A Circular Economy: Chemical, Microbiological and Environmental Implications of Mineral and Organic Fertilizers Use in Soils

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

Deadline for manuscript submissions: 25 September 2024 | Viewed by 32235

Special Issue Editor


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Guest Editor
1.Department of Agricultural and Environmental Chemistry, University of Agriculture in Krakow, al. Mickiewicza 21, 31-120 Krakow, Poland
2. Department of Mineralogy, Petrography and Geochemistry, Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow, Poland
Interests: mineral and organic fertilizers; waste management; biochar; compost; soil organic matter
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Special Issue Information

Dear Colleagues,

The continuous pressure on natural resources and the related environmental pollution are a source of concern around the world. In addition, the intensive development of industry causes a direct or indirect impact on the environment and human health and wellbeing as a result of the production of large quantities of waste and the emission of toxic chemicals. The circular economy is gaining more and more importance; developing new, environmentally friendly technologies; minimizing generation of waste and pollution; and reducing the negative impact of human activities on the environment. Particular attention, in the context of environmental impact, should be given both to important nutrients for plants and impurities that may be introduced into the soil along with fertilizers. The need to protect the environment is forcing us to take a new look at the problems of fertilization and the use of components of applied fertilizers. In recent years, the quality and health of soil fertilized with organic fertilizers (inculing waste), as part of the principles of sustainable development and the circular economy, is widely recognized by and of great interest to a wide range of scientists around the world.

The following are some of the major areas in which papers are solicited:

  • A circular economy in waste management;
  • Innovative practices in the management of organic fertilizers;
  • Monitoring of soil pollution with trace elements and organic contaminants;
  • Reclamation and revitalization of contaminated soils;
  • Ecotoxicity assessments and ecological risk assessment;
  • Organic fertilization impact on soil fertility and its effect on soil environment and plants;
  • Agricultural usefulness of organic fertilizers and waste products enriching soil with organic matter (sludges, industrial composts) and raw materials deacidifying soils (calcium, calcium–magnesium fertilizers);
  • Comparison of the effect of organic and mineral fertilization on soil quality and yield quality;
  • Fertilization value of organic materials and organic fertilizers
  • Best practices in solid waste collection and recycling—generation and characterization of waste;
  • Recycling and reuse;
  • Treatment (mechanical, biological, chemical, thermal, other);
  • Innovative mineral fertilizers with the addition of organic matter.

Dr. Monika Mierzwa-Hersztek
Guest Editor

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Keywords

  • circular economy
  • organic matter
  • nutrients
  • plant quality
  • exogenic organic matter
  • soil improvers
  • waste management
  • ecological risk assessment
  • microorganisms
  • enzymatic activity
  • soil pollution

Published Papers (19 papers)

