Use Of Organic Amendments Research Articles

Role of Biocontrol Agents in Suppressing Plant Pathogen: A Compressive Analysis

Biocontrol agents have emerged as important tools in the quest for sustainable agriculture, offering environmentally friendly alternatives to chemical pesticides for managing plant pathogens and pests. This comprehensive review explores the advancements in biocontrol agent research, focusing on the exploration of new agents, genetic engineering, and integration into Integrated Pest Management (IPM) systems. The discovery of novel biocontrol agents from diverse environments, including plant microbiomes and marine ecosystems, has expanded the arsenal available for agricultural use, while genetic engineering and synthetic biology have enhanced the efficacy of existing agents by improving their production of antimicrobial metabolites and stress tolerance. Additionally, the development of synthetic microbial consortia and innovative delivery systems, such as encapsulation and nanotechnology, has improved the stability and application efficiency of biocontrol agents in various agricultural settings. The review also highlights the importance of sustainable and eco-friendly approaches, such as the use of organic amendments and crop rotation, to enhance the effectiveness of biocontrol strategies. These methods not only improve soil health and biodiversity but also reduce the reliance on chemical inputs. However, the widespread adoption of biocontrol agents faces challenges, including environmental variability, host specificity, and the need for supportive regulatory frameworks. Harmonizing regulatory processes, promoting public awareness, and providing incentives for sustainable practices are essential for overcoming these barriers. International cooperation and knowledge exchange are crucial for advancing research and ensuring that biocontrol agents become integral components of modern agriculture. This review underscores the potential of biocontrol agents to contribute significantly to global food security and environmental sustainability, provided that ongoing research and innovation continue to address existing challenges and expand their practical applications in diverse agricultural contexts.

A Comprehensive Overview on Sustainable Vegetable Gardening: Eco-friendly Approaches to Home Grown Production

Sustainable vegetable gardening is an eco-friendly practice that integrates organic farming principles, resource conservation, and biodiversity promotion to produce nutritious, chemical-free food while minimizing environmental impact. This approach emphasizes soil health through the use of organic amendments, crop rotation, composting, and mulching to improve fertility and water retention. Water conservation techniques, such as drip irrigation and rainwater harvesting, are employed to optimize water use, especially in arid regions. Pest and disease management relies on integrated pest management (IPM), biological controls, companion planting, and the use of organic pesticides to reduce chemical input while maintaining crop health. Sustainable homegrown produce has been shown to have superior nutritional content compared to commercially grown produce, and the avoidance of synthetic chemicals reduces the risk of pesticide residue exposure. Gardening fosters healthy eating habits by connecting individuals to their food sources, encouraging the consumption of fresh, unprocessed vegetables, and contributing to food security. The mental and physical health benefits of gardening, including reduced stress, increased physical activity, and improved mental well-being, further highlight its holistic value. However, challenges such as the initial setup costs, time investment, pest management, and knowledge gaps can hinder widespread adoption. Addressing these challenges requires greater access to resources, educational initiatives, and the development of climate-resilient practices tailored to specific regions. Future trends in sustainable gardening include the adoption of technological innovations, such as smart irrigation systems, automation, and vertical farming, which offer scalable solutions for urban and small-scale gardeners. The COVID-19 pandemic has underscored the importance of resilient, local food systems, and sustainable gardening is poised to play a critical role in addressing future food security concerns.

Monitoring of indicators and bacterial succession in organic-amended technosols for the restoration of semiarid ecosystems

