scholarly journals Effects of Municipal Solid Waste Compost Supplemented with Inorganic Nitrogen on Physicochemical Soil Characteristics, Plant Growth, Nitrate Content, and Antioxidant Activity in Spinach

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 53
Author(s):  
Rui Machado ◽  
Isabel Alves-Pereira ◽  
Miguel Robalo ◽  
Rui Ferreira

In this study, we evaluated the effects of municipal solid waste compost supplemented with inorganic N on the physicochemical properties of soil, plant growth, nitrate concentration, and antioxidant activity in spinach. Experiments were carried out in neutral and acidic soils that were low in organic matter. A fertilized soil was used as a control, while four compost treatments—two compost rates of 35 and 70 t ha−1, supplemented or not with inorganic N (92 kg N ha−1 as Ca (NO3)2)—were applied by fertigation. The addition of compost increased the soil organic matter content and pH in both soils. The compost supplementation with N greatly increased the shoot dry weight and spinach fresh yield by nearly 109%. With the highest compost rate and 43% N applied, the yield increased in both soils, similar to results obtained in fertilized soil (3.8 kg m−2). The combined application of compost and N could replace inorganic P and K fertilization to a significant extent. The compost application at both rates and in both soils considerably decreased shoot Mn concentrations.

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Giovanni Garau ◽  
Pier Paolo Roggero ◽  
Stefania Diquattro ◽  
Matteo Garau ◽  
Maria Vittoria Pinna ◽  
...  

Highlights- Water Treatment Residuals, Red Muds, Municipal Solid Waste Compost and Biochar can reduce labile PTE in contaminated soils.- When used as amendments, WTR, RM, MSWC and BCH improve soil chemical fertility of PTE-polluted soils.- WTR, RM, MSWC and BCH stimulate soil enzyme activity and heterotrophic bacterial abundance in PTE-polluted soils.- WTR, RM, MSWC and BCH can be used as strategic amendments to enhance plant growth in environments polluted by PTE.   Potentially toxic elements (PTE), e.g. As, Sb, Cd, Cu, Pb, Zn, can severely impact soil element cycling, organic matter turnover and soil inhabiting microbiota. Very often this has dramatic consequences for plant growth and yield which are greatly restricted in PTE-contaminated soils. The use of innovative amendments to reduce the labile pool of such soil contaminants, can result as a feasible and sustainable strategy to improve the fertility and functionality of PTE-contaminated soils as well as to exploit these latter from an agronomic point of view. Water treatment residuals (WTR), red muds (RM), organic-based materials originating from the waste cycle, e.g. municipal solid waste compost (MSWC) and biochar (BCH), have emerged in the last decades as promising amendments. In this paper, we report a synthesis of the lessons learned from research carried out in the last 20 years on the use of the above-mentioned innovative amendments for the manipulation of soil fertility and functionality in PTE-contaminated soils. The amendments considered possess physico-chemical properties useful to reduce labile PTE in soil (e.g. alkaline pH, porosity, Fe/Al phases, specific functional groups and ionic composition among the others). In addition, they contain organic and inorganic nutrients which can contribute to improve the soil chemical, microbial and biochemical status. This is often reflected by a higher organic matter content in amended soils and/or an increase of the cation exchange capacity, available P and total N and/or dissolved organic C. As a result, soil microbial abundance, in particular heterotrophic fungi and bacteria, and enzyme activities (e.g. dehydrogenase, urease and β-glucosidase) are commonly enhanced in amended soils, while plant growth can be significantly stimulated. Overall, the obtained results suggest that the studied amendments can be used to reduce PTE bioavailability in polluted soils, improve soil microbial status and functionality, and enhance the productivity of different crops. This can offer a precious opportunity for the productive recovery of PTE-polluted soils.


2010 ◽  
Vol 2 (1) ◽  
pp. 145-158
Author(s):  
S.P. Gautam ◽  
P.S. Bundela ◽  
A. K. Pandey ◽  
R.K. Jain ◽  
P.R. Deo ◽  
...  

Municipal solid waste (MSW) compost is increasingly used in agriculture as a soil conditioner but also as a fertilizer. Proponents of this practice consider it an important recycling tool since MSW would otherwise be land ûlled and critics are concerned with its often elevated metal concentrations. Large amounts of MSW compost are frequently used in agriculture to meet crop N requirements and for the addition of organic matter. The main concern is loading the soil with metals that can result in increased metal content of crops. Furthermore, in some cases, metals and excess nutrients can move through the soil proûle into groundwater. Municipal solid waste compost has also been reported to have high salt concentrations, which can inhibit plant growth and negatively affect soil structure. A review of relevant agricultural studies is presented as well as recommendations for improving MSW compost quality. Its safe use in agriculture can be ensured with source separation (or triage of MSW to be composted) as well as the development and implementation of comprehensive industry standards.


2020 ◽  
Author(s):  
Iria Benavente-Ferraces ◽  
Fátima Esteban ◽  
Denis Courtier-Murias ◽  
Ana Rey ◽  
Claudio Zaccone ◽  
...  

<p>Biochar application is now considered to be one of the most promising agricultural practices to mitigate climate change. However, to fully assess the benefits of biochar, we still need to better understand its effects on soil properties, and particularly on native soil organic matter (SOM) dynamics.</p><p>In this work, we investigated soil respiration and changes in SOM pools (mineral-free, intra-aggregate, and mineral-associated SOM) as affected by the application of 20 t / ha per year of biochar alone or combined with mineral fertilizer, municipal solid waste compost, or sewage sludge. The experiment was run for 7 years in a semiarid agricultural soil. We found that biochar had no effect on soil respiration with respect to mineral fertilization and no amendment (control), and tended to decrease CO<sub>2 </sub>emissions from soils amended with municipal solid waste compost and sewage sludge. Biochar accumulated mainly in the mineral-free SOM fraction and its addition, especially in combination with municipal solid waste compost, promoted the amount of SOM occluded with aggregates and associated to mineral surfaces.</p><p>Acknowledgments: to the Spanish MICINN (MINECO, AEI, FEDER, EU) for supporting the research project AGL2016-75762-R.</p>


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