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15 pages, 2797 KiB  
Article
Silicon Fertilizer Addition Can Improve Rice Yield and Lodging Traits under Reduced Nitrogen and Increased Density Conditions
by Liqiang Dong, Tiexin Yang, Liang Ma, Rui Li, Yingying Feng and Yuedong Li
Agronomy 2024, 14(3), 464; https://doi.org/10.3390/agronomy14030464 - 26 Feb 2024
Viewed by 1004
Abstract
Reducing nitrogen fertilizer application, selecting a reasonable planting density, and adding silicon fertilizer can be used together to decrease excessive nitrogen fertilizer inputs in rice fields, reduce production costs, and ensure stable rice yield. However, the dynamics of the stem and internodes, as [...] Read more.
Reducing nitrogen fertilizer application, selecting a reasonable planting density, and adding silicon fertilizer can be used together to decrease excessive nitrogen fertilizer inputs in rice fields, reduce production costs, and ensure stable rice yield. However, the dynamics of the stem and internodes, as well as the changes in the physical and physiological characteristics of rice under a combination of these three strategies, are still unclear. In this study, we aimed to clarify these effects to improve the efficiency of rice production in northeastern China. A 2-year field experiment was conducted using five treatments: a conventional densification treatment (DM), a densification combined with reduced N input (−20%) treatment (DLM), and three densifications combined with reduced N input (−20%) and basal silicon fertilizer treatments (low fertilizer: DLMS1; medium fertilizer: DLMS2; and high fertilizer: DLMS3). This study revealed that the addition of silicon fertilizer improved rice yield compared to that under reduced nitrogen or increased density treatments alone, prevented excessive ineffective tillering after a density increase, and increased the number of productive panicles. Among the treatments, the DLMS3 treatment had the highest yields of 10.53 t/ha and 10.73 t/ha over the 2 years. Reducing nitrogen and increasing density reduced the weight and length of single panicles, while the addition of silicon fertilizer was beneficial for improving stem toughness, improving the physical and physiological characteristics of the plants and panicles, and enhancing plant bending resistance. Among the treatments, DLMS3 had the highest bending resistance, which increased by 440.1 g and 503.8 g compared to the lowest values in the DM treatment in 2020 and 2021, respectively. Nitrogen reduction resulted in the lowest lodging index values, with DLMS3 having the lowest values in both years, which decreased by 19.6% and 22.5% compared to the highest values in DM (2020) and DLM (2021), respectively. This study indicates that the application of 150.0 kg/ha silicon fertilizer in combination with reduced nitrogen and increased density (DLMS3) reduces the lodging index while ensuring rice yield, preventing a tradeoff between yield reduction and lodging due to a density increase or due to nitrogen reduction combined with a density increase and allowing for a reduction in nitrogen fertilizer input, which could ensure a uniform yield and an increase in lodging resistance. These results provide a scientific basis for rice cultivation measures that lead to high yield and lodging resistance while protecting the environment. Full article
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15 pages, 2550 KiB  
Article
Linkages of Enzymatic Activity and Stoichiometry with Soil Physical-Chemical Properties under Long-Term Manure Application to Saline-Sodic Soil on the Songnen Plain
by Cheyu Zhai, Xiaotong Feng, Changjie Liu, Yang Li, Jiaming Fan, Juan Zhang and Qingfeng Meng
Agronomy 2023, 13(12), 2972; https://doi.org/10.3390/agronomy13122972 - 30 Nov 2023
Cited by 1 | Viewed by 859
Abstract
Excess Na+ and high pH result in poor structures in Saline-Sodic soils, which reduces extracellular enzyme activity (EEA) and causes nutrient limitations. The application of manure improved the Physical-Chemical properties of soil and balanced the soil nutrient supply, which was reflected in [...] Read more.
Excess Na+ and high pH result in poor structures in Saline-Sodic soils, which reduces extracellular enzyme activity (EEA) and causes nutrient limitations. The application of manure improved the Physical-Chemical properties of soil and balanced the soil nutrient supply, which was reflected in the soil EEAs and stoichiometry. Five experimental treatments were designed according to the manure application duration as follows: manure application for 11 years (11a), 16 years (16a), 22 years (22a), and 27 years (27a) and a control treatment with no manure application (CK). The results of the redundancy analysis (RDA) showed that physical properties (mean weight diameter (MWD)) and EEA (β–glucosidase (BG)) significantly increased and bulk density (ρb) significantly decreased when the nutrient content increased. Additionally, soil pH, electrical conductivity (EC), exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) significantly decreased after manure application. Based on stepwise multiple linear regression models (SMLR), total nitrogen (TN) was the dominant variable that significantly increased EEA, and the Mantel test showed that soil C:N significantly influenced enzyme stoichiometry. Furthermore, RDA showed that pH, soil C:N and TN were the main factors influencing EEAs and enzyme stoichiometry. Soil EEAs significantly increased with TN and decreased with pH and soil C:N, which affected enzyme stoichiometry. The enzyme stoichiometry increased from 1:2.1:1.2 and 1:2.7:1.5 to 1:1.7:1.2, and the vector angle (vector A) increased, which showed that the N limitation was relieved after the application of manure. The vector length (vector L) showed no significant difference in the C limitation at depths of 0–20 cm and significantly increased at depths of 20–40 cm. In conclusion, soil EEAs and stoichiometry improved with changes in TN and soil C:N, and pH decreased with changes in the soil structure after the application of manure, which accelerated the soil nutrient cycle and balanced the soil nutrient supply. Full article
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14 pages, 1025 KiB  
Article
Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?
by Ana García-Randez, Evan A. N. Marks, María Dolores Pérez-Murcia, Luciano Orden, Javier Andreu-Rodriguez, Encarnación Martínez Sabater, María Teresa Cháfer and Raúl Moral
Agronomy 2023, 13(10), 2585; https://doi.org/10.3390/agronomy13102585 - 9 Oct 2023
Viewed by 1254
Abstract
In Spain and other Mediterranean countries, significant quantities of semi-solid olive mill waste are generated, which should be preferentially applied to agricultural soils to close nutrient cycles. However, two-phase olive mill waste (termed alperujo in Spanish) is known to pose risks to soil [...] Read more.
