Applications of Biochar and Other Organic Amendments within a Sustainable Agriculture and Circular Economy

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Soil and Plant Nutrition".

Deadline for manuscript submissions: closed (15 March 2021) | Viewed by 94127

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Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (IRNAS-CSIC), Reina Mercedes Av. 10, 41012 Seville, Spain
Interests: climate and environment; carbon sequestration; soil quality; soil organic matter; soil amendments; biochar; analytical and applied pyrolysis
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Chemical Biological Centre, Umeå University, Umeå, Sweden

Special Issue Information

Dear Colleagues,

Soil organic matter (SOM) constitutes approximately 2/3 of the global terrestrial C pool; therefore, the dynamics of organic carbon (OC) in soils control a large part of the terrestrial C cycle. On the other hand, SOM plays a vital role not only in biological aspects but also in soil fertility and quality. Thus, the decline of SOM represents one of the most serious threats facing many arable lands of the world. At the same time, human activities have caused a net release of CO2 to the atmosphere of about 800 Gt C per year and particularly, forest conversion to agriculture can release up to 75 % of stored soil organic carbon as CO2. Furthermore, it is well-known that intensive agricultural practices are worldwide drivers of soil, water, and atmosphere pollution.

In an attempt to change that trend, sustainable agriculture is being promoted in the context of a circular economy. During the last few decades, several organic amendments (e.g., biochar, manure, etc.) have been rediscovered and recognized as an efficient strategy for soil preservation. Specifically, the application of different organic amendments has been found to improve soil quality, SOM, aggregate stability, nutrient retention, plant N use efficiency, influence microbial activity and population as well as soil gaseous emissions. In addition, they offer a sustainable approach for managing wastes and to produce added value products.

Taking into account the current context of fostering a sustainable agriculture and circular economy, this Special Issue seeks to increase the knowledge of novel advances concerning the application of biochar and other organic amendments in agriculture, as well as to develop knowledge regarding the restoration of degraded soils, covering biological, chemical, physical, biochemical, and environmental aspects.

Dr. José M. De la Rosa
Dr. Marina Paneque
Guest Editors

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Keywords

  • Biochar
  • sustainable agriculture
  • organic amendments
  • waste management
  • biomass
  • soil quality

Published Papers (25 papers)

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Research

18 pages, 2629 KiB  
Article
Crop Production and Phosphorus Legacy with Long-Term Phosphorus- and Nitrogen-Based Swine Manure Applications under Corn-Soybean Rotation
by Yan Zhang, Tiequan Zhang, Yutao Wang, Chinsheng Tan, Lei Zhang, Xinhua He, Tom Welacky, Xiulan Che, Xiaodong Tang and Zhengyin Wang
Agronomy 2021, 11(8), 1548; https://doi.org/10.3390/agronomy11081548 - 1 Aug 2021
Cited by 8 | Viewed by 2324
Abstract
The traditional manure management strategy, based on crop N needs, results in accumulation of phosphorus (P) in soil due to the imbalance of N/P ratio between crop requirement and manure supply. This study was conducted from 2004 to 2013 to evaluate the effects [...] Read more.
The traditional manure management strategy, based on crop N needs, results in accumulation of phosphorus (P) in soil due to the imbalance of N/P ratio between crop requirement and manure supply. This study was conducted from 2004 to 2013 to evaluate the effects of P-based liquid and solid swine manure (LMP and SMP, for P-based liquid and solid swine manure, respectively) application, in comparison with N-based application (LMN and SMN, for N-based liquid and solid swine manure, respectively), on crop yield and soil residual P under corn (Zea mays L.)–soybean (Glycine max L.) rotation in a Brookston clay loam soil of the Lake Erie basin, ON, Canada. Chemical fertilizer P (CFP) and non-P treatments were included as controls (CK). For liquid manure treatments, corn yield for LMN showed a lower annual corn yield (7.82 Mg ha−1) than LMP (9.36 Mg ha−1), and their differences were even statistically significant at p < 0.05 in some cropping years. The annual corn yield of LMP was also higher than those of SMP (7.45 Mg ha−1) and SMN (7.41 Mg ha−1), even the CFP (8.61 Mg ha−1), although the corresponding yield differences were not significant (p < 0.05) in some cropping years. For soybean, the plots with P application produced an average of 0.98 Mg ha−1 greater annual yields than CK. No significant differences were found between CFP and manure treatments. The annual corn yield of SMN was close to that of the CK (7.19 Mg ha−1). The grain P removal (GPR) of SMN (18.6 kg ha−1) for soybean was significantly higher than that of the other treatments. The above-ground-P uptake (AGPU) in SMN, for both corn and soybean, was significantly higher than that of the other five treatments. The soil test P (STP) presented clear stratification, concentrating in the top 30 cm soil depth after 10 years of application. The contents of STP with LMN and SMN increased from 7.1 mg P kg−1 to 12.4 and 45.5 mg P kg−1, respectively. The sum of STP mass (0–30 cm) with LMP (31.6 kg ha−1) was largely identical to that with CFP (30.1 kg ha−1); however, with SMN (173.7 kg ha−1), it was significantly higher than the rest of the treatments. Manure P source availability coefficients were averaged at 1.06 and 1.07 for LMP and SMP, respectively. The addition of phosphorus-based liquid or solid swine manure can overcome the drawback of traditional N-based applications by potentially reducing the adverse impact on water quality while sustaining crop agronomic production. Full article
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16 pages, 2197 KiB  
Article
Nitrogen Source Influences the Effect of Plant Growth-Promoting Rhizobacteria (PGPR) on Macadamia integrifolia
by Marta Gallart, Chanyarat Paungfoo-Lonhienne, Axayacatl Gonzalez and Stephen J. Trueman
Agronomy 2021, 11(6), 1064; https://doi.org/10.3390/agronomy11061064 - 25 May 2021
Cited by 10 | Viewed by 3510
Abstract
The potential of plant growth-promoting rhizobacteria (PGPR) to improve plant growth and nutrient acquisition has received increased attention. This study investigated the synergistic effects of combining PGPR Paraburkholderia sp. SOS3 with the addition of inorganic N fertilizer (iN) or a combined application of [...] Read more.
