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Heavy metals, such as chromium (Cr), are continuously introduced into the environment through human activities, notably from the excessive use of pesticides, synthetic fertilizers, and irrigation with sewage and industrial wastewater. These substances induce oxidative stress in plants, disrupting crucial morphological and biochemical processes. Seed germination and early plant development are vital stages in the life cycle of plants, heavily reliant on nitrogen metabolism and associated biochemical pathways for energy accumulation. This study aimed to assess the phytotoxic effects of chromium on the growth and biochemical parameters of germinating seedlings from two maize varieties, Pak-Afgoi and Neelem Desi. The findings revealed significant suppression caused by chromium, leading to reduced seed germination rates, embryonic growth, vigor index, and biomass. Nitrogen and protein levels, as well as nitrate reductase activity, were notably affected, with Pak-Afgoi showing lower decreases compared to Neelem. Carbohydrate mobilization and total sugar content also decreased with rising chromium concentrations, although Pak-Afgoi exhibited better nitrogen and carbohydrate utilization rates. Furthermore, oxidative stress markers like hydrogen peroxide (H2O2) and malondialdehyde (MDA) indicated damage to growth and biochemical attributes in maize. Interestingly, proline levels increased with higher chromium concentrations, suggesting a protective role in maintaining seedling viability during metabolic disruptions. These results underscore the detrimental impact of chromium on maize growth by altering plant nitrogen and carbohydrate metabolisms and inducing oxidative stress. [ABSTRACT FROM AUTHOR]

Increasing biological nitrogen (N) fixation (BNF) in maize production could reduce the environmental impacts of N fertilizer use, but reactive N in the rhizosphere of maize limits the BNF process. Using non-transgenic methods, we developed gene-edited strains of Klebsiella variicola (Kv137-2253) and Kosakonia sacchari (Ks6-5687) bacteria optimized for root-associated BNF and ammonium excretion in N-rich conditions. The aim of this research was to elucidate the mechanism of action of these strains. We present evidence from in vitro, in planta and field experiments that confirms that our genetic remodeling strategy derepresses BNF activity in N-rich systems and increases ammonium excretion by orders of magnitude above the respective wildtype strains. BNF is demonstrated in controlled environments by the transfer of labeled 15N2 gas from the rhizosphere to the chlorophyll of inoculated maize plants. This was corroborated in several 15N isotope tracer field experiments where inoculation with the formulated, commercial-grade product derived from the gene-edited strains (PIVOT BIO PROVEN® 40) provided on average 21 kg N ha-1 to the plant by the VT-R1 growth stages. Data from small-plot and on-farm trials suggest that this technology can improve crop N status pre-flowering and has potential to mitigate the risk of yield loss associated with a reduction in synthetic N fertilizer inputs. [ABSTRACT FROM AUTHOR]

Organic carbon based amendments can improve soil structure and fertility, as well as increase composition and diversity of soil microbial community. One of the major functions of improving soil fertility is to achieve effective nitrogen (N) management and mineralization. In this study, 746 paired observations were pooled from 20 long-term field experiments to verify the hypothesis that compared to synthetic only fertilization, long-term application of organic fertilization alone or in combination with synthetic fertilization could strengthen multiple internal pathways for soil N supply under various climatic conditions. We found that long-term application of synthetic N fertilizers alone or in combination with phosphorus (P) and potassium (K) led to an increase only in the recalcitrant organic N mineralization rate (MNrec) by 210% and 263%, respectively. However, long-term application of organic fertilizers alone or in combination with synthetic N fertilizers increased MNrec, labile organic N mineralization rate (MNlab) and release of adsorbed ammonium from cation exchange sites (RNH4a) by 160% and 200%, 153% and 353%, and 1025% and 541%, respectively. This indicates that organic fertilization can strengthen multiple internal pathways for mineral N production. The long-term co-application of organic and synthetic fertilizers stimulated MNlab (197%), MNrec (151%) and RNH4a (563%) in subtropical regions, but it had no effect on heterotrophic nitrification (ONrec). In contrast, it stimulated MNrec (505%), RNH4a (633%) and ONrec (184%) in temperate regions, with no observed effect on MNlab. These data confirm that if one N supply source is shut-off under specific climatic conditions the other pathways continue to provide N. The meta-analysis advances our understanding of agroecosystems and as such help to improve frameworks for enhancing soil health. [ABSTRACT FROM AUTHOR]

Malnutrition is one of the greatest challenges faced by humanity, which may be addressed by improving crop productivity to ensure food security. However, extensive use of synthetic fertilizers can lead to soil fertility degradation. This study highlights the potential of combining nanotechnology with biotechnology to enhance the germination rates of commercially important crop seeds. Bacterial biosurfactant extracted from a newly isolated Klebsiella sp. strain RGUDBI03 was used as a reducing and capping agent for the synthesis of zinc oxide nanoparticles (ZnO NPs) through a simple method. Extensive characterization of ZnO NPs through electron microscopic analysis showed well-dispersed, homogeneous NPs with a size range of 2–10 nm. High-resolution transmission electron microscopy (HR-TEM) images also revealed molecular fringes of 0.26 nm in single crystal ZnO NPs, with approximately 50% of the NPs exhibiting a size range of 2–4 nm. X-ray diffraction (XRD) results of ZnO NPs indicated the presence of (100), (002), (101), (102), (200), and (112) planes, confirming their crystalline nature. The presence of C = C–H, C = C, C–H, and C = C groups in both the bacterial biosurfactant and ZnO NPs, as depicted by Fourier-transform infrared spectroscopy (FTIR) spectra, confirmed the function of the biosurfactant as a reducing and capping agent. The nano-primed chickpea (Cicer arietinum) and rice (Oryza sativa) seeds showed an increase in water uptake rate, 89% and 92% respectively, compared to the control (73% and 44%), leading to an enhanced germination rate of 98% and 76%, compared to their respective controls (80% and 30%) under optimized conditions. Additionally, the nano-primed seeds exhibited higher levels of α-amylase activity in both seeds (0.37 mg/g for chickpea and 2.49 mg/g for rice) compared to the control. Notably, the ZnO NP priming solution exhibited no cytotoxicity on red blood cells and earthworms (Eudrilus eugeniae), indicating their non-cytotoxic and eco-friendly nature for future field trials. [ABSTRACT FROM AUTHOR]

The major crop, soybean, forms root nodules with symbiotic rhizobia, providing energy and carbon to the bacteria in exchange for bioavailable nitrogen. The relationship is host-specific and highly host-regulated to maximize energy efficiency. Symbiotic nitrogen fixation (SNF) is greener than synthetic fertilizer for replenishing soil fertility, contributing to yield increase. Nodulation Outer Protein P (NopP) and NopI of the type 3 secretion system (T3SS) of the rhizobium determine host specificity. Sinorhizobium fredii CCBAU25509 (R2) and CCBAU45436 (R4) have different NopP and NopI variants, affecting their respective symbiotic compatibilities with the cultivated soybean C08 and the wild soybean W05. Swapping the NopP variants between R2 and R4 has been shown to switch their compatibility with C08 with the rj2/Rfg1 genotype. To understand the effects of Nops on host compatibility, analyses on the transcriptomic data of W05 roots and nodules inoculated with S. fredii strains containing Nop variants uncovered many differentially expressed genes related to nodulation and nodule functions, providing important information on the effects of Nops on hosts and nodules. [ABSTRACT FROM AUTHOR]

The biochemical composition of sapropels from Maloe Simaginskoe Lake, which were studied using modern methods of atomic emission spectrometry (ICP-AE) and high-performance liquid chromatography (HPLC), is presented. This source of organic matter is now the least in demand in the country; many deposits have been abandoned. However, such organic colloids and their humic extracts are not inferior in their spectrum of action to extracts from peat or coal. The predominance of the proportion of potassium and sodium in the gross composition of macroelements is shown. Among microelements, both in bulk and in mobile forms, iron and manganese ions dominated. Apparently, the Fe cation is bound in polyligand forms with carboxylic acids. The ratio of these two elements in the samples averaged 10 : 1—Fe : Mn. The content of heavy metals was within the limits acceptable for sapropel fertilizers according to GOST R 54000-2010. The results obtained during this study can be used further in the biotechnology of intensive crop production, when growing crops in a hydroponic environment while minimizing the use of synthetic fertilizers. In addition, since carbohydrates were found in all samples of the raw materials studied, the extracts can be used to develop modified nutrient media in agricultural microbiology to stabilize the titer of beneficial rhizobacteria. [ABSTRACT FROM AUTHOR]