In Spain and other Mediterranean countries, significant quantities of semi-solid olive mill waste are generated, which should be preferentially applied to agricultural soils to close nutrient cycles. However, two-phase olive mill waste (termed alperujo in Spanish) is known to pose risks to soil quality and plant production when applied to soil in large quantities. Alperujo has high contents of polyphenol substances, which can inhibit microbial growth and are also phytotoxic in nature. However, when applied in appropriate quantities and following specific methods, it is possible that the practice may not pose any risks, and this requires evaluation. As a waste management option, direct application of alperujo can supply plant nutrients and organic matter to degradation-prone Mediterranean soils. In order to validate this circular economy fertilization and soil protection strategy, an 18-month field experiment was undertaken, applying moderate quantities of alperujo on permanent crop groves throughout the Spanish region of Valencia. Eleven experimental parcels with permanent crops managed by farmers were identified to test two scenarios: a single application of 10 t/ha, and a second application of 10 t/ha after 10 months. Soil chemical parameters were assessed at 0, 6, 10, and 18 months. Soil organic carbon, total Kjeldahl nitrogen, pH, electrical conductivity, nitrates, and polyphenol contents were modified by alperujo application, but these effects were highly transient in nature, with generally no lasting effects after 4–6 months for either application scenario. Also, qualitative evaluations carried out by farmers revealed few effects, although some reductions in erosive processes and improvements in plant vigor were noted. As such, based on the measured parameters, it is concluded that the direct soil application of alperujo olive mill wastes at low application rates did not lead to any lasting detrimental effects on soil quality or compromise the productivity of permanent crops in this Mediterranean region. Full article
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17 pages, 6254 KiB  
Article
Effect of Chemical Fertilizer with Compound Microbial Fertilizer on Soil Physical Properties and Soybean Yield
by Chenye Fu, Weiran Ma, Binbin Qiang, Xijun Jin, Yuxian Zhang and Mengxue Wang
Agronomy 2023, 13(10), 2488; https://doi.org/10.3390/agronomy13102488 - 27 Sep 2023
Cited by 3 | Viewed by 1720
Abstract
Compound microbial fertilizer is a new type of environmentally friendly slow-release fertilizer that can effectively improve the physical and chemical properties of the soil, significantly improve the ecological environment, and promote the sustainable development of agriculture. In this study, we conducted a field [...] Read more.
Compound microbial fertilizer is a new type of environmentally friendly slow-release fertilizer that can effectively improve the physical and chemical properties of the soil, significantly improve the ecological environment, and promote the sustainable development of agriculture. In this study, we conducted a field experiment to evaluate the impact of different applications of chemical fertilizer combined with composite microbial fertilizer on soil physical properties and soybean yields at Heshan Farm, Heilongjiang Province, China, during 2021–2022. Soybean varieties “Jinyuan 55” and “Keshan 1” were treated with three treatments implemented as follows: T1 (conventional fertilization), T2 (50% N fertilizer + compound microbial fertilizer), and T3 (0 N fertilizer + compound microbial fertilizer). Compared to conventional fertilization (T1 treatment), the application of composite microbial fertilizers (T2 and T3) resulted in a decrease in soil bulk density and an increase in porosity. Notably, we observed that moderate application of the composite microbial fertilizer (T3) led to a decrease in the volume fraction of clay particles and an increase in the volume fraction of sand particles. Furthermore, all treatments exhibited high content of agglomerates larger than 5 mm at 0–20 cm. The application of composite microbial fertilizers (T2 and T3) promoted the formation of large soil agglomerates and reduced the presence of micro-agglomerates smaller than 0.25 mm. In 2021–2022, The soybean yield increased by 13.02% in the T2 treatment compared with the T1 treatment and decreased by 9.34% in the T3 treatment. We concluded that the appropriate application of compound microbial fertilizer can help protect black soil, enhance the self-repair capability of black soil, and improve soybean quality in abnormal precipitation years. These results provide an actionable basis for constructing and developing green fertilizer systems for the soybean industry. Full article
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22 pages, 7963 KiB  
Article
Responses of Soil Microbial Communities in Soybean–Maize Rotation to Different Fertilization Treatments
by Yunlong Wang, Liqiang Zhang, Fangang Meng, Zixi Lou, Xiaoya An, Xinbo Jiang, Hongyan Zhao and Wei Zhang
Agronomy 2023, 13(6), 1590; https://doi.org/10.3390/agronomy13061590 - 13 Jun 2023
Cited by 4 | Viewed by 1538
Abstract
Rotation and fertilization are important methods used to improve crop yield. In particular, crop rotation is an effective means of enhancing ecosystem diversity; however, there exist relatively few studies regarding the effects of long-term maize–soybean rotation and fertilization on soil microbial communities. To [...] Read more.
Rotation and fertilization are important methods used to improve crop yield. In particular, crop rotation is an effective means of enhancing ecosystem diversity; however, there exist relatively few studies regarding the effects of long-term maize–soybean rotation and fertilization on soil microbial communities. To further understand the changes in soil microbial community structure under long-term maize–soybean rotation and fertilization, we used a 9-year-old experimental site with maize–soybean rotation as the research object and soybean continuous cropping as a control. We explored the growth effects of soybean and the changes in soil microbial communities under the soybean–maize rotation system and fertilization treatments by analyzing the physicochemical properties of the soil, crop agronomic traits, yield, and changes in soil microbial community structure. The results show that, in comparison with soybean continuous cropping, the yield of soybeans was increased by 12.11% and 21.42% under maize–soybean rotation with different fertilization treatments, respectively. Additionally, there was a significant increase in the agronomic effects of nitrogen following rotation combined with fertilization. Moreover, the soil pH, SOM, and nutrient status were also improved. Bryobacter, Gemmatimonas, and Rhodanobacter were the dominant bacteria. Rotation treatment increased the relative abundance of Bryobacter and Rhodanobacter, and fertilization treatment increased the relative abundance of Gemmatimonas. Rotation also increased the stability of the bacterial community structure and strengthened the symbiotic relationship between species. The prediction of nitrogen-related functional genes indicates that rotation increased soil ammonification and nitrification. Heterocephalacria and Mrakia were the dominant fungal genera under crop rotation. The abundance of Saccharomyces Mrakia was significantly positively correlated with ammonium nitrogen levels and crop yield. Crop rotation increased the abundance of Saccharomyces Mrakia and reduced the abundance of Fusarium, but fertilization increased the abundance of Fusarium. Functional gene prediction also indicates that the relative abundance of plant pathogens was significantly reduced. This study provides a theoretical basis for soil microbial diversity and ecosystem service function in long-term soybean–maize rotation. Full article
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16 pages, 2391 KiB  
Article
Effects of Incorporating Different Proportions of Humic Acid into Phosphate Fertilizers on Phosphorus Migration and Transformation in Soil
by Jianyuan Jing, Shuiqin Zhang, Liang Yuan, Yanting Li, Yingqiang Zhang, Xinxin Ye, Ligan Zhang, Qizhong Xiong, Yingying Wang and Bingqiang Zhao
Agronomy 2023, 13(6), 1576; https://doi.org/10.3390/agronomy13061576 - 10 Jun 2023
Cited by 1 | Viewed by 1471
Abstract
Incorporating humic acid (HA) into phosphate fertilizers to produce HA-enhanced phosphate fertilizers (HAPs) can improve the migration and availability of fertilizer-derived phosphorus (P) in soil. However, the optimal proportion of HA remains inconsistent. Here, we investigated the effects of HAPs with different HA [...] Read more.