The potential of plant growth-promoting rhizobacteria (PGPR) to improve plant growth and nutrient acquisition has received increased attention. This study investigated the synergistic effects of combining PGPR Paraburkholderia sp. SOS3 with the addition of inorganic N fertilizer (iN) or a combined application of inorganic N with organic manure-based fertilizer (iNoN) at low and high levels of N fertilization on Macadamia integrifolia seedling growth. We studied plant growth, mineral N in soil-leachate, and media physicochemical and microbial characteristics. Growth of seedlings fertilized with iNoN at high N level (iNoN 100) was enhanced by PGPR inoculation, with an increase of 32% in total biomass and 43% in N uptake, compared with uninoculated seedlings. No significant PGPR effect was observed on growth under low or high inorganic N treatments but PGPR significantly reduced N leaching after 3 weeks of fertilization. We found a positive relationship between media and plant δ15N and plant N uptake, and a strong increase in microbial-biomass N under the most productive fertilization treatment (iNoN 100 with PGPR), compared with the other N treatments (without or with PGPR). The results suggest that PGPR improves N acquisition by reducing mineral N loss and increasing plant N availability, but that these effects depend on the N form and N level. Full article
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15 pages, 600 KiB  
Article
Morphophysiological, Enzymatic, and Elemental Activity in Greenhouse Tomato Saladette Seedlings from the Effect of Plant Growth-Promoting Rhizobacteria
by Tomás Juan Álvaro Cervantes-Vázquez, Ana Alejandra Valenzuela-García, María Gabriela Cervantes-Vázquez, Tania Lizzeth Guzmán-Silos, Erika Lagunes Fortiz, Pablo Preciado Rangel and Edgar Omar Rueda-Puente
Agronomy 2021, 11(5), 1008; https://doi.org/10.3390/agronomy11051008 - 20 May 2021
Cited by 8 | Viewed by 2891
Abstract
The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production [...] Read more.
The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production of seedlings. Plant-growth-promoting rhizobacteria (PGPR) are characterized by improving plant growth through different mechanisms and can be an option for reducing the misuse of chemical fertilizers. The importance of the application of strains, evaluating various inoculation methods (in seed, soil, foliar spraying, and root immersion), should be evaluated to propose biofertilization packages in a specific crop. Thus, the study aimed to determine the effect of PGPR (Bacillus paralicheniformis, Acinetobacter guillouiae, Aeromonas caviae, and Pseudomonas lini) vs. nutrient solution and distilled water in the seedlings stage of saladette-type tomato on morphophysiological variables, nitrate reductase (NR) enzyme activity, and plant minerals via tissue analysis under greenhouse conditions. The four PGPR were inoculated by different methods (inoculation in seed, sprinkling, and both) in saladette-type tomato seedlings under greenhouse conditions and evaluated in vivo 40 days after sowing for morphophysiological variables, such as seedling height; stem diameter; root displaced volume; fresh and dry weight matter of the leaves, stems, and roots; leaf area; and nitrate reductase enzyme activity. The effect of the inoculation of PGPR showed significant results for Pseudomonas lini vs. the control, with 40% higher values, on average, for plant height, stem diameter, displaced root volume, and fresh weight of root, leaf, and stem. The response of enzymatic and mineral content in seedlings was variable with nutrient solution and significant with distilled water. Studies related to the promotion of plants in the subsequent phenological stages of a tomato, considering the selected PGPR, should be considered in future research. Full article
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16 pages, 7330 KiB  
Article
Utilization of Inorganic Nanoparticles and Biochar as Additives of Agricultural Waste Composting: Effects of End-Products on Plant Growth, C and Nutrient Stock in Soils from a Mediterranean Region
by Jorge Medina, Marcela Calabi-Floody, Humberto Aponte, Christian Santander, Marina Paneque, Sebastian Meier, Marco Panettieri, Pablo Cornejo, Fernando Borie and Heike Knicker
Agronomy 2021, 11(4), 767; https://doi.org/10.3390/agronomy11040767 - 14 Apr 2021
Cited by 8 | Viewed by 3274
Abstract
This study was conducted to evaluate the effect of compost produced with agricultural residues and oat-based biochar, iron oxide and halloysite nanoparticles as additives of the process of composting on soil chemical properties, nutrient status and growth of ryegrass Lolium perenne L. For [...] Read more.
This study was conducted to evaluate the effect of compost produced with agricultural residues and oat-based biochar, iron oxide and halloysite nanoparticles as additives of the process of composting on soil chemical properties, nutrient status and growth of ryegrass Lolium perenne L. For this, a 90-day mesocosm experiment was carried out under greenhouse conditions. Bare soil and a basal fertilization treatment were compared to soils amended with nonadditive compost (NA compost), compost supplied with oat-based biochar (Bioch compost), iron oxide nanoparticles (Fe compost), and halloysite nanoparticles (Ha compost). Compost supplied with nanoparticles and biochar combined were also considered. The incorporation of compost with or without additives increased the content of total C and N in soil, with N diminishing (total and mineral forms) and C/N modifications after 90 days. The addition of compost and co-composted treatments also increased the total contents of main nutrients such as Ca, K, P and S. Furthermore, the supply of additives into composting did not increase the concentration of trace toxic elements. At the end of the experiment, plant biomass increased by the addition of the different organic amendments, with the highest shoot biomass in soils amended with compost supplied with nanoparticles. These results suggest that the addition of compost based on agricultural residues with additives such as halloysite or biochar improves chemical properties and nutritional status of soil that favor and increase plant growth of Lollium perenne stablished in soils from the Mediterranean Region. Full article
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13 pages, 1017 KiB  
Article
Changes in the Bio-Availability of Phosphorus in Pyrochars and Hydrochars Derived from Sewage Sludge after Their Amendment to Soils
by Marina Paneque, José María de la Rosa, Antonio F. Patti and Heike Knicker
Agronomy 2021, 11(4), 623; https://doi.org/10.3390/agronomy11040623 - 25 Mar 2021
Cited by 6 | Viewed by 1804
Abstract
The expected shortage of global phosphate has enforced the search for alternative resources for P fertilizers. Therefore, the present study focuses on the turnover of phosphorus (P) of hydrochars and pyrochars derived from sewage sludge (SS) in soils during plant growth. We designed [...] Read more.
The expected shortage of global phosphate has enforced the search for alternative resources for P fertilizers. Therefore, the present study focuses on the turnover of phosphorus (P) of hydrochars and pyrochars derived from sewage sludge (SS) in soils during plant growth. We designed a pot experiment in which Lolium perenne L. was allowed to grow on a Calcic Cambisol amended with SS-derived chars. Hydrothermal carbonization (HTC) yielded the SS-hydrochars (200 °C, 260 °C; 30 min, 3 h), whereas the SS-pyrochars were obtained after dry pyrolysis (600 °C, 1 h). Increasing severity of HTC lowered the recovery of total P (PT) from the feedstock to 76%. The Olsen-P diminished from 4% PT in the untreated sludge to 1% PT in the hydrochars, whereas the pyrochars exhibited an Olsen-P between 3 and 6%. At the end of the pot experiment, the soils amended with pyrochars and with hydrochars produced at 200 °C contained more Olsen-P than the unamended soils, proving that P-rich chars can indeed serve as a P fertilizer. Part of the P sequestered in the chars turned into a mobile form during the experiment. After addition of our chars, the soil pH remained alkaline, allowing the conclusion that P could not have been solubilized through just abiotic processes. We suggest that biological and biochemical processes are involved in this mobilization. This work demonstrates that, in order to evaluate the efficiency of an organic amendment as a P fertilizer, the knowledge of their P availability alone is not sufficient and a better understanding of the biochemical processes involved in the cycling of its immobilized P is certainly required. Full article
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12 pages, 325 KiB  
Article
Lipid and Yield Evaluation in Salicornia bigelovii by the Influence of Chitosan-IBA, in Conditions of the Sonora Desert
by Gerardo Zapata-Sifuentes, Pablo Preciado-Rangel, Reyna Roxana Guillén-Enríquez, Francisca Sánchez Bernal, Ramon Jaime Holguin-Peña, Carlos Borbón-Morales and Edgar Omar Rueda-Puente
Agronomy 2021, 11(3), 428; https://doi.org/10.3390/agronomy11030428 - 26 Feb 2021
Cited by 3 | Viewed by 1907
Abstract
The present investigation aimed to evaluate the effect of Chitosan-Indole Butyric Acid (IBA) in the seed of Salicornia bigelovii under field conditions in Sonora, Mexico. During two vegetative cycles (2018/2019–2019/2020), cuttings of S. bigelovii were treated with 100 and 50% Chitosan from shrimp [...] Read more.