Agricultural environmental pollution needs to be reduced in our future. The biggest obstacles to preventing this situation are that agricultural inputs such as synthetic fertilizers increase product yield and scattered agricultural areas. This study involves the optimization of the production process of an easy-to-apply organic fertilizer with high nutritional value by subjecting bat guano, one of the valuable organic fertilizers, to anaerobic digestion together with cattle manure. Response surface method Box-Behnken design, a statistical model, was used for process optimization. The process input parameters were temperature, cattle manure, and bat manure, and the response value was considered as 2% total nitrogen. As a result of the optimization for a total nitrogen value of 2%, the optimum mixture ratio was determined as cattle manure 77.0448%, bat manure 12%, and temperature 40 °C. Analysis results showed that the addition of bat manure increased the N, P, K, and humic and fulvic acid values in the fertilizer. The study revealed that strong organic fertilizers can be used to increase the value of cattle manure organically. It also offers very promising results based on reducing agricultural pollution and ensuring agricultural sustainability. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO), as a short-lived climate forcer, has direct and indirect detrimental impacts on environmental quality and human health. The amount of nitrogen (N) fertilizer application to agricultural soils is considered a robust predictor of total NO emissions, but the estimates of cropland NO emissions have large uncertainties due to the widely used constant emission factors (EF) as e.g., default values recommended by Intergovernmental Panel on Climate Change (IPCC) methodologies. By compiling 223 field experiments with at least three N-input levels across various croplands, we performed a meta-analysis to determine how soil NO emissions respond to N inputs. Our results showed for the first time that the mean change in EF per unit of additional N input (∆EF) across all available data was significantly higher as compared to zero, indicating that the NO response to N additions increased significantly faster than the assumed linear. On average, upland grain crops showed significantly higher ∆EF than that of horticultural crops or lowland rice. A higher ∆EF was also appeared in sites with mean annual precipitation < 600 mm, mean annual temperature ≥ 15 °C, soil organic carbon ≥ 14 g C kg− 1 or total N ≥ 1.4 g N kg− 1, and where synthetic N fertilizers were usually applied. By assuming various N application rates, the IPCC default (0.7% or 1.1%) EF model would have overestimated or underestimated NO emissions compared to our ∆EF model. Overall, our meta-analysis results exert high potential to improve estimates of cropland NO inventories, and help address disparities in global NO budgets and develop more targeted mitigation efforts. [ABSTRACT FROM AUTHOR]

The current study explored the contamination of heavy metals in the paddy fields of Kashmore district treated with synthetic fertilizer and mixed fertilizer, based on the route of input (irrigation water, fertilization, atmospheric precipitation) and output fluxes (surface runoff, water leaching, and crop biomass). The soil and irrigation water quality of selected paddy fields treated with synthetic fertilizer and mixed fertilizer was also examined according to the standard protocol. Moreover, the measurement of heavy metals in soil, input and output was done by atomic absorption spectrometry. The principal component analysis data indicated that the paddy field-5 and paddy field-6 soils treated with synthetic fertilizer and paddy field-5 soils treated with mixed fertilizer showed high distribution scores for physicochemical parameters and heavy metals. The bioaccumulation and translocation of heavy metals in the studied paddy field indicated that the soils and irrigation water of paddy fields treated with synthetic fertilizer and mixed fertilizer are suitable for rice cultivation. The elevated levels of heavy metals in soils treated with mixed fertilizer might be due to heavy metals contamination in irrigation water, synthetic fertilizers, and livestock manures. The experimental data showed an insignificant difference in heavy metal contents in different parts of all paddy fields (p < 0.05). The atmospheric deposition is a significant input contributor of heavy metals in contamination in paddy fields. The rice straw uptake is a prime source of heavy metals in paddy fields, but their removal may efficiently decrease the intake of heavy metals from studied paddy fields. [ABSTRACT FROM AUTHOR]

Synthetic fertilizers have been revolutionary in the way that the increased production of food crops has increased as a result of the application of synthetic fertilizers. Despite the fact that global N, P, and K consumption have increased from 64.9, 25.9, and 18.2 kg/ha in the year 2000 to 85.5, 33.2, and 20.4 kg/ha, respectively, they are still relatively low. Additionally, excessive use of inorganic fertilizers has also resulted in a deterioration of environmental systems, especially that of water resources. The presence of this toxic substance inside the human body is therefore due to the fact that it enters the body through the food chain and causes serious illnesses, such as cancer. For instance, in most countries, the maximum nitrate concentration for drinking water is restricted to between 45 and 50 mg/L. Besides promoting the use of chemicals and the application of fertilizers in farming, there should be a push to encourage the sustainable use of biofertilizers to protect the environment and human health. Composts that have been developed from various waste materials, such as poultry farms, dairy farms, and other sources, have proven to be very rich in N, P, and K. For example, compost generated from dairy farm wastes can provide a value of 45,100, 7300, and 9100 mg/kg of N, P, and K, respectively. In order to make the use of these biofertilizers in agriculture possible, it will be necessary to spread awareness among the farmers so that they can adopt the concepts of sustainable management in agriculture. [ABSTRACT FROM AUTHOR]

The increasing global demand for food, coupled with concerns about the environmental impact of synthetic fertilizers, underscores the urgency of developing sustainable agricultural practices. Nitrogen-fixing bacteria, known as diazotrophs, offer a potential solution by converting atmospheric nitrogen into bioavailable forms, reducing the reliance on synthetic fertilizers. However, a deeper understanding of their interactions with plants and other microbes is needed. In this study, we introduce a recently developed label-free 3D quantitative phase imaging technology called dynamic quantitative oblique back-illumination microscopy (DqOBM) to assess the functional dynamic activity of diazotrophs in vitro and in situ. Our experiments involved three different diazotrophs (Sinorhizobium meliloti, Azotobacter vinelandii, and Rahnella aquatilis) cultured on media with amendments of carbon and nitrogen sources. Over 5 days, we observed increased dynamics in nutrient-amended media. These results suggest that the observed bacterial dynamics correlate with their metabolic activity. Furthermore, we applied qOBM to visualize microbial dynamics within the root cap and elongation zone of Arabidopsis thaliana primary roots. This allowed us to identify distinct areas of microbial infiltration in plant roots without the need for fluorescent markers. Our findings demonstrate that DqOBM can effectively characterize microbial dynamics and provide insights into plant-microbe interactions in situ, offering a valuable tool for advancing our understanding of sustainable agriculture. [ABSTRACT FROM AUTHOR]

In soilless cultivation, plants are grown with nutrient solutions prepared with mineral nutrients. Beneficial microorganisms are very important in plant nutrition. However, they are not present in soilless culture systems. In this study we investigated the impact of introducing Plant Growth Promoting Rhizobacteria (PGPR) as an alternative to traditional mineral fertilizer in hydroponic floating lettuce cultivation. By reducing mineral fertilizers at various ratios (20%, 40%, 60%, and 80%), and replacing them with PGPR, we observed remarkable improvements in multiple growth parameters. Applying PGPR led to significant enhancements in plant weight, leaf number, leaf area, leaf dry matter, chlorophyll content, yield, and nutrient uptake in soilles grown lettuce. Combining 80% mineral fertilizers with PGPR demonstrated a lettuce yield that did not significantly differ from the control treatment with 100% mineral fertilizers. Moreover, PGPR application improved the essential mineral concentrations and enhanced human nutritional quality, including higher levels of phenols, flavonoids, vitamin C, and total soluble solids. PGPR has potential as a sustainable substitute for synthetic mineral fertilizers in hydroponic floating lettuce cultivation, leading to environmentally friendly and nutritionally enriched farming. [ABSTRACT FROM AUTHOR]

Emissions of nitrous oxide (N2O), a potent greenhouse gas, from farmland have been recognized to be affected by soil pH and nitrogen (N) fertilizer application. However, the interactive effects of soil pH and N fertilizer type on N2O emissions and their influencing mechanism are poorly understood. A field experiment was conducted to elucidate the impacts of synthetic fertilizer and manure on soil properties and N2O fluxes along a soil acidity gradient (soil pH = 6.8, 6.1, 5.2, and 4.2) in the Huai River Basin, and a lab incubation experiment was performed to understand the underlying mechanisms of changed N2O flux. Low soil pH inhibited the ammonia-oxidizing bacteria abundance and thereby reduced the N2O production by nitrification under both synthetic fertilizer and manure application. The N2O production by denitrification was also reduced with declining soil pH, likely due to the decreased nirS and nirK abundances, and lower NO3−. However, low soil pH reduced the nosZ abundance and increased (nirS + nirK)/nosZ ratio, resulting in the increased N2O/(N2O + N2) ratio. Finally, with the decreased nitrification and denitrification, soil N2O emission was significantly reduced with declining soil pH regardless of fertilizer types. Compared with synthetic fertilizer, manure application increased soil nutrients (total N, dissolved organic C, and NO3−), nirK abundance, and (nirS + nirK)/nosZ ratio in the soils with pH of 5.2 and 4.2, thereby promoting N2O production by denitrification and N2O/(N2O + N2) product ratio in acidic soils. Consequently, soil N2O emission was increased with manure application in acidic soils. This study provides novel insight and improves our understanding of how soil pH regulates nitrification, denitrification, and N2O emissions from soils amended with chemical fertilizer and manure, which gives guidance on developing N management strategies for sustainable production and N2O mitigation in acid soils. [ABSTRACT FROM AUTHOR]