Incorporating humic acid (HA) into phosphate fertilizers to produce HA-enhanced phosphate fertilizers (HAPs) can improve the migration and availability of fertilizer-derived phosphorus (P) in soil. However, the optimal proportion of HA remains inconsistent. Here, we investigated the effects of HAPs with different HA proportions (0.1–10% w/w) on water-soluble P fixation rate, P migration, P transformation, and soil microorganisms, and analyzed the main P forms in HAP using Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The results showed that incorporating 0.1% HA had no impact on P migration and transformation, whereas incorporating 0.5–10% HA increased the migration distance and cumulative migration of fertilizer-derived P by 0–5 mm and 17.1–30.3%, respectively, compared with conventional phosphate fertilizer (CP). Meanwhile, HAPs with 0.5–10% HA significantly reduced the water-soluble P fixation rate by 18.3–25.6%, and significantly increased the soil average available P (AP) content in 0–40 mm soil layer around the P application site by 6.2–12.9% relative to CP, partly due to the phosphate monoesters in HAPs. Clustering analysis revealed that 0.5% HA had similar effects relative to higher HA proportions (1% and 5%), and the inhibition of HAP with 0.5% HA on bacteria and fungi was also greater than that of CP due to the high concentration of soil P. Overall, 0.5% was determined to be the optimal amount of HA for HAP production, which provided a theoretical basis for the development of high-efficiency phosphate fertilizer. Full article
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19 pages, 1200 KiB  
Article
Impact of Sandy Soil Amendment with Dairy Slurry Treated through pH Adjustment on Nutrient and Coliform Leaching
by Joana Rodrigues, Rita Fragoso, Luísa Brito and David Fangueiro
Agronomy 2023, 13(4), 1176; https://doi.org/10.3390/agronomy13041176 - 20 Apr 2023
Viewed by 1673
Abstract
Livestock farming produces high volumes of animal slurry that can be sanitized using low-cost treatments by pH adjustment, reducing pathogen contamination, and promoting slurry valorization as a safe fertilizer. This work aims to evaluate the impact of sandy soil amendment with dairy slurry [...] Read more.
Livestock farming produces high volumes of animal slurry that can be sanitized using low-cost treatments by pH adjustment, reducing pathogen contamination, and promoting slurry valorization as a safe fertilizer. This work aims to evaluate the impact of sandy soil amendment with dairy slurry treated by pH adjustment on the potential release of nutrients and coliforms into groundwater. A laboratory soil column leaching experiment was conducted and the surface application of six treatments was tested: raw dairy slurry, dairy slurry acidified with H2SO4, dairy slurry alkalinized with KOH, alkalinized/neutralized dairy slurry, mineral fertilizer, and a control. The fertilizer application rate was 0.08 g N kg−1 dry soil. Leachates were analyzed for pH, electrical conductivity, N-NH4+ and N-NO3, macro- and micronutrients, and fecal coliforms. Results showed that amendment with dairy slurry led to significantly lower nitrate leaching potential than mineral fertilizer (maximum 16.1 vs. 50.4%). The use of hygienized slurry by alkalinization decreased the potential leaching of coliforms relative to raw slurry. However, incomplete sanitization by acidification strongly promoted coliform leaching and the risk of groundwater contamination. It can be concluded that the use of alkalinized dairy slurry is a safer solution than raw slurry with regard to the risk of groundwater pollution. Full article
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18 pages, 1625 KiB  
Article
Nutrient Potential Leachability in a Sandy Soil Amended with Manure-Based Fertilisers
by Joana Prado, Paula Alvarenga, Henrique Ribeiro and David Fangueiro
Agronomy 2023, 13(4), 990; https://doi.org/10.3390/agronomy13040990 - 28 Mar 2023
Viewed by 1934
Abstract
The application of manure-based fertilisers (MBFs) is considered an important practice for achieving agricultural sustainability. However, the potential losses of nutrients to the environment need to be thoroughly evaluated. This study aimed to assess nutrients’ potential leachability from a sandy soil, fertilised with [...] Read more.
The application of manure-based fertilisers (MBFs) is considered an important practice for achieving agricultural sustainability. However, the potential losses of nutrients to the environment need to be thoroughly evaluated. This study aimed to assess nutrients’ potential leachability from a sandy soil, fertilised with MBFs produced by mixing manure from one single animal species with N- or P-mineral fertilisers, to achieve target N:P ratios (1:1, 2:1 and 0.5:1). MBFs were prepared by combining pig slurry, cattle slurry or poultry manure with N- and P-mineral fertilisers, or slurry-derived materials, obtained by solid–liquid separation. A leaching experiment was set-up in soil columns treated with MBFs, for 59 days, with seven leaching events. Poultry manure application to soil led to higher potential N leaching, while pig slurry induced higher P leaching. All 2:1 MBFs decreased P leaching, relative to the original manure, with the higher reduction (52%) being observed for pig slurry with urea. The addition of urea to poultry manure also diminished its potential for N leaching. The behaviour of P-enriched materials, pig slurry solid fraction and both 0.5:1 MBFs obtained with phosphoric acid addition showed a higher risk of P leaching, while the use of superphosphate as a P-mineral source decreased the risk of P leaching. Concluding, it is possible to use specific MBFs, enriched with N and P from mineral sources, and have lower N and P leaching potential, reducing the risks associated with manure soil application, while increasing their interest as alternative fertilisers. Full article
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22 pages, 6096 KiB  
Article
Chemical Speciation of Trace Elements in Soil Fertilized with Biomass Combustion Ash and Their Accumulation in Winter Oilseed Rape Plants
by Małgorzata Szostek, Ewa Szpunar-Krok and Anna Ilek
Agronomy 2023, 13(3), 942; https://doi.org/10.3390/agronomy13030942 - 22 Mar 2023
Cited by 3 | Viewed by 1159
Abstract
The impact of fertilization of fly ashes from biomass combustion (BAs) on the changes in the chemical speciation of trace elements (Zn, Cu, Cr, Ni, Pb, Cd) in Gleyic Chernozem soil was analyzed in field-experiment conditions, under cultivation of winter oilseed rape plants. [...] Read more.
The impact of fertilization of fly ashes from biomass combustion (BAs) on the changes in the chemical speciation of trace elements (Zn, Cu, Cr, Ni, Pb, Cd) in Gleyic Chernozem soil was analyzed in field-experiment conditions, under cultivation of winter oilseed rape plants. The three-year field experiment was carried out in southeastern Poland (50°3′ N, 22°47′ E). The three-stage sequential extraction procedure developed by the Measurements and Testing Program (BCR) was used for the fractionation of trace elements in BAs and soil. The risk assessment code (RAC) coefficient was used to assess potential soil contamination with trace elements from Bas. The total content of Zn, Cu, Cr, Ni, Pb, and Cd in BAs used in the experiment was 470, 311, 29, 78, 38, and 3.7 mg kg−1, respectively. The present study showed that the application of BAs significantly increased the total concentration of Zn and Cu in the surface layer of the Gleyic Chernozem soil, and did not significantly increase the concentration of Cr, Ni, Pb, and Cd. Generally, using BAs does not significantly change the chemical speciation of trace elements in soil. Regardless of the applied fertilization, residual fraction (F4) was the most abundant, whereas the exchangeable/extractable (F1) fraction and reducible (F2) fraction were present in the smallest amounts. Due to the low share of exchangeable/extractable fraction (F1), the BAs used in the experiment were characterized by a low RAC coefficient; hence, their use as a soil fertilizer is relatively safe for the environment. The BAs fertilization did not cause significant changes in the content of trace elements in the different parts of the winter oilseed rape plants. Due to the relatively high content of trace elements in fly ashes from biomass combustion, an analysis of the content of individual trace element fractions should be carried out to assess their actual impact on the environment. This can help indicate further actions that should be taken to limit their negative environmental impact. Full article
