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The article presents a study which investigated how urea use over an extended period affects the qualities of the soil. The researchers showed that yearly applications of urea over an extended time caused soil acidification and reduced the amount of exchangeable bases in the soil. Factors that have an impact on the crop yield are mentioned. Also noted are farmers' perception on the impact of chemical fertilizer on environment.

The article provides information on an experiment conducted in Randomized Complete Block Design (RCBD) with ten treatments and three replications to evaluate growth, yield, and quality parameters of chili, an important vegetable and spice crop. Topics discussed include one of the most important uses of nano technology, effect of Nano DAP and urea on growth yield and quality of chili, and environmental problems caused by chemical fertilizers.

Due to nitrogen fertilizers consumption and unsafe wastewater networks of cities, now nitrate pollution is one of the challenging issues of surface and groundwater pollution. In case of this contaminant present in drinking water causes 'Blue Baby' disease for infants, cancers, and harmful for pregnant women. So, it is very important to assess nitrate concentration for maintaining better health precaution. Nitrate concentration, dispersion and its distribution status were evaluated in Warangal District, India. The samples show that nitrate concentration in Warangal is very high in both urban and agriculture area which have maximum level of 49.5 & 83.3 mg/liter as (NO3 - N); average value of 40.3 and 69 mg/l respectively. Even though in urban area the amount of concentration is somehow low, but it also is in harmful level. Nitrate dispersion could be observable from the high standard deviations which are 7.4 for urban area and 12.065 for agriculture area, it means nitrate dispersion in agriculture area is more than urban area's groundwater and it is clearly observed from normal distribution curves. This high spread out on nitrate concentration shows many variations of nitrate sources from many different locations that various amount of nitrate pollutions is infiltrated into groundwater. [ABSTRACT FROM AUTHOR]

The paper presents selected issues of managing nutrients from natural fertilizers used in Polish agriculture. The analysis covered changes in the livestock population and stocking density, the number and share of farms using natural fertilization, fertilized area and the level of consumption of particular nutrients from manures. Spatial analysis was carried out at the level of voivodeships (NUTS-2) and concerned the determination of the amount of nutrient from natural fertilizers in 2017-2020. The presented results indicate that the level of stocking density has the greatest impact on regional differences in the management of natural fertilizers. This diversity is also manifested in the share of farms using natural fertilization in individual voivodeships. Natural fertilizers in Poland, mainly manure, are used on 27% of UAA in good agricultural and environmental condition (UAA in GAEC). The share of four voivodeships, ie Podlaskie, Wielkopolskie, Łódzkie and Mazowieckie, covers 55% of the total area fertilized with manures in the country. In the years 2017-2020, the average consumption of solid manure in the country was 44.3 million t, poultry manure 0.9 million t, liquid manure 8.0 million m³ and slurry 14.6 million m³. The highest intensity of natural fertilization was found in the Podlaskie voivodeship, the average consumption was 11.4 t ha-1 of all agricultural land, while in Poland the average consumption was estimated at 4.6 t ha-1 of UAA in GAEC. The highest doses per fertilized area were applied in the Podlaskie, Warmińsko-Mazurskie, Lubelskie, Lubuskie and Pomorskie voivodeships and it was directly related with the level of consumption of NPK from natural fertilizers in these voivodeships. In the analyzed period, the average doses of nitrogen, phosphorus and potassium applied to the manures' fertilized area in Poland were 87 kg N ha-1, 29 kg P2O5 ha-1, 113 kg K2O ha-1, respectively. The highest nutrient consumption in natural fertilizers was observed in Podlaskie voivodeship. Based on the analyses, it can be concluded that the Podlaskie voivodeship is a leader in the intensity of natural fertilizer management in Poland. [ABSTRACT FROM AUTHOR]

This paper establishes an analysis framework to investigate the effect of the awareness of consequences and the ascription of responsibility on farmers' organic fertilizer application behaviors (OFABs). Using questionnaire survey data from Hubei Province, one of the main grain-producing areas in China, this study employed both mediating effects and moderating effect analytical methods to analyze the influencing mechanism of the awareness of consequences and ascription of responsibility on farmers' OFABs. The results show that, firstly, the awareness of consequences and ascription of responsibility have a significant positive impact on farmers' OFABs. The improvement in farmers' awareness of consequences and ascription of responsibility can effectively promote the utilization of organic fertilizers for enhanced ecological production. Secondly, the awareness of consequences and ascription of responsibility have a significant positive impact on farmers' OFABs through individual farmers' personal norms. Increasing farmers' awareness of consequences and ascription of responsibility firstly stimulates their personal norms; then, personal norms have a positive impact on farmers' OFABs. Thirdly, farmers' social norms can positively regulate the relationship between personal norms and their OFABs. The higher the social norms of farmers, the more their social norms can have a positive regulating effect on their OFABs. Therefore, in the future, it will be necessary to vigorously promote farmers' awareness of consequences and ascription of responsibility, in order to enhance farmers' social norms, and to improve the level of farmers' social norms, in order to greatly promote farmers' engagement in OFABs. This will ultimately better promote rural ecological environmental protection and ecological civilization construction. [ABSTRACT FROM AUTHOR]

