Application Of Organic Amendments Research Articles

Coriander (Coriandrum sativum L.) in Combination with Organic Amendments and Arbuscular Mycorrhizal Inoculation: An Efficient Option for the Phytomanagement of Trace Elements-Polluted Soils.

The cultivation of coriander (Coriandrum sativum L.) destined for essential oils production was recently presented as an innovative and economically viable alternative for the phytomanagement of trace elements (TE)-polluted soils. However, Cd accumulation in shoots has proven to be an obstacle in the valorization of the distillation residues and the development of these phytotechnologies. The present study aimed to evaluate the effect of arbuscular mycorrhizal fungus (Funneliformis mosseae) inoculation and organic amendment application on the soil TE bioavailability and plant uptake, as well as on the soil quality and health improvement. The application of compost and sewage sludge improved the growth of coriander and Cd and Zn immobilization in soil, resulting in reduced Cd plant uptake. A synergistic effect of arbuscular mycorrhizal fungi (AMF) inoculation and organic amendments was observed in the decrease in the extractable soil Cd and Zn concentrations, but not in the Cd plant uptake. Despite a significant decrease in Cd accumulation in shoots, coriander retained its accumulative phenotype, with a metal bioconcentration factor close to 1. Furthermore, both the vegetation and the organic amendments improved the soil quality and health by increasing its microbial biomass, as estimated by phospholipid fatty acids, soil enzyme activities (dehydrogenase, phosphatase, β-glucosidase, and cellubiosidase), and the bacterial metabolic function and diversity. The findings demonstrate the potential of C. sativum, particularly in combination with organic amendments and AMF inoculation, for the phytomanagement of TE-polluted soils and soil quality and health improvement.

Nitrogen fertilization value of compost and dried dung in soils with contrasting synthetic nitrogen fertilization histories

AbstractIf the production of forage for dairy cattle is to become less reliant on synthetic nitrogen (N) fertilizers, there is need to better understand and account for the N contributed by on‐farm and imported organic amendments. A 254‐day aerobic soil incubation study (typical length of a growing season in many temperate dairying regions) quantified the inorganic (mineral) N supply from a commercial compost and dried bovine dung (i.e., on‐farm effluent solids). Amendments were incubated in soils with contrasting synthetic N fertilization histories (i.e., 70–100 vs. 350–400 kg N/ha per year) to evaluate if higher synthetic N fertilization histories would reduce the lag time that often exists between organic amendment application and significant release of inorganic N for plant uptake. This proposition was based on previous research, which showed greater soil inorganic N availability accelerating organic amendment decomposition. Our experiment did find that the release of inorganic N from evaluated organic amendments was greater in soils with higher synthetic N fertilization histories, but that this effect was not apparent until after the first 6‐months of this 9‐month experiment. Despite this finding, soils with contrasting synthetic N fertilization histories were not found to differ in their initial inorganic N content, nor microbial activity or other physiochemical properties known to affect N mineralization. Our study highlighted the long‐term vision needed when transitioning from synthetic N fertilizers to organic amendments, with most of the N present in the compost and dried dung remaining unavailable for forage production (i.e., remained bound in organic carbon‐based molecules).

Soil Quality Index of Young and Differently Managed Almond Orchards under Mediterranean Conditions

Sustainable agriculture has drawn attention to the maintenance and enhancement of soil health. However, research on soil quality has been carried out mainly in field crops and, to a lesser extent, in mature orchards, neglecting the relevance of assessing the soil quality status in the first years of tree plantations. Therefore, the aim of this study was to assess the soil quality index of young almond orchards located in marginal lands and managed under different practices. The survey was carried out in the Teruel Province (Northeast Spain), in three almond orchards: Alacón (2 years old, 0.75 ha, rainfed, conventionally managed), San Martín (1 year old, 0.4 ha, irrigated, organically managed), and Valdealgorfa (6 years old, 0.2 ha, rainfed, organically managed). The composite soil samples were taken from three spots within each orchard. To determine the soil quality index, four main soil functions were considered: filtering and buffering, nutrient supply, water relations, and crop limitation. The soil quality indices were 0.55, 0.75, and 0.54 for Alacón, San Martín, and Valdealgorfa orchards, respectively. These values suggested that the evaluated soils are adequate for almond production, although they require management actions to improve their quality (for instance, the application of organic amendments) and increase the sustainability of these agroecosystems. Furthermore, this work provides a framework for the assessment of the soil quality in tree orchards at a young stage.