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14 pages, 5022 KiB  
Article
Chemical and Morphologic Characterization of Sylvite (KCl) Mineral from Different Deposits Used in the Production of Fertilizers
by John R. Castro-Suarez, Fredy Colpas-Castillo and Arnulfo Taron-Dunoyer
Agronomy 2023, 13(1), 52; https://doi.org/10.3390/agronomy13010052 - 23 Dec 2022
Cited by 2 | Viewed by 1625
Abstract
In the present work, four (4) samples of sylvite (KCl) from different deposits in Canada, Belarus and Germany were analyzed in order to determine the differences between them in terms of chemical composition, morphology and impurities present. Different non-instrumental and instrumental techniques were [...] Read more.
In the present work, four (4) samples of sylvite (KCl) from different deposits in Canada, Belarus and Germany were analyzed in order to determine the differences between them in terms of chemical composition, morphology and impurities present. Different non-instrumental and instrumental techniques were used. A scanning electron microscope analysis showed that the particles are completely amorphous. Bueno mineral has particles with the largest area (with 91.4% particles larger than 0.50 mm), and the BPC mineral samples have those with the smallest area (with 49.9% particles smaller than 0.50 mm). The Bueno mineral has the highest angle of repose. Bueno mineral has the highest surface area and pore volume when compared to the other KCl minerals. On the other hand, the BPC KCl mineral presented a lower surface area and pore volume. The problem mineral has the highest percentage composition of K. Blanco mineral did not present Al, and the element Mo was not detected in the Blanco and Bueno mineral. The IR bands of O-H, C-N, N-H and C=O bonds were observed. These results are useful for the fertilizer industry. These differences can produce adverse effects in a subsequent application in fertilizer production processes. Such differences can be attributed to the origin of this mineral, the way it is obtained and exploited, or to the transport and storage process through the use of anticompacting additives due to the high hygroscopicity of the mineral. Full article
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18 pages, 5761 KiB  
Article
Effects of Freezing–Thawing Processes on Net Nitrogen Mineralization in Salinized Farmland Soil
by Qiang Zhao, Jingwei Wu, Chenyao Guo, Jifeng Zhang, Xin Wang, Yawen Liu, Hang Zhao and Rui Zhang
Agronomy 2022, 12(12), 2986; https://doi.org/10.3390/agronomy12122986 - 28 Nov 2022
Cited by 1 | Viewed by 1399
Abstract
Nitrogen is an indispensable and limiting element for plant and microbial growth. To investigate the combined effects of salinity and freezing–thawing (FT) processes on soil inorganic nitrogen (SIN) transformation in seasonally freezing salinized farmland, laboratory incubation experiments were conducted under five soil salt [...] Read more.
Nitrogen is an indispensable and limiting element for plant and microbial growth. To investigate the combined effects of salinity and freezing–thawing (FT) processes on soil inorganic nitrogen (SIN) transformation in seasonally freezing salinized farmland, laboratory incubation experiments were conducted under five soil salt content (SSC) treatments (0.08%, 0.25%, 0.35%, 0.50%, and 0.70%), four FT temperature treatments (C (5 °C), FT (−5 + 5 °C), FT (−10 + 5 °C), and FT (−15 + 5 °C)), and two soil water content (SWC) treatments (40% and 80% of maximum water holding capacity (WHC)). Ammonium (NH4+-N) and nitrate (NO3-N) nitrogen were monitored at the first, second, fifth, and eighth incubation days. The FT processes increased relative NH4+-N content by 13%, 39%, and 77% with the decreasing of freezing temperature from −5 °C to −15 °C compared with C (5 °C) treatments, respectively. FT (−5 + 5 °C) and FT (−15 + 5 °C) treatments decreased the relative NO3--N contents by 4% and 6% compared with C (5 °C) treatments, respectively. Under FT treatments, the increment of relative NH4+-N content was higher in low-SSC treatments and lower in high-SSC treatments. The relationship between relative NO3-N content and SSC gradually changed from a decrease in C (5 °C) to an increase in FT (−15+5 °C) treatments. SWC decreased NH4+-N content in high-SSC and low-freezing temperature treatments (SSC × freezing temperature < −2.5%· °C), while NH4+-N increased in low-SSC and unfrozen treatments. The variations of SIN/Rmin (nitrogen mineralization rate) were mostly affected by NO3-N/Rnit (net nitrification rate) and NH4+-N/Ra (net ammonification rate) in C (5 °C) and FT treatments, respectively. Overall, the results suggested that enhanced salinity inhibited the effects of freezing temperature on NH4+-N and NO3-N formation, respectively. The increase in SWC weakened the NH4+-N formation induced by the decrease in freezing temperature, and this function increased with the increase in salinity. Full article
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20 pages, 2614 KiB  
Article
Dynamic and Migration Characteristics of Soil Free Amino Acids in Paddy Soil Applied with Milk Vetch
by Jing Yang, Yi Lin, Christopher Rensing, Liming Zhang, Biqing Zhou, Shihe Xing and Wenhao Yang
Agronomy 2022, 12(11), 2621; https://doi.org/10.3390/agronomy12112621 - 25 Oct 2022
Viewed by 1330
Abstract
To explore the attribution factors and migration characteristics of free amino acids (FAAs) in paddy soils after green manure application during the entire growth period of rice. Amino acid analyzer, quantitative PCR, and high-throughput sequencing were used to analyze the effects of different [...] Read more.
To explore the attribution factors and migration characteristics of free amino acids (FAAs) in paddy soils after green manure application during the entire growth period of rice. Amino acid analyzer, quantitative PCR, and high-throughput sequencing were used to analyze the effects of different application rates of milk vetch on FAAs in paddy soil under equal nitrogen, phosphorus, and potassium conditions. Soil FAAs concentration at different growth stages was highest at the seedling stage and lowest at the tillering stage. The concentration of threonine, alanine, valine, isoleucine, leucine, and phenylalanine was most abundant during the growth period, accounting for 59.42–76.46% of the respective FAAs pool. The application of milk vetch was shown to increase the soil FAAs concentration, especially glutamic acid, which increased by 368.17–680.78%, but the excessive application had an inhibitory effect. Soil bacteria were critical factors affecting soil FAAs dynamics, among which Bacteroidetes, Firmicutes, and Nitrospirae contributed 56.89% to the FAAs dynamics. FAAs displayed significant vertical profile characteristics, and the mobility of serine, glycine, and proline was high. Conclusively, the application of milk vetch was able to significantly change the concentration and composition of soil FAAs, which were affected by soil bacteria. Full article
