Application Of Soil Amendments Research Articles

Impact of plant-based soil amendments on improvement of mortgaged Farmland

A field experiment was conducted in Maoming, Guangdong, China to evaluate the effects of different plant-based soil amendments on soil quality, nutrient availability, plant growth, and land value. The application of plant-based soil amendments significantly increased the plant height, stem diameter, and biomass yield of corn, soybean, and rice crops. The greatest improvement was observed in corn crops, with a 12.6% increase in plant height, a 15% increase in stem diameter, and a 25.6% increase in biomass yield. Plant based soil amendments significantly improve soil quality, increase nutrient availability, and promote plant growth and productivity. Economic analysis shows that the use of plant-based soil amendments significantly increases the value of land, providing potential benefits for mortgage lenders and borrowers. This study emphasizes the importance of sustainable land use practices and the potential of plant-based soil improvement as an effective means of increasing land value. Bangladesh J. Bot. 53(3): 823-833, 2024 (September) Special

The Effect Addition of Soil Amandments and PGPR (Plant Growth Promoting Rhizobacteria) on the Growth and Yield of Cotton Plants Intercropped with Corn Plants in Dry Land of North Lombok Regency of Indonesia

This research investigates the effect of soil amendments in the form of cow, form goat manures and PGPR biofertilizer on cotton plants intercropped with corn in the dry lands of North Lombok Regency. The research aims is to determine the growth and yield response of cotton plants due to the application of soil amendments and PGPR in an intercropped system with corn in dryland areas. The research was conducted from December 2023 to June 2024 in Andalan Village, Bayan District, North Lombok Regency. The method used is an experimental method with field trials. The design used was Randomized Block Design (RBD), incorporating two factors: soil amendment treatment (P) as the main plot and PGPR (K) concentration treatments as the subplot. Soil amendments consisted of three levels: P0 (no cow manure and no goat manure), P1 (20 tons/ha cow manure), P2 (20 tons/ha goat manure). PGPR concentration consisted of four levels: K0 (without PGPR), K1 (20 ml/liter PGPR application), K2 (30 ml/liter PGPR application), and K3 (40 ml/liter PGPR application). The research results indicated that the application of 20 tons/ha of goat manure (P2) produced the highest average across all observed parameters (plant height, number of leaves, branch number, stem diameter, and plant yield). Similarly, the application of 40 ml/liter PGPR produced the highest average for these observed parameters. Based on the results of the land equivalent ratio (LER) analysis, this integration system shows highly suitable and relevant to be applied in the dry lands of North Lombok.

Application of soil amendments to reduce the transfer of trace metal elements from contaminated soils of Lubumbashi (Democratic Republic of the Congo) to vegetables

The extraction of copper and cobalt from mines has led to the contamination of agricultural soils by trace metal elements (TMEs) (e.g. Cu: 204 to 1355 mg/kg). The mining industry is one of the sources of metal discharges into the environment, contributing to water, soil, and air contamination and causing metabolic disorders in the inhabitants of the city of Lubumbashi (R.D. Congo). This study assessed the effectiveness of organocalcareous soil improvers applied to TME-contaminated soils to reduce their transfer to plants. Following a factorial design, increasing doses of organic soil improvers (chicken droppings and sawdust) and agricultural lime were applied to the soils of three market gardens (high, medium, and low Cu contamination). The experiment was monitored for 60 days. Soil physicochemical properties (pH, TOC, and total and available copper, cobalt, lead, cadmium, and zinc (mg/kg)) were determined for the three gardens and in the vegetable biomass. The daily consumption index of the vegetables was determined based on total TME content. The results show that organocalcareous soil improvers did not promote plant growth and survival on soils with high and medium levels of copper contamination. However, on soils with low copper content, organocalcareous soil improvers improved germination and plant survival and reduced the transfer of metals from the soil to the plants. The best germination and plant survival rates were obtained with the lightly contaminated market garden. In addition, the organo-limestone amendments applied to the soils slightly increased the soil pH from acidic to slightly acidic, with pH values ranging from (5.43 ± 0.07 to 7.26 ± 0.33). The daily vegetable consumption index obtained for cobalt in the low-contaminated garden ranged from (0.029 to 0.465 mg/60 kg/day), i.e. from 0.5 to 8.45 times higher than the FAO/WHO limit, unlike the other trace metals (Cd, Cu and Pb) for which the daily consumption index found was lower than the FAO/WHO limit. Organocalcareous soil improvers can only be applied to soils with low levels of TME contamination, but for soils with medium to high levels of metal contamination, new soilless production techniques such as hydroponics or bioponics are needed.