New approach combining food value with nutrient budgeting provides insights into the value of alternative farming systems

AbstractSustainable farming systems provide food for humans while balancing nutrient management. Inclusion or exclusion of livestock has nutrient management implications, as livestock produce food from otherwise inedible crops and their manure is a valuable soil conditioner. However, plant‐based diets are becoming more widespread due to perceived environmental benefits. We measure both food production in terms of nourishment to humans (in this study measured by protein, fat, starch and sugar production) and nutrient sustainability in terms of fertiliser use of six rotational farming systems with differences in nutrient management approaches. The arable practices included were the application of synthetic fertilisers, a range of organic amendments, incorporation of crop residues and legume cultivation. Livestock and associated products were included in some systems but excluded in others. The production of protein, fat, starch and sugar was combined with the balance of nitrogen (N), phosphorus (P) and potassium (K) into an overall measure of nutrient use efficiency of human macronutrient production. Across all systems considered, N use efficiency (5–13 kg protein/kg applied N) was lower than P (84–772 kg protein/kg applied P) or K (63–2060 kg protein/kg applied K), and combining synthetic fertiliser use with organic amendment applications raised production significantly while balancing P and K management, regardless of which organic amendment was used. Legume‐supported rotations without livestock produced more protein, starch and sugar per unit area than those with livestock. Nutrient balances and nutrient use efficiencies were more sensitive to management changes than purely food production. Using this approach allowed us to identify areas for improvement in food production based on the specific nutritional value of offtakes as opposed to yield overall.

Effects of application of horticultural soil amendments on decomposition, quantity, stabilisation and quality of soil carbon

Application of organic soil amendments is commonplace in horticulture to improve soil fertility. Whether this practice can also augment the soil carbon (C) pool has been of increasing interest in recent years. We used a controlled field experiment that has received annual applications of six different horticultural soil amendments for seven consecutive years. Each amendment was examined in terms of its contribution to bulk C and the distribution of C between theoretical pools, as defined by physical fractionation. Physical fractionation was combined with 13C nuclear magnetic resonance spectroscopy with cross-polarization and magic angle spinning (CPMAS NMR) analysis. Results indicated that the difference in total C concentration between treatments resulted from an increase in unprotected, free, particulate organic matter (fOM), rather than an increase in soil organic matter being occluded in aggregates or in organo-mineral complexes, and that C persisted in the fOM fraction as a result of accumulation in the alkyl C region. Unlike fresh litter or plant residues, organic amendments have undergone decomposition during the composting process (or during formation in the case of peat), in the absence of mineral soil components. This ex situ decomposition (and possible stabilization through acquired recalcitrance) could reduce the opportunity to become physically or chemically protected through association with the soil mineral phase following addition to soil. Carbon:Nitrogen (C:N) of amendment material likely influenced the rate of amendment decomposition. In addition, C:N determines the decomposition of plant litter inputs, as determined by the tea bag index.

The Effects of Rabbit-Manure-Derived Biochar Co-Application with Compost on the Availability and Heavy Metal Uptake by Green Leafy Vegetables

