects the nutrients uptake by adding nutrients to the soil after the decomposition of organic matter which increase the nutrients availability (Li et al, 2021;Liu et al, 2021).…”

“…The salinity stress leads to an imbalance in nutritional and hormonal status in plants (Kumar et al, 2019;Yang and Guo, 2018). The plant growing under saline conditions directs most of its energy to secrete compounds that help to resist salt stress, and thus the nutrients uptake is reduced Abo-Elyousr et al, 2022). Under the current study, increasing the water salinity reduced the uptake of N, P, and K by quinoa plants.…”

“…The results obtained proved the ability of organic matter to reduce the negative effects of salt on the growth of quinoa and to improve the absorption of nutrients, especially P and K. The addition of organic matter affects the nutrients uptake by adding nutrients to the soil after the decomposition of organic matter which increase the nutrients availability (Li et al, 2021;Liu et al, 2021). On the other hand, application of carbon-rich organic materials form complexes with essential elements that increase their availability and thus increase the ability of the plant to absorb them (Abo-Elyousr et al, 2022). The addition of organic matter improves the soil properties and increases the activity of soil enzymes, which improves the root growth and helps in absorbing the plant nutrients (Li et al, 2021;Liu et al, 2021).…”

The critical role of biochar to mitigate the adverse impacts of drought and salinity stress in plants

“…Similarly, BC application also improved nutrient availability, soil quality, and soil organic matter. All the studied BC rates increased the soil organic carbon (SOC); however, the application of 2.5% BC significantly improved the SOC by 10% as compared to other rates ( Abo-Elyousr et al., 2022 ). Similarly, BC application also improved dehydrogenase activity, enhanced soil microbial biomass and organic matter stability, and led to a significant increase in nutrient absorption in saline soil ( Abo-Elyousr et al., 2022 ).…”

Putting Biochar in Action: A Black Gold for Efficient Mitigation of Salinity Stress in Plants. Review and Future Directions

“…Salinity stress imposes negative effects on soil enzymatic and microbial activities . The application BC improves soil microbial and enzymatic activities by increasing the SOC and absorption of nutrients . Biochar-mediated increase in soil microbial activity under saline conditions is also linked with improved soil aggregate stability, nutrient release, and stimulated increase in root exudation and soil carbon sequestration .…”