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11 pages, 1429 KiB  
Article
Unveiling the Impacts of Biochar, Manure and Their Optimal Combinations on Microbiological Soil Health Indicators and Lettuce Biomass
by Adnan Mustafa, Jiri Holatko, Tereza Hammerschmiedt, Jiri Kucerik, Tivadar Baltazar, Antonin Kintl, Ondrej Malicek, Zdenek Havlicek and Martin Brtnicky
Agronomy 2022, 12(10), 2307; https://doi.org/10.3390/agronomy12102307 - 26 Sep 2022
Cited by 1 | Viewed by 1679
Abstract
Continuous use of chemical fertilizers has deteriorated soil health and crop productivity. Replenishing soil nutrients and microbial activity with eco-friendly soil amendments such as biochar and manure is therefore necessary to sustain soil health for crop production. However, studies are limited regarding the [...] Read more.
Continuous use of chemical fertilizers has deteriorated soil health and crop productivity. Replenishing soil nutrients and microbial activity with eco-friendly soil amendments such as biochar and manure is therefore necessary to sustain soil health for crop production. However, studies are limited regarding the evaluation of biochar and poultry manure effects on soil health, attributed mainly to microbial extracellular enzymes and respiration. Therefore, the present study was designed to investigate the effects of poultry manure and biochar on soil physico-chemical and microbiological properties and lettuce biomass accumulation in a pot experiment. The pots were amended with poultry manure either alone and or in combination with low (10%) and high (20%) rates of biochar. The treatments included were; (i) control, (ii) manure alone (M), (iii) manure plus 10% biochar (M + B10, and (iv) manure plus 20% biochar (M + B20). Results revealed that soil extracellular enzymes related to C, N, and P mineralization, soil basal (BR), and substrate induced respirations (SIR) were significantly affected by applied manure and manure–biochar. However, there were large differences observed for applied amendments regarding various soil and crop parameters. Specifically, the manure combined with a high rate of biochar (M + B20) enhanced total carbon (TC) content, dehydrogenase activity (DHA), BR, and all SIRs except Arginine-IR. On the other hand, manure combined with a low rate of biochar (M + B10) resulted in enhanced lettuce aboveground dry biomass (AGB-dry). The manure treatment alone (M), however, proved to be the most influential treatment in improving soil enzymes (β-glucosidase, N-acetyl-β-d-glucosaminidase and phosphatase) involved in C, N, and P mineralization compared to the other treatments and control. Thus, it was concluded that the sole application of M and M + B20 improved both fertility and soil health, which therefore could be a promising direction for the future to enhance soil quality and crop productivity. Full article
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14 pages, 1650 KiB  
Article
Soil Biological Activity, Carbon and Nitrogen Dynamics in Modified Coffee Agroforestry Systems in Mexico
by Diana Ayala-Montejo, Eduardo Valdés-Velarde, Gerardo Sergio Benedicto-Valdés, Esteban Escamilla-Prado, Rufo Sánchez-Hernández, Juan Fernando Gallardo and Pablo Martínez-Zurimendi
Agronomy 2022, 12(8), 1794; https://doi.org/10.3390/agronomy12081794 - 29 Jul 2022
Cited by 2 | Viewed by 2379
Abstract
(1) Background: Coffee agroforestry systems (CAFS) in Veracruz, Mexico, are being displaced by avocado monocultures due to their high economic value. This change can generate alterations in the type of organic residues produced and soil biological activity (SBA) which is sensitive to climatic [...] Read more.
(1) Background: Coffee agroforestry systems (CAFS) in Veracruz, Mexico, are being displaced by avocado monocultures due to their high economic value. This change can generate alterations in the type of organic residues produced and soil biological activity (SBA) which is sensitive to climatic variations, changes in floristic composition, and agronomic management. It can be evaluated through soil respiration and macrofauna, both related to soil carbon (C) and nitrogen (N) dynamics. The objective was to: (1) Analyze the variation of SBA as well as the C and N dynamics in modified coffee agroforestry systems; (2) Methods: Three CAFS (renewed, intensive pruning, and with the introduction of avocados) and an avocado plantation were compared. The evaluations were conducted during the period 2017–2019. Soil parameters (respiration, macrofauna, C and N contents) and C content of plant biomass were measured in plots of 25 × 25 m2 from three soil depths in triplicate. Spearman’s test and a principal component analysis were performed to determine the structural dependence on C and N dynamics; (3) Results: The introduction of avocado showed the lowest soil respiration values (with 193 g CO2 ha−1 h−1 at 0–10 cm depth), this system did not display soil macrofauna and increased soil organic carbon content. The soil C/N ratio was sensitive to the introduction of avocado. Correlation between soil respiration and litter-related parameters was positive, but it was negatively correlated with soil organic matter and total soil nitrogen, explaining 67.7% of the variation; (4) Conclusions: Modification of CAFS generated variations in the SBA and soil C and N contents. Full article
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25 pages, 8470 KiB  
Article
Mitigation of CaCO3 Influence on Ipomoea batatas Plants Using Bacillus megaterium DSM 2894
by Ahmed A. M. Awad, Alshaymaa I. Ahmed, Alaa H. Abd Elazem and Atef A. A. Sweed
Agronomy 2022, 12(7), 1571; https://doi.org/10.3390/agronomy12071571 - 29 Jun 2022
Cited by 3 | Viewed by 1400
Abstract
The application of PGPB is considered a surrogate approach to reducing the amounts of phosphorus fertilizers applied in addition to its role in improving nutrient availability under stress conditions. The objective of this study was to evaluate five levels of calcium superphosphate (CSP); [...] Read more.
The application of PGPB is considered a surrogate approach to reducing the amounts of phosphorus fertilizers applied in addition to its role in improving nutrient availability under stress conditions. The objective of this study was to evaluate five levels of calcium superphosphate (CSP); ultimately, CSP was applied in five levels: CSP20, CSP40, CSP60, CSP80, and CSP100 were applied at 69, 138, 207, 276, and 345 kg ha−1, respectively, and two treatments of Bacillus megaterium DSM 2894 (with and without) were applied on sweet potato (Beauregard cv.) plants grown in calcareous soils in the 2019 and 2020 seasons in Egypt. Some macro- and micronutrient (i.e., nitrogen (N), phosphorus (P), calcium (Ca), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu)) uptake, antiradical power (ARP), and protein and total root yields (TRYs) were determined. The plants inoculated with B. megaterium DSM 2894 had increased leaf N, P, and Mn contents in both seasons; in addition, Ca was increased in the second season. Furthermore, all of the root nutrient contents (except N) as well as the ARP and TRY were increased in both seasons as compared with those of the noninoculated plants. On the other hand, the maximum values of the leaf Ca, Fe, and Cu contents and the root Ca, Fe, and Zn contents were recorded with the CSP20 treatment in both seasons. CSP60 was the superior treatment for N (in the leaves), Mn (in the roots), ARP, protein contents, and TRY in both seasons and for the leaf Zn content in the 2019 season. The application of the CSP100 treatment gave the highest values for the leaf and root P contents and the root Cu contents in both seasons as well as for the leaf Mn content in the first season and the root N content in the 2020 growth season. Thus, it was concluded that the application of CSP20, CSP60, and CSP100 treatments with the B. megaterium DSM2894 mixture gave the best values compared to the use of CSP or DSM2894 individually to attenuate CaCO3-induced damage. Full article