The use of organic amendments to enhance plant growth is increasing due to horticulture activities and vegetable cultivation in urban areas. Consequently, as organic amendments impact heavy metal solubility and plant uptake of unknown contaminants, the risk of human exposure to potentially toxic elements from contaminated soils and compost is increasing. Biochar co-application with compost may reduce the risk-related increased metal uptake by edible plants. To verify this thesis, a greenhouse experiment was established to examine the effects of rabbit-manure-derived biochar (RBC) on Cu, Cr, Cd and Pb uptake by five green leafy vegetables (lettuce—Lactuca sativa L., spinach—Spinacia oleracea L., corn salad—Valerianella locusta L., kale—Brassica oleracea L., mustard greens—Brassica juncea L.) cultivated in compost substrate and soil amended with a 30% (v/w) mix of compost and biochar. The results indicated that the addition of biochar decreased Cu, Cr, Cd and Pb availability in the tested substrates, reducing the uptake of Cd in spinach by 61% and Pb in mustard greens by 73%. The application of RBC also had some adverse effects, such as enhanced accumulation of Cr by kale, lettuce and mustard greens cultivated in compost. Compost co-application with biochar to soil decreased the availability of metals, reducing the content of Pb and Cd in tissues of the tested vegetables, while uptake of Cu and Cr was enhanced in spinach and lettuce by 20%. In conclusion, the application of compost and biochar can be beneficial in improving the quality of urban soil used for horticulture purposes. However, more attention by gardeners should be paid to soil and compost testing in terms of heavy metal contamination and possible adverse effects of organic amendments application for green leafy vegetable cultivation.

Effect of organic farming on the restoration of soil quality, ecosystem services, and productivity in rice–wheat agro-ecosystems

Excess use of hazardous agrochemicals and inorganic fertilizers resulted negative impact on environmental outcomes and degraded soil function, biological diversity, and ecosystem services. A 15-year long-term (2004–05 to 2017–18) field experiment was conducted to improve the ecosystem services with soil quality restoration and stabilization of yield through agronomic manipulation in the rice (Oryza sativa)–wheat (Triticum aestivum) system under Indo-Gangetic Plains (IGP). Three crop management practices (i) organic crop management, (ii) inorganic crop management, and (iii) integrated crop management were evaluated at four locations (i) Jabalpur, (ii) Ludhiana, (iii) Pantnagar, and (iv) Modipuram in a factorial randomized block design and replicated thrice at each location. Among the spatial variation, the highest soil quality indicators like soil microbial biomass carbon (0.52 mg g−1), fungal (46.2 CFU × 104 CFU), bacterial (54.2 CFU × 106 CFU), and actinomycetes viable cells (23.0 CFU × 106 CFU), and nutrients (available N and available P) were observed at Pantnagar than other location. The soil pH varied from 7.2 to 8.3, and the lowest bulk density (ρb) was recorded at Jabalpur and Modipuram. Subsequently, higher system productivity (8,196.7 kg ha−1) and net returns were obtained in Pantnagar > Ludhiana, and it was 44.1–63.4% higher than in Modipuram and Jabalpur. Among the crop management, organic crop management significantly improved (p < 0.05) ρb, soil organic carbon, available N, available P, and available K by 3.7%, 33.3%, 16.4%, 37.8%, and 20.3% over inorganic crop management, respectively. Similarly, the highest bacterial, fungal, and actinomycetes viable cell counts were found under the organic plots, followed by integrated plots. In terms of productivity, integrated crop management (ICM) had increased the system productivity by 4.7%–6.7% and net returns by 22.2% and 23.5% over inorganic and organic crop management. Similarly, the highest sustainability yield index (SYI) was recorded in integrated crop management (0.77) as compared to inorganic (0.74) and organic management (0.75). The soil quality index was estimated as 0.60, 0.53, and 0.54 in organic, inorganic, and ICM, respectively. Hence, the study indicated that the application of organic amendments under organic or integrated crop management improves the system’s resiliency and sustainability. Therefore, the study concludes that towards organic approach (integrated application of organic amendments with a gradual reduction in mineral fertilizers) is better suitable for keeping the rice–wheat system productivity and sustainable in the long term.

A long-term field experiment confirms the necessity of improving biowaste sorting to decrease coarse microplastic inputs in compost amended soils