The present investigation aimed to evaluate the effect of Chitosan-Indole Butyric Acid (IBA) in the seed of Salicornia bigelovii under field conditions in Sonora, Mexico. During two vegetative cycles (2018/2019–2019/2020), cuttings of S. bigelovii were treated with 100 and 50% Chitosan from shrimp exoskeletons and indole butyric acid at 0.937 and 1.25 g·kg−1 and placed in basins under conditions of the Sonora desert, Mexico. Variables were measured: seed production, physicochemical analysis and lipid profile of the seed. The results affected significant increases (p < 0.05) in the evaluated variables, highlighting the treatment based on Chitosan 100%—IBA 0.937 g·kg−1. The results based on chitosan and IBA in cuttings, are a biostimulant in the morpho-physiology, yield production, and lipid content of S. bigelovii. Large-scale studies as a production system should be considered in further studies. Full article
19 pages, 5931 KiB  
Article
Biochar Promotes Nitrogen Transformation and Tomato Yield by Regulating Nitrogen-Related Microorganisms in Tomato Cultivation Soil
by Lili Guo, Huiwen Yu, Wenquan Niu and Mourad Kharbach
Agronomy 2021, 11(2), 381; https://doi.org/10.3390/agronomy11020381 - 20 Feb 2021
Cited by 9 | Viewed by 2793
Abstract
Nitrogen (N) transformation in soil directly determines the effectiveness of N for plant growth. Biochar has received evermore attention because of its significant ability to improve soil. However, the effects of biochar on N-related microorganisms (Lycopersicon esculentum Mill.) in tomato cultivation [...] Read more.
Nitrogen (N) transformation in soil directly determines the effectiveness of N for plant growth. Biochar has received evermore attention because of its significant ability to improve soil. However, the effects of biochar on N-related microorganisms (Lycopersicon esculentum Mill.) in tomato cultivation soil, N transformation, utilisation of water and N fertiliser, and tomato yield remain unclear. The objective of this study was to investigate the responses of N-related microorganisms to biochar and N fertilisation in soil, along with the implications of biochar for altering N transformation, N uptake by tomatoes, and utilisation of water and N fertiliser. A two-year greenhouse experiment containing six biochar levels under drip irrigation (0, 10, 30, 50, 70, and 90 t ha−1) and two N fertiliser application rates (190 and 250 kg ha−1) was conducted in the northwest of China. The results showed that adding biochar significantly promoted urease activity, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and the number of amoA-type nitrifiers in the soil. The MBC:N ratio and the number of nirS-type denitrifiers were significantly inhibited when the added amount of biochar was greater than or equal to 30 t ha−1. Moreover, biochar can increase the water content in the soil and can reduce the N lost to leaching. The inorganic N (NO3 and NH4+) in the soil could be better maintained in the rootzone and better absorbed by tomato plants when adding 30, 50, and 70 t ha−1 of biochar. The amount of N fertiliser could be reduced by 24% without a significant loss of tomato yield when the amount of biochar added was over 30 t ha−1. It was indicated that the yield of tomatoes and the net profits were quadratically related to the application rate of biochar. In the test area, 53 t ha−1 of biochar with 190 kg ha−1 of N and 44.6 t ha−1 of biochar with 190 kg ha−1 of N were calculated to be the best amounts from the perspectives of tomato yield and net profit, respectively. Thus, biochar promotes N transformation by regulating N-related microorganisms; hence, it increases the inorganic N in the roots of the plants, reduces N lost to leaching, and significantly promotes the N absorption of tomatoes. The results in this research are of great significance for the development of management strategies for tomato maintenance, environmental protection, and resource conservation. Full article
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22 pages, 2470 KiB  
Article
Azospirillum brasilense and Solarized Manure on the Production and Phytochemical Quality of Tomato Fruits (Solanum lycopersicum L.)
by Alfonso Andrade-Sifuentes, Manuel Fortis-Hernández, Pablo Preciado-Rangel, Jorge Arnaldo Orozco-Vidal, Pablo Yescas-Coronado and Edgar Omar Rueda-Puente
Agronomy 2020, 10(12), 1956; https://doi.org/10.3390/agronomy10121956 - 12 Dec 2020
Cited by 8 | Viewed by 3661
Abstract
Tomato is a vegetable crop with probiotic interest. Currently subject to a global biosecurity emergency due to the epidemic caused by COVID-19, humanity is seeking to maintain its health and become stronger by eating vegetables that have probiotic properties. Considering the request of [...] Read more.
Tomato is a vegetable crop with probiotic interest. Currently subject to a global biosecurity emergency due to the epidemic caused by COVID-19, humanity is seeking to maintain its health and become stronger by eating vegetables that have probiotic properties. Considering the request of tomato farmers in the Comarca Lagunera (CL) region, the objective of this work consisted of determining the impact of bioinoculation with Azospirillum brasilense (Ab) and solarized manure (M) on the yield and phytochemical quality of tomato fruits produced in shade mesh. Seeds of the saladette variety TOP 2299 were inoculated with Ab at 1 × 108 CFU.mL. Before 46 days after being sowed, seedlings were transplanted in soil enriched with manure solarized at a rate of 0, 40, 80, 120 and 160 t ha−1; a chemical fertilization (CHF) treatment was also adopted (366-95-635). Emergence, growth, root length, bromatological studies (protein and lipids in plant), yield and organoleptic (Vit C, phenols, flavonoids and lycopene) variables were considered. The results show that biofertilization based on Ab + M40 can be an alternative to produce tomato in shade-house conditions in the CL compared with non-inoculated and CHF treatments. Full article
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15 pages, 1354 KiB  
Article
Interactive Effects of Biochar and Sewage Sludge on Bioavailability and Plant Uptake of Cu, Fe, and Zn, and Spinach (Spinacia oleracea L.) Yields under Wastewater Irrigation
by Ugele Majaule, Oagile Dikinya and Bruno Glaser
Agronomy 2020, 10(12), 1901; https://doi.org/10.3390/agronomy10121901 - 2 Dec 2020
Cited by 2 | Viewed by 2092
Abstract
Biochar can influence bioavailability of micronutrients and crop yields in sewage sludge-treated soils, but the mechanisms of its effects remain poorly understood. Therefore, this field experiment was conducted on a Luvisol and Cambisol to investigate the bioavailability and uptake of some micronutrients and [...] Read more.