Restoration of mining sites is essential to ensure ecosystem services and biodiversity. One restoration strategy employed in arid and semi-arid zones is the use of organic amendments to establishment technosols. However, it is necessary to monitor the restoration progress in order to select appropriate amendments. This study monitored the effects of compost gardening, greenhouse horticulture and stabilized sewage sludge, and their blends. We focused on soil physical and chemical indicators and bacterial community structure and diversity during the 30 months after application. Organic amendments increased total organic carbon and nitrogen within six months, staying elevated compared to natural soils over 30 months. Electrical conductivity rose then stabilized, the pH slightly decreased but stayed alkaline, and water holding capacity improved in treated technosols. Bacterial diversity increased in amended technosols compared to control. Alpha diversity varied with treatment and time, peaking at 18 months. Technosols with plant compost showed reduced bacterial richness at 30 months, while those with sewage sludge and its mixtures maintained it. The bacterial community analysis showed significant differences among treatments and times, highlighting dominant phyla like Proteobacteria and Bacteroidetes. PCoA analysis showed clear separation of bacterial communities from treated, natural, and control soils, with notable differences between plant and sludge treatments. Soil variables such as TOC, TN, EC and water holding capacity explained more than 82 % of the variation in bacterial communities. Eighty-three indicator taxa were identified that explained the differences between the microbial communities of treated and untreated soils, highlighting the importance of taxa such as Pelagibacterium spp., Roseivirga spp. and Cellvibrio spp. in preserving soil health. In short, organic amendments improve soil properties and promote the diversity and stability of beneficial microbial communities in semi-arid mined soils, underlining their crucial role in the restoration and long-term maintenance of degraded soils.

Leaf and soil nutritional composition of purple passion fruit (Passiflora edulis Sims) as influenced by organic nutrients amended with biofertilizer consortium

The use of organic nutrient regimes is regarded as holistic and ecological approach for agricultural sustainability. It offers improved soil health, increased crop growth and enhanced fruit quality, whilst minimizing costs and sustaining the use of natural resources. The present investigation was conducted over two consecutive seasons, viz. 2021–22 and 2022–23 at Mizoram University, Aizawl, India to study the effect of different combinations of organic manures along with consortium of biofertilizers on leaf and soil characteristics of purple passion fruit (Passiflora edulis Sims). The investigation comprises of fourteen treatments of various combinations of organic manures along with consortium of biofertilizers, viz. farmyard Manure (FYM) vermicompost (VC) pig manure (PIM), poultry manure (POM), Azospirillum, phosphate solubilizing bacteria (PSB), potash solubilizing bacteria (KSB), and vesicular arbascular mycorrhiza (VAM). The results demonstrated that the use of organic amendments in combination with biofertilizers enhanced leaf nutrient status as well soil properties in the passion fruit orchard. Among the different treatment combinations used in the investigation, POM + Azospirillum + PSB + KSB + VAM was the most efficient in improving the leaf and soil nutrient status of passion fruit. This consortium may achieve high microbial load, high nutrient availability for soil which results in better growth of the crop. This treatment may therefore be recommended as an alternative option to meet the demand for long term maintenance of soil fertility as well agro-ecosystem conservation and sustainability.

The Effects of Organic Fertilizers and NPK on Growth and Yields of Cowpea (Vigna unguiculata. L) in Kano Plains Kisumu, Kenya

Excessive use of inorganic mineral fertilizers as an agronomic practice has resulted in the depletion of soil organic matter of soils of many regions thereby rendering such soils infertile and unable to maintain sustainable production. The use of organic amendments provides the immediate strategy for compensating for soil carbon depletion thereby reducing land degradation. The purpose of this study was to evaluate the effects of six organic amendments on the growth and yield of Cowpea (Vigna unguiculata L) as compared to the conventional use of inorganic fertilizer NPK. The organic amendments were Boom Max, Ecoplanting, Evergrow, Dung slurry, Filter mud, and Market waste slurry applied to the soil at 8.33 t/ha against NPK (9:15:20) at 250 kg/ha. The experiment was laid in a RCBD. Data on growth and yields was collected on 10 tagged plants per plot. The results showed differences among treatments. Mature composts (Boom Max, Ecoplanting, and Evergow) resulted in a significantly (p< 0.05) higher germination percentage (53.49% on average) compared to that of Filter mud (41.50%) and the slurries (34.18% on average) while all the composts resulted in 25% higher number of branches on the average in season two as compared to the bio-slurries. In season three, Boom Max gave the highest germination percentage (41.02%) which was significantly higher than those of Evergrow (29.80 %), Filter mud and Dung slurry (27.18% on average) and NPK and Market waste slurry (5.64% on average) but not different from that of Ecoplanting. Five of the amendments had significantly better germination rates than NPK by an average of 20%. There were no significance differences (P≤0.05) in growth parameters between the mature composts and the NPK fertilizer, suggesting that the mature composts were equally efficient in nutrient supply to the crop as did the NPK fertilizer for plant growth. The application of organic amendments produced significant improvements in fresh leaf yields of the cowpea crop, with the highest yield recorded from the Boom Max applied plot (5781 kg on average), which was not different from others in seasons one and three but significantly different from that of NPK in season three. It can be concluded that depending on choice or type of amendment, organic manures are capable of producing similar or better results of crop growth and yields as the inorganic fertilizers.