Diffusion of innovative soil management practices for sustainable vegetable farming

Vegetable farmers in Sokoto state, Nigeria are disadvantaged by problem soils that are generally low in nutrient content, leading to below optimum output. As a result, this research was undertaken to disseminate innovative soil management practices through participatory on-farm trials using household waste compost, vermicompost, and biochar as treatments toward ensuring sustainable vegetable farming. The research covered a sequence of 3 main activities; including baseline survey through focus group discussion (FGD), pre and post project soil sample analyses (0-15cm and 15-30cm depths) and trials, and dissemination of findings via result demonstration, respectively. Findings from the baseline revealed that, the vegetable farmers were vulnerable and never had contact with an extension worker, living below $50/month and confronted by dwindling vegetable output due to acidity and low nutrient content of the soil. Amaranth, cabbage, lettuce, tomatoes, peppers, onions, and carrot were the mainly cultivated vegetables by the farmers. Soil management practices in the research sites were occasional application of inorganic fertilizers and traditional application of municipal waste, crop residue and refuse, which was due to inadequate knowledge on sustainable management practices of the soil. Application of organic amendments including household waste compost, vermicompost, and biochar caused tremendous variation in post-project soil properties (EC, K, Na, Ca, Mg, CEC, N, OC and P). Similarly, yield and benefit cost ratio of the trial crop (amaranth) significantly improved due to the amendments. Hence, application of organic soil amendments especially household waste and biochar would be worthwhile for sustainability of vegetable farming in Sokoto state, Nigeria.

Enhancing wheat productivity, quality and nutrient uptake through application of phosphate rich organic manure and soil amendments under Typic Hapludalfs

Enhancing wheat productivity, quality and nutrient uptake through application of phosphate rich organic manure and soil amendments under Typic Hapludalfs

Towards a high-quality fertilizer based on algae residues treated via hydrothermal carbonization. Trends on how process parameters influence inorganics

The use of beach-cast macroalgae as a fertilizer (F) or soil amendment (SA) is coming back into focus, due to its highly efficient transformation of CO2, nutrients, salts and minerals from its aqueous surroundings into biomass. This research studied the hydrothermal carbonization (HTC) of Fucus vesiculosus macroalgae to hydrochar and evaluated its feasibility for use in soil applications. F. vesiculosus was submitted to HTC following a full factorial design of experiments with three HTC process parameters varied to assess their impact on the hydrochars: temperature (T: 160, 190, 220 °C), solid content (%So: 20, 35%), and process water recirculation (PWrec: yes and no). In general, F. vesiculosus and its hydrochars were rich in nutrients, but also contained regulated heavy metals. Investigation of the partitioning behavior of inorganic elements between the hydrochars and process water showed that heavy metals like Cr, Pb, Co and Cu tended to accumulate in the hydrochar, unaffected by HTC conditions. Nutrients such as P, N, B, and Mn were primarily found in the hydrochar and could be partially influenced to transfer to process water by changing %So and T. The correlation between the mass fractions of 22 elements in the hydrochar and HTC process parameters was studied. T was the most influential parameter, showing a significant positive correlation for eleven elements. %So and PWrec showed inconsistent effects on different elements. When process water was recirculated, some elements decreased (Ca, Cd, Fe) while others increased (K, Na, B, N) in the hydrochar. Assessment against various regulations and standards for F and SA revealed that F. vesiculosus complied with Cd limit values for most rules including the EURF and B, and was regulated only in the RAL for SA, over the limit value. In contrast, the limit value of Cd for both F and SA applications was surpassed in the 13 hydrochars. The contents of N, P, K, S, and Na in the feedstock and hydrochars complied with European F and SA rules, while they were too high for German rules on SA. The other limits for F rules were achieved (under certain HTC process parameters) except for P (lower than the requirements in F for F. vesiculosus and its hydrochars).Graphical