Biochar can influence bioavailability of micronutrients and crop yields in sewage sludge-treated soils, but the mechanisms of its effects remain poorly understood. Therefore, this field experiment was conducted on a Luvisol and Cambisol to investigate the bioavailability and uptake of some micronutrients and spinach (Spinacia oleracea L.) yields grown in soil amended with biochar and sewage sludge. Ten treatments arranged in randomized complete block design with three levels of biochar (0, 2.5, 5 t/ha) and sewage sludge (0, 6, 12 t/ha) and combinations thereof were applied. High rate of sole sewage sludge, and its combination with biochar significantly (p < 0.05) increased yield on the Luvisol. On the Cambisol, only marginal yield increase resulted from high rates of sole organic amendments and chemical fertilizer, while co-applications decreased yields. Co-amendments generally increased bioavailability of micronutrients relative to sole amendments in the order Fe > Cu = Zn, with greater increase on the Cambisol, but uptake of micronutrients decreased with co-application rates of amendments. Contents of micronutrients in plant leaves were within the normal range, except for a combination of highest dosage of co-amendments on the Cambisol (Fe; 560 mg/kg), which resulted in leaf necrosis and 7% yield depression. The results showed greater yield response of spinach to co-application of amendments on the Luvisol. Full article
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19 pages, 1765 KiB  
Article
Beneficial Effects of Biochar-Based Organic Fertilizer on Nitrogen Assimilation, Antioxidant Capacities, and Photosynthesis of Sugar Beet (Beta vulgaris L.) under Saline-Alkaline Stress
by Pengfei Zhang, Fangfang Yang, He Zhang, Lei Liu, Xinyu Liu, Jingting Chen, Xin Wang, Yubo Wang and Caifeng Li
Agronomy 2020, 10(10), 1562; https://doi.org/10.3390/agronomy10101562 - 14 Oct 2020
Cited by 27 | Viewed by 3530
Abstract
The Songnen Plain, whose climatic conditions are perfectly suited to sugar beet growth, is located in northeastern China. Unfortunately, this region has a lot of saline-alkaline land, which is the most important factor limiting sugar beet production. This study was undertaken to determine [...] Read more.
The Songnen Plain, whose climatic conditions are perfectly suited to sugar beet growth, is located in northeastern China. Unfortunately, this region has a lot of saline-alkaline land, which is the most important factor limiting sugar beet production. This study was undertaken to determine whether biochar-based organic fertilizer could alleviate the negative effect of saline-alkaline soil on sugar beet yield and whether such an effect correlated with changes in nitrogen assimilation, antioxidant system, root activity, and photosynthesis. Three treatments were established: Chemical fertilizers were applied to neutral soil (CK), chemical fertilizers were applied to saline-alkaline soil (SA), and biochar-based organic fertilizer was applied to saline-alkaline soil (SA + B). Our results showed that saline-alkaline stress significantly inhibited the nitrogen assimilation and antioxidant enzymes activities in root, root activity, and photosynthesis, thus significantly reducing the yield and sugar content of sugar beet. Under saline-alkaline conditions, the application of biochar-based organic fertilizer improved the activities of nitrogen assimilation enzymes in the root; at the same time, the antioxidant enzymes activities of the root were significantly increased for improving root activity in this treatment. Moreover, the application of biochar-based organic fertilizer could improve the synthesis of photosynthetic pigments, PSII (Photosystem II) activity, stomatal opening, and photosynthesis of sugar beet under saline-alkaline conditions. Hence, the growth and yield of sugar beet were improved by applying biochar-based organic fertilizer to saline-alkaline soil. These results proved the significance of biochar-based organic fertilizer in alleviating the negative effect of saline-alkaline stress on sugar beet. The results obtained in the pot experiment may not be viable in field conditions. Therefore, in the future, we will verify whether biochar-based organic fertilizer could alleviate the adverse effects of saline-alkaline stress on sugar beets yield under field conditions. Full article
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20 pages, 2333 KiB  
Article
Biochar Impacts on Acidic Soil from Camellia Oleifera Plantation: A Short-Term Soil Incubation Study
by Qianqian Song, Yifan He, Yuefeng Wu, Shipin Chen, Taoxiang Zhang and Hui Chen
Agronomy 2020, 10(9), 1446; https://doi.org/10.3390/agronomy10091446 - 22 Sep 2020
Cited by 4 | Viewed by 2310
Abstract
Nowadays, biochar is increasingly used widely as an important soil amendment to enhance soil nutrients availability. Therefore, we investigated the effect of C.oleifera shell biochar (CSB) on C.oleifera plantation soils to provide evidence that C. oleifera shell as a raw material [...] Read more.
Nowadays, biochar is increasingly used widely as an important soil amendment to enhance soil nutrients availability. Therefore, we investigated the effect of C.oleifera shell biochar (CSB) on C.oleifera plantation soils to provide evidence that C. oleifera shell as a raw material in biochar has great potential to be a soil amendment. For this, a short-term incubation experiment was conducted in controlled conditions to evaluate the effects of CSB application on two soil chemical properties, microbial biomass, and enzymatic activity. We compared two acidic soils, mixed with CSB of three pyrolysis temperatures (300, 500, and 700 °C), and two application rates (3% and 5% (w/w)), incubated for 180 days. The results showed that the soil pH, total P (TP), and available P (AP) significantly increased under 5CSB700 in two soils, and indicated CSB application rate and pyrolysis temperature had a significant impact on soil pH, TP, and AP (p < 0.05). CSB application also significantly increased the total inorganic P in two soils and presented a significantly positive correlation with soil pH, TP, and AP under redundancy analysis. The results suggested that CSB application has a variable effect on soil enzymatic activity, microbial biomass C (MBC), and microbial biomass P (MBP) on average, while it increased the soil microbial biomass N (MBN) in both soils. We concluded that CSB could be a soil amendment to increase soil nutrients of C.oleifera plantation soils. Before the application of biochar to C.oleifera plantation forest soils, long-term studies are required to assess the effects of biochar under field conditions and its promoting effect on the growth of C. oleifera. Full article
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13 pages, 978 KiB  
Article
Biochar Application in Combination with Inorganic Nitrogen Improves Maize Grain Yield, Nitrogen Uptake, and Use Efficiency in Temperate Soils
by Peter Omara, Lawrence Aula, Fikayo B. Oyebiyi, Elizabeth M. Eickhoff, Jonathan Carpenter and William R. Raun
Agronomy 2020, 10(9), 1241; https://doi.org/10.3390/agronomy10091241 - 23 Aug 2020
Cited by 22 | Viewed by 3070
Abstract
Biochar (B) has shown promise in improving crop productivity. However, its interaction with inorganic nitrogen (N) in temperate soils is not well-studied. The objective of this paper was to compare the effect of fertilizer N-biochar-combinations (NBC) and N fertilizer (NF) on maize ( [...] Read more.