Permaculture Management of Arable Soil Increases Soil Microbial Abundance, Nutrients, and Carbon Stocks Compared to Conventional Agriculture

Conventional agricultural practices severely deplete the soil of essential organic matter and nutrients, increasing its vulnerability to disease, drought, and flooding. Permaculture is a form of agroecology adopting a whole ecosystem approach to create a set of principles and design frameworks for enriching soil fertility, but there is little scientific evidence of its efficiency. This study compares two permaculture managed sites with a conventional arable site to investigate the effect of permaculture management on soil fertility. We used phospholipid fatty acid analysis to estimate microbial abundance and diversity and related these to measured soil nutrients and carbon stocks. The potential of permaculture management to mitigate soil greenhouse gas emissions was assessed during a laboratory soil incubation and measurement of greenhouse gases via gas chromatography. Overall, the permaculture managed allotments had three times higher microbial biomass, one and a half times higher nitrogen, and four times higher carbon content than the arable site. Permaculture soils had larger carbon dioxide and nitrous oxide fluxes compared to arable soil, but all sites had a mean negative flux in methane. Permaculture management by use of organic amendments and no-dig practices provides a constant slow release of nutrients and build-up of organic matter and carbon and consequently promotes greater bacterial and fungal biomass within the soil.

The fruit quality and nutrient content of kiwifruit produced by organic versus chemical fertilizers.

Currently, organic farming has become a feasible approach for the production of high-quality fruits. To evaluate the response of fruit quality and mineral nutrition contents of Hayward Kiwifruit affected by different organic and inorganic fertilizers, the present study was conducted in Citrus and Subtropical Fruits Research Center, Iran, in 2017-2021, as a randomized block design with three replications. The studied treatments were organic fertilizers (cow, vermicompost and Azolla) and chemical fertilizers. After 4 years of fertilization, the fruit's nutritional elements content and some fruit bioactive compounds were evaluated after 3 months of cold storage and then analyzed by the principal component analysis (PCA) method. The use of organic amendments boosted the calcium, phosphorus, potassium and iron content of the kiwifruits compared to chemical fertilizers. The highest fruit potassium and phosphorus content were recorded in the cow manure treatment. The lowest amount of nitrate and the highest calcium, zinc, copper and manganese accumulation were recorded in the fruits treated with vermicompost. In addition to mineral nutrients, the dry matter, total soluble solids, total phenolic and antioxidant capacity of kiwifruit were improved by the application of vermicompost amendment compared to the other fertilizer sources. However, the highest fruit vitamin C and total soluble carbohydrates were measured in the cow manure treatment. The PCA results of the fruit quality indices indicated that fertilization treatments were ranked as vermicompost (1.88) > cow manure (1.63) = chemical (1.60) > Azolla (1.54). It is concluded that the application of 40 kg of vermicompost or 40 kg of cow manure in the next rank in Hayward kiwifruit orchards in March (growth stage beginning of bud swelling) may be a more suitable approach for improving the nutritional quality of the fruit. © 2024 Society of Chemical Industry.

The Ability of Vermicompost to Mitigate the Impacts of Salinity Stress on Soil Microbial Community: A Review

Soil salinity is a major challenge in many developing countries, affecting soil fertility and crop productivity. Salinity directly affects the soil microbiome through osmotic pressure and ion toxicity, resulting in diminished microbial biomass and activity. Additionally, indirect repercussions involve reduced organic carbon inputs and aggregate stability, reducing microbial diversity and functions. Salinity induces a microbial community shift toward the abundance of halotolerant and halophile microorganisms. The use of organic amendments is a promising approach. Indeed, the application of vermicompost, with its rich nutrient and organic matter content, proves effective in counteracting the impact of salinity on the soil microbiome by providing available nutrients, decreasing the plasmolysis of cells by reducing the Na+/K+and Na+/Ca2+ratios, improving the soil texture, increasing the microbial diversity, and shifting the soil microbiome toward the abundance of beneficial soil microbiota. Despite these positive effects, carefully considering the initial EC of both soil and vermicompost and the applied quantity is crucial to ensuring maximum benefits. Overall, vermicompost holds considerable potential as a sustainable management strategy to mitigate the impact of salinity on soil microbiome, promoting overall soil health and enhancing crop production.

