Soil Productivity Research Articles

Counseling of How to Make Organic Fertilizer Enriched with Phosphate Solubilizing Bacteria to the Community in Tanjung Raja Sub-District

The village of Talang Balai Baru 1, located in the sub-district of Tanjung Raja in the Ogan Ilir Regency, is characterized by a type of land known as lowland, locally called “lebak” land, which is characterized by low soil fertility. This factor, among others, contributes to a decrease in crop productivity. To address this challenge, it is imperative to employ organic fertilizer in optimal amounts. Specifically, the harvested straw is primarily incinerated, with a limited portion being utilized as chicken manure fertilizer. Despite the abundance of local resources like chicken manure and straw, they are underutilized. Therefore, there is a need to harness these resources for the production of organic fertilizers enriched with phosphate-solubilizing bacteria (PSB). This enriched organic fertilizer is expected to provide essential nutrients to plants and improve soil fertility, thereby boosting soil and crop productivity. The project, conducted from July 29, 2024, to August 27, 2024. The method employed in this study is counseling and socialization regarding the production of BPF-enriched organic fertilizer and its subsequent application by partner farmers. The results of this counseling and socialization demonstrate the high level of support among the residents of Talang Balai Baru 1 Village for this program, as evidenced by their ability to utilize BPF-enriched organic fertilizer on their respective fields. This will contribute to an enhancement in soil and plant productivity.

Проблема впливу глобальної зміни клімату на розвиток аграрної галузі в Україні: історичний екскурс

The purpose of the work is to reveal specific issues of climate change, their impact on the development and management of agriculture in Ukraine, caused by intense warming: uneven distribution of precipitation; the increase in the number and intensity of extreme weather phenomena - droughts (droughts), dry spells, etc., as well as the scientific development of Ukrainian scientists in developing the problem. Methodology. The specified historical research is based on the use of general scientific principles of objectivity, systematicity, historicism, comprehensiveness. The subject-chronological and comparative-historical methods used by us are of great importance and their synthetic role in reflecting the progressive development of knowledge about climate change and finding ways to prevent negative effects on agricultural plants. The comparative-historical method contributed to the selection and characterization of the peculiarities of the accumulation of knowledge about extreme climatic phenomena, their development within the climatic zones of Ukraine. By analyzing the scientific work of scientists, the process of overcoming current problems, implementing new scientific developments into practice is traced. The scientific novelty consists in the generalization of the scientific achievements of scientific research institutions of Ukraine on the study of the nature of global climatic phenomena, their influence on the development of agricultural production in different soil and climatic zones of the country through the ways of overcoming crisis phenomena proposed by Ukrainian scientists. For the first time, the works of the outstanding scientist-agriculturalist A. O. Babich of the late 90s and early decades of the 20th century on the problem of global climate change became the object of a separate scientific study. Conclusions. In conclusion, we note that further global and regional climate warming can cause irreversible climate changes with a violation of the climatic balance, and the consequences of dangerous natural hydrometeorological phenomena can become catastrophic, which can lead to changes in the conditions of human life. As the analysis showed, droughts are exacerbated by high plowing of agricultural land, non-compliance with the soil protection system of land cultivation, weak development of moisture-saving technologies and drought-resistant crops and varieties. The industry of crop production is most affected by the adverse factors of drought, dry spells and dust storms, which are often characterized by unpredictability both in terms of their manifestations and the force of their impact on crops. In order to conduct agricultural production, there is a need to review the structure of sown areas by climatic zones of Ukraine, to include in the range of growing adapted to the phenomena of dehydration and prolonged overheating during the hot period and drought, the newest adapted varieties of plants. The efforts of agrarian science and production should be directed not to the exhaustion of natural forces, but to the neutralization and weakening of the effect of droughts and dry spells by a system of measures, including the results of the latest research in meteorology, agriculture and crop production.