Biochar (B) has shown promise in improving crop productivity. However, its interaction with inorganic nitrogen (N) in temperate soils is not well-studied. The objective of this paper was to compare the effect of fertilizer N-biochar-combinations (NBC) and N fertilizer (NF) on maize (Zea mays L.) grain yield, N uptake, and N use efficiency (NUE). Trials were conducted in 2018 and 2019 at Efaw and Lake Carl Blackwell (LCB) in Oklahoma, USA. A randomized complete block design with three replications and ten treatments consisting of 50, 100, and 150 kg N ha−1 and 5, 10, and 15 Mg B ha−1 was used. At LCB, yield, N uptake, and NUE under NBC increased by 25%, 28%, and 46%, respectively compared to NF. At Efaw, yield, N uptake, and NUE decreased under NBC by 5%, 7%, and 19%, respectively, compared to NF. Generally, results showed a significant response to NBC at ≥10 Mg B ha−1. While results were inconsistent across locations, the significant response to NBC was evident at LCB with sandy loam soil but not Efaw with silty clay loam. Biochar application with inorganic N could improve N use and the yield of maize cultivated on sandy soils with poor physical and chemical properties. Full article
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23 pages, 3008 KiB  
Article
Influence of Rice Husk Biochar and Compost Amendments on Salt Contents and Hydraulic Properties of Soil and Rice Yield in Salt-Affected Fields
by Nguyen Thi Kim Phuong, Chau Minh Khoi, Karl Ritz, Tran Ba Linh, Dang Duy Minh, Tran Anh Duc, Nguyen Van Sinh, Thi Tu Linh and Koki Toyota
Agronomy 2020, 10(8), 1101; https://doi.org/10.3390/agronomy10081101 - 30 Jul 2020
Cited by 30 | Viewed by 5052
Abstract
Soil salinity may damage crop production. Besides proper management of irrigation water, salinity reduction can be achieved through soil amendment. The objectives of this study were to evaluate the effects of rice husk biochar and compost amendments on alleviation of salinity and rice [...] Read more.
Soil salinity may damage crop production. Besides proper management of irrigation water, salinity reduction can be achieved through soil amendment. The objectives of this study were to evaluate the effects of rice husk biochar and compost amendments on alleviation of salinity and rice growth. Field experiments were conducted at two salt-affected paddy rice fields located in distinct sites for five continuous crops. Treatments, with four replicates, consisted of continuous three rice crops per year (RRR), two rice crops rotated with fallow in spring–summer crop (FRR), FRR plus compost at 3 Mg ha−1 crop−1 (FRR + Comp), and biochar at 10 Mg ha−1 crop−1 (FRR + BC). Salt contents and hydraulic properties of soils, plant biomass, and plant uptake of cations were investigated. Soil bulk density (BD), exchangeable sodium (Na+), and exchangeable sodium percentage (ESP) were reduced remarkably by biochar application. Biochar application significantly increased other soil properties including total porosity, saturated hydraulic conductivity (Ksat), soluble and exchangeable potassium (K+), K+/Na+ ratio, available P, and total C. Compost application also improved BD, total porosity, and available P, but not exchangeable Na+ and ESP. Total aboveground biomass of rice showed a trend of FRR + BC > FRR + Comp > FRR > RRR. Relatively higher K+ uptake and lower Na+ uptake in rice straw in FRR + BC resulted in a significant two times higher K+/Na+ ratio over other treatments. Our results highlight that biochar amendment is a beneficial option for reducing ESP and providing available K+ and P under salinity-affected P-deficient conditions, hence improving straw biomass. Full article
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27 pages, 3201 KiB  
Article
Evaluation of Recycled Materials as Hydroponic Growing Media
by Nicole Kennard, Ross Stirling, Ankush Prashar and Elisa Lopez-Capel
Agronomy 2020, 10(8), 1092; https://doi.org/10.3390/agronomy10081092 - 28 Jul 2020
Cited by 17 | Viewed by 10480
Abstract
Conventional soilless growing media, such as perlite, are mined from nonrenewable resources and can only be disposed of in landfills after limited use. There is a need to investigate novel, sustainable growing media adapted from waste or engineered to be reused over multiple [...] Read more.
Conventional soilless growing media, such as perlite, are mined from nonrenewable resources and can only be disposed of in landfills after limited use. There is a need to investigate novel, sustainable growing media adapted from waste or engineered to be reused over multiple cycles. This study investigated waste almond shells and a recycled plastic drainage plank as hydroponic growing media alternatives. Physiochemical properties were evaluated, and a germination and greenhouse growth trial was conducted to understand the effect these media have on production and nutritional quality of lettuce (Lactuca sativa L. cv. Catalogna Verde). Drought testing was carried out to understand how the media affected the lettuce’s response to water stress. In comparison to perlite, yields under regular irrigation were reduced by 52% in almond shells and 72% in plastic planks, although lettuce grown in almond shells still obtained commercially relevant yields. Reduced yields in almond shells were likely caused by the shell’s high salinity. Lettuce growth in plastic planks was limited by impeded root growth and low water-holding capacity. In conclusion, with minor alterations, almond shells could be used as a sustainable growing media alternative to perlite in hydroponic lettuce production. More research is needed to manufacture the planks to be conducive to plant growth. Full article
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17 pages, 1360 KiB  
Article
Effect of Biochar Application and Re-Application on Soil Bulk Density, Porosity, Saturated Hydraulic Conductivity, Water Content and Soil Water Availability in a Silty Loam Haplic Luvisol
by Lucia Toková, Dušan Igaz, Ján Horák and Elena Aydin
Agronomy 2020, 10(7), 1005; https://doi.org/10.3390/agronomy10071005 - 13 Jul 2020
Cited by 65 | Viewed by 5821
Abstract
Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk [...] Read more.
Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk density, porosity, saturated hydraulic conductivity, soil water content and selected soil water constants at the experimental site in Dolná Malanta (Slovakia) in 2019. Biochar was applied and re-applied at the rates of 0, 10 and 20 t ha−1. Nitrogen fertilizer was applied annually at application levels N0, N1 and N2. In 2019, these levels were represented by the doses of 0, 108 and 162 kg N ha−1, respectively. We found that biochar applied at 20 t ha−1 without fertilizer significantly reduced bulk density by 12% and increased porosity by 12%. During the dry period, a relative increase in soil water content was observed at all biochar treatments—the largest after re-application of biochar at a dose of 20 t ha−1 at all fertilization levels. The biochar application also significantly increased plant available water. We suppose that change in the soil structure following a biochar amendment was one of the main reasons of our observations. Full article
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17 pages, 3454 KiB  
Article
Assessing Nitrogen Cycling in Corncob Biochar Amended Soil Columns for Application in Agricultural Treatment Systems
by Joseph R. Sanford and Rebecca A. Larson
Agronomy 2020, 10(7), 979; https://doi.org/10.3390/agronomy10070979 - 8 Jul 2020
Cited by 5 | Viewed by 2197
Abstract
Biochar soil amendment to agricultural systems can reduce nitrogen (N) leaching; however, application to agricultural nitrogen treatment systems has not been extensively explored. The objective of this study was to assess the impact on N leaching in soils receiving repeated N applications which [...] Read more.
Biochar soil amendment to agricultural systems can reduce nitrogen (N) leaching; however, application to agricultural nitrogen treatment systems has not been extensively explored. The objective of this study was to assess the impact on N leaching in soils receiving repeated N applications which may be observed in agricultural treatment systems. In this study, 400 °C, 700 °C, and oxidized 700 °C corncob biochar was amended to sandy loam soil columns at 5% (wt/wt) to assess the impacts to N cycling following repeated synthetic N applications. Columns received weekly applications of either organic N (ORG-N), ammonium (NH4+-N), or nitrate (NO3-N) and the N effluent, gaseous emissions, and soil N retention was measured. Biochar produced at 400 °C significantly reduced N leaching compared to control columns by 19% and 15% for ORG-N and NH4+-N, respectively, with application concentrations similar to silage bunker runoff. For NO3-N applications, 700 °C biochar significantly reduced leaching by 25% compared to the controls. The primary mechanism reducing N effluent for biochar amended columns was enhanced soil retention of ORG-N and NO3-N. Biochar surface chemistry analysis measured an increase in oxygenated functional groups and cationic minerals on the biochar surface, which likely enhanced retention through cationic bridging or the development of an organomineral layer on the biochar surface. Results indicated biochar amendment to agricultural treatment systems receiving N runoff may reduce the risk of N leaching. Full article
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11 pages, 1784 KiB  
Article
Biochar-Ca and Biochar-Al/-Fe-Mediated Phosphate Exchange Capacity are Main Drivers of the Different Biochar Effects on Plants in Acidic and Alkaline Soils
by Roberto Baigorri, Sara San Francisco, Óscar Urrutia and José María García-Mina
Agronomy 2020, 10(7), 968; https://doi.org/10.3390/agronomy10070968 - 5 Jul 2020
Cited by 11 | Viewed by 2704
Abstract
Because of the low consistency of the results obtained in the field, the use of biochar as a soil amendment is controversial. Thus, in general, in acidic soils, results are positive, while in alkaline soils, they are non-significant or even negative. The results [...] Read more.
Because of the low consistency of the results obtained in the field, the use of biochar as a soil amendment is controversial. Thus, in general, in acidic soils, results are positive, while in alkaline soils, they are non-significant or even negative. The results regarding biochar action in acidic soils have been related to a lime-like effect due to its alkaline pH and the high doses normally used. However, the causes of biochar effects in alkaline soils remain unknown. Our objective was to explore the chemical mechanism of biochar interaction in acidic and alkaline soils. We used well-characterized biochar as a component of two complex N and PK granulated fertilizers at two different doses (1% and 5%). These fertilizers were applied to wheat cultivated in pots containing an alkaline soil and grown for 60 days. No effect was shown for the N-biochar fertilizer application. However, the PK-biochar fertilizer application caused a decrease in crop yield. In addition, the adsorption isotherms of Al, Fe, Mo, Mn, and Phosphate (Pi) in biochar were also studied. The results showed that Fe and Al were rapidly adsorbed in biochar, while Pi was only adsorbed on the Fe-, Al-biochar complex. Desorption experiments showed that P and Fe/Al were not desorbed from the P-Fe/Al-biochar complex by water or the Olsen reagent, while partial desorption was observed when HCl 0.1 M was used. This blockage of Fe/Al and P through Fe/Al bridges in biochar could partially explain the negative effects in alkaline soils. After these studies, soil solution sorption experiments were carried out in both acidic and alkaline soils and were complemented with a greenhouse trial using tomato plants. The results showed that biochar enhanced foliar Ca and N content, as well as growth in acidic soil only, and the possible mechanism of the failure in alkaline soils. Full article
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23 pages, 1314 KiB  
Article
Integrating Biochar and Inorganic Fertilizer Improves Productivity and Profitability of Irrigated Rice in Ghana, West Africa
by Dilys S. MacCarthy, Eric Darko, Eric K. Nartey, Samuel G. K. Adiku and Abigail Tettey
Agronomy 2020, 10(6), 904; https://doi.org/10.3390/agronomy10060904 - 25 Jun 2020
Cited by 16 | Viewed by 3847
Abstract
The efficiency of mineral fertilizer use in most soils in Sub-saharan Africa is low. Prominent among the reasons for this is low soil carbon stock. In this study, we hypothesized that in the short term, combined use of biochar and inorganic fertilizer in [...] Read more.
The efficiency of mineral fertilizer use in most soils in Sub-saharan Africa is low. Prominent among the reasons for this is low soil carbon stock. In this study, we hypothesized that in the short term, combined use of biochar and inorganic fertilizer in irrigated rice (Oryza sativa var KRC Baika) cropping systems will increase soil organic carbon storage, N recovery and agronomic efficiency of N use (above world average of 55% and 20 kg grain·kg−1·N respectively) and improved economic returns compared to the sole use of inorganic fertilizer. A two-year (4‒cropping cycles) field trial was, thus, conducted on a Vertisol. The experiments were designed as split–plot with two (0 and 10 t·ha−1) biochar and four (0, 45, 90, 120 kg·ha−1·N) nitrogen application rates. Additionally, the effect of biochar on the chemical properties of the soil was investigated using standard protocols. Biochar application improved the soil organic carbon storage in the topsoil. There were significant interactions between the application of biochar and nitrogen fertilizer on yield parameters. Introducing biochar significantly increased root volume and nutrient (N, P and K) uptake, resulting in increased grain and straw yield. Grain yields under biochar amended plots were higher than sole fertilizer amended plots in 14 out of 16 instances (cropping cycles × N rates). The increase in grain yield was between 12 to 29% across N rates. Biochar amendment also enhanced agronomic N use and apparent N recovery efficiencies in 3 out of the 4 cropping cycles. Gross margin indicated that biochar application under irrigated rice cropping systems is economically feasible in all cropping cycles and N rates. However, the value cost ratio of biochar application was higher than for sole inorganic fertilizer in three out of the four cropping cycles (each cropping cycle has three N rates). The soil organic carbon storage of biochar amended soil increased by 17% under unfertilized condition and by 32% under fertilized condition. To enable the promotion and efficient use of the biochar technology in enhancing productivity and profitability in irrigated rice, extension officers and farmers will need to be trained on how to char the rice husk to reduce emissions prior to upscaling the technology to farmers. Full article
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15 pages, 1017 KiB  
Article
Changes in Soil Properties and Bacterial Community Composition with Biochar Amendment after Six Years
by Shuxiu Fan, Jiacheng Zuo and Hangyu Dong
Agronomy 2020, 10(5), 746; https://doi.org/10.3390/agronomy10050746 - 21 May 2020
Cited by 32 | Viewed by 3429
Abstract
Changes in soil physicochemical properties and bacterial community composition were investigated six years after biochar amendment at 0%, 4%, 8% and 12% (w/w), which were coded as C0, C1, C2 and C3, respectively. Results showed that some soil characteristics were sustainable, as they [...] Read more.