Microplastic (MP) input into agroecosystems is of particular concern as their sources are diverse (mulching films, biosolid application, wastewater irrigation, flooding, atmospheric input, road runoff). Compost application, which is needed to sustain soil ecosystem services in the context of a circular economy, may be a source of microplastics. The aim of this study was to evaluate how different composts derived from urban wastes impact the nature and quantity of coarse (2–5 mm) microplastics (CMP) in soils, using a long-term field experiment in France. Composts resulting from different levels of urban waste sorting were investigated. Our approach included the isolation of microplastics from composts and amended soils followed by their characterization using pyrolysis GC/MS spectrometry. We found that coarse microplastic concentrations varied from 26.9 to 417 kg per hectare depending on the compost type, after 22 years of bi-annual application. These values may be higher than for conventional agricultural practices, as application rate was twice as high as for normal practices. Composts made from municipal solid waste were by far the organic amendments leading to the highest quantity of plastic particles in soils, emphasizing the urgent need for limiting plastic use in packaging and for improving household biowaste sorting. Our results strongly suggest that standards regulating organic matter amendment application should take microplastics into account in order to prevent contamination of (agricultural) soils. Moreover, although no impacts on the soil bio-physico-chemical parameters has been noted so far. However, given the huge microplastic inputs, there is an urgent need to better evaluate their effect on soil functioning.

Influence of Organic Amendments on Soil Carbon Sequestration Potential of Paddy Soils under Two Irrigation Regimes

Soil organic carbon (OC) is one of the most important soil components regulating soil quality, fertility and agronomic productivity as well as the global carbon (C) cycle. Soil acts as a sink for global C, which can be influenced by the water regime and organic matter (OM) management in field. The aim of this study is to evaluate the effect of the application of different organic amendments on C sequestration in paddy soils under contrasting irrigation regimes. A 4-month pot experiment was conducted under net house conditions and the treatments were composed of two organic amendments: rice straw (RS) and poultry manure (PM); four application rates of amendment: 0 g (control), 2.5 g, 5.0 g and 15.0 g kg−1 soil; and two irrigation regimes: (i) continuous waterlogging condition (CWL) and (ii) alternate wetting and drying (AWD). After the incubation period, soil samples were collected from the pot and isolated into labile (>53 µm) and mineral-associated (<53 µm) OM. Bulk (before and after incubation) and fractionated soil samples were analyzed for OC, total nitrogen (N), C:N ratio; and C sequestration percentage was calculated. Relatively higher amounts of soil OC were present in CWL condition (1.23%) than AWD (1.13%). The C sequestration potential also showed the similar trend (CWL: 47% > AWD: 35%). This was explained by the induced aerobic condition in between the anerobic condition in AWD and the continuous anaerobic condition in CWL which resulted in a difference in OM decomposition. The mineral-associated OM fraction (<53 µm) was higher in the CWL condition than AWD condition which also indicated the importance of the chemical stabilization of OC (OC bound to minerals) in the CWL condition. The application of PM led to a significant increase (45%) in C sequestration potential than RS (37%). This could be attributed to C:N ratio and probable biochemical composition of amendments which resulted in lower decomposability of PM than RS, and also in line with the higher distribution of OC in mineral-bound OM than labile fraction. The application of higher organic amendments did not increase OC content, and declined C sequestration potential in soils as the microbial activity presumably did not match with the amendment amount. Overall, C sequestration potential was higher with 5 g PM kg−1 soil application under CWL-irrigated paddy soil. The findings indicated the need to pay more attention to the selection of the proper type and rate of organic amendments for higher C sequestration in soil under a specific irrigation system for sustainable agriculture.

Effects of Different Organic Amendments on Soil Improvement, Bacterial Composition, and Functional Diversity in Saline–Sodic Soil

The agricultural productivity of farmland in Northeast China’s Liaohe Plain is restricted by the salinity and sodicity of the soils, which have additionally low organic matter content. In order to improve saline–sodic soils, organic amendments are frequently applied. Our objective was to clarify how different organic amendments affect the diversity and composition of soil microbes, as well as how these factors are related to crop yield. In 2020–2021, we conducted an experiment with different organic amendments. The treatments included the application of crop residue incorporation (SR), lignite humic acid (LHA; 6 ton/ha), or cow manure (FM; 30 ton/ha), and a control (CK). The results show that, compared with CK, the content of SOM in soil treated with organic amendments increased by 5.3–7.4 g/kg; the available potassium (AK) of the LHA treatment was significantly higher than that of the FM and SR treatments by 32.17 and 42.79 mg/kg, respectively; and the available phosphorus (AP) of the LHA treatment was significantly higher than that of the SR treatment by 7.19 mg/kg. The pH and EC1:5 values of the LHA treatment were significantly lower than those of CK by 1.36 units and 0.2 mS/cm, respectively. The application of organic amendments and changes in environmental conditions also significantly affected community structure and increased soil microbial richness and diversity. SR treatment increased the abundance of Acidobacteria. Further FAPROTAX (Functional Annotation of Prokaryotic Taxa) analysis showed that organic amendments can increase the abundance of microbes involved in the carbon and nitrogen cycle processes, such as aerobic_ammonia_oxidation, aerobic_chemoheterotrophy, nitrification, etc., which increases the kernel number per row and increases crop yield. LHA can increase the microbial abundance of the nitrogen cycle and reduce soil carbon mineralization, while also increasing soil nutrients and crop yield. This study provides a comprehensive understanding of the application of organic amendments in saline–sodic cultivated land.