The Relationships Between Soil Health, Production, and Management Decisions Through Farmers’ Eyes: A Case Study of Tennessee Large-Scale Vegetable Farms

Understanding farmers’ perceptions of soil health is valuable for developing strategies to increase the adoption of conservation practices. A combination of soils with poor soil fertility, low levels of soil organic matter, and the use of production practices that, although necessary for vegetable production, could negatively impact soil health makes the exploration of how large-scale vegetable producers in Tennessee perceive soil health and manage soils interesting. Using information from semi-structured interviews with operators of three Tennessee large-scale vegetable farms, we explored farmers’ perceptions of soil health and how those perceptions connect with adoption decisions. Our results suggest that farmers’ perceptions of soil health reflect a broad perspective that includes crop productivity and disease pressure. Profitability exerted a stronger influence on farmers’ decision-making than soil health. Nonetheless, farmers recognized that there is an association between soil health and profitability. The farmers included in this study found value in the information provided by soil health tests to confirm the benefits of soil management practices. The results presented in this study will contribute to the design of future studies aiming to investigate the relationship between farmer perceptions of soil health and the adoption of best soil management practices among large-scale vegetable growers.

Review on Integrated Nutrient Management on Yield and Yield Components of Okra in Ethiopia

Maintaining soil fertility necessitates applying inorganic and organic fertilizer sources in balance. Vegetable crops cannot be successfully produced without proper plant nutrition. Though little is known about it, okra is a crop that is commonly farmed in western Ethiopia and is rather adaptable. Grown across Ethiopia, okra is a vegetable crop with significant economic value, especially in the southwest region. For okra's output to increase integrated use of chemical and organic fertilizer on yield and yield components is essential. By optimizing the benefits from all available plant nutrient sources in an integrated manner, integrated nutrient supply/management, or INS, aims to maintain or improve soil fertility and plant nutrient supply to an optimal level for sustaining the desired crop productivity. This includes enhancing or maintaining soil productivity through a balanced use of fertilizers that are organic and biological sources of plant nutrients. Increase the amount and effectiveness of plant nutrients in the soils to reduce losses to the environment. However, the integrated nutrient management system (INMS) continues to be the means of preserving and perhaps enhancing soil fertility for long-term crop yield and lowering the cost of inorganic (fertilizer) inputs for all agricultural production.

Lands Evaluation in Hydromorphic Environment: Case of Developed Rice Lowland Soils in the Province of Ziro, Burkina Faso

Sustainable soil management became a major concern for rice farming in Burkina Faso. Rained rice production offers potential thanks to the national rice policy oriented towards the developing of lowlands. However, effective soil fertility management through the promotion of good agricultural practices is essential in this agricultural area to meet the goal. It involves the evaluation of the land, as it can provide important information on which to base rational decisions on land management. A study was carried out in order to promote soil fertility sustainable management on two rice-growing lowlands in the province of Ziro. The soils of the sites were characterized and sampled for the physicochemical parameters analysis. The suitability of the soils for rice cropping was thus assessed. It emerges from the study that the dominant soils in the developed rice lowlands are hydromorphic soils. The hydromorphic soils are suitable types of soils for rice production. The results on the physical parameters show that the soils of the lowlands mainly have a coarse surface texture. The organic matter content is low and the pH values vary from weakly to very strongly acidic. The useful soil water reserve is medium to high. The contents of the major nutrients (N, P and K) are very low as are the values of the CEC, which indicates a low level of chemical fertility of the soils according to the complete range. The evaluation of rice lowlands revealed that soils are moderately suitable for rice production and their major constraint is the availability of nutrients. Current producer practices related to soil fertility management are unfavorable to sustainable land management. The study shows the need for appropriate crop fertilization, better management of crop residues and periodic monitoring of fertility essential parameters for the sustainability of soil productivity.

Potential of biochar to mitigate methane production in paddy soils—application of a new incubation and modelling approach

AbstractPaddy soils are a significant source of methane (CH4) affecting the global climate. Therefore, it is important to investigate both emission mitigation strategies and the underlying biogeochemical processes. The application of biochar into paddy soils has emerged as a promising measure to mitigate CH4 emissions. However, it has not yet been clarified why such effects are usually weaker in field studies than in laboratory incubations and which properties of biochar specifically decrease the production of CH4. We conducted two incubation experiments, one with 1.5% addition of untreated biochars and one with same amounts, but pH-levelled, rinsed biochars. According to the common experimental design of existing incubation studies (experiment 1) biochar addition induced a mean soil pH increase of 0.28 after anaerobic incubation compared to the contro. In these treatments, biochar significantly extended the pre-methanogenic stage (mean 24.23%). However, this effect was weakened or even reversed when pH-levelled, rinsed biochars were amended in experiment 2, which was intended to mimic the persistent long-term effects in the field. This indicated that the provision of electron accepting capacities to suppress methanogenesis may be less important than previously thought. The addition of biochar significantly lowered CH4 production rates m in both experiments with no significant influence of the pH (mean 25.89%), though. Our study demonstrated that incubation studies on CH4 production in paddy soils can be improved by separating the pre-methanogenic and the methanogenic stage. This facilitates future research to compare characteristics of biochar, but also combinations of measures to optimise CH4 mitigation strategies.