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15 pages, 3394 KiB  
Article
Combined Organic and Inorganic Fertilization Can Enhance Dry Direct-Seeded Rice Yield by Improving Soil Fungal Community and Structure
by Xiaohong Guo, Jiajun Liu, Lingqi Xu, Fujing Sun, Yuehan Ma, Dawei Yin, Qiang Gao, Guiping Zheng and Yandong Lv
Agronomy 2022, 12(5), 1213; https://doi.org/10.3390/agronomy12051213 - 18 May 2022
Cited by 8 | Viewed by 1962
Abstract
Direct seeding of rice has emerged as a strategy for sustainable rice (Oryza sativa L.) production because of advantages, such as fewer production links, labor and farmland water-saving, easy mechanization, and high economic benefits. However, few studies have investigated the effects of [...] Read more.
Direct seeding of rice has emerged as a strategy for sustainable rice (Oryza sativa L.) production because of advantages, such as fewer production links, labor and farmland water-saving, easy mechanization, and high economic benefits. However, few studies have investigated the effects of different organic fertilizers on soil fungal community and rice yield in dry direct-seeded paddy fields. In order to select the best combination of organic fertilizer and chemical fertilizer, field experiments were used to evaluate the role of no fertilizer (F0); CF, conventional NPK fertilizer, OF1, biochar + conventional NPK fertilizer; OF2, seaweed bioorganic fertilizer + conventional NPK fertilizer; OF3, Jishiwang bioorganic fertilizer + conventional NPK fertilizer; and OF4, attapulgite organic fertilizer + conventional NPK fertilizer on microbial structure and diversity and rice yield. Under Jishiwang bioorganic fertilizer + conventional NPK fertilization, the number of fungal OTUs was 365 and ranged from 1 to 9. The Ascomycota relative abundance was increased by 28.25% under Jishiwang bioorganic fertilizer application compared with CF, but the Basidiomycota decreased. Sordariomycetes and Leotiomycetes relative abundances were increased under organic fertilization. The relative abundance of dung saprotrophs, fungal parasites, and leaf saprotrophs was increased under organic fertilizer compared to CF, and animal pathogens decreased, but organic fertilizers also increased plant pathogens. Rice yield was increased under Jishiwang bioorganic fertilizer + conventional NPK fertilizer and was positively correlated with Ascomycota and Sordariomycetes relative abundances. The use of Jishiwang bioorganic fertilizer + conventional NPK fertilizer improves fungal community diversity and rice yield. Full article
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15 pages, 1443 KiB  
Article
Influence of Organomineral Fertiliser from Sewage Sludge on Soil Microbiome and Physiological Parameters of Maize (Zea mays L.)
by Małgorzata Hawrot-Paw, Małgorzata Mikiciuk, Adam Koniuszy and Edward Meller
Agronomy 2022, 12(5), 1114; https://doi.org/10.3390/agronomy12051114 - 4 May 2022
Cited by 4 | Viewed by 2110
Abstract
The use of a soil fertiliser results in high, good quality yields. The most widely used fertilisers are mineral or organic, but there is increasing attention on organomineral fertilisers produced from sewage sludge. These contain beneficial components which may improve soil fertility and [...] Read more.
The use of a soil fertiliser results in high, good quality yields. The most widely used fertilisers are mineral or organic, but there is increasing attention on organomineral fertilisers produced from sewage sludge. These contain beneficial components which may improve soil fertility and thus plant productivity, but there are some concerns associated with their application due to their composition. Using a short-term pot experiment the effect of such a soil conditioner called FS, produced from sewage sludge after stabilisation with lime, on the qualitative−quantitative composition and activity of soil microorganisms and selected physiological parameters of the maize was analysed. The study was carried out in a completely randomised design, including a control (soil + lime + NPK). The application of the FS had a positive effect on the soil pH, equivalent to the application of lime. Organomineral fertiliser, as a source of organic carbon and macroelements, had a positive effect on the number of soil microorganisms and their activity, and this influence was stable during maize vegetation. FS did not influence the gas exchange activity of maize, the content of assimilation pigments in leaves or and the efficiency of the photosynthetic apparatus determined by chlorophyll “a” fluorescence analysis, but it increased the light absorption efficiency of the PSII photosystem. Differences in biomass yield from organomineral and mineral fertilisation were statistically insignificant. Full article
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34 pages, 11679 KiB  
Article
Nutrient Contents and Productivity of Triticum aestivum Plants Grown in Clay Loam Soil Depending on Humic Substances and Varieties and Their Interactions
by Ahmed A. M. Awad, Ashraf B. A. El-Taib, Atef A. A. Sweed and Aya A. M. Omran
Agronomy 2022, 12(3), 705; https://doi.org/10.3390/agronomy12030705 - 14 Mar 2022
Cited by 6 | Viewed by 2314
Abstract
Due to an extreme increase in population growth, Egypt suffers from a widening gap in the quantity of imported wheat compared with production and local consumption. Two field trials were conducted during the 2018/2019 and 2019/2020 seasons with three levels of humic substances [...] Read more.
Due to an extreme increase in population growth, Egypt suffers from a widening gap in the quantity of imported wheat compared with production and local consumption. Two field trials were conducted during the 2018/2019 and 2019/2020 seasons with three levels of humic substances (HSs) as a foliar spray (1.0, 2.0 and 4.0 g L−1; HS1, HS2 and HS3) and three levels (5.04, 7.56 and 10.08 kg ha−1; HS4, HS5 and HS6) as a soil application. These were applied three times (30, 45 and 60 days after sowing) in comparison with the control (HS0) to evaluate the performance of three wheat varieties (Seds1 (V1), Misr2 (V2) and Giza168 (V3)) grown in clay loam soil. The experiment was set up according to the split-plot structure in a randomized complete block design; however, the varieties were set as the main plot and treatments were a sub-main plot. Generally, the data indicated that the soil application treatments recorded maximum values for most growth and yield attributes, except for spike length and grain weight per spike, SPAD reading and total grain yield in the first season, and leaf area and biological yield in the second season. HS1, HS2, HS5, and HS6 were the superior treatments for most of the nutrient contents studied. Regarding the influence of variety, the results showed that V3 recorded maximum values for LA, SpL, TGW, TGY and leaf Zn and Cu contents in both seasons; PH, GWS and leaf N content in the first season; and SPAD reading, BY and leaf K, Fe and Mn contents in the second season. V1 was the superior variety for GWS, BY, leaf K and Mn contents in the 2018/2019 season and PH, GNS in the second season, followed by V2, which had the greatest values for leaf P contents in both seasons, and SPAD reading, GNS and leaf Fe content in the 2018/2019 season and GWS and leaf N content in the second season. Full article
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Review