Effects of organic amendments, biofertilisers and biodynamic preparations on soil properties and leaf nutrient concentrations in grapevine

ABSTRACT Excessive and unbalanced use of chemical fertilisers can lead to depletion of physical and chemical properties of the soil and have negative impacts on the environment. This investigation was conducted at Mizoram University, Aizawl, Mizoram, India and aimed to evaluate effects of organic amendments, biofertilisers and biodynamic preparations on soil properties and leaf nutrient status of grapevine. The experiment was laid out in randomised block design with 14 treatments consisting of different combinations of organic amendments, biofertilisers and biodynamic preparations viz. farmyard manure (FYM), vermicompost (VC), pig manure (PIM), neem cake (NC), Azospirillum, phosphate solubilising bacteria (PSB), potash solubilising bacteria (KSB), Trichoderma harzianum, cow pat pit (CPP) and biodynamic preparations BD500 and BD501. The results demonstrated that the use of organic amendments in combination with biofertilisers and biodynamic preparations enhanced leaf nutrient status as well soil properties in the vineyard. Among all the tested combinations, the highest concentrations of Mn, Zn, chlorophyll a, b and total chlorophyll in the leaves and concentrations of soil organic carbon, inorganic carbon, total carbon, total N, available N, P, K, Mn and Zn, cation exchange capacity (CEC) and abundance of bacteria and Actinomycetes in the soil were recorded with application of PIM + Azospirillum + PSB + KSB + T. harzianum + CPP + BD 500 + BD 501. This treatment was therefore recommended as a suitable option to meet the demand for long-term maintenance of soil fertility as well agroecosystem conservation and sustainability.

Effect of long-term compost fertilization on the distribution of organic carbon and nitrogen in soil aggregates

Soil fertility is mainly related to soil total organic carbon (C) that should be preserved in order to optimize soil quality and functionality. Consequently, the use of organic amendments could be a possible strategy to increase soil C and nitrogen (N) storage particularly in orchard systems where the disturbance of soil is reduced thus making favorable conditions for C and N stabilization.The aim of this study was to evaluate the distribution and stabilization of organic C and total N in aggregate fractions after a 14-years-period of compost application to a peach orchard. The trial was conducted in the south-eastern Po valley, on a commercial nectarine orchard and the following treatments were compared in a complete randomized block design with four replicates: 1. unfertilized control; 2. mineral fertilization; 3. compost at a rate of 10 Mg dry weight ha−1 yr−1. At the end of orchard lifetime, soil was sampled from the row at four depths (0–0.15, 0.16–0.25, 0.26–0.45, and 0.46–0.65 m) and physically fractionated to separate macroaggregates (> 250 μm), microaggregates (250–50 μm) and silt and clay (< 50 μm) that were analyzed for organic C, total N, δ13C, and δ15N.Compost addition induced a significant increase of macroaggregates (66%), no changes in microaggregates and a decrease of silt and clay (22%) compared to control and mineral fertilization. With compost the accumulation of organic C and total N content in the macroaggregates was four-five times higher than the other two treatments in all the depths, therefore almost 50% of the soil organic C was in this fraction, compared to 20–24% in the control and mineral. In the micro-aggregates more C and N accumulated only in the two top layers, while no effect was observed in the silt and clay fraction. From macro-to microaggregates to the silt and clay fraction, the C/N ratio shifted from 9 to 7.5 to 6 on average indicating that the C and N stabilized in the finer fractions is mainly of microbial origin. The enrichment in C and N isotopic composition from macro-to micro to silt and clay is also indicative of the isotopic fractionation due to microbial metabolism and the consequent stabilization of microbial residues in the finer fractions. In the control and mineral, only receiving orchard litter, this change was observed in all the layers, on the contrary, with compost similar δ13C and δ15N values characterized the fractions in the top soil layer suggesting the occlusion of compost in all the fraction. With depth the macroaggregates maintained the same δ13C and δ15N values indicating consistent redistribution of compost in deep soil layers, while the finest fractions showed a progressive enrichment of δ13C due to the presence of C fractionated during microbial metabolism and progressively stabilized. In conclusion, compost supply leads to positive effects on C and N accumulation and stabilization also in the deeper layers favoring the increase of long-term soil fertility and C storage.