Increased methane production associated with community shifts towards Methanocella in paddy soils with the presence of nanoplastics

BackgroundPlanetary plastic pollution poses a major threat to ecosystems and human health in the Anthropocene, yet its impact on biogeochemical cycling remains poorly understood. Waterlogged rice paddies are globally important sources of CH4. Given the widespread use of plastic mulching in soils, it is urgent to unravel whether low-density polyethylene (LDPE) will affect the methanogenic community in flooded paddy soils. Here, we employed a combination of process measurements, short-chain and long-chain fatty acid (SCFAs and LCFAs) profiling, Fourier-transform ion cyclotron resonance mass spectrometry, quantitative PCR, metagenomics, and mRNA profiling to investigate the impact of LDPE nanoplastics (NPs) on dissolved organic carbon (DOC) and CH4 production in both black and red paddy soils under anoxic incubation over a 160-day period.ResultsDespite significant differences in microbiome composition between the two soil types, both exhibited similar results to NPs exposure. NPs induced a change in DOC content and CH4 production up to 1.8-fold and 10.1-fold, respectively. The proportion of labile dissolved organic matter decreased, while its recalcitrance increased. Genes associated with the degradation of complex carbohydrates and aromatic carbon were significantly enriched. The elevated CH4 production was significantly correlated to increases in both the PCR-quantified mcrA gene copy numbers and the metagenomic methanogen-to-bacteria abundance ratio. Notably, the latter was linked to an enrichment of the hydrogenotrophic methanogenesis pathway. Among 391 metagenome-assembled genomes (MAGs), the abundance of several Syntrophomonas and Methanocella MAGs increased concomitantly, suggesting that the NPs treatments stimulated the syntrophic oxidation of fatty acids. mRNA profiling further identified Methanosarcinaceae and Methanocellaceae to be the key players in the NPs-induced CH4 production.ConclusionsThe specific enrichment of Syntrophomonas and Methanocella indicates that LDPE NPs stimulate the syntrophic oxidation of LCFAs and SCFAs, with Methanocella acting as the hydrogenotrophic methanogen partner. Our findings enhance the understanding of how LDPE NPs affect the methanogenic community in waterlogged paddy soils. Given the importance of this ecosystem, our results are crucial for elucidating the mechanisms that govern carbon fluxes, which are highly relevant to global climate change.

The Effect of Organic and Conventional Farming on Land Quality and Farmer Profits in Batur Village, Getasan District, Semarang Regency

The Green Revolution transformed traditional farming systems into conventional farming systems that use chemical fertilizer and pesticides and led to a decline in soil quality. The decline in soil quality can be overcome by implementing organic farming which is beneficial for maintaining and improving soil quality, product quality, and farmer welfare. In Batur Village, Getasan District, Semarang Regency, there are 35 farmer groups and 5 of them are organic farmer groups with a land area of ± 34.4 ha. This study aims to determine the effect of organic and conventional farming on land quality and farm profits in Batur Village, Getasan Subdistrict, Semarang Regency, which is expected to be used as a promotion of organic farming practices. The research method used was the composite method for soil sampling and interviews to determine farm profits. The results were analysed using independent sample T-test. The results of the analysis showed that soil properties were not significantly different, but the values of C-organic, N-total, permeability, field capacity, pH, soil consistency, and total soil microbial count of organic farming were higher than those of conventional farming, while the values of salinity and porosity were higher in conventional farming and the production costs of organic farming were lower.