Organic matter, carbon, and nitrogen relationships of regreened forest soils in an industrially impacted landscape

Context Soil organic matter (SOM) is largely composed of carbon (C) and nitrogen (N), the proportions of which often change with soil depth. The relationships between SOM, C, and N in forest soils can be greatly altered in degraded landscapes and understanding these relationships is integral for successful forest restoration planning. Aims The current study investigated SOM, C, and N relationships in highly degraded forest soils by depth following regreening (one-time application of soil amendments and afforestation). Additionally, the use of standard C:OM ratios (which are commonly used to estimate soil C) were assessed. Methods The SOM, C, and N were measured at five different depths, at nine sites, ranging in time since regreening treatment applications across one of the world’s largest regreening programmes in the City of Greater Sudbury, Canada. Key results The C:OM and C:N ratios decreased with soil depth while N:OM increased. The C and N were significantly correlated with SOM at all depths (excluding the L horizon). The C:OM ratio was lower than standard values and did not change between 16 and 41 years since the application of 10 Mg ha−1 of dolomitic limestone. Conclusions Despite massive soil degradation, SOM, C, and N relationships over soil depth at the regreening sites are consistent with unimpacted forest soils. Applying commonly used C:OM ratios drastically overestimated soil C pools, especially at lower depths. Implications Even in the most degraded landscapes, restoration can improve soil properties. Standard C:OM ratios should be used with caution.

Application of New Polymer Soil Amendment in Ecological Restoration of High-Steep Rocky Slope in Seasonally Frozen Soil Areas.

In seasonally frozen soil areas, high-steep rocky slopes resulting from open-pit mining and slope cutting during road construction undergo slow natural restoration, making ecological restoration generally challenging. In order to improve the problems of external soil attachment and long-term vegetation growth in the ecological restoration of high-steep rocky slopes in seasonally frozen areas, this study conducted a series of experiments through the combined application of polyacrylamide (PAM) and carboxymethyl cellulose (CMC) to assess the effects of soil amendments on soil shear strength, water stability, freeze-thaw resistance, erosion resistance, and vegetation growth. This study showed that the addition of PAM-CMC significantly increased the shear resistance and cohesion of the soil, as well as improving the water stability, freeze-thaw resistance, and erosion resistance, but the internal friction angle of the soil was not significantly increased after reaching a certain content. Moderate amounts of PAM-CMC can extend the survival of vegetation, but overuse may cause soil hardening and inhibit vegetation growth by limiting air permeability. It was observed by a scanning electron microscope (SEM) that the gel membrane formed by PAM-CMC helped to "bridge" and bind the soil particles. After discussion and analysis, the optimum application rate of PAM-CMC was 3%, which not only improved the soil structure but also ensured the growth of vegetation in the later stage under the optimum application rate. Field application studies have shown that 3% PAM-CMC-amended soil stably attaches to high-steep rocky slopes, with stable vegetation growth, and continues to grow after five months of freeze-thaw action, with no need for manual maintenance after one year.

Enhanced Phytoremediation of Heavy Metals By Soil-applied Organic And Inorganic Amendments: Heavy Metal Phytoavailability, Accumulation, And Metal Recovery

ABSTRACT Phytoremediation, an eco-friendly and cost-effective technique for remediating heavy metal-contaminated soils, can be significantly enhanced through the application of soil amendments. This study investigates the impact of Foliar spraying of both organic (fulvic acid, auxin, Compost, and coconut coir) and inorganic (sulfur) amendments on the phytoavailability, accumulation, and recovery of heavy metals: Arsenic-As, Mercury-Hg, Cadmium-Cd and Lead-Pb in contaminated soils. Field experiment was conducted using hyperaccumulator plant species; T. capensis and H. psittacorum with varying amendment treatments to assess their effectiveness in improving phytoremediation outcomes. The results demonstrate that specific amendments significantly increase heavy metal uptake and translocation within plants by altering soil pH, cation exchange capacity, and microbial activity, thus enhancing metal solubility and bioavailability. Furthermore, the study evaluates the potential of these amendments to not only facilitate metal recovery but also to restore soil health and fertility. The findings underscore the potential of tailored amendment strategies in optimizing phytoremediation processes, offering a sustainable solution for heavy metal remediation in polluted environments.