Applications of humic and fulvic acid under saline soil conditions to improve growth and yield in barley.

Enriching the soil with organic matter such as humic and fulvic acid to increase its content available nutrients, improves the chemical properties of the soil and increases plant growth as well as grain yield. In this study, we conducted a field experiment using humic acid (HA), fulvic acid (FA) and recommended dose (RDP) of phosphorus fertilizer to treat Hordeum vulgare seedling, in which four concentrations from HA, FA and RDP (0.0 %, 50 %, 75 % and 100%) under saline soil conditions . Moreover, some agronomic traits (e.g. grain yield, straw yield, spikes weight, plant height, spike length and spike weight) in barley seedling after treated with different concentrations from HA, FA and RDP were determined. As such the beneficial effects of these combinations to improve plant growth, N, P, and K uptake, grain yield, and its components under salinity stress were assessed. The findings showed that the treatments HA + 100% RDP (T1), HA + 75% RDP (T2), FA + 100% RDP (T5), HA + 50% RDP (T3), and FA + 75% RDP (T6), improved number of spikes/plant, 1000-grain weight, grain yield/ha, harvest index, the amount of uptake of nitrogen (N), phosphorous (P) and potassium (K) in straw and grain. The increase for grain yield over the control was 64.69, 56.77, 49.83, 49.17, and 44.22% in the first season, and 64.08, 56.63, 49.19, 48.87, and 43.69% in the second season,. Meanwhile, the increase for grain yield when compared to the recommended dose was 22.30, 16.42, 11.27, 10.78, and 7.11% in the first season, and 22.17, 16.63, 11.08, 10.84, and 6.99% in the second season. Therefore, under salinity conditions the best results were obtained when, in addition to phosphate fertilizer, the soil was treated with humic acid or foliar application the plants with fulvic acid under one of the following treatments: HA + 100% RDP (T1), HA + 75% RDP (T2), FA + 100% RDP (T5), HA + 50% RDP (T3), and FA + 75% RDP (T6). The result of the use of organic amendments was an increase in the tolerance of barley plant to salinity stress, which was evident from the improvement in the different traits that occurred after the treatment using treatments that included organic amendments (humic acid or fulvic acid).

Effects of long-term application of inorganic fertilizer and organic amendments on the amounts of fractionated soil organic carbon and their determining factors in paddy fields

ABSTRACT To investigate how the long-term application of inorganic fertilizer and organic amendments affects the accumulation of organic matter in physico-chemically fractionated components in paddy soils and how the accumulation is determined by soil properties and anthropogenic carbon input, we studied the effect of variable management of inorganic fertilizer and organic amendments for > 50 years on the amounts of accumulated soil organic carbon (SOC) in fractionated components in three paddy fields. SOC was fractionated into four components based on their physical and chemical properties: (1) light fraction (LF) derived from plant residues, (2) heavy fraction (HF) containing stable aggregates, (3) oxidizable fraction (OxF) and (4) non-oxidizable fraction (NOxF) forming organo-mineral complexes with fine-textured minerals. On average, the amount and percentage of accumulated C in the four fractions were as follows: OxF (6.63 gC kg−1 soil, 46%) > NOxF (5.32, 35) > LF (1.68, 12) > HF (1.12, 7.2), suggesting about 80% of SOC was in fine, stable fractions. The amount of accumulated C in all fractions increased slightly with the application of inorganic fertilizer, while it increased considerably with the use of organic amendments. In addition, the application of fertilizers and amendments raised the proportion of C content in LF and HF, which are labile and related to soil fertility. Stepwise multiple regression analysis using two principal component analysis scores of soil properties and anthropogenic C input further revealed that the labile fractions (LF and HF) were more strongly determined by the management of fertilizers and amendments, while the stable fractions (OxF and NOxF) were more strongly determined by soil-specific properties, mainly the amorphous nature of the soil. These results indicate that the use of certain amounts of organic amendments would be recommended to carry out rational management to improve soil fertility and C sequestration in paddy fields, with the application of amorphous minerals as an additional option.