Changes in soil physicochemical properties and bacterial community composition were investigated six years after biochar amendment at 0%, 4%, 8% and 12% (w/w), which were coded as C0, C1, C2 and C3, respectively. Results showed that some soil characteristics were sustainable, as they were still affected by biochar addition after six years. Compared to the control, biochar-treated soils had higher pH, total carbon (TC), C/N, total nitrogen (TN), available phosphorus (AP) and available potassium (AK). Soil pH, C/N and the content of TC, TN and AK all increased along with the increase of biochar dosage. The results of Illumina MiSeq sequencing demonstrated that biochar enhanced soil bacteria diversity and modified the community composition over time. The relative abundance of Nitrospirae and Verrucomicrobia phylum increased but that of Acidobacteria phylum decreased significantly in biochar amended soils. The addition of biochar also enriched some bacterial genera, such as uncultured Nitrosomonadace, uncultured Gemmatimonadac, uncultured Nitrospiraceae and Magnetovibrio. In particular, the relative abundance of uncultured Nitrospiraceae was enhanced by 16.9%, 42.8% and 73.6% in C1, C2 and C3, respectively, compared to C0. Biochar has a potential role in enhancing the abundance of bacteria involved in N cycling. Soil pH, TC, TN, TK and AK, were closely related to alterations in the composition of the soil bacterial community. Meanwhile, these soil properties were significantly influenced by biochar amendment, which indicates that biochar affected the soil microbial community indirectly by altering the soil characteristics in the long term. Full article
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19 pages, 3162 KiB  
Article
Effects of Soft Rock and Biochar Applications on Millet (Setaria italica L.) Crop Performance in Sandy Soil
by Yingying Sun, Ningning Zhang, Jiakun Yan and Suiqi Zhang
Agronomy 2020, 10(5), 669; https://doi.org/10.3390/agronomy10050669 - 18 May 2020
Cited by 17 | Viewed by 2687
Abstract
In arid and semi-arid regions, desertification threatens crop production because it reduces the soil’s capacity to retain water and soil nutrients. At two fertilizer levels (90 kg N hm−2 and 45 kg P hm−2 and 270 kg N hm−2 and [...] Read more.
In arid and semi-arid regions, desertification threatens crop production because it reduces the soil’s capacity to retain water and soil nutrients. At two fertilizer levels (90 kg N hm−2 and 45 kg P hm−2 and 270 kg N hm−2 and 135 kg P hm−2), the effects of soft rock (sand: soft rocks = 3:1) and biochar (4500 kg hm−2) applications on soil moisture, soil nutrients, and millet (Setaria italica L.) photosynthesis, yield, and its agronomic traits (biomass, thousand kernel weight, harvest index) were investigated in a field experiment in the Mu Us Sandy Land of China in 2018–2019. The addition of biochar and soft rock singly increased soil water content, alkali-hydrolyzed nitrogen (AN), total nitrogen (TN) and phosphorus (TP), and organic matter content significantly, suggesting that their application may increase the nutrient and water holding capacity of soil. Application of biochar and soft rock singly increased the net photosynthesis rate of millet flag leaf, at the flowering stage, from 15.97% to 56.26%. Biochar and soft rock application increased the yield range (2109.0 kg hm−2 to 5024.7 kg hm−2) from 5.26% to 54.60% under the same fertilizer level. Correlation analyses showed grain yield was significantly correlated with photosynthesis rate at the flowering stage, which was significantly correlated with soil AN at flowering, soil TP at flowering and harvest, and soil TN at flowering. These results indicated that the application of biochar and soft rock singly could increase soil fertilizer holding capacity to improve the photosynthesis rate at flowering, and, therefore, lead to improvements in crop yield. Full article
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17 pages, 1500 KiB  
Article
Effects of Biochar to Excessive Compost-Fertilized Soils on the Nutrient Status
by Chen-Chi Tsai and Yu-Fang Chang
Agronomy 2020, 10(5), 683; https://doi.org/10.3390/agronomy10050683 - 12 May 2020
Cited by 6 | Viewed by 2816
Abstract
Positive effects of a biochar–compost mix on soil nutrient status in infertile soil have been reported, but the potential effect of biochar amendments in excessive compost-fertilized soils has not been extensively studied. Excessive application of compost can result in the accumulation of nutrients [...] Read more.
Positive effects of a biochar–compost mix on soil nutrient status in infertile soil have been reported, but the potential effect of biochar amendments in excessive compost-fertilized soils has not been extensively studied. Excessive application of compost can result in the accumulation of nutrients and heavy metals (Cu and Zn). Thus, the objective of this study is to investigate the effect of biochar–excessive compost co-application on soil nutrient status. We hypothesized that biochar co-application could have positive effects on the absorption of excessive nutrients of Cu and Zn. A 371-day laboratory incubation study was conducted to evaluate the effects of the lead tree (Leucaena leucocephala (Lam.) de. Wit) biochar produced at 750 °C on the dynamics of the soil nutrients. Three Taiwan rural soils were selected, including slightly acidic Oxisols (SAO), mildly alkaline Inceptisols (MAI), and slightly acid Inceptisols (SAI). The biochar treatments include control (0%) and 0.5%, 1.0%, and 2.0% (w/w). In each treatment, 5% (w/w) poultry-livestock manure compost was added to test excessive application. The results indicated that the biochar treatments had a significant increase effect on soil pH, total carbon (TC), total nitrogen (TN), C:N ratio, and available K concentration. The effect of biochar on electrical conductivity (EC) and available P, Ca, Mg, Fe, Mn, Cu, Pb, and Zn was insignificant. The effect of biochar, with relatively low application rates (<2% by wt), low surface area, and less surface function group, was eliminated by excessive compost (5% by wt). In addition to carbon sequestration and nitrogen conservation, biochar addition has no effect on the absorption of the excessive nutrients Cu and Zn in three studied soils. Full article
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18 pages, 5387 KiB  
Article
Beneficial Effects of Biochar and Chitosan on Antioxidative Capacity, Osmolytes Accumulation, and Anatomical Characters of Water-Stressed Barley Plants
by Yaser Hafez, Kotb Attia, Salman Alamery, Abdelhalim Ghazy, Abdullah Al-Doss, Eid Ibrahim, Emad Rashwan, Lamiaa El-Maghraby, Ahmed Awad and Khaled Abdelaal
Agronomy 2020, 10(5), 630; https://doi.org/10.3390/agronomy10050630 - 29 Apr 2020
Cited by 115 | Viewed by 5822
Abstract
The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll [...] Read more.