Practice of Improving Saline–Alkali Soil with Bio-Humic Acid

The improvement and exploitation of saline–alkali soil is a hot topic worldwide. Analysis of soil aggregate structure and water and of the salt transport law, a new technology that uses humic acid as a saline–alkali soil amendment has been proposed. These advancements may effectively improve the soil aggregate structure of saline–alkali soil at the source. In this study, biological pyrolysis liquid was modified to produce soil modifier for saline–alkali land, and this soil modifier was used in a rice planting experiment. The results show that the application of a bio-humic acid soil amendment in the amount of 3000 kg/ha and its combination with humic acid fertilizer produced rice yields as high as 9750 kg/ha. At the same time, the pH of the soil was reduced from 10.81 to 8.95 (with bio-humic acid soil amendment content of 3000 kg/ha), and the soil organic matter demonstrated a trend of increasing with an increased amount of bio-humic acid soil amendment. The content of calcium, magnesium, and trace elements in the soil were clearly increased with the use of the amended soil in comparison with the normal group. With this amendment, saline–alkali land could be transformed and planted in the same year, increasing the potential yearly income for the land. This may be efficient and environmentally friendly, encouraging the agricultural circular economy.

Response of ectomycorrhizal fungi to full and selective removal of an invasive tree in riparian woodland

The Brazilian pepper tree (Schinus terebinthifolius) is an invasive species that requires significant disturbance to eradicate. Previous studies have identified associations between the Brazilian pepper tree and ectomycorrhizal fungi (EMF). However, limited research has explored the connection between disturbance from removal and the effect on EMF. This study investigated the sensitivity of EMF and the broader fungal community to the full and selective removal of the Brazilian pepper tree. During the selective removal of Brazilian pepper tree, we examined the mycorrhizal community of the Arroyo willow (Salix lasiolepis) to assess the influence of the restoration disturbance on native species. We used ITS2 sequencing to identify the EMF present during the restoration. Our expectation was that both removal efforts would reduce the presence of EMF. Contrary to our predictions, full removal increased EMF richness and relative abundance in the soil. As anticipated, selective removal reduced the richness and relative abundance of EMF associated with soil. Selective removal led to a decrease in the richness of EMF in arroyo willow roots with no effect on relative abundance. Moreover, fungal community composition in soil and roots shifted significantly during selective and full removal. However, the community composition of EMF, specifically, remained constant across treatment types. During full removal efforts, the application of organic soil amendments may have contributed to the increase in the diversity and relative abundance of EMF. Selective removal will require additional measures, such as soil amendments, to curtail the loss of EMF.

A Comprehensive Perception of Biological Control Potential of Endophytes and Quality Refinement of Lagenaria siceraria.

Agriculture and livestock management practices known as organic farming rely more on internal processes than external inputs. Natural environments depend heavily on diversity, and organic farming incorporates both the stated purpose of fostering diversity as well as the use of diversity as a management tool. A more complete understanding of agriculture in terms of agro-ecology has begun to be questioned by the traditional reductionist approach to the study of agriculture. Therefore it is necessary to be aware more about the significance of microbes in processes including soil growth, plant nourishment, and the eradication of plant disease, pest, and weeds. In this study, fluorescent Pseudomonas strain (EFP56) and Trichoderma harzianum were studied for antifungal and antibacterial activity against four common root rot fungi and four common laboratory bacteria in vitro experiments. Furthermore, soil-borne disease surveillance and nutritional quality of Lagenaria siceraria, fluorescent Pseudomonas strain (EFP56) and Trichoderma harzianum were combined with neem cake and cotton cake to check their efficacy. Through the application of organic soil amendments in combination with biocontrol agents improved the quality of vegetables and their nutritional value by raising their polyphenol, carbohydrate, and protein content as well as enhancing antioxidant scavenging status. The experiments were conducted in pots and in fields to confirm their efficacy rate. The final outcomes also revealed greater induction of defense system, disease lessening and enriched fruit quality. Consortium of neem cake and cotton cake with bio-stimulants can regulate biotic as well as abiotic stress.