Vermicompost as Organic Amendment: Effects on Some Soil Physical, Biological Properties and Crops Performance on Acidic Soil: A Review

One of the most precious natural resources is soil, which provides ecological functions necessary for life's survival and sustenance. Therefore, preserving and enhancing soil health is crucial for agricultural and ecological sustainability. However, careless application of mineral fertilizer lowers fertility and organic matter and has negative impacts on the environment, ground water quality, and soil health, whereas the use of organic amendments is essential for enhancing soil health. In order to improve the physical, biological, and crop productivity of acidic soil, this review emphasizes the potential of vermicompost as a soil conditioner. Thus, adding organic amendments to soil is a management tactic that can boost microbial populations, activity, and variety, enhances soil fertility and improve soil structure. Vermicompost (VC) is one type of organic amendment that is created when earthworms and soil microorganisms interact. The end product has a high degree of maturity, high porosity, aeration, drainage, water storage capacity, and microbial activity. As a result, applying this amendment encourages biological activity, which raises the soils' potential for production both directly through increased nutrient availability and indirectly through improved physical characteristics. Similarly, the addition of vermicompost (VC) to soil raised its pH levels, phosphorus, potassium, calcium, magnesium, and total organic carbon; it also enhanced the soil's cation exchange capacity, microbial biomass carbon, micronutrient content, and nitrogen content, all of which increased crop yield. In addition to raising crop yield and improving soil quality and nutrient availability, vermicompost also strengthens crop resistance to pests and diseases. By adding essential nutrients, humic acids, growth-regulating hormones, and enzymes to the soil, it acts as an organic fertilizer that improves plant nutrition, photosynthesis, and overall crop quality.

Developing land-use planning scenarios in Türkiye to reduce water-induced soil erosion

Summary Because soil erosion constrains agricultural productivity and overuse of soils exacerbates erosion, land use can only be sustained through the implementation of land evaluation. We studied five land-use scenarios including erosion-reducing land terracing and contour farming using ILSEN modelling. These scenarios’ rates of soil loss were determined using the revised universal soil loss equation (RUSLE) method. We found that all the erosion-reducing scenarios reduced soil loss compared to the current land use of the study area; in the non-agricultural land use, soil erosion was reduced 4.25 times. The model is expected to inform reduction of soil erosion in geographies characterized by rugged topography.

Current status and the significance of local wisdom biofertilizer in enhancing soil health and crop productivity for sustainable agriculture: A systematic literature review

Soil fertility is recognized as a crucial factor in supporting plant growth and productivity. The utilization of biofertilizers as environmentally friendly fertilizers is aimed at enhancing soil fertility and plant productivity. This study aims to explore the potential of local material for developing local wisdom biofertilizers (LWB) for achieving sustainable agriculture. A systematic literature review was conducted using bibliometric analysis, Preferred Reporting Items for Systematic Reviews, and Meta-Analyses (PRISMA) method, employing the Scopus search engine with the keywords "local AND wisdom AND biofertilizer" OR "biofertilizer" OR "local AND microorganism" OR "soil AND health OR crop AND productivity OR sustainable agriculture". The search yielded 704 articles, of which 11 were deemed eligible after selection. Based on the literature review, it was found that there are local materials, including fish waste, seaweed, Azolla, fruit waste, Moringa oleifera, microalga, bamboo roots, banana hump, golden snail, mangrove leaves, fruit, and vegetable waste that can be used as raw materials for LWB to improve soil health, plant growth, and productivity. The development of LWB as a new fertilizer technology faces challenges such as lack of regulations, low public trust, limited farmer awareness, weak promotion, and raw material shortages. Further research is needed to intensively study and enhance the effectiveness of LWB through enrichment using beneficial microorganisms.

Soil and Site Productivity Effects on Above- and Belowground Radiata Pine Carbon Pools at Harvesting Age.

Pinus radiata D. Don is the most widely planted forest species in Chile, making it crucial to understand carbon pools in adult plantations. This study aimed to evaluate the effect of soil type and site productivity on the total carbon stock in adult radiata pine plantations, considering sites with contrasting water and nutrient availability. We selected 10 sites with sandy and recent volcanic ash soils, representing a productivity gradient. At each site, three 1000 m2 plots were established to quantify the carbon stock of total biomass using allometric equations and in situ carbon assessments of the forest floor and mineral soil (up to 1 m deep). The results indicated significantly higher carbon stocks in the mineral soil of recent ash sites (281.4 Mg ha⁻1) compared to sandy soils (139.9 Mg ha⁻1). The total site carbon was also higher in recent ash (473.2 Mg ha⁻1) than in sandy sites (330.9 Mg ha⁻1). A significant relationship was found between stand productivity and soil organic carbon (r2 = 0.88), as well as total carbon stock (r2 = 0.91) when considering soil type. These findings highlight the importance of including assessments up to 1 m depth and developing soil type and productivity models to improve site carbon stock estimates.