Enhancement of Soil Organic Carbon, Water Use Efficiency and Maize Yield (Zea mays L.) in Sandy Soil through Organic Amendment (Grass Peat) Incorporation

The efficient use of organic amendment (OM) is considered an economic, environmental and sustainable practice to improve soil quality, especially the accumulation of organic carbon (C) and water use efficiency (WUE) in dryland agriculture. However, the effect of different OM on soil nutrients, organic carbon fractions, water content and maize yield is unclear in arid and semi-arid regions with sandy soil. Field experiments with four OM, grass peat (GP), biochar (BC), organic fertilizer (OF) and maize straw (MS), were conducted with an equivalent amount of C input on the southeastern edge of Mu Us Sandy Land in China. Results indicated that the soil nutrients and labile organic carbon (DOC, MBC, KMnO4-C and POC) concentrations were higher under OM (GP, BC, OF and MS) treatments than in CK in the 0–0.10 m soil layers. GP treatment remarkably improved carbon pool index values (1.63, 2.51 and 2.24, respectively) in all layers compared to CK (1.00). At maturity stages of maize, the soil water content (SWC) under GP and OF treatments (11.3–13.4%) was remarkably higher than that in CK treatment (around 10.0%). Yield and WUE were remarkably greater in GP and OF treatments compared to CK. The results proved that GP amendment is superior for barren sandy soil than BC, OF and MS treatments in improving soil nutrients, organic carbon sequestration, WUE and crop yield in China.

Arbuscular Mycorrhizal (AM) Fungi Symbiosis in Sustainable Production of Sorghum (Sorghum bicolor L. Moench) Under Drought Stress: An Emerging Biofertilizer in Dryland Areas

Sorghum (Sorghum bicolor L. Moench) is an important cereal crop grown in arid and semiarid regions where water and other resources are limited. Changes in temperature and rainfall patterns have resulted in frequent droughts, which caused significant yield loss in sorghum. In recent years, there has been an increasing interest in sorghum cultivation due to its resilience to climate change and potential source of food and income. The symbiotic interaction of sorghum with Arbuscular Mycorrhizal fungi (AMF) has been found to induce several physiological and molecular changes that improve the ability of sorghum to withstand drought stress. This symbiotic relationship enhances water and nutrient uptake, osmotic adjustment, activation of stress‐responsive genes, stomatal regulation, and antioxidant defense, leading to improved drought tolerance in sorghum. Agricultural practices such as reduced tillage, cover cropping, intercropping, crop rotation, and the use of organic amendments promote the diversity and effectiveness of AM fungal symbiosis. Such agricultural practices create more favorable conditions for AM fungal establishment and growth while reducing dependence on synthetic fertilizers. In this review, we highlight AM fungal symbiosis on sorghum growth, physiology, and molecular mechanisms underlying the beneficial effects of AM fungal symbiosis under moisture deficit conditions. Overall, the present review elucidates sorghum production and breeding success in Ethiopia, the symbiotic mechanisms between plants and AM fungi, the prospects of biofertilizers in sustainable agriculture, the potential of AM fungal symbiosis as a sustainable approach to improve sorghum production and its synergistic effect with other crop management practices.