In India, the rice paddy is cultivated as one or two crops per year using synthetic fertilizers and organic manures. Although the application of agrochemicals enhances the soil's heavy metals, the influence of cultivation patterns on the metal accumulation in rice paddy soil is not documented. Such information could provide a basis for controlling heavy metals in rice paddy soil. Therefore, the investigation was carried out to assess the influence of cultivation patterns on heavy metal accumulation. The study was made during the cultivation and noncultivation periods of single and double cropping patterns. The heavy metals viz. Zn, Cu, Mn, Fe, Ni, Cr, and Pb were analyzed in soil after acid extraction using AAS. The result revealed that, in both cropping patterns, the heavy metals content was high during the noncultivation period compared to cultivation period, and only Cu and Pb showed significant differences between the periods (Single cropping F1,25 = 7.291, p = 0.012 and F1,25 = 7.820, p = 0.010; double cropping F1,25 = 9.242, p = 0.005 and F1,25 = 7.746, p = 0.010 respectively). Compared to single cropping, Zn, Cu, Mn, and Pb contents were high in double cropping. The Mn, Ni, and Cr content showed significant differences between the cropping pattern (Mn: F1,55 = 18.20, p = 0.0001; Ni: F1,55 = 5.764, p = 0.020; Cr: F1,55 = 4.283, p = 0.043). The study indicates that the difference in the heavy metal content of the rice paddy soils is attributed to managerial and cultivation practices. [ABSTRACT FROM AUTHOR]

The predicting groundwater nitrate pollution risk, especially in terms of changes in fertilizing, has not been fully investigated so far. In particular, there is no comprehensive method to assess this risk in areas of different land use type, and not only in agricultural areas. The aim of this study was to develop a novel multicriteria methodology for groundwater nitrate pollution risk assessment, which meets these issues. A further aim was to determine how much this risk would change if the amount of organic and synthetic fertilization was reduced. An assumption was that groundwater pollution risk is a combination of the potential adverse impacts of land use, fertilization, and intrinsic groundwater vulnerability to pollution. The impact of fertilization was holistically evaluated by balancing nitrogen from spatially differentiated the size of the breeding, species of livestock, manure and synthetic fertilizers input, and spatially differentiated topsoil, with nitrogen uptake by different crops. The nitrate concentration in the leachate was used as a measure of the impact of fertilization. This concentration was compared to the natural baseline nitrate concentration in groundwater. Three fertilization scenarios for groundwater pollution risk assessment in two study areas were discussed. Under typical agricultural, climatic, soil, and geological conditions in Europe for the current total fertilization level of 95-120 kg N ha−1 groundwater nitrate pollution risk is low and moderate, but for fertilization of 150-180 kg N ha−1, a reduction in the total fertilization (synthetic and manure) by 40 to 50% may be required to achieve low risk of degradation of natural groundwater quality. Predictive simulations of groundwater nitrate pollution risk confirmed that reducing synthetic and organic fertilization has an effect, especially in areas with intensive fertilization. This method may allow for a holistic and scenario-based assessment of groundwater pollution risk and may help decision-makers introduce solutions to manage this risk under conditions of climate change, preservation of groundwater quality, and food security. [ABSTRACT FROM AUTHOR]

Diazotrophs can help minimize the use of synthetic nitrogen fertilizers by fixing atmospheric dinitrogen in agricultural ecosystems. However, the diazotroph community affected by biochar application is still poorly explored in the paddy fields. Here, a field study with three different biochar application rates, namely control (CK, no biochar amendment), low (LB, 24 t ha−1 applied once), and high (HB, 48 t ha−1 applied once), was employed in a double rice paddy. The impacts of biochar on diazotrophic abundance/community composition, soil chemical and biological properties, and rice biomass were examined 3‒4 years after application. The abundance and community composition of diazotrophs were measured with quantitative polymerase chain reaction and amplicon sequencing, respectively. Biochar application significantly enhanced the diazotrophic abundance by 13.1–94.2% compared with CK, which might result from increased stubble and root biomass, soil Olsen-P, total P, and total organic C. Compared to HB, LB significantly increased diazotrophic abundance by 5.6–20.8% three years post-addition, which was probably due to the increased stubble and root biomass. The variations in the alpha diversity index in diazotroph community composition from biochar treatments was decreased over time, relative to CK. Diazotrophic community Bradyrhizobium, Geobacter, Azospirillum, and Pseudodesulfovibrio had a significantly higher relative abundance in biochar treatments than in CK, which can endophytically colonize the rice roots or utilize a wide range of organic carbon sources. Our results demonstrate that biochar amendment could be a useful measure to promote soil available N pool in double rice paddies. [ABSTRACT FROM AUTHOR]

The present study reports the application of feather hydrolysates (FHs) obtained from the hydrolysis of chicken feathers by Bacillus safensis LAU 13 (KJ461434) and Aquamicrobium defluvii FH 20 (OM281847.1) as organic nitrogen fertilizer for the cultivation of Corchorus olitorius, Celosia argentea and Amaranthus caudatus. Foliar treatment of the vegetables with FHs (100%, v/v) remarkably improved their growth and yield performances. The FHs induced over 1.5-fold improvement in root length, shoot height, shoot fresh weight, dry weight, leaf number, leaf area and chlorophyll contents of the vegetables compared to water after 6 weeks of cultivation. In most cases, FHs at optimal levels displayed better growth promotion than NPK fertilizer. FHs elevated the nitrogen content (25.53–29.79%), organic carbon (33.77–38.96%), and microbial load (102–104 cfu/g) of soil after 6 weeks. Vegetables fertilized with FHs showed improvements in crude protein, crude fibre, ash, phenols, flavonoids, and proanthocyanidin contents to controls. Also, about 1.1-fold improvement in hydrogen peroxide and DPPH radicals scavenging activities was obtained. Significant lipid peroxidation inhibition against ferrous ion (Fe2+) damage in precision-cut liver slices with higher catalase activities was recorded. Thus, the bacterial FHs significantly enhanced the growth, nutritional and antioxidant properties of the vegetables as well as soil nutrient and biological activities. Hence, the application of the bacterial FHs can be substituted for synthetic fertilizer to promote sustainable agricultural food production in an ecologically benign manner. Bacterial feather hydrolysates improved growth, nutritional and nutraceutical qualities of vegetables as eco-friendly biofertilizers. [ABSTRACT FROM AUTHOR]

Sustainable agriculture is a key factor to meet the global demand of food supply. In recent years, nanotechnology has been adopted as a promising tool for achieving the sustainable agriculture. The advent of nanotechnology may play a significant role from farm to fork, by improving the yield and quality. Several approaches are utilized viz nano-farming, nanoparticles-enabled smart delivery system, nanofertilizers, nanomaterials to enhance the quality by promoting the seed germination, increasing biochemical constituents, adaptation and resistance to diseases. Polyherbal nanoformulation (PHNF) was formulated using green nanotechnology with the assistance of triphala extract and silver nitrate solution. Synthesized PHNF was physico chemically confirmed for the formation of nanosized particles. This research focuses on applications of polyherbal nanoformulation (PHNF) on plant growth promotion in Vigna radiata and Trigonella foenum-graecum. Germinating seeds were sprayed with 1 ppm, 5 ppm, 10 ppm of PHNF and compared with the control. Upon PHNF treatment the growth parameters including shoot length, root length and fresh weight were increased in all two tested species. There was a gradual increase in the photosynthetic pigments including total chlorophyll, chlorophyll a, chlorophyll b, carotenoids and biochemical constituents including proteins and carbohydrates and is concentration dependent. These results suggested that polyherbal nanoformulation can be used as an alternative to chemical fertilizers to overcome the drawbacks of synthetic fertilizers and to provide eco-friendly solution for plants and protect the ecosystem from hazardous chemicals. [ABSTRACT FROM AUTHOR]