Patterns of fruit and seed production and characteristics of soil seed bank of desert plant Hypecoum erectum L. (Papaveraceae)

Patterns of fruit and seed production and characteristics of soil seed bank of desert plant Hypecoum erectum L. (Papaveraceae)

The Role of Sudanese Forests Agro-ecosystem in Improving the Cation Exchange Capacity and Exchangeable Bases of a Sandy Soil in Western Burkina Faso

The objective of this study is to evaluate the influence of Sudanese forests on the chemical equilibrium and exchangeable bases of sandy soils in the Bondoukuy region. The study examines the impact of forest cover on soil fertility and the mechanisms through which these natural ecosystems promote soil health and productivity in the region. The Cation Exchange Capacity (CEC) of soil represents its capacity to retain and exchange nutrient cations with plant roots. In Sudanian Forests Agro-ecosystem, sandy soils are characterized by a dominance of coarse particles, which exhibit a low specific surface area and low cation retention capacity, in contrast to clayey soils. A low CEC restricts soil fertility and the capacity of the soil to sustainably provide essential nutrients to plants. It was hypothesized that the CEC of the topsoil in forests of western Burkina Faso would demonstrate a significant increase due to substantial environmental changes during the fallow period. To test this hypothesis, a comparison was made between soil fertility in forests and fallows, and that of cultivated plots, which were considered the control for this increase. A total of 15 plots were selected, with five plots allocated to each situation. The vegetation and soil of the plots were described in detail. Composite soil samples were taken from the 0-20 cm horizon. The soil analyses in the laboratory were conducted on several parameters, including texture, pH-H2O, pH-KCl, carbon, nitrogen, CEC and exchangeable bases. The results of the observations enabled the classification of the soils as tropical ferruginous soils with iron and manganese sesquioxides. The original materials indicate that the soil exhibits sandy properties. This was demonstrated by the granulometric study, which revealed that the soils under investigation exhibited an essentially sandy texture on the surface horizon. This results in a low retention capacity for exchangeable bases. The woody vegetation of the forest exhibits a greater diversity of flora than that of the fallows. This has a significant impact on the enhancement of the CEC, due to the replenishment of the soil with plant debris of varying organic compositions. The overall pH is slightly acidic, with a range of 5.63 to 5.71. The soils of forests exhibit higher concentrations of carbon and nitrogen than those of the fallows and fields. The observation of chemical balances has enabled the identification of forests as an environment conducive to optimal plant nutrition. Overall, forests enhance the CEC and exchangeable bases, despite the values being below the threshold recommended for tropical sandy soils. It is therefore necessary to implement measures to promote sustainable agriculture and enhance agricultural productivity in this region, where soil nutrients are naturally scarce.

Evaluation of environmental risk factors associated with survival of generic E. coli in organic integrated crop-livestock systems in California and Minnesota

IntroductionIntegrated crop-livestock systems (ICLS) improve soil health and productivity but may lead to the transfer of foodborne pathogens to fresh produce from soil contaminated with the feces of grazing animals.Methods and resultsOver 2 years (2021–2022), organic ICLS field trials were conducted in California (CA) and Minnesota (MN) to examine the presence of foodborne pathogens (Escherichia coli O157, non-O157 Shiga toxin producing E. coli (STEC), and Listeria monocytogenes) across three treatments (fallow, cover crop without grazing, and cover crop with grazing by small ruminants) in soils and produce. A Random Forest (RF) analytical approach was used to determine potential associations between meteorological and soil chemical factors, and the generic E. coli (gEc) presence in soil. The persistence of gEc in soil, as an indicator of fecal contamination, was evaluated using mixed effect zero-inflated negative binomial (ZINB) models, considering top-ranked meteorological factors identified from RF analyses. One produce sample (cucumber) tested positive for non-O157 STEC (0.6%, 1/157) from grazed soil in MN, with no other foodborne pathogens detected in produce. Soil contamination by non-O157 STEC increased in 2022 (2.7%, 15/552) compared to 2021 (0%, 0/504) from both states, aligning with the increased prevalence of non-O157 STEC in post-grazed fecal samples from sheep in CA (41.7%, 5/12) and goats (42.5%, 17/40) in MN in 2022. Concentrations (Most Probable Number/100 g) of gEc in grazed soil returned to levels comparable to non-grazed or fallow treatments within 87–147 days post-graze (DPG) in both years, with a significant decrease predicted after 32 DPG. Interestingly, non-O157 STEC was detected in soil even after concentrations of gEc declined 115–147 DPG.DiscussionAlthough the effects of meteorological factors and soil chemical characteristics were not as influential as treatment or sampling day effects, ZINB analyses with identified meteorological factors in grazed soil suggested that regional differences in gEc counts were likely influenced by maximum air/soil temperatures on the sampling day. Further investigation is needed to evaluate the adoption of the NOP 90-120-day interval rules between manure application by grazing and harvest, considering a wider range of environmental regions and the potential cumulative effect of continuous ICLS in the same field on pathogen loads.