The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll concentrations, and relative water content. However, electrolyte leakage (EL%), lipid peroxidation (MDA), soluble sugars, sucrose and starch contents significantly increased as a response to drought stress. Additionally, 1000 grain weight, grains yield ha−1 and biological yield significantly decreased in stressed barley plants, also anatomical traits such as upper epidermis, lower epidermis, lamina, and mesophyll tissue thickness as well as vascular bundle diameter of flag leaves significantly decreased compared with control. The use of biochar and chitosan led to significant increases in plant height, number of leaves, and chlorophyll concentrations as well as relative water content; nevertheless these treatments led to significant decreases in electrolyte leakage (EL%) and lipid peroxidation (MDA) in the stressed plants. Moreover, anatomical and yield characters of stressed barley plants were improved with application of biochar and chitosan. The results proved the significance of biochar and chitosan in alleviating the damaging impacts of drought on barley plants. Full article
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10 pages, 1331 KiB  
Article
Wheat Straw Biochar and NPK Fertilization Efficiency in Sandy Soil Reclamation
by Magdalena Bednik, Agnieszka Medyńska-Juraszek, Michał Dudek, Szymon Kloc, Agata Kręt, Beata Łabaz and Jarosław Waroszewski
Agronomy 2020, 10(4), 496; https://doi.org/10.3390/agronomy10040496 - 1 Apr 2020
Cited by 19 | Viewed by 4275
Abstract
Intensive land use including cultivation may result in soil degradation. Restoring natural conditions or utility values called reclamation usually requires prior improvement of soil properties by using fertilizers or soil amendments. Special attention is paid to biochar, as it can improve soil physical [...] Read more.
Intensive land use including cultivation may result in soil degradation. Restoring natural conditions or utility values called reclamation usually requires prior improvement of soil properties by using fertilizers or soil amendments. Special attention is paid to biochar, as it can improve soil physical and chemical properties. Therefore, amendment is potentially useful for preparation of degraded soil for future vegetation. In pot experiments, we studied the effect of wheat straw biochar (5% v/w) (soil with biochar (S + BC)), two rates of mineral fertilizer (no fertilizer as a control set (SC) and single initial dose of fertilizer (S + NPK)), and combination of biochar and fertilizer (S + B C + NPK) on sandy soil properties and grass growth. Biochar significantly increased soil pH, total organic carbon content (TOC), and volumetric water content (VWC, +24% after one week of measurements). However, dry mass of grass shoots was lower in S + BC than in SC (−38%). It was also observed that, in fertilizer, applied sets high concentrations of salts caused crust formation, surface cracking, and overdrying. Considering the results, biochar may be useful for increasing sandy substrate fertility, providing proper conditions for revegetation during reclamation. Full article
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14 pages, 1444 KiB  
Article
Effects of the Application of Biochar in Four Typical Agricultural Soils in China
by Huanhuan Wang, Tianbao Ren, Yuqing Feng, Kouzhu Liu, Huilin Feng, Guoshun Liu and Hongzhi Shi
Agronomy 2020, 10(3), 351; https://doi.org/10.3390/agronomy10030351 - 4 Mar 2020
Cited by 6 | Viewed by 2875 | Retraction
Abstract
The purpose of this study was to explore the effects of biochar application on soils in the main tobacco-producing areas in China. The study was conducted in four study regions in China, where the same three experimental treatments were set up in each [...] Read more.
The purpose of this study was to explore the effects of biochar application on soils in the main tobacco-producing areas in China. The study was conducted in four study regions in China, where the same three experimental treatments were set up in each area, including a control (CK), a treatment involving the application of chemical fertilizer (F), and a treatment involving the application of biochar (B). We analyzed the basic physical and chemical properties, microbial diversity, and root system of tobacco plants. The results show that: Biochar increased the soil pH, which was most obvious in the study site in Shaowu City, Fujian Province (FUS), where the soil pH increased by 22.64% and 27.49% compared with soil under the CK and F treatments, respectively. Biochar increased the microbial biomass carbon (MBC) content, and increased the soil content of available nitrogen, phosphorus, and potassium; this effect was most obvious in FUS. The root activity in plots treated with biochar increased by 6.95% and 13.72% compared to the CK and F plots, respectively. Similarly, the number of root tips increased by 89.76% and 21.48% compared to the CK and F plots, respectively. In short, biochar improved the physical soil structure, increased the soil pH, and promoted the effectiveness of soil nutrients. Furthermore, biochar improved the bacterial soil diversity, enriched the population structure of soil bacteria, and promoted the healthy development of flue-cured tobacco roots. However, the demand for and types of biochar suitable for use in different tobacco-planting soils need further study. Full article
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18 pages, 1104 KiB  
Article
Biochar, Vermicompost, and Compost as Soil Organic Amendments: Influence on Growth Parameters, Nitrate and Chlorophyll Content of Swiss Chard (Beta vulgaris L. var. cycla)
by Angela Libutti, Vincenzo Trotta and Anna Rita Rivelli
Agronomy 2020, 10(3), 346; https://doi.org/10.3390/agronomy10030346 - 3 Mar 2020
Cited by 35 | Viewed by 6851
Abstract
Soil addition with organic amendments is an issue that receives growing attention in the agricultural sector. However, the effects of such materials on plant growth and crop yield are highly variable in the literature. This study aims to evaluate the influence of soil [...] Read more.
Soil addition with organic amendments is an issue that receives growing attention in the agricultural sector. However, the effects of such materials on plant growth and crop yield are highly variable in the literature. This study aims to evaluate the influence of soil addition with biochar (from vine pruning residues), vermicompost (from cattle manure), and three different composts (from olive pomace or cattle anaerobic digestate), on the quali-quantitative response of Swiss chard (Beta vulgaris L. var. cycla) grown in pots. The organic amendments were applied to the soil in two doses to provide 140 and 280 kg N ha−1, respectively. Two growth cycles were considered, and, at each leaf cut, plants were analyzed for growth parameters (height, fresh weight, leaf number, and leaf area) and qualitative characteristics (nitrogen, nitrate, and pigment leaf content). Swiss chard responded positively to organic amendment and, particularly when the soil was treated with compost from animal wastes, higher plant growth and pigment leaf content were observed. Nitrate leaf content was always well below the NO3 thresholds established by the European Commission Regulations. Biochar application did not show a positive effect on the quali-quantitative characteristics of Swiss chard, likely due to benefits that may be achieved over time. Full article
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