Effect of the application of organic amendment and microorganisms that promote plant growth on tomato production (Solanum lycopersicum L.)

It is important to conserve and improve water use efficiency and crop productivity in arid and semi-arid zones. For which, the use of beneficial microorganisms and water retainers can help in the tolerance of plants to drought conditions. Therefore, the objective of this work was to determine the effect of inoculation with MPCV- plant growth promoting microorganisms (Azospirillum brasilense and mycorrhizal fungi) and the application of organic amendment of potassium acrylate on the production of tomato plants (Solanum lycopersicum L.). A greenhouse trial was carried out with a completely randomized experimental design with 4 treatments (T1: Control without application of amendment or MPCV; T2: application of K acrylate amendment; T3: with MPCV inoculation; T4: with joint application of K acrylate amendment and MPCV), with 15 replicates. The highest production and size of tomato fruits was achieved with the inoculation of MPCV (T3) and with the application of K acrylate (T2) individually. The inoculation with Azospirillum brasilense and mycorrhizal fungi, and the application of the organic amendment of potassium acrylate at the time of transplanting tomato (Solanum lycopersicum L.) improves growth and increases its production.

Relationships of priming effects with organic amendment composition and soil microbial properties

• We assessed for interactions between priming effects, soil microbial dynamics, and organic amendment (OA) composition. • Priming effects correlated closely with OAs’ hot water to total carbon concentrations. • Priming effects can be reduced by composting, but not fermenting, OAs before application. • Microbial properties correlated better with energetic than stoichiometric OA characterizations. • Relationships can be used in the preliminary approximation of OA sequestration efficiency. Soil organic carbon (SOC) sequestration through the application of organic amendments (OAs) is considered an important strategy to offset anthropogenic CO 2 emissions while simultaneously enhancing soil quality and food security. The efficiency of SOC sequestration, however, depends on the priming effect which is influenced by interactions of OA composition with soil microbial response variables (MRVs). Yet, there remain large uncertainties surrounding the mechanisms and relationships defining these interactions, hampering the identification of OAs most effective for SOC sequestration and hindering the inclusion of OA dynamics in soil carbon models. In this study therefore, we performed an integrated assessment of these interactions for a cropland soil amended with wood chips, waterway residues, and isotopically enriched road-verge grasses, compost, and bokashi. Changes in 11 microbial properties and priming effects (for isotopically labelled OAs) were monitored for 150 days and related to 22 characterizations of OA composition. We demonstrate that i) hot water extractable to total carbon ratios of OAs are superior predictors of priming effects, ii) dissolvable to hot-water extractable carbon ratios are most closely related to variation in MRV expressions, and iii) priming effects correlate significantly with changes in several MRVs. Findings advocate for the adoption of energetic principles in modelling and predicting microbially-mediated soil carbon dynamics and suggest that application of OAs with high hot water to total carbon concentrations – potentially achievable by composting, but not fermenting, OAs prior to application – can allow for more efficient SOC sequestration.

Organic amendments improved soil quality and reduced ecological risks of heavy metals in a long-term tea plantation field trial on an Alfisol.