The overuse of chemical fertilizers and pesticides has not only reduced the agricultural products qualities, but also taken a toll on the rural ecological environment. In the case of widespread overuse of agrochemical inputs, how to reduce the use intensities has become the predominant hinder for the high-quality development of agriculture in contemporary China. From the point of view that the urban-rural transformation of China calls for the reallocation of rural land and agricultural workforce, this paper theoretically analyzed the impact of farmers' willingness to abdicate land usufruct on the intensity of fertilizers and pesticides use. We categorized land usufruct abdication into partial-abdication and total-abdication, and the intensities of fertilizers and pesticides use were proxied by the expenditure on fertilizers and pesticides per mu, respectively. To address the endogeneity issue, the treatment effects model (TEM) was applied to the household survey data collected from 853 households in Shandong, Jiangsu and Anhui provinces in China in July and August 2019. The results showed that: Given the compensation standards, 50. 40% and 34. 50% of the farmer households intended to partially or totally abdicate their land usufruct, respectively; the expenditures on fertilizers and pesticides were 93.24 and 97.44 yuan/mu higher for those having willingness to partially or totally abdicate land usufruct compared to their counterparts, respectively. The results suggested that the stronger the willingness to abdicate land usufruct, the higher the intensities of fertilizers and pesticides use. The robustness test also revealed that farmers' willingness to abdicate land usufruct positively affected the intensities of fertilizers and pesticides use. To further reduce the overuse of agrochemical inputs and realize the development of green agriculture, it is necessary to comprehensively improve the institutional arrangement of land usufruct abdication for rural migrant farmers, actively cultivate large-scale agricultural business entities, and promote optimal allocation of farmlands. [ABSTRACT FROM AUTHOR]

For soil and environmental remediation, biochar/struvite composites are prepared by the crystallization-adsorption method. The recovery rates of N, P, and Mg in the solution increase to 99.02%, 97.23%, and 95.22%, respectively, by forming 10% biochar/struvite composite. X-ray diffraction (XRD) patterns acquired from the 10% biochar/struvite composite show a crystalline structure of MgNH4PO4·6H2O (PDF no. 15-0762) and release of the main nutrient elements (N, P, Mg) from the 10% biochar/struvite composite increases significantly compared to struvite. The solubility of the biochar/struvite composite is the highest in 0.5 mol/L HCl, second in 20 g/L citric acid, and lowest in water. The power function equation describes more precisely the cumulative release of N, P, and Mg from the biochar/struvite composite in distilled water, whereas it follows the simple Elovich equation in 20 g/L critic acid and first-order kinetics equation in 0.5 mol/L HCl. Leaching experiments are performed on the biochar/struvite composite in soil, and the results indicate that the biochar/struvite composite has a longer cycle of release of nutrients than traditional chemical fertilizers and has large potential as a slow-release fertilizer. [ABSTRACT FROM AUTHOR]