Replacing chemical fertilizers with non-toxic waste that meet all fertilizing purposes, including ash from plant biomass and their management is becoming the important goal of sustainable agriculture concerning energy plants production in a closed system. This study aims to explore a novel strategy for utilizing natural sorghum ash together with digestate and ecological compounds, to replace synthetic fertilizers, for the energy plant development improvement and thus reduction of the environment pollution. Sorghum, as an energy plant, cultivated in low quality sandy and podzolic soils, in Central and North Poland climate, was fertilized with different doses of YaraMila Complex, a synthetic fertilizer (0, 150, 300 kg ha−1 Each dose was supplemented with different amounts of sorghum ash (0.5, 1, 2 and 4 t ha−1), used alone or with addition of APOL-HUMUS (soil improver; 10 L ha−1), biogas plant digestate (30 m3 ha−1) and Stymjod (nano-organic leaf fertilizer; 5 L ha−1). Added to each YaraMila Complex dose, the applied ash amounts (optimally 2–4 t ha−1), increased growth of plants, crop biomass, index of chlorophyll content, net photosynthesis, transpiration, stomatal conductance, content of intercellular CO2, activity of acid and alkaline phosphatase, RNase and dehydrogenase and energy properties. Sorghum ash used with the lesser YaraMila Complex doses of 0 or 150 kg ha−1 caused the enhanced growth of plants more than the doubled YaraMila Complex amounts applied alone (150 or 300 kg ha−1, correspondingly). Additionally, applied biogas plant digestate, APOL-HUMUS and Stymjod further increased the plant growth. This indicates that the application of natural sorghum ash accelerates energy plant development, can reduce by half the recommended synthetic fertilizer doses on poor and marginal soil and enables the cultivation of sorghum in a closed production cycle. [ABSTRACT FROM AUTHOR]

The modern agricultural work mainly involves the use of synthetic fertilizers and large scale deforestation. The numerous agricultural activities around the Darna and the Gangapur Reservoirs of the Nashik Distirct, India have started the environmental issues such as an early or rapid eutrophication and heavy metal accumulations. Agricultural runoff and industrial wastes are proved to be the potential sources of heavy metals. The heavy metals may accelerate the effect of pollution on the environment with the decline in the biodegradability of the organic pollutants. The impacts of the anthropogenic activities with the passing time have been recorded in the form of geochemical elements accumulated as the part of bottom sediments of the reservoirs. The present study has revealed that the heavy metal concentration from the core sediments of the reservoirs displays the moderately high to highly positive inter-correlation. The historical profiles of both the reservoirs show the highest enrichments for Cr, Ni, Cu, Co, V, Sc and Eu. The impact of metal pollutants on both the reservoirs is explored with regard to the ages derived from the 210Pb geochronology and the constant rate of supply (CRS) model. [ABSTRACT FROM AUTHOR]

The ever-increasing population has pressurized the world to increase food production, which consequently resulted in intensive production and consumption of synthetic fertilizers. Fertilizers are the most essential elements to meet the increasing food demand and ensure food security. Besides increasing crop production, chemical fertilizers have adversely affected soil and environmental health. Specifically, imbalance and extensive utilization of urea fertilizers have enhanced greenhouse gas production and polluted the ground as well as surface water resources via volatilization, leaching, and eutrophication processes. Overall, utilization of the majority of chemical fertilizers resulted in huge economic losses and poses serious health hazards to the ecosystem. Approximately 80–90% of phosphorus and 40–70% of nitrogen are lost from applied chemical fertilizers. Therefore, slow-release fertilizers (SRFs) have been developed to enhance agricultural production with the least environmental and fiscal losses on a suitable and sustainable basis. Despite the progressive development of SRF fabrication, the widespread application of such fertilizers is uncommon and needs further investigation. Therefore, this review article aimed to discuss the types, synthesis techniques, and nutrient-release mechanisms of SRFs for sustainable agricultural production and environmental health. Furthermore, recent advances in SRF development including biochar-based SRF fabrication and the strategic use of nanotechnology in SRF synthesis have been reviewed and discussed. The application of SRFs is considered a green and environment-friendly technology, which provides the sustainable pathways for enhancing crop growth and quality. The SRFs improve the plant nutrition and minimize the environmental impacts of the conventional fertilizers by reducing the fertilizer losses along with reduced applications of irrigation. However, due to higher production costs, commercial manufacturing and widespread use of SRFs are still not common. Thus, the synthesis processes, types, environmental and agricultural impacts, application mechanisms, and future prospects of SRFs have been discussed in detail, specifically biochar-based SRFs and nanofertilizers have been elaborated in this review which are considered promising among the SRFs. [ABSTRACT FROM AUTHOR]

Nutrient-rich waste streams from domestic and industrial sources and the increasing application of synthetic fertilizers have resulted in a huge-scale influx of reactive nitrogen and phosphorus in the environment. The higher concentrations of these pollutants induce eutrophication and foster degradation of aquatic biodiversity. Besides, phosphorus being non-renewable resource is under the risk of rapid depletion. Hence, recovery and reuse of the phosphorus and nitrogen are necessary. Over the years, nutrient recovery, low-carbon energy, and sustainable bioremediation of wastewater have received significant interest. The conventional wastewater treatment technologies have higher energy demand and nutrient removal entails a major cost in the treatment process. For these issues, bio-electrochemical system (BES) has been considered as sustainable and environment friendly wastewater treatment technologies that utilize the energy contained in the wastewater so as to recovery nutrients and purify wastewater. Therefore, this article comprehensively focuses and critically analyzes the potential sources of nutrients, working mechanism of BES, and different nutrient recovery strategies to unlock the upscaling opportunities. Also, economic analysis was done to understand the technical feasibility and potential market value of recovered nutrients. Hence, this review article will be useful in establishing waste management policies and framework along with development of advanced configurations with major emphasis on nutrient recovery rather than removal from the waste stream. [ABSTRACT FROM AUTHOR]

Nitrogen transport from terrestrial to aquatic environments could cause water quality deterioration and eutrophication. By sampling in the high- and low-flow periods in a highly disturbed coastal basin of Southeast China, hydrochemical characteristics, nitrate stable isotope composition, estimation of potential nitrogen source input fluxes, and the Bayesian mixing model were combined to determine the sources and transformation of nitrogen. Nitrate was the main form of nitrogen. Nitrification, nitrate assimilation, and NH4+ volatilization were the main nitrogen transformation processes, whereas denitrification was limited due to the high flow rate and unsuitable physicochemical properties. For both sampling periods, non-point source pollution from the upper to the middle reaches was the main source of nitrogen, especially in the high-flow period. In addition to synthetic fertilizer, atmospheric deposition and sewage and manure input were also major nitrate sources in the low-flow period. Hydrological condition was the main factor determining nitrate transformation in this coastal basin, despite the high degree of urbanization and the high volume of sewage discharge in the middle to the lower reaches. The findings of this study highlight that the control of agricultural non-point contamination sources is essential to pollution and eutrophication alleviation, especially for watersheds that receive high amounts of annual precipitation. [ABSTRACT FROM AUTHOR]

Microalgae are microscopic organisms that have a broad range of applications, from wastewater treatment, CO2 mitigation to therapeutic proteins, and pharmaceuticals. Recently, the combination of wastewater treatment-based microalgae and the use of the obtained biomass as biofertilizers/stimulants/pesticides have been highly emphasized for their use in the agriculture field. Biofertilizers are a need of today's agriculture practices due to the increasing demand for food to feed a hungry planet while avoiding chemical contamination by the over-application of synthetic fertilizers. There is a constant need for modern techniques for the use of microalgae in a sustainable manner to harness their products to their full extent. Various types of bioreactors are available on the market, each with its own advantages and disadvantages, which, based on their efficiency, can be used for microalgae cultivation. This review aims at reporting recent developments in microalgae biotechnology, especially related to CO2 mitigation, wastewater purification, biofuel, feedstock, future food, therapeutic proteins, pharmaceuticals, and biofertilizers, highlighting some of the current research in this field and future development priorities. [ABSTRACT FROM AUTHOR]