Tea plantation can cause strong soil degradation, e.g. acidification, basic nutrient decrease and microbial diversity loss, naturally by its root activity and secondary by practically tremendous synthetic N input. Organic amendments application is considered a practical way to mitigate the above adverse consequence. However, the trade-off between agronomic and environmental effects on the application of the organic amendments is still under debate. Herein, we conducted a long-term field experiment with four treatments, including control (without and fertiliser) (CK), chemical fertiliser treatment (CF), chicken manure treatment (CM) and chicken manure combined with biochar treatment (CMB) to investigate the effects of organic amendments application on soil quality, heavy metal contamination and tea production in a tea plantation. Totally 16 plots were arranged randomly with a completely randomised design. The results showed that CM and CMB treatments improved soil nutrient, mitigated soil acidification and ameliorated soil porosity compared to CF treatment. CMB treatment displayed a relatively high tea yield and quality in three consecutive years of monitoring. However, CM and CMB treatments elevated the heavy metal (HM) potential ecological risk (RI) and Nemerow's composite index (Ps). CM treatment significantly increased available As, Pb, Cu and Zn concentrations compared to CF treatment, while CMB treatment significantly decreased available Cr and Cu concentrations and slightly decreased available Cd, Pb and Ni concentrations compared to CM treatment. But the increase of available As and Zn in CMB treatment compared to CM treatment also indicated adverse effects of biochar addition. The PLS-PM model showed HM risk had direct negative effects on tea quality. Moreover, soil fungal community revealed positive effects on tea yield and negative effects on tea quality. Overall, our study proved that CMB treatment could improve soil quality, reduce available Cr and Ni concentrations, maintain tea yield and increase tea quality.

Closing rice yield gaps in Africa requires integration of good agricultural practices

Despite decades of international research and development efforts focusing on increased rice production in Africa, there is large yield gap, and the local production still needs to be complemented by rice imports to meet consumption demands. This paper aims to provide an overview of published research findings on rice yield gaps and the effects of ‘good agricultural practices’ (GAPs) on rice yield and nutrient use efficiency. The majority of previous studies were from irrigated lowlands, and quantified rice yield gaps as farmer-based (difference between ‘actual yield’ and ‘best farmers’ yield’) and model-based yield gaps (difference between ‘actual yield’ and ‘potential yield for irrigated and water-limited potential yield for rainfed rice’). The mean farmer- and model-based yield gaps were 3.1 and 5.0 t ha–1 for irrigated lowland (IL); 3.1 and 7.7 t ha–1 for rainfed lowland (RL); 2.0 and 6.0 t ha–1 for rainfed upland (RU), respectively in Africa. An analysis of studies from literature on GAPs in Africa revealed that most studies (64 %) were from IL and a wide range of yield increases following individual components of GAPs across environments. A median yield increase of 1.0 t ha–1 was achieved with improved water conservation practices in IL, whereas improved weed management increased yields by 0.7 t ha–1, mainly in IL compared to farmers’ practices. Application of inorganic fertilizers and/or organic amendments increased the yield by 0.8–1.2 t ha–1 across the environments. Integration of GAPs increased the median yield by 2.1 and 1.5 t ha–1 in IL and RL, respectively. The calculated agronomic efficiency of N, P and K from fertilizer experiments were within the desirable levels mainly in the IL and RL environments and comparable to the values from similar environments in Asia. For instance, the agronomic efficiency of N was 21, 13 and 12 kg kg–1, respectively for IL, RL and RU in Africa. Although rice yield gaps in Africa can be substantially reduced by introduction of integrated GAPs to farmers, there is large difference between model-based yield gaps and yield gain obtained by integrated GAPs. Further efforts are needed to identify factors causing this difference. We recommend a research and development focus on rainfed lowland rice systems, which have the largest model-based yield gaps by partially converting them to irrigated systems, and on improving nutrient use efficiencies and closing nutrient cycles.