To address nitrogen (N)-related environmental pollution, development of an economical, slow-release urea fertilizer is the need of the hour. A study was conducted on the reduction of nitrogen released from granular urea fertilizer by applying sulfur, gypsum, bentonite, and starch as coating material. Paraffin wax was used as a binder. The dissolution rates were studied by changing the composition of coating mixture using high-performance liquid chromatography. SEM was used to study the morphology of coated urea in terms of smoothness and uniformity. The ultraviolet spectroscopy analysis further authenticated the release behavior of coated urea in terms of nitrogen concentration. Coating material reduced the release rate of nitrogen from urea fertilizer, significantly. Mixture of sulfur and gypsum coating on urea gave slowest release rate of nitrogen from urea fertilizer, i.e., 37%, as compared to uncoated urea and thus seems to be the most promising binding material for product development. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Long-term effects of biochar and fertilizer N on crop yields were studied. • Biochar combined with fertilizer N showed a strong positive effect on crop yields. • The regression models were built to forecast the highest yield and net income. • Low application rate of biochar can create high economic benefits. Abstract Biochar has been used as an amendment to reduce soil acidity and increase soil nutrients content and crop yields. While many laboratory studies have focused on the short-term effects of single application of biochar on soil properties, little is known about the long-term effects of biochar combined with nitrogen fertilizer on soil pH, available P content, and crop yields. Additionally, few studies have investigated the optimal biochar and nitrogen fertilizer application proportions in worldwide. A five-year field trial was conducted to study the effects of biochar (0, 5, 20 and 40 t ha−1) combined with nitrogen fertilizer (0, 60, 90, 120 kg ha−1) on soil pH, available P, rapeseed, and sweet potato yield. Multi-dimensional nonlinear regression models were built to predict the highest crop yields and the optimal economical biochar and nitrogen fertilizer application rate. The results were as follows: high dose of biochar (20 and 40 t ha−1) combined with nitrogen fertilizer can significantly increase soil pH, available P content, rapeseed and sweet potato yields in the first year; however, the effectiveness on these metrics weakened over time, biochar needed to be applied approximately every three years in the rapeseed-sweet potato rotation system in order to maintain the positive effects on crop yields. The multi-dimensional regression models showed that the highest yields of rapeseed and sweet potato are 3.34 t ha−1 and 39.7 t ha-1 when the application rates of biochar were 80.8 t ha-1 and 59.4 t ha-1 respectively. However, high dosages of biochar can increase crop yields without increasing net income. The highest net income was $29,206 ha−1 5y−1 ($5841 ha−1 y−1) when the application rates of biochar and nitrogen fertilizer are 11.4 t ha-1 and 102 kg ha-1, respectively. The integrated use of biochar and nitrogen fertilizer was a promising strategy to obtain higher and sustained productivity of the rapeseed-sweet potato cropping system in upland red soil. From the point of view of crop yields and economic benefits, 11.4 t ha−1 biochar was the optimal biochar application rates for the local farmers. [ABSTRACT FROM AUTHOR]

Our understanding and quantification of global soil nitrous oxide (N2O) emissions and the underlying processes remain largely uncertain. Here, we assessed the effects of multiple anthropogenic and natural factors, including nitrogen fertilizer (N) application, atmospheric N deposition, manure N application, land cover change, climate change, and rising atmospheric CO2 concentration, on global soil N2O emissions for the period 1861–2016 using a standard simulation protocol with seven process‐based terrestrial biosphere models. Results suggest global soil N2O emissions have increased from 6.3 ± 1.1 Tg N2O‐N/year in the preindustrial period (the 1860s) to 10.0 ± 2.0 Tg N2O‐N/year in the recent decade (2007–2016). Cropland soil emissions increased from 0.3 Tg N2O‐N/year to 3.3 Tg N2O‐N/year over the same period, accounting for 82% of the total increase. Regionally, China, South Asia, and Southeast Asia underwent rapid increases in cropland N2O emissions since the 1970s. However, US cropland N2O emissions had been relatively flat in magnitude since the 1980s, and EU cropland N2O emissions appear to have decreased by 14%. Soil N2O emissions from predominantly natural ecosystems accounted for 67% of the global soil emissions in the recent decade but showed only a relatively small increase of 0.7 ± 0.5 Tg N2O‐N/year (11%) since the 1860s. In the recent decade, N fertilizer application, N deposition, manure N application, and climate change contributed 54%, 26%, 15%, and 24%, respectively, to the total increase. Rising atmospheric CO2 concentration reduced soil N2O emissions by 10% through the enhanced plant N uptake, while land cover change played a minor role. Our estimation here does not account for indirect emissions from soils and the directed emissions from excreta of grazing livestock. To address uncertainties in estimating regional and global soil N2O emissions, this study recommends several critical strategies for improving the process‐based simulations. The ensemble of terrestrial biosphere models indicates that global soil N2O emissions have increased from 6.3 ± 1.1 Tg N2O‐N/year in the preindustrial period (the 1860s) to 10.0 ± 2.0 Tg N2O‐N/year in the recent decade (2007–2016). Cropland soil emissions increased from 0.3 Tg N2O‐N/year to 3.3 Tg N2O‐N/year over the same period, accounting for 82% of the total increase, among which 54% attributes to nitrogen fertilizer application. Regionally, China, South Asia, and Southeast Asia underwent rapid increases in cropland N2O emissions since the 1970s. However, European cropland N2O emissions appear to have decreased by 14%. [ABSTRACT FROM AUTHOR]