Bacterial Endophytes and Their Contributions to Alleviating Drought and Salinity Stresses in Wheat: A Systematic Review of Physiological Mechanisms

Drought and salinity stresses significantly threaten global wheat productivity, limiting growth and reducing yields, thus endangering food security worldwide. These stresses disrupt physiological processes, impair photosynthesis, and hinder optimal growth and yield by diminishing water uptake, causing osmotic stress, ion toxicity, and oxidative stress. In response, various mitigation strategies have been explored, including breeding for stress-tolerant cultivars, improved irrigation techniques, and the application of exogenous osmoprotectants and soil amendments. Among these strategies, the emergence of rhizospheric and endophytic growth-promoting microorganisms has attracted significant attention. Therefore, a systematic review was undertaken to illustrate the role of endophytic bacteria in enhancing wheat tolerance to drought and salinity stresses. This review analyzes physiological mechanisms and research trends, identifies gaps, and discusses implications for sustainable agriculture. An analysis of the literature related to endophytic bacteria in wheat was conducted using databases of major publishers from 2004 to 2023. The review explores their mechanisms, such as phytohormone production and stress-responsive gene induction, emphasizing their contribution to plant growth and stress resilience. The current research trends indicate a growing interest in utilizing endophytic bacteria to mitigate these stresses in wheat cultivation, with studies focusing on understanding their physiological responses and interactions with wheat plants. Future research should concentrate on elucidating the role of endophytic bacteria in enhancing host plant tolerance to multiple stressors, as well as aspects like endophytic mechanism of action , endophytic lifestyle, and transmission pathways. Overall, endophytic bacteria offer promising avenues for sustainable agricultural practices, aiding in crop resilience and food security amid environmental challenges.

Rock Phosphate and Biochar Effects on Greenhouse Gas Emissions and Soil Fertility in Southern Alberta Potato Field

The application of biochar soil amendment and rock phosphate fertilizer to the soil could lead to achieving net zero emissions and food security; however, the effectiveness of using biochar and rock phosphate in southern Alberta brown chernozemic soil is not yet assessed. In the first trial of this study, varying levels of urea (N), with varying levels of biochar (B) were applied. The same level of rock phosphate (RP) and triple super phosphate (TSP) were applied to compare efficiency of the two fertilizers. The second trial involved applying the same nutrients, but with higher levels than the first trial. The results indicated that the fertilizer application rates did not affect the growth and yield of potatoes because of the application rates of the fertilizer and fertility status of the soil, whereas in the second trial, TSP and RP treatments had the same growth and yield. Furthermore, the high application rate of nitrogen fertilizer and RP with or without biochar in the potato plot emitted high nitrous oxide gas emissions while the low application rate of nitrogen fertilizer and RP kept the carbon dioxide in the soil. Nevertheless, in the second experiment, the application of biochar and rock phosphate reduced nitrous oxide and carbon dioxide emissions. We observed high residual nitrogen and manganese nutrients after harvest in the plot treated to rock phosphate and biochar. Therefore, rock phosphate and biochar have the potential to increase food production and mitigate climate change.

Bioremediation of Crude Oil Contaminated Saline Soil Using a Bacterial Consortium and Different Carriers

AbstractBioremediation of crude‐oil‐contaminated soils is critical to supporting soil ecosystem health and functioning. Here, to explore the potential for different remediation strategies to restore soil microbial functioning and enhance remediation, three strains of bacteria, Bacillus toyonensis, Bacillus sp. and Bacillus cereus, were inoculated to saline, crude oil‐contaminated soil collected from Azadegan Oil Field, Iran. Bacteria were added using different carriers, including corn biochar, humic acid, chitosan and kaolin, and free bacteria as a control. Changes in soil metal concentrations and residual crude oil were determined after 60 days of incubation. Soil respiration, microbial biomass, and enzyme (dehydrogenase and catalase) activities were measured. The carriers accompanying a bacterial consortium were more efficient than free bacteria in removing crude oil and heavy metals from soil, and they performed better in removing n‐alkanes with carbon chains of C12–24. The oil removal rate and metal immobilization efficiencies were greatest in soils with chitosan‐bacteria treatment, with removal of crude oil, Al, Pb, Sr, and Cr (93%, 63%, 37%, 54%, and 15%, respectively) greater than for soils with free cells without treatment (61%, 54%, 9%, 50%, and 3%, respectively). Soil electrical conductivity decreased after application of bacterial mixtures with and without carriers. The inoculation of bacteria and application of soil amendments increased soil microbial biomass carbon and the activity of catalase and dehydrogenase. Overall, our results indicated the greatest potential remediation was achieved by applying immobilized microorganisms in chitosan to accelerate the biodegradation of crude oil and the removal of heavy metals.