Human urine concentrates 88% of the nitrogen and 50% of the phosphorus excreted by humans, making it a potential alternative crop fertilizer. However, knowledge gaps remain on the fate of nitrogen in situations favouring NH3 volatilization and on the availability of P from urine in soils. This study aimed at identifying the fate of nitrogen and phosphorus supplied by human urine from source separation toilets in a calcareous soil. To this end, a spinach crop was fertilized with 2 different doses of human urine (170 kgN ha−1 + 8.5 kgP ha−1 and 510 kgN ha−1 + 25.5 kgP ha−1) and compared with a synthetic fertilizer treatment (170 kgN ha−1 + 8.5 kgP ha−1) and an unfertilized control. The experiment was conducted in 4 soil tanks (50-cm depth) in greenhouse conditions, according to a randomized block scheme. We monitored soil mineral nitrogen over time and simulated nitrogen volatilization using Hydrus-1D and Visual Minteq softwares. We also monitored soil phosphorus pools, carbon, nitrogen and phosphorus (CNP) in microbial biomass, soil pH and electrical conductivity. Only an excessive input of urine affected soil pH (decreasing it by 0.2 units) and soil conductivity (increasing it by 183%). The phosphorus supplied was either taken up by the crop or remained mostly in the available P pool, as demonstrated by a net increase of the resin and bicarbonate extractable P. Ammonium seemed to be nitrified within about 10 days after application. However, both Visual Minteq and Hydrus models estimated that more than 50% of the nitrogen supplied was lost by ammonia volatilization. Overall, our results indicate that direct application of urine to a calcareous soil provides available nutrients for plant growth, but that heavy losses of volatilized nitrogen are to be expected. Our results also question whether long-term application could affect soil pH and salinity. [ABSTRACT FROM AUTHOR]

The great challenge of reducing soil nutrient depletion and assuring agricultural system productivity in low-income countries caused by limited synthetic fertilizer use necessitates local and cost-effective nutrient sources. We estimated the changes of the nitrogen budget of agricultural systems in the East African Community from 1961 to 2018 to address the challenges of insufficient nitrogen inputs and serious soil nitrogen depletion in agricultural systems of the East African Community region. Results showed that total nitrogen input increased from 12.5 kg N ha-1yr-1 in the 1960s to 21.8 kg N ha-1yr-1 in the 2000s and 27 kg N ha-1yr-1 in the 2010s. Total nitrogen crop uptake increased from 12.8 kg N ha-1yr-1 in the 1960s to 18.2 kg N ha-1yr-1 in the 2000s and 21.8 kg N ha-1yr-1 in the 2010s. Soil nitrogen stock increased from -2.0 kg N ha-1yr-1 in the 1960s to -0.5 kg N ha-1yr-1 in the 2000s and 0.3 kg N ha-1yr-1 in the 2010s. Our results allow us to substantiate for the first time that soil nitrogen depletion decreases with increasing input of nitrogen in agricultural systems of the East African Community region. This suggests that increases in nitrogen inputs through biological nitrogen fixation and animal manure are the critical nitrogen management practices to curb soil nitrogen depletion and sustain agricultural production systems in the East African Community region in order to meet food demand for a growing population. [ABSTRACT FROM AUTHOR]

Analysis of soil samples collected from 16 rice paddy fields located in the Western Ghats region was performed to quantify the concentration of Cu, Zn, Mn, Fe, Ni, Cr, Cd, and Pb using atomic absorption spectroscopy. High concentrations of these heavy metals were found in rice paddy fields regularly cultivated using agrochemicals. We compared this concentration with soils of rice paddy field that was not under cultivation. Cu, Zn, Mn, Fe, Cr, Ni, Pb, and Cd showed increases of 1.2, 1.3, 2.3, 2.2, 1.8, 2.8, 1.8, and 8.5 times, respectively, in the rice paddy fields cultivated with synthetic fertilizers such as NPK, urea, potash, diammonium phosphate, etc., and several categories of pesticides belonging to the class organophosphates, carbamates, and acetanilide herbicide. In contaminated sites, the heavy metals exhibited maximum correlation with soil moisture content (SMC) (Zn, Fe, Cr, Ni, and Cd), soil organic content (SOC) (Fe, Cr, Ni, and Cd), and water holding capacity (WHC) (Cu, Pb, and Cd) than those observed for the reference site. The principal component analysis (PCA) revealed a total of 77.944% variance of heavy metals contributed from WHC (40.259%), SMC (20.854%), and SOC (16.832%). This indicates the build-up of heavy metals in rice paddy soils under the strong influence of moisture content, water holding capacity, and organic carbon content of the soil. [ABSTRACT FROM AUTHOR]

Human dire need for environmental sustainability have triggered researchers to seek for organic substrates as an alternative to synthetic fertilizers in order to enhance bioremediation. Presently, nitrogen-rich organic substrate not only proffered the solution but also have proven useful in enhancing the rate of bioremediation. Animal manure is a nitrogen-rich organic substrate which has been found very effective for stimulating plant growth. Some of the animal manure used by researchers are poultry droppings, cow dung, goat manure, and pig manure. In all the papers reviewed, it was gathered that animal manure enhances bioremediation by providing nutrients favoring microbial growth and activities responsible hydrocarbon degradation. However, of the four commonly used animal manure, poultry droppings was severally reported to be a better biostimulant. Also, animal manure when sun-dried and pulverized yielded better results. It was observed that animal manure serves as substrates for earthworms which further accelerates the potential of the earthworms to remediate the soil. Also, the pollution of soil by crude oil causes a surge in its carbon content which may slow down microbial growth and activities. Thorough review of literatures, however, indicates that animal manure is capable of providing appropriate nutrient concentrations to offset such imbalance. Studies continue to lay credence to the efficacy of animal manure in enhancing microbial growth and activities responsible for the biodegradation of hydrocarbons contained in crude oil. Furthermore, the co-application of animal manure with other bioremediation strategies, such as phytoremediation and vermiremediation, should be combined for effective bioremediation of oil-contaminated environment. [ABSTRACT FROM AUTHOR]

This paper aims to assess the sustainability of coffee production in Brazil by a framework at the farm level. The framework developed comprises four dimensions of sustainability structured from the literature review. Primary data were collected from 20 coffee farms selected from the most producing communities in the Planalto de Vitória da Conquista locality, sited in Centro-Sul Baiano middle region at the Bahia state. The main environmental issues identified related to coffee farmers are inadequate management of water consumption, influenced by the lack of knowledge about irrigation techniques in some cases, and the use of synthetic fertilizers and pesticides. The economic evaluation of the activity revealed a low index of producers belonging to a class organization. In social aspects the issues are low level of technical/technological instruction for coffee producers, temporary workers are often used, the old age of most producers, the lack of family succession for the activity, low incomes, the high number of temporary workers, and the absence of the worker gains. As for the technical dimension, only half of the farmers invest in innovation, which causes high obsolescence of their equipment and machinery and a low participation rate in training courses. In the environmental dimension, the farmers return the packages of pesticides to the stores where they bought them. In the technical dimension, most farmers perform soil analysis. Besides addressing the identified challenges, the initiatives can help achieve the Sustainable Development Goals, especially the 9th, 12th, and 13th. [ABSTRACT FROM AUTHOR]

Soil gross mineral N production and consumption processes are crucial regulators of plant productivity and N loss from croplands. Substituting synthetic fertilizers by integrating legumes in cultivation systems is common in organic farming, but research on its long-term impact on dynamics of gross soil N transformation and associated environmental N loss is scarce. In particular, studies at a temporal resolution that allows for a mechanistic understanding of long-term effects of organic farming are missing. Therefore, we determined gross N turnover rates of ammonification, nitrification, and ammonium and nitrate immobilization at monthly temporal resolution during a full green rye-maize cropping sequence. Measurements were carried out at sites with same pedo-climatic background but organic farming (OF) and integrated farming (IF) history. During green rye growing, N turnover rates for OF and IF were low and not significantly different, likely owing to low temperatures. During silage maize growing, IF exhibited significantly higher average N turnover rates of 1.86, 4.46, and 5.57 mg N kg⁻1 dry soil d⁻1 for gross ammonification, ammonium immobilization, and nitrate immobilization, respectively, compared to OF values of 1.11, 1.80, and 2.90 mg N kg⁻1 dry soil d⁻1. The significantly higher N turnover rates were likely due to higher soil organic C, N and microbial biomass which result from different long-term management practices. Especially the increased immobilization potential on the IF site contributed to significantly lower area-scaled N₂O emissions (1.45 vs. 4.36 kg N ha⁻1) during periods of high nitrification. This shows that for low SOC soils, integrated farming history with high C return enhances soil N cycling and reduces the risk of N losses in the form of N2O emission. [ABSTRACT FROM AUTHOR]