Short term effects in soil quality under different cover crops of no tillage vegetables organic production in fragile soils in Southeastern Brazil

Short term effects in soil quality under different cover crops of no tillage vegetables organic production in fragile soils in Southeastern Brazil

Nitrate toxicity and health hazards: Problems and mitigation challenges

Abstract Nitrogenous fertilizers are considered an essential input for productive agriculture and the factor highly responsible for higher biomass production. Unfortunately, intensive mineral fertilization brings tremendous changes in soil fertility and productivity, but productivity decreases rapidly in cereal-based cropping systems or without legumes. The excessive use of mineral nitrogenous fertilizers reported an increase in potential health hazards and environmental problems such as groundwater contamination, eutrophication, acid rain, the greenhouse effect, and methemoglobinemia in humans. With future applications’ elevated use and prognosis, this problem may expand to several folds in the approaching decades. Large consumption of defiled water or food with higher concentrations of nitrates (according to the US Environmental Protection Agency (EPA), the permissible limit is 7 mg.kg −1 body weight per day) causes severe infant diseases such as Blue Baby Syndrome, respiratory ailments, gastric cancer, birth malformation and other health problems which earlier were rarely explained or explored worldwide. The unsustainable agronomic practices resulted in our soil being stripped of natural health and blind dependency on mineral fertilizers, ultimately leading to poor human and environmental health. There is an immediate need for new technologies related to farming systems to meet Sustainable Development Goals (SDGs) in view of changing climate. Various sustainable practices such as applying organic manures, precision N management, Soil Test Crop Response (STCR) approach, and nitrogen (N) inhibitors hold tremendous potential to reduce the ill effects of nitrates and secure the food chain if adopted on a large scale.

Health Risk Assessment of Heavy Metals in Soil-crop System in Different Ecological Regions of Ningxia

Heavy metals are characterized by toxicity，non-biodegradability，and accumulation in the food chain；hence，o the distribution of heavy metals in farmland soils and crop food safety have attracted much attention. A total of 1 274 soil samples and crop samples were collected from farmland in Ningxia from 2017 to 2021 and bioconcentration coefficients were used based on the analysis of the elemental contents of Zn，Cr，Ni，Cu，Pb，As，Cd，and Hg. The ecological risk index and correlation analysis were used to characterize the heavy metal content and health risk assessment of the soil-crop system in Ningxia. The results showed that the soils in the study area were alkaline and the mechanical composition was dominated by pulverized and sandy grains，with a relatively small content of clay grains. The heavy metal contents in the soils were in the following order：Zn>Cr>Ni>Cu>Pb>As>Cd> Hg. Except for that of Cu and Ni，the contents of other heavy metals in the soils of the northern region were higher than those of the central and southern regions. The ecological risk index of soil heavy metals was Hg>Cd>As>Cu>Pb>Ni>Cr>Zn and the proportion of points with low and medium ecological risk index levels was high（98.58%），indicating that the soil environment was generally good. The average content of the eight heavy metals in crops did not exceed the limit value，and the average health risk index value was <1. However， the health risk index（HRI）of As in individual crops existed at points >1 in all three sub-regions and individual points with high values of HRI（HRI>1）for Cu and Ni were observed in crops in the northern region and for Pb in the north and south of the country，which require further attention. From the bioconcentration factor，crops showed no accumulation effect （BCF<1）for heavy metals such as As，Cd，Cr，Cu，Ni，Pb，and Zn and although the average uptake of Hg by crops did not show accumulation，a total of 31 crops in the three ecological zones showed some accumulation（BCF>1），which also requires further monitoring. Analysis using the Mantel's test showed that except for As and Ni in crops，which had a weak correlation with Cu content in the soil（0.05>Mantel's P>0.01），the other heavy metals in crops did not have a significant correlation with the corresponding soil heavy metals （Mantel's P≥0.05），indicating that the heavy metal contents in crops were less affected by soil heavy metals. RDA analysis showed that the sand content had a strong positive correlation with the transfer coefficients of heavy metals such as Hg，Ni，Pb，and Cd，while the powder content showed a strong negative correlation；however，the transfer coefficients of Cu，Zn，As，and Cr were not much affected by the mechanical composition of soils，and the correlation between the soil organic matter content and the transfer coefficients of heavy metals was also small. In summary，the quality of the soil environment and crops in the study area is generally good；however，attention must still be paid to the areas with high heavy metal content or exceeding the standard value to strictly control the input of pollutants，and at the same time，establishing long-term monitoring of the quality status of soil and agricultural products in the crop production area is a necessary control initiative.