Potential and Constraints of Use of Organic Amendments from Agricultural Residues for Improvement of Soil Properties

Agricultural residues are produced in large quantities and their management is an issue all over the world. Many of these residues consist of plant materials in different degrees of transformation, so returning them back to soil is a management option that closes loops in a circular economy context. The objective of this paper is to summarize current knowledge on the options and effects of reusing agricultural residues as organic soil amendments. The reuse of these residues in soil is a good solution for minimizing the problems associated with their management, while improving soil health and ecosystem functions. While some agricultural residues can be applied directly to soil, others will need previous transformations such as composting to improve their properties. This allows the recovery of plant nutrients and increase in soil organic matter contents, with many positive effects on the soil’s physical, chemical and biological properties, and ultimately, crop production, although potential risks derived from some materials must also be considered. The concept of regenerative agriculture and soil management using organic soil amendments contribute to the significant enhancement of soil biodiversity, the protection of the environment and climate goal achievement.

Organic Amendments for Soil Reclamation: A Review

The principle that presents human activities and forms the basis of sustainable soil management must not negatively impact future generations. The soil can be degraded by human activity, natural events like erosion and other factors. Degraded or disturbed soil sometimes lacks organic matter when compared with neighbouring undisturbed areas. Organic amendments that are produced in huge quantity worldwide and have the potential to be widely used for soil reclamation include animal manure, biosolids, waste from fruit pulp, kitchen trash, paper mills, wood scraps, crop residues, etc. This review article explores the mechanisms through which organic addition alters physical, chemical and biological properties of the soil and defines significance of organic amendments in the soil reclamation, with a focus on amendment types and application rates for soil amelioration and biomass production. A large-scale use of organic amendments can speed up the initial reclamation process and produce self-sustaining net production. Though easily decomposable organic additions may have immediate but transient impacts, stable and less decomposable molecules may cause effects that last longer. Organic additions consisting of waste products from the forestry, urban and agricultural sectors are used to achieve land reclamation to attain mutual benefits.

Organic amendment application affects the release behaviour, bioavailability, and speciation of heavy metals in zinc smelting slag: Insight into dissolved organic matter

Organic amendments are commonly used in assisted phytostabilization of mine wastes by improving their physicochemical and biological properties. These amendments are susceptible to leaching and degradation, resulting in the generation of dissolved organic matter (DOM), which significantly influences the geochemical behaviour of heavy metals (HMs). However, the geochemical behaviour of HMs in metal smelting slag driven by organic amendment-derived DOM remains unclear. In this study, we investigated the impact of cow manure-derived DOM on the release behaviour, bioavailability, and speciation of HMs (Cu, Pb, Zn, and Cd) in zinc smelting slag using a multidisciplinary approach. The results showed that DOM enhanced the weathering of the slag, with a minimal impact on the slag’s mineral phases, except for causing gypsum dissolution. The DOM addition resulted in a slight increase in HM release from the slag during the initial inoculation period, followed by a reduction in HM release during the later period. Furthermore, the DOM addition increased the diversity and relative abundance of the bacterial community. This, in turn, led to a decrease in the dissolved organic carbon (DOC) content and enhanced the transformation of labile DOM compounds into recalcitrant compounds. The variation in HM release during various inoculation periods can be attributed to the bacterial decomposition and transformation of DOM, which further enhanced the transformation of HM fractions. Specifically, during the later period, DOM promoted the conversion of a portion of the reducible and oxidizable fractions of Cu, Pb, and Zn into the acid-soluble and residual fractions. Moreover, it partially transformed the reducible, oxidizable, and residual fractions of Cd into the acid-soluble fraction. Overall, this study provides new insights into the geochemical behaviour of HMs in slag governed by the coupling effect of DOM and the bacterial community. These findings have implications for the use of organic amendments in assisted phytostabilization of metal smelting slag. Environmental implicationMetal smelting slag is hazardous due to its high levels of HMs, and its improper disposal has serious consequences for the ecosystem. Organic amendments are employed in assisted phytostabilization of the slag site by improving its microecological properties. However, the impact of organic amendment-derived DOM on HM migration and transformation in slag remains unclear. This study indicated that the coupling effects of DOM and microbes governed the geochemical behaviour of HMs in slag. These findings provide new insights into how organic amendments impact the geochemical behaviour of HMs in slag, contributing to the development of phytostabilization technology.