Soils are the basis of life on land and the ways in which we manage them for crop production, impact their role, functions and quality. Conventional farming uses industrial inputs to a level that is economically justified, whilst organic farming systems avoid mineral fertilizers and synthetic chemical pesticides. This study investigates the long-term effect of organic and conventional farming systems on soil quality. The DOK trial (bioDynamic, bioOrganic, Konventionell (German for conventional)) running since 1978 in Therwil (CH), compares bioorganic (BIOORG), biodynamic (BIODYN), and conventional (CONFYM) farming systems at two farmyard manure intensities corresponding to 0.7 and 1.4 livestock units per hectare with a purely mineral fertilized system (CONMIN) and an unfertilized control (NOFERT). The treatments in the DOK trial vary in plant protection and receive system-specific organic matter inputs differing in rate and quality. With this work, we revisit the soil organic carbon (SOC) dynamics across 42 years and redefine the previous perception of mainly declining SOC contents after 21 years of organic and conventional management (Fliessbach et al. 2007). After 42 years, we found SOC contents to be increased in BIODYN 1.4 and to a lesser extent also in BIOORG 1.4. CONFYM 1.4 showed stable SOC contents, while systems fertilized with manure of 0.7 livestock units and CONMIN lost SOC. SOC loss was highest in NOFERT. Enhanced biological soil quality under organic and particularly biodynamic management highlights the close link between soil biology and SOC changes. The impact of farming systems on SOC was detectable after 2 decades of continuous management. We conclude that recycling manure at a level of 1.4 livestock units per hectare permits maintenance of SOC levels and that composting manure, as performed in BIODYN 1.4, helps to further increase SOC levels and improve biological soil quality. [ABSTRACT FROM AUTHOR]

Seaweeds are valuable marine resources having multifaceted usages in modern agriculture. Extracts from different seaweeds have been used since many years in agriculture practice to improve plant growth and to enhance the yield. At present, the excessive use of synthetic chemicals and fertilizers imposes a global health hazard and pollutes agricultural lands worldwide. Thus, promoting the use of natural plant growth regulators and fertilizers, such as seaweeds, is recommended with promising outputs. Moreover, the seaweed extract-based biostimulants having plant growth -promoting capacity and aiding in improving the overall plant resilience are highly desirable. In addition, the seaweed extracts can improve the soil health and soil fertility. In this review, the different methods of obtaining the seaweed extract-based biostimulants are discussed. Additionally, the role of such biostimulants in plant growth promotion, mitigating plant abiotic and biotic stresses, and improving soil quality is illustrated and the underlying mechanism is discussed. In addition, some important applications of the seaweed extracts in other than agricultural area have been discussed in brief. Moreover, the future prospects of the seaweed extract-based biostimulants are presented with emphasizing on the economic significance. [ABSTRACT FROM AUTHOR]

Soil fauna play a crucial role in sustaining agro-ecosystem functions. Crop straw is recommended for application to agricultural fields to improve soil quality. However, the effects of crop straw combined with different synthetic fertilizers on the soil faunal community remain unclear, and knowledge regarding purple soil is limited. Using the conserved cytochrome c oxidase I (COI) gene as markers, we examined the responses of the soil faunal community to different fertilization in upland purple soil of southwestern China. The accuracy of the morphological and molecular methods in characterizing soil nematodes was compared. Our results showed that different fertilization treatments significantly changed the soil faunal community structure (Adonis test, R2 = 0.43, P = 0.011). Sixteen biomarkers were identified according to LEfSe (linear discriminant analysis effect size). The diversity and species number of soil fauna were closely related to soil organic matter (SOM) and total phosphorus (TP) (P < 0.05). This study indicates that crop straw return can improve the soil fertility and diversity of soil fauna in purple soil. Additionally, the morphological approach and molecular method based on the COI gene can be considered as complementary approaches in characterizing soil nematode community. [ABSTRACT FROM AUTHOR]

Engineering cereals to express functional nitrogenase is a long-term goal of plant biotechnology and would permit partial or total replacement of synthetic N fertilizers by metabolization of atmospheric N2. Developing this technology is hindered by the genetic and biochemical complexity of nitrogenase biosynthesis. Nitrogenase and many of the accessory proteins involved in its assembly and function are O2 sensitive and only sparingly soluble in non-native hosts. We generated transgenic rice plants expressing the nitrogenase structural component, Fe protein (NifH), which carries a [4Fe-4S] cluster in its active form. NifH from Hydrogenobacter thermophilus was targeted to mitochondria together with the putative peptidyl prolyl cis‐trans isomerase NifM from Azotobacter vinelandii to assist in NifH polypeptide folding. The isolated NifH was partially active in electron transfer to the MoFe protein nitrogenase component (NifDK) and in the biosynthesis of the nitrogenase iron-molybdenum cofactor (FeMo-co), two fundamental roles for NifH in N2 fixation. NifH functionality was, however, limited by poor [4Fe-4S] cluster occupancy, highlighting the importance of in vivo [Fe-S] cluster insertion and stability to achieve biological N2 fixation in planta. Nevertheless, the expression and activity of a nitrogenase component in rice plants represents the first major step to engineer functional nitrogenase in cereal crops. Functional mitochondrial NifH expression in transgenic rice paves the way for engineering functional nitrogenase in staple cereal crops. [ABSTRACT FROM AUTHOR]

Food systems are primary drivers of human and environmental health, but the understanding of their diverse and dynamic co-transformation remains limited. We use a data-driven approach to disentangle different development pathways of national food systems (i.e. 'transformation archetypes') based on historical, intertwined trends of food system structure (agricultural inputs and outputs and food trade), and social and environmental outcomes (malnutrition, biosphere integrity, and greenhouse gases emissions) for 161 countries, from 1995 to 2015. We found that whilst agricultural total factor productivity has consistently increased globally, a closer analysis suggests a typology of three transformation archetypes across countries: rapidly expansionist, expansionist, and consolidative. Expansionist and rapidly expansionist archetypes increased in agricultural area, synthetic fertilizer use, and gross agricultural output, which was accompanied by malnutrition, environmental pressures, and lasting socioeconomic disadvantages. The lowest rates of change in key structure metrics were found in the consolidative archetype. Across all transformation archetypes, agricultural greenhouse gases emissions, synthetic fertilizer use, and ecological footprint of consumption increased faster than the expansion of agricultural area, and obesity levels increased more rapidly than undernourishment decreased. The persistence of these unsustainable trajectories occurred independently of improvements in productivity. Our results underscore the importance of quantifying the multiple human and environmental dimensions of food systems transformations and can serve as a starting point to identify potential leverage points for sustainability transformations. More attention is thus warranted to alternative development pathways able of delivering equitable benefits to both productivity and to human and environmental health. [ABSTRACT FROM AUTHOR]

To feed the continuously expanding world's population, new crop varieties have been generated, which significantly contribute to the world's food security. However, the growth of these improved plant varieties relies primarily on synthetic fertilizers, which negatively affect the environment and human health; therefore, continuous improvement is needed for sustainable agriculture. Several plants, including cereal crops, have the adaptive capability to combat adverse environmental changes by altering physiological and molecular mechanisms and modifying their root system to improve nutrient uptake efficiency. These plants operate distinct pathways at various developmental stages to optimally establish their root system. These processes include changes in the expression profile of genes, changes in phytohormone level, and microbiome-induced root system architecture (RSA) modification. Several studies have been performed to understand microbial colonization and their involvement in RSA improvement through changes in phytohormone and transcriptomic levels. This review highlights the impact of genes, phytohormones, and particularly root microbiota in influencing RSA and provides new insights resulting from recent studies on rice root as a model system and summarizes the current knowledge about biochemical and central molecular mechanisms. [ABSTRACT FROM AUTHOR]

Long-term different tillage system field trials can provide vital knowledge about sustainable changes in soil health indices and crop productivity. This study examined cotton productivity and soil health indices under different tillage systems and organic materials. The present study was carried out at MNS University of Agriculture, Multan to explore the effect of different tillage systems: conventional tillage (T1), conservation tillage (T2), and organic materials: control (recommended dose of synthetic fertilizers; 160:90:60 kg ha−1NPK), poultry manure (10 t ha−1 PM), compost (10 t ha−1 CM), farmyard manure (20 t ha−1 FYM), and biochar (7 t ha−1 BC) on cotton productivity and soil health indices. Two years field trials showed that different tillage systems and organic materials significantly improved the growth, morphological, and yield attributes of cotton and soil health indices. The cotton showed highest seed cotton yield (3692–3736 kg ha−1), and soil organic matter (0.809–0.815%), soil available nitrogen (74.3–74.6 mg kg−1), phosphorus (7.29–7.43 mg kg−1), and potassium (213–216 mg kg−1) under T2 in comparison to T1 system during both years of field experiment, respectively. Similarly, PM (10 t ha−1) showed highest seed cotton yield (3888–3933 kg ha−1), and soil organic matter (0.794–0.797%), nitrogen (74.7–75.0 mg kg−1), phosphorus (7.39–7.55 mg kg−1), and potassium (221–223 mg kg−1) when these are compared to FYM (20 t ha−1), CM (10 t ha−1), and BC (7 t ha−1) during both years of field experiment, respectively. These findings indicate that conservation tillage system with application of 10 t ha−1 PM are the best practices for the sustainable cotton production and to ensure improvement in the soil health indices under arid climatic conditions. [ABSTRACT FROM AUTHOR]