Responses of soil microbial community activities and soil physicochemical properties to coal fly ash soil amendment

BackgroundHundreds of millions of tons coal fly ash are produced annually to support economic development and industrial production. However, directly applying coal fly ash to agricultural production can decrease the land productivity and pose a threat to the ecosystem due to the poor physicochemical properties and seriously heavy metal pollution.MethodsIn this study, a field experiment to investigate the effects of coal fly ash as a soil amendment was conducted in Hebei province, China. The coal fly ash (CFA) soil field was mixed with the carrier soil (CS, without containing coal fly ash) at different rates (0–40% mass content) in the 0–20 cm layer of top soil and then mixed with a rotovator. The soil was then amended with 0.45–1.80 kg·m− 2 of G1 soil amendment for planting corn.PurposeThe purpose of this study is to investigate the response mechanism of soil microbial community activities, and soil physicochemical properties to soil amendment and carrier soil in coal fly ash soil.Key resultsThe study found that the G1 amendment, which consisted of humic acid, polyacrylamide, zeolite powder, and FeSO4·7H2O, improved the soil chemical properties and physical structure by increasing soil bulk density and macroaggregates. The highest corn yield was observed in B5 (20% CS and 1.3500 kg·m− 2 G1). Meanwhile, the abundance of microorganisms that facilitate the circulation of soil nutrients such as Acidobacteria (77.05%), Sphingomonas (25.60%), Nitrospira (20.78%), Streptomyces (11.32%), and Gaiella (10.20%) was increased.ConclusionsOverall, our results indicate that the use of coal fly ash soil as a amendment can enhance soil sustainability by improving soil microbial functions. These findings provide a reference for the development and application of coal fly ash soil amendments.

Aplikasi Formulasi Bahan Pembenah Tanah terhadap Beberapa Sifat Kimia Tanah Berpasir dan Produksi Tanaman Padi

Sandy soil is part of the soil fraction with low nutrient content, organic matter, and cation exchange capacity. This is due to the leaching process so that nutrients are easily lost. The research aimed to improve the chemical characteristics of sandy soil and rice crop production due to the application of humic acid and silica. This research used of Completely Randomized Design method using soil amendment materials, namely humic acid (A) at the of 60 kg/ha and silica (S) at the of 5 tons/ha consisting of 6 combinations of comparisons repeated 4 times. Variables of analysis parameters include pH, cation exchange capacity, organic matter, N-NH4+, N-NO3- and rice crop production. The data obtained were analyzed by analysis of variance (ANOVA). If the results showed a significant effect, it was continued with the Honestly Significant Difference (HSD) test at the 5% level. The results showed that the application of soil amendment in the from humic acid and silica with various treatments on sandy soil was only able to improve CEC by 3,18% and Organic-C by 0,08%. In contrast soil pH and N-available didn`t give significant results in improving soil chemical properties and rice crop production. It`s recommended to conduct further research on the dose used in soil amendments so that it can effect nitrogen parameters and rice crop production in sandy soil. Keywords: humic acid, silica, sandy soil

Response of agronomic and physiological traits of flue-cured tobacco (Nicotiana tabacum L.) to plant stem cell soil amendments