An Investigation into the Effects of Organic Amendments in a Saline Environment on Soil Chemical Characteristics, Growth, and Yield of Rice in the South of Senegal

Context of the Study: The use of organic amendments could help increase the resilience of lowland rice in Lower Casamance to salinity. The aim of this study was to test the effect of different organic amendments (biochar and compost) on the salinity tolerance of lowland rice in Basse Casamance.&#x0D; Objective: The aim was to test the effect of different organic amendments on the salinity tolerance of rice in the lowlands of the villages of Selecky and Essyl in Lower Casamance.&#x0D; Methodology: A split-plot design was adopted with two factors: the type of organic amendment with 4 treatments (biochar, compost, compost + biochar and the control) and salinity with two treatments (salted and unsalted zones). These treatments were repeated 3 times in two consecutive years, 2020 and 2021, at the Selecky and Essyl sites. Physico-chemical characteristics as well as rice growth and production parameters were studied.&#x0D; Results: In the saline zone, soil amendments significantly increased the number of tillers and the height of rice plants compared with controls (p&lt;0.05). Average rice yield and plant biomass were significantly higher in the amended plots at Selecky in both experimental years (p&lt;0.05). At Essyl, on the other hand, height, number of tillers, rice yield and plant biomass were lower in the 2nd year of experimentation. Organic amendments had a significant effect (p&lt;0.05) on rice production and yield parameters in the salt zone.

Impact of manures and fertilizers on yield and soil properties in a rice-wheat cropping system.

The use of chemical fertilizers under a rice-wheat cropping system (RWCS) has led to the emergence of micronutrient deficiency and decreased crop productivity. Thus, the experiment was conducted with the aim that the use of organic amendments would sustain productivity and improve the soil nutrient status under RWCS. A three-year experiment was conducted with different organic manures i.e. no manure (M0), farmyard manure @ 15 t ha-1 (M1), poultry manure @ 6 t ha-1(M2), press mud @ 15 t ha-1(M3), rice straw compost @ 6 t ha-1(M4) along with different levels of the recommended dose of fertilizer (RDF) i.e. 0% (F1), 75% (F2 and 100% (F3 in a split-plot design with three replications and plot size of 6 m x 1.2 m. Laboratory-based analysis of different soil as well as plant parameters was done using standard methodologies. The use of manures considerably improved the crop yield, macronutrients viz. nitrogen, phosphorus, potassium and micronutrients such as zinc, iron, manganese and copper, uptake in both the crops because of nutrient release from decomposed organic matter. Additionally, the increase in fertilizer dose increased these parameters. The system productivity was maximum recorded under F3M1 (13,052 kg ha-1) and results were statistically identical with F3M2 and F3M3. The significant upsurge of macro and micro-nutrients in soil and its correlation with yield outcomes was also observed through the combined use of manures as well as fertilizers. This study concluded that the use of 100% RDF integrated with organic manures, particularly farmyard manure would be a beneficial resource for increased crop yield, soil nutrient status and system productivity in RWCS in different regions of India.

Soil Fertility and Phosphorus Leaching in Irrigated Calcareous Soils of the Mediterranean Region

To ensure soil quality and soil health, it is necessary to improve fertilization practices while minimizing environmental impacts. The aim of this study was to record the state of the art on soil fertility related to fertilization management (organic and/or mineral) and to detect environmental challenges in highly productive fields. A soil survey was set up in a new irrigated area (c. 20 years old), in the north-eastern part of Spain, which is mainly devoted to double annual crop rotations of cereals and maize. The area also supports an important animal rearing activity. The survey covered 733 ha of calcareous soils, owned by 35 farmers. At each farm, fertilization management was recorded, and soil was analyzed for nutrients and heavy metals. Multivariate analyses were performed. Total N, P, Cu and Zn, and available P, Cu, Zn and Mn soil concentrations were associated to the use of organic amendments. Heavy metals concentrations were below established thresholds. Available P (Olsen-P) was identified as an indicator of the previously adopted fertilization management and of the potential of P leaching towards deeper soil layers. Regression analyses were performed. A displacement of available P from the uppermost layer (0–0.3 m) occurs in the breakpoint of 86 mg P kg−1 soil. Preventative actions might be established from 53 mg P kg−1 soil due to the slowdown in P immobilization. Our results reinforce the importance of setting up P threshold soil levels for best practices of fertilization, as a basis for sustainable agriculture intensification.