Agriculture, which serves as a lifeline for us, is unequivocally vital for an agriculture-dependent economy like Bangladesh, not only for its food supply but also because of its significant contribution towards achieving Sustainable Development Goals (SDGs) 1 and 2. However, in a third-world nation like Bangladesh, where farming practices largely circumvent the environmental consequences, raised our concern. In this milieu, this study is a novel attempt to explore the association between agricultural ecosystem and environmental degradation in Bangladesh using a long time spanning from 1972 to 2018. We observed a long-run association between the agroecosystem and CO2 emission. Further, findings from the dynamic autoregressive distributed lag (DARDL) simulation model revealed that the environmental quality of Bangladesh is heavily distorted by total cereal production, total livestock head, enteric methane emissions, N2O emissions from manure application, and CO2 equivalent N2O emissions from synthetic fertilizers in the short and long run, whereas agricultural technology, pesticide use in agriculture, and burned biomass crop residue deteriorated the environmental quality only in the long run. The counterfactual diagram entailed from the DARDL model projected the trend of CO2 emission in response to positive and negative changes in the analyzed variables. Lastly, this study established a causal relationship between the agroecosystem and environmental degradation using frequency domain causality. Indeed, our study will aid in reshaping agricultural practices in an eco-friendly manner to mitigate environmental degradation and help formulate pragmatic policy actions so that agro-lead nations can thrive in the race of achieving SDGs 1, 2, and 13. [ABSTRACT FROM AUTHOR]

Biological nitrogen fixation (BNF) is the reduction of N2 into NH3 in a group of prokaryotes by an extremely O2-sensitive protein complex called nitrogenase. Transfer of the BNF pathway directly into plants, rather than by association with microorganisms, could generate crops that are less dependent on synthetic nitrogen fertilizers and increase agricultural productivity and sustainability. In the laboratory, nitrogenase activity is commonly determined by measuring ethylene produced from the nitrogenase-dependent reduction of acetylene (ARA) using a gas chromatograph. The ARA is not well suited for analysis of large sample sets nor easily adapted to automated robotic determination of nitrogenase activities. Here, we show that a reduced sulfonated viologen derivative (S2Vred) assay can replace the ARA for simultaneous analysis of isolated nitrogenase proteins using a microplate reader. We used the S2Vred to screen a library of NifH nitrogenase components targeted to mitochondria in yeast. Two NifH proteins presented properties of great interest for engineering of nitrogen fixation in plants, namely NifM independency, to reduce the number of genes to be transferred to the eukaryotic host; and O2 resistance, to expand the half-life of NifH iron-sulfur cluster in a eukaryotic cell. This study established that NifH from Dehalococcoides ethenogenes did not require NifM for solubility, [Fe-S] cluster occupancy or functionality, and that NifH from Geobacter sulfurreducens was more resistant to O2 exposure than the other NifH proteins tested. It demonstrates that nitrogenase components with specific biochemical properties such as a wider range of O2 tolerance exist in Nature, and that their identification should be an area of focus for the engineering of nitrogen-fixing crops. [ABSTRACT FROM AUTHOR]

Dairy products play an important role in human nutrition, but at the same time, the dairy sector is a major contributor to global warming. The conversion from conventional to organic milk production could reduce the carbon footprint due to the elimination of synthetic fertilizers and strong reliance on closed on-farm nutrient cycling. We present one of the first studies to comprehensively estimate the climate-change impacts of the conversion to organic production of a large-scale dairy operation in central Germany. We used detailed farm data and a carbon footprint approach based on the IPCC tier-2 methodology to estimate greenhouse gas (GHG) emissions associated with feed production, animal husbandry, and animal rearing. Our results show that the carbon footprint per kg of energy-corrected milk (ECM) decreased by 9% during the first year of conversion to organic milk production. Conversely, livestock emissions per kg ECM increased by 12% in the first conversion year due to the increase in methane emissions from enteric fermentation, but this increase was more than offset by the decrease in emissions from feed production. Emissions from internal and external feed production per kg ECM decreased by 17% and 29%, respectively. Our study helps to understand how individual emission sources change as a result of a farm's conversion to organic production. This research is important and timely, as the European Union is pursuing ambitious goals to increase the area under organic farming, although the impact of the conversion period on GHG emissions has been insufficiently studied. [ABSTRACT FROM AUTHOR]

Groundwater pollution of the watershed is mainly influenced by the multifaceted interactions of natural and anthropogenic processes. In this study, classic chemical and multivariate statistical methods were utilized to assess the groundwater quality and ascertain the potential contamination sources affecting the groundwater quality of Galma sub-watershed in a tropical savanna. For this purpose, the data set of 18 groundwater quality variables covering 57 different sampling boreholes (BH) was used. The groundwater samples essentially contained the cations in the following order of dominance: Ca2+ > Na+ > Mg2+ > K+. However, the anions had HCO3– > Cl– > SO4–2 > NO3– respectively. The hydrochemical facies classified the groundwater types of the sub-watershed into mixed Ca–Mg–Cl type of water, which means no cations and anions exceeds 50%. The second dominant water type was Ca–Cl. The Mg–HCO3 water type was found in BH 9, and Na–Cl water type in BH 29 of the studied area. The weathering of the basement rocks was responsible for the concentrations of these ions in the groundwater chemistry of the sub-watershed. Hierarchical cluster analysis (HCA) grouped the groundwater samples (boreholes) into five clusters that are statistically significant regarding the similarities of groundwater quality characteristics. The principal component analysis (PCA) extracted two major principal components explained around 65% of the variance and suggested the natural and anthropogenic processes especially the agricultural pollutants including synthetic fertilizers, and leaching of agricultural waste as the main factors affecting the groundwater quality. The integrated method proved to be efficient and robust for groundwater quality evaluation, as it guaranteed the precise assessment of groundwater chemistry in the sub-watershed of the tropical savanna. The findings of this investigation could be useful to the policy makers for developing effective groundwater management plans for the groundwater resources and protection of the sub-watershed. [ABSTRACT FROM AUTHOR]

Technical best management practices are the dominant approach promoted to mitigate agriculture's significant contributions to environmental degradation. Yet very few social science studies have examined how farmers actually use these practices. This study focuses on the outcomes of farmers' technical best management practice adoption related to synthetic nitrogen fertilizer management in the context of Midwestern corn agriculture in the United States. Moving beyond predicting the adoption of nitrogen best management practices, I use structural equation modeling and data from a sample of over 2500 farmers to analyze how the number of growing season applications a farmer uses influences the rate at which synthetic nitrogen is applied at the field-level. I find that each additional application of N during the growing season is associated with an average increase of 2.4 kg/ha in farmers' average N application rate. This result counters expectation for the outcome of this practice and may suggest that structural pressures are leading farmers to use additional growing season applications to ensure sufficiently high N rates, rather than allowing them to reduce rates. I conclude by discussing the implication of this study for future research and policy. [ABSTRACT FROM AUTHOR]

Purpose: Studying the legume nodule microbiome is important for understanding the development and nutrition of the plants inhabited by the various microbes within and upon them. We analyzed the microbiomes of these underground organs from both an important crop plant (Medicago sativa) and a related legume (M. polymorpha) using metagenomic and culture-based techniques to identify the main cultivatable contributors to plant growth enhancement. Methods: Using high-throughput sequencing, culturing, and in planta techniques, we identified and analyzed a broad population of the bacterial taxa within Medicago nodules and the surrounding soil. Results: Fifty-one distinct bacterial strains were isolated and characterized from nodules of both Medicago species and their growth-promoting activities were studied. Sequencing of 16S rRNA gene amplicons showed that in addition to Ensifer, the dominant genus, a large number of Gram-positive bacteria belonging to the Firmicutes and Actinobacteria were also present. After performing ecological and plant growth-promoting trait analyses, selecting the most promising strains, and then performing in planta assays, we found that strains of Bacillus and Micromonospora among others could play important roles in supporting the growth, health, and productivity of the host plant. Conclusion: To our knowledge, the comparison of the biodiversity of the microbiota of undomesticated vs. cultivated Medicago roots and nodules is novel and shows the range of potential Plant Growth-Promoting Bacteria that could be used for plants of agricultural interest. These and other nodule-isolated microbes could also serve as inoculants with rhizobia with the goal of replacing synthetic fertilizers and pesticides for sustainable agriculture. [ABSTRACT FROM AUTHOR]