Highlights • Nitrous oxide emissions were higher in the apple orchard than in the wheat field. • Summer rainfall and winter snowfall were the principal controllers of N 2 O fluxes. • A moisture threshold associated with rainfall triggered higher N 2 O emissions. • Nitrous oxide emission due to land use change was altered by precipitation in arid region. Abstract The conversions of cropland to forest, or other tree-based systems, are considered to be important processes affecting regional and global greenhouse gas budgets, especially for nitrous oxide (N 2 O). From April 2007 to March 2009, in the rain-fed semi-arid climate of the Loess Plateau, China, soil N 2 O emissions were measured using static chambers from a winter wheat field and an apple orchard, which had been established in part of the wheat field 23 years earlier.Annual average N 2 O emissions from the apple orchard (2.40 kg N 2 O ha−1yr−1) were 12.15% higher than those in the wheat field (2.14 kg N 2 O ha−1yr−1). Seasonal rainfall, in combination with higher nitrogen fertilization, had a promoting effect on N 2 O emissions in the apple orchard compared with the wheat field. The amounts and patterns of summer rainfall and winter snowfall were the principal controllers of seasonal and annual N 2 O fluxes in these rain-fed semi-arid regions, likely through their influence on soil moisture content. Since there may be a moisture threshold associated with summer rainfall and winter snowfall triggering higher N 2 O emissions, climatic regimes should be taken into account when assessing the effects of land use on N 2 O emissions in the Loess Plateau. [ABSTRACT FROM AUTHOR]

Abstract Nutrient pollution is of worldwide environmental and health concerns due to extensive use of nitrogen fertilizers and release of livestock waste, which induces nitrite compounds in aquatic systems. Herein a surface-enhanced Raman scattering (SERS) sensor is developed for nitrite detection based on coupling between the plasmonic gold nanostars and the silver nanopyramid array. When nitrite is present in the assay, an azo group is formed between the 1-naphthylamine-functionalized silver nanopyramids and the 4-aminothiophenol-functionalized gold nanostars. This not only generates the SERS spectral fingerprint for selective detection, but also creates "hot spots" at the gap between the Au nanostars and the Ag nanopyramids where the azo group is located, amplifying SERS signals remarkably. Finite-difference time-domain (FDTD) simulation shows a SERS enhancement factor of 4 × 1010 at the "hot spots". As a result, the SERS sensor achieves a limit of detection of 0.6 pg/mL toward nitrite in water, and enables nitrite detection in real-world river water samples. In addition, this sensor eliminates the use of any Raman reporter and any expensive molecular recognition probe such as antibody and aptamer. This highly sensitive, selective and inexpensive SERS sensor has unique advantages over colorimetric, electrochemical and fluorescent devices for small molecule detection. Graphical abstract Image 1 Highlights • Label-free: no any sensing signal label/reporter is used to construct the SERS sensor. • High specificity: the newly formed azo group generates unique SERS spectral fingerprints for nitrite detection. • High sensitivity: the SERS enhancement factor reaches ∼4 × 1010, allowing a limit of detection of 0.6 pg/mL. • Low cost: the sensor design has eliminated the use of a Raman label and expensive reagents such as aptamers and antibodies. [ABSTRACT FROM AUTHOR]

The nutrient availability to plants is major limiting factor determining the crop production. Chemical fertilizers are, no doubt, a milestone to fulfill the nutrient deficiency but presently mankind is facing a huge threat of environment damage as well as resource depletion. At the same time population explosion is also a major concern. To feed such a large population (8.5 x 109 in 2025) unexploited resources should be used to enhance the crop production and to improve quality of soil. The various plant specific nitrogen fixing, phosphate solubilizing, potassium solubilizing and zinc mobilizing microorganisms can be used to enhance the bioavailability of nutrients to plants. This biological method is not only sustainable for long run but also economical and thus can be used as biofertilizers. These microorganisms can be commercially made available to farmers in the form of carrier based, liquid or encapsulated formulations containing latent or active forms. Apart from nutrient mobilization, they can also act as bioenhancers and biopesticides. However, efficiency and acceptance of biofertilizer among farmers is still a big concern. This review article focuses on efficiency of biofertilizers to replace or supplement the synthetic fertilizers for soil fertilization. [ABSTRACT FROM AUTHOR]

Phosphate fertilizers were first implicated by Schroeder and Balassa (Science 140(3568):819-820, 1963) for increasing the Cd concentration in cultivated soils and crops. This suggestion has become a part of the accepted paradigm on soil toxicity. Consequently, stringent fertilizer control programs to monitor Cd have been launched. Attempts to link Cd toxicity and fertilizers to chronic diseases, sometimes with good evidence, but mostly on less certain data are frequent. A re-assessment of this "accepted" paradigm is timely, given the larger body of data available today. The data show that both the input and output of Cd per hectare from fertilizers are negligibly small compared to the total amount of Cd/hectare usually present in the soil itself. Calculations based on current agricultural practices are used to show that it will take centuries to double the ambient soil Cd level, even after neglecting leaching and other removal