Black shank disease is an important factor limiting the yield of flue-cured tobacco. Soil amendments have the potential to improve soil health and increase crop yield and quality. However, the application effects of soil amendments have not been elucidated in flue-cured tobacco. Here, we conducted field experiments in the major tobacco planting area, Exploring the effects of plant stem cell soil amendments at different levels on the occurrence and physiological growth of tobacco black shank disease, The purpose is to evaluate the effectiveness of plant stem cell soil amendments and recommend feasible applied rates. Plant stem cell soil amendments are applied at four levels: T0 (0 kg ha−1), T1 (1500 kg ha−1), T2 (2250 kg ha−1), and T3 (3000 kg ha−1). Nutrient absorption, agronomic traits, dry matter quality, chemical composition, and economic benefits of flue-cured tobacco black shank disease were explored. The results showed that the application of plant stem cell soil amendments effectively reduced the incidence rate of tobacco black shank disease, and significantly improved the agronomic traits (leaf number, plant height, leaf length, and width) and dry matter quality of flue-cured tobacco. At the same time, the nutrient content (N, P, and K), the proportion of high-quality tobacco leaves, and the content of coordinated chemical components (total nitrogen, total plant alkali, total sugar, reducing sugar, potassium and chlorine) of flue-cured tobacco plants were increased. In addition, the application rate of stem cell soil amendment at 3000 kg ha−1 showed the best effect on reducing the occurrence of black shank disease, which resulted in improved tobacco yields and economic benefits to the greatest extent of flue-cured tobacco. The study indicates that plant stem cell soil amendments can significantly enhance the yield and quality of flue-cured tobacco and offers an effective method for sustainable crop production in the tobacco industry.

Influences of tobacco straw return with lime on microbial community structure of tobacco-planting soil and tobacco leaf quality.

Soil amendment is an important strategy for improving soil quality and crop yield. From 2014 to 2019, we conducted a study to investigate the effects of tobacco straw return with lime on soil nutrients, soil microbial community structure, tobacco leaf yield, and quality in southern Anhui, China. A field experiment was conducted with four treatments: straw removed (CK), straw return (St), straw return with dolomite (St+D), and straw return with lime (St+L). Results showed that after 5 years of application, the St+L significantly increased the soil pH by 16.9%, and the contents of soil alkaline nitrogen (N) and available potassium (K) by 17.2% and 23.0%, respectively, compared with the CK. Moreover, the St+L significantly increased tobacco leaf yield (24.0%) and the appearance (9.1%) and sensory (5.9%) quality of flue-cured tobacco leaves. The addition of soil conditioners (straw, dolomite, and lime) increased both the total reads and effective sequences of soil microorganisms. Bacterial diversity was more sensitive to changes in the external environment compared to soil fungi. The application of soil amendments (lime and straw) promoted the growth of beneficial microorganisms in the soil. Additionally, bacterial species had greater competition and limited availability of resources for survival compared to fungi. The results showed that soil microorganisms were significantly influenced by the presence of AK, AN, and pH contents. These findings can provide an effective method for improving the quality of flue-cured tobacco leaves and guiding the amelioration of acidic soil in regions where tobacco-rice rotation is practiced.

Differential responses of photosynthesis, yield and soil properties 4 years after a single application of zeolites and biochar in a rainfed olive orchard

AbstractOlive orchards represent a key agricultural system in the Mediterranean Basin. Soil degradation processes associated with unsustainable agronomic practices and climate change could severely impact the sustainability of Mediterranean rainfed olive orchards. In this context, soil amendments are important tools that can be used to enhance soil fertility for sustained environmental quality and plant performance. In this study, a field trial was conducted for 4 years in olive tree (Olea europaea L.) to assess the effects of a mineral fertilizer compound and the combination with a single application of zeolites or biochar on the physiological and biochemical performance, tree nutritional status, crop yield and soil chemical and biological properties to gain knowledge towards more sustainable management. Our results showed that the addition of zeolites and biochar to mineral fertilizer ameliorated the physiological and biochemical performance, as evidenced by consistent increments of relative water content, stomatal conductance and net photosynthesis and by lower signs of oxidative stress during the periods of greater climate adversity. However, crop yield was not significantly different among soil treatments. On the other hand, soil chemical and biological traits at the surface layer (0–10 cm) have shown different and relevant responses after 4 years of soil amendment application. In fact, zeolite supply stood out as increased pH, extractable K, cation exchange capacity, microbial biomass carbon and microbial biomass quotient and reduced extractable Cu. Furthermore, zeolites induced positive changes in soil enzymatic activity, leading to increases in 10 enzymes involved in C, N and P cycles. In contrast, the effects of biochar on soil properties were much more reduced, given that it decreased the microbial biomass nitrogen and enhanced the activities of three P‐cycle enzymes. In summary, our data demonstrated that both soil amendments can be an interesting complement to mineral fertilization, in order to increase trees' resilience under rainfed conditions and to promote soil health, although the use of zeolites appears to be a more promising strategy because of the induction of higher soil sustainability.