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Purpose: This study was conducted to investigate variations in the stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) of agricultural soils under different land uses (i.e., paddy, upland, and orchard) that subjected to different fertilization management (i.e., 15 N-depleted synthetic fertilizer and 13C- and 15 N-enriched livestock manure and compost application). Materials and methods: Soil samples were collected from paddy, upland, and orchard fields in an intensive agricultural area, and forest (pine and oak) soils were additionally included as background soils. The C and N concentrations and isotope ratios of both bulk and water-extractable soil fractions were analyzed. Results and discussion: The δ13C and δ15N of agricultural soils were higher than those of forest soils, reflecting repeated manure and compost applications (for both δ13C and δ15N) and higher N loss (for δ15N) in agricultural soils. Among agricultural soils, orchard (− 24.2‰ for δ13C and + 10.6‰ for δ15N) and upland (− 25.4‰ and + 9.6‰, respectively) soils which received higher rates of manure and compost were more enriched with 13C and 15N compared with paddy (− 28.0‰ and + 4.9‰, respectively). Such differences in the isotopic compositions among agricultural soils were also found for water-extractable soil fractions. Conclusions: Our study suggests that δ13C and δ15N of agricultural soils are affected by land use types with different fertilization management, particularly application of 13C- and 15 N-enriched livestock manure and compost. The δ13C and δ15N could be used as chemical indicators to evaluate the effects of the application of manure and compost on soil C and N dynamics. [ABSTRACT FROM AUTHOR]

Rice production relies on large amounts of synthetic nitrogen fertilizer to meet crop nutritional demands. However, the current fertilizer use efficiency is poor, with an average of 30–50% of total applied nitrogen (N) recovered in grains. Consequently, optimizing N availability and N use efficiency (NUE) has become a major target for rice yield improvement, and looking for quantitative trait loci (QTL) associated with NUE can provide useful information for developing nitrogen efficient rice genotypes. The present study aims to identify QTLs associated with NUE and its two components, agronomic NUE (agNUE) and grain nitrogen increase rate (GIR). A recombinant inbred line population (RIL) derived from a cross between Nipponbare and OM052, consisting of 159 F3 individuals was developed and cultivated in low-N (8 kg N/0.67 ha, N8) and high-N (18 kg N/0.67 ha, N18) conditions. Specific length amplified fragment sequencing (SLAF) was used to genotype the RILs and construct a high-density linkage map spanning 1587.70 cM, consisting 2707 SLAF markers with an average interval of 0.59 cM between adjacent marker loci. QTL analysis confirmed four significant QTLs distributed among chromosome 1, 6, and 11, with the proportion of phenotypic variance explained by each QTL ranging from 2.96 to 11.11% and LOD scores from 1.67 to 3.75. Functional annotation of genes located within the QTL intervals revealed NUE putative candidate genes. Overall, the QTLs identified in this study contribute information that could be useful for NUE improvement in rice. [ABSTRACT FROM AUTHOR]

The perception of phytoremediation is efficiently utilized as an eco-friendly practice of green plants combating and cleaning up the stressed environment without harming it. The industrial revolution was followed by the green revolution which fulfilled the food demands of the growing population caused an increase in yield per unit area in crop production, but it also increased the use of synthetic fertilizers in agriculture. Globally, the intensive use of inorganic fertilizers in agriculture has led to serious health problems and irreversible environmental damage. Biofertilizers improve the growth of the plant and can be applied as an alternative to chemical/synthetic fertilizers. Cyanobacteria, bacteria, and fungi are known as some of the principal microbe groups used to produce biofertilizers that form symbiotic associations with plants. Microorganisms perform a key role in phosphate solubilization and mobilization, nitrogen fixation, nutrient management, biotic elicitors and probiotics, and pollution management (biodegradation agents), specifically bacteria which also help in atmospheric nitrogen fixation and are thus available for the growth of the plant. Management or biodegradation of hazardous chemical residues and heavy metals produced by a huge number of large-scale industries should be given primary importance to be transformed by various bacterial strains, fungi, algae. Currently, modern omics technologies such as metagenomic, transcriptomic, and proteomic are being used to develop strategies for studying the ecology of microorganisms, as well as their use in environmental monitoring and bioremediation. This review briefly discusses some of the major groups of microorganisms that can perform different functions responsible for plant health, crop production, phytoremediation and also focus on the omics techniques reportedly used in environmental monitoring to tackle the pollution load. [ABSTRACT FROM AUTHOR]

This paper presents EuropeAgriDB v1.0, a dataset of crop production and nitrogen (N) flows in European cropland 1961–2019. The dataset covers 26 present-day countries, detailing the cropland N harvests in 17 crop categories as well as cropland N inputs in synthetic fertilizers, manure, symbiotic fixation, and atmospheric deposition. The study builds on established methods but goes beyond previous research by combining data from FAOSTAT, Eurostat, and a range of national data sources. The result is a detailed, complete, and consistent dataset, intended as a basis for further analyses of past and present agricultural production patterns, as well as construction of scenarios for the future. Measurement(s) agricultural process Technology Type(s) Survey Factor Type(s) year • geographic location Sample Characteristic - Environment agriculture Sample Characteristic - Location Europe Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.14893077 [ABSTRACT FROM AUTHOR]

Identifying sources of nitrate contamination has been a long-term challenge in areas with different land uses. We investigated the biogeochemical processes and quantified the contribution of potential nitrate sources in the Nanyang Basin, the source area of the South to North Water Diversion Project in China. Hydrogeochemical characteristics, the dual-isotope method (δ15N-NO3− and δ18O-NO3−), and the Bayesian mixing model (SIAR) were combined. The results for 160 samples indicated that mean nitrate concentrations of residential area (162.83 mg L−1) and farmland (75.71 mg L−1) were higher compared with those of surface water (16.15 mg L−1) and forest (36.25 mg L−1). Hydrochemical facies and molar ratios of major ions indicated that the natural environment was greatly impacted by anthropogenic activities. Nitrification, ammonium volatilization, and mixing effects were the dominant processes in nitrogen transformation. The contributions of different sources to nitrate contamination were 45.41%, 35.81%, 17.87%, and 0.91% for sewage and manure, soil organic nitrogen, synthetic fertilizer, and atmospheric deposition, respectively. Undeveloped infrastructure and sewage disposal in rural areas were the main causes of nitrate contamination. Our results provide a theoretical basis for the development of measures to guarantee long-term water supply of the South to North Water Diversion Project. [ABSTRACT FROM AUTHOR]

Summer-season groundwater from three agricultural basins (i.e., El Potosi, Sandia and Cieneguilla) in drought-prone northeast Mexico was assessed for drinking and irrigation by evaluating their physicochemical parameters with respect to the World Health Organization Guidelines for drinking water quality (WHO, Geneva, 2011) standards, and by estimating water quality indices (DWQI and IWQI). Facies of Ca–Mg–HCO3, Ca–Mg–Cl and Ca–Mg–SO4 mostly reflected the influences of aquifer lithologies. Ca exceeded WHO (2011) maximum allowable limit in most of the samples due to dissolution of gypsum-bearing limestone. Most of the samples (69–93%) were in excellent and good categories (DWQI < 100) for drinking and the samples of poor to very poor categories (7–31%) had salinity above the recommendation of WHO (2011). Fluoride of > 1.5 mg/L in 13% samples from the El Potosi Basin could expose some population to dental and skeletal fluorosis. Similarly, nitrate (> 42 mg/L), mostly from synthetic fertilizers, in 13% samples of the Sandia Basin might affect human health through methemoglobinemia in infants. In the context of irrigation suitability, the samples with > 75% permeability in the Donnen classification are good for irrigation. US Regional Salinity Laboratory classification, however, grouped most groundwater the from El Potosi Basin (medium-salinity hazard) as suitable for irrigation, whereas most samples from the Cieneguilla Basin and half of the samples from Sandia Basin (high-salinity hazard) should only be used to irrigate salt-tolerant plants with enhanced drainage condition. IWQI values also suggested that most samples (low-restriction category) are suitable only for irrigating light texture and moderately permeable soils. The groundwater management in this region should involve practices to increase water holding capacity of the substrate and modify the frequency of watering as per plant demand. [ABSTRACT FROM AUTHOR]