The use of phosphate rock and plant growth promoting microorganisms for the management of Urochloa decumbens (Stapf.) R.D. Webster in acidic soils.

Forage production in tropical soils is primarily limited by nutrient deficiencies, especially nitrogen (N) and phosphorus (P). The use of phosphate rock by plants is limited by its low and slow P availability and microbial phosphate solubilization is the main mechanism for P bioavailability in the soil-root system. The objectives of this study were (i) select a nitrogen-fixing bacteria which could be used as a co-inoculant with the Penicillium rugulosum IR94MF1 phosphate-solubilizing fungus and (ii) evaluate under field conditions the effect of inoculation combined with phosphate rock (PR) application on yield and nutrient absorption of a Urochloa decumbens pasture which was previously established in a low-fertility, acidic soil. Various laboratory and greenhouse tests allowed for the selection of Enterobacter cloacae C17 as the co-inoculant bacteria with the IR94MF1 fungus. Later, under field conditions, a factorial, completely randomized block design was used to evaluate the inoculation with the IR94MF1 fungus, the IR94MF1+C17 co-inoculation, and a non-inoculated control. Two levels of fertilization with PR treatment (0 kg/ha and 200 kg/ha P2O5) were applied to each. During five consecutive harvests it was observed that the addition of biofertilizers significantly increased (p < 0.05) the herbage mass and N and P assimilation compared to the non-inoculated control. However, no statistically significant differences were observed for the PR application as P source. P. rugulosum IR94MF1 is capable of solubilizing and accumulating P from the phosphate rock, making it available for plants growing in acid soils with low N content. These inoculants represent a good option as biofertilizers for tropical grasses already established in acidic soils with low N content.

Biodiversity of key soil phylotypes is associated with increased plant richness and productivity following agricultural abandonment and afforestation

Abstract Anthropogenic land use modifications are causing severe degradation of terrestrial ecosystems, and multiple revegetation strategies are emerging globally to counteract the loss of plant richness and productivity. While soil microorganisms are essential for plant community dynamics, the role of soil microbial biodiversity in regulating changes in plant richness and productivity under different revegetation strategies remains unknown. We used multitrophic co‐occurrence networks to identify soil network modules of strongly co‐occurring phylotypes along a 50‐year revegetation chronosequence of agricultural abandonment and afforestation. Soil biodiversity within these modules was related to soil nutrient cycling functions, plant richness and productivity (understorey layer in afforestation), elucidating how these network modules are associated with changes in plant richness and productivity. Plant richness and productivity increased simultaneously following both agricultural abandonment and afforestation. However, the biodiversity of key soil taxa within distinct network modules was associated with these coupled increases through the regulation of different nutrient cycling functions. Key soil phylotypes within the network modules involved in nitrogen (N) cycling correlated with the simultaneous increase in plant richness and productivity following agricultural abandonment. In contrast, those involved in phosphorus (P) and sulphur (S) cycling were linked to the coupled responses of both plant richness and productivity under afforestation. This reflects the divergent microbial mechanisms associated with the coupled increase in plant richness and productivity along the revegetation chronosequence for both agricultural abandonment and afforestation. Synthesis. Our findings provide correlative evidence that the biodiversity of key phylotypes within soil network modules is closely associated with the simultaneous increase in plant richness and productivity following the cessation of agricultural management. We identify key soil taxa, specific to each revegetation strategy, that could serve as potential targets for genomic and cultivation‐based approaches to counteract plant community degradation. Revegetation efforts to enhance plant richness and productivity should focus on soil phylotypes associated with N cycling after agricultural abandonment and those involved in P and S cycling during afforestation.