Dynamics of carbon loss from an Arenosol by a forest to vineyard land use change on a centennial scale

Abstract. Few studies have focused on Arenosols with regard to soil carbon dynamics despite the fact that they represent 7 % of the world's soils and are present in key areas where food security is a major issue (e.g., in Sahelian regions). As for other soil types, land use changes (from forest or grassland to cropland) lead to a loss of substantial soil organic carbon (SOC) stocks and have a lasting impact on the SOC turnover. Here we quantified long-term variations in carbon stocks and their dynamics in a 80 cm deep Mediterranean Arenosol that had undergone a forest-to-vineyard land use change over a 100 years ago. Paired sites of adjacent plots combined with carbon and nitrogen quantification and natural radiocarbon (14C) abundance analyses revealed a C stock of 53 t ha−1 in the 0–30 cm forest soil horizon, which was reduced to 3 t ha−1 after long-term grape cultivation. Total organic carbon in the vineyard was dramatically low, with around 1 g C kg−1, and there was no vertical gradient as a function of depth. 14C showed that deep plowing (50 cm) in the vineyard plot redistributed the remaining carbon both vertically and horizontally. This remaining carbon was old (compared to that of the forest), which had a C:N ratio characteristic of microbial organic matter and was probably stabilized within organomineral associations. Despite the drastic degradation of the organic matter (OM) pool in this Arenosol, this soil would have a high carbon storage potential if agricultural practices, such as grassing or organic amendment applications, were to be implemented within the framework of the 4 per 1000 initiative.

Carbon to nitrogen ratio and quantity of organic amendment interactively affect crop growth and soil mineral N retention

Using organic amendments to improve arable soils in the long term is a careful balancing act of applying amendments with the right carbon to nitrogen ratio (C:N ratio) at adequate quantity to avoid nitrogen (N) leaching while promoting or retaining crop growth in the short term. So far, most studies examining the relationship between C:N ratio and N mineralization and immobilization were done without plants. In this study we explored how crop biomass and N leaching change with increasing C:N ratio and quantity of organic amendments to arable soil. We conducted an open-air mesocosm experiment with organic amendments application across a range in C:N ratio (10 to 60) and quantity (10 to 50 ton ha-1) to sandy arable soil using a full-factorial design. Spring wheat was planted and grown for six months during which three rainfall events were simulated to test treatment effects on N leaching. Applying amendments with a C:N ratio of 20 and higher decreased crop biomass and increased mineral soil N, while amendments with a C:N ratio of 10 had the opposite effect. Applying larger quantities of amendments reinforced the effect of the C:N ratio on crop biomass. N leaching remained unaffected by either amendment C:N ratio or quantity or even mineral fertilizer as N leaching only occurred in the control treatment without plants. Our results suggests that growing a crop is adequate to prevent N leaching. Applying organic amendments do not pose a different risk regarding N leaching when compared to mineral fertilizer and slurry.

Evaluating the Rhizosphere and Endophytic Microbiomes of a Bamboo Plant in Response to the Long-Term Application of Heavy Organic Amendment.

Root-associated bacteria play a major role in plant health and productivity. However, how organic amendment influences root-associated bacteria is uncertain in Lei bamboo (Phyllostachys praecox) plantations. Here, we compared the rhizosphere and endophytic microbiomes in two Lei bamboo plantations with (IMS) and without (TMS) the application of organic amendment for 16 years. The results showed IMS significantly increased (p < 0.05) the relative abundance of Proteobacteria and significantly decreased (p < 0.05) the relative abundance of Acidobacteria, Bacteroidetes, and Verrucomicrobiota. The root endophytic Proteobacteria and Acidobacteria were significantly higher in abundance (p < 0.05) in the IMS than in the TMS, while Actinobacteria and Firmicutes were significantly lower in abundance. Five taxa were assigned to Proteobacteria and Acidobacteria, which were identified as keystones in the rhizosphere soil microbiome, while two species taxonomically affiliated with Proteobacteria were identified as keystones in the root endophytic microbiota, indicating this phylum can be an indicator for a root-associated microbiome in response to IMS. The soil pH, soil total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), available potassium (AK), and TOC:TP ratio were significantly correlated (p < 0.05) with the bacterial community composition of both rhizosphere soils and root endophytes. TMS increased the microbial network complexity of root endophytes but decreased the microbial network complexity of rhizosphere soil. Our results suggest IMS shapes the rhizosphere and endophytic bacterial community compositions and their interactions differently, which should be paid attention to when designing management practices for the sustainable development of forest ecosystems.