Jump to: Research

27 pages, 477 KiB  
Review
The Effects of Manure Application and Herbivore Excreta on Plant and Soil Properties of Temperate Grasslands—A Review
by Arne Brummerloh and Katrin Kuka
Agronomy 2023, 13(12), 3010; https://doi.org/10.3390/agronomy13123010 - 7 Dec 2023
Cited by 1 | Viewed by 1721
Abstract
This review provides an overview of grassland studies on the effects of manure application and herbivore excreta on plant and soil properties in temperate grasslands. Grass biomass from grazing or mowing is mainly used for animal products such as milk or meat, as [...] Read more.
This review provides an overview of grassland studies on the effects of manure application and herbivore excreta on plant and soil properties in temperate grasslands. Grass biomass from grazing or mowing is mainly used for animal products such as milk or meat, as well as for energy or raw materials for biorefineries. Manure application or grazing has a significant impact on several plant and soil properties. There are effects on soil chemical properties, such as increased carbon sequestration, improved nutrient availability, and increased pH. Additionally, several physical soil properties are improved by manure application or grazing. For example, bulk density is reduced, and porosity and hydraulic conductivity are greatly improved. Some biological parameters, particularly microbial biomass and microbial and enzyme activity, also increase. The use of manure and grazing can, therefore, contribute to improving soil fertility, replacing mineral fertilizers, and closing nutrient cycles. On the other hand, over-application of manure and overgrazing can result in a surplus of nutrients over plant needs and increase losses through emission or leaching. The lost nutrients are not only economically lost from the nutrient cycle of the farm but can also cause environmental damage. Full article

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Microbial activity and soil organic matter quality as affected by ameliorative liming
Authors: Kateřina Boturová1*, Lubica Pospíšilová1, Jakub Prudil1, Luboš Sedlák1, Ladislav Menšík2, Lukáš Hlisnikovský2
Affiliation: 1 Mendel University in Brno, Faculty of AgriSciences, Department of Agrochemistry, Soil Science, Microbiology and Plant Nutrients, Zemědělská 1, 613 00 Brno, Czech Republic; xboturo1@mendelu.cz 2 Crop Research Institute, Division of Crop Management Systems, Drnovská 507/73, 161 06 Praha 6-Ruzyně, Czech Republic; ladislav.mensik@vurv.cz; l.hlisnik@vurv.cz * Correspondence: xboturo1@mendelu.cz
Abstract: Increasing the management intensity of grasslands through fertilizing and liming has attracted more attention to their quality. Liming, besides the neutralization of acids, has various impacts on biota, nutrient cycles and soil organic matter quality. The regression models corrected according to Scott's criterion of multicollinearity (SC = 0.1908 and -0.4586) and the Fisher-Snedecor model were used for evaluation of the amount of microbial biomass, basal soil respiration, soil organic carbon (SOC) and nutrient content. These were determined during 2014-2019 after the long-term yearly liming (1.4 t.ha-1 CaO) in Dystric Stagnosol. The main hypothesis was that alteration of soil reaction gives a rapid response of soil biota activity. Results showed that the residues in both models have a normal distribution (Jarque-Berr normality test) and autocorrelation is in-significant (Wald's autocorrelation test). Results also showed that pH is a key factor affecting the amount of SOC, microbial biomass (Cmic) and basal soil respiration (BSR). Increasing the soil reaction was related to the increase of biota activity and SOC decrease. The Cmic/SOC ratio increased with more favorable conditions and a strong significance for the overall soil chemical properties, physico-chemical properties, and temporary immobilization of macro-and micronutrients. The multivariate exploratory techniques (PCA, FA, and CLU) divided two different systems (Control and Liming) according to soil reaction, amount of microbial biomass, basal soil respiration, nitrogen, phosphorus, potassium and calcium content. Furthermore, changes in fractional composition of soil organic matter were evaluated.

Title: Nutrients’ potential leachability in a sandy soil amended with manure-based fertilizers
Authors: Joana Prado*, Paula Alvarenga, Henrique Ribeiro and David Fangueiro*
Affiliation: LEAF, TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, Portugal
Abstract: The application of manure-based fertilizers (MBFs) is considered an important practice to achieve agriculture sustainability. However, the potential losses of nutrients to the environment need to be thoroughly evaluated. This study aimed to assess nutrients’ potential leachability from a sandy soil, fertilized with MBFs produced by mixing manure from one single animal species with N- or P-mineral fertilizers, to achieve target N:P ratios (1:1, 2:1 and 0.5:1). MBFs were prepared by combining pig slurry, cattle slurry or poultry manure with N- and P-mineral fertilizers, or slur-ry-derived materials, obtained by solid-liquid separation. A leaching experiment was set-up in soil columns treated with MBFs, for 59 days, with seven leaching events. Poultry manure application to soil led to higher potential N leaching, while pig slurry induced higher P leaching. All 2:1 MBFs decreased P leaching, relative to the original manure, with the higher reduction (52%) being ob-served for pig slurry with urea. The addition of urea to poultry manure also diminished its potential N leaching. The behaviour of P-enriched materials, pig slurry solid fraction and both 0.5:1 MBFs obtained with phosphoric acid addition, showed a higher risk of P leaching, while the use of su-perphosphate as mineral-P source decreased the risk of P leaching. Concluding, it is possible to use specific MBFs, enriched with N and P from mineral sources, and have lower N and P leaching potential, reducing the risks associated with manure soil application, while increasing their interest as alternative fertilizers.

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