Assessment of soil fertility status in cotton-based cropping systems in Cote d’Ivoire

Cotton is the main cash crop in northern Côte d’Ivoire, where intensive cultivation along with low external inputs has led to a decline in crop yields due to soil degradation. The present study aims to assess the evolution of soil fertility during the 2013 and 2021 periods in the cotton basin area of Côte d’Ivoire. More specifically, the study (i) identified the limiting physico-chemical parameters of soil fertility, and (ii) analysed the state of evolution of soil fertility in 2013 and 2021 in the cotton basin of Côte d’Ivoire. For this purpose, a total of 64 soil samples were taken in 2013 and in 2021 on the same cotton plots on the 0-20 cm horizon. Chemical analyses of the soil samples in the laboratory were carried out on the following parameters: particle size distribution, pH water, total nitrogen (NT), Potassium (K+), Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+) and Cation exchange capacity (CEC). The results of the soil analyses showed that the sandy-clay textured topsoils dominate the whole study area in both years. This leads to a low retention capacity of exchangeable bases. Determination of the soil pH showed that the pH varies from slightly acidic to neutral (6.5&amp;lt;pH&amp;lt;7). The most limiting chemical properties are Cation exchange capacity (CEC) and the sum of the exchangeable bases (SEB) in the department of Korogho, Boundiali, and Ferkessedougou and the most limiting chemical properties in the department of Mankono are CEC. However, during the period from 2013 to 2021 the content of exchangeable cations (Ca2+, Mg2+ and K+) and the base saturation (BS) increased significantly in all the departments, more precisely in the department of Mankono. Although we observed a slight increase in the chemical properties of the soils in 2021 compared to 2013, the values were still below the minimum required threshold. This result implies that the soils have poor physico-chemical properties and consequently a low level of fertility, which compromises the sustainability of the cotton production system. The application of organic and mineral amendments is therefore essential to increase the nutrient content of these soils.

Enmiendas líquidas orgánicas en la reducción de cadmio en suelo, hojas y almendras de cacao

The objective of the study was to evaluate the effect of the application of two organic amendments (biol and liquid carbon) on the cadmium of the soil, leaves and almonds of the cocoa crop, plantation CCN-51 (Theobroma cacaoL.), five years of production, in the province of Huamalíes, Huánuco region, Peru. The research used a completely randomized block design (RCDB) with a factorial arrangement of 3 x 3 + 1 additional control. Total cadmium in the soil, leavesand cocoa beans was evaluated. The lowest content of total cadmium in the soil was determined when applying 50 L/ha of biol (0.13 ppm of cadmium) and when applying 4 L/ha of liquid carbon (0.12 ppm of cadmium); while, without the application of organic liquid amendments, the average value was 0.36 ppm of cadmium. Likewise, T5 (80 L/ha of biol + 4L/ha of liquid carbon) reduces the available cadmium content of the soil by 73.58%; while T4 decreases the cadmium content in leaves and almonds by 43.83% and 62.96%, respectively.

Organic amendments role in reducing drought stress in Alcea Rosea L.

Water scarcity and dwindling natural resources due to global warming are negatively impacting ornamental plant survival. Soil fertility remains a problem in arid and semiarid regions. In this study, the effects of four media (arable soil, arable soil + cow manure, arable soil + rice hull, arable soil + wheat straw) on macronutrient content and quantitative characteristics of Alcea rosea L. under drought stress were investigated. Application of organic amendments mitigated the negative effects of drought in the soil and increased the available organic macronutrients. The application of organic amendments increased the total N, P, and K content in the soil and leaves of hollyhock. Total soluble sugars (by 11.9%), RWC (by 8.75%) and phenolics (by 36.4%) of hollyhock were significantly improved by the application of organic amendments at 80% FC. The amended soil (soil + cow manure) increased the activities of superoxide dismutase and ascorbate peroxidase at 80% FC. Moreover, the soil + cow manure proved to be the best supplement to improve leaf area and dry weight. In conclusion, the application of organic amendments can be successfully used as a cost-effective management method to improve soil fertility and crop production in arid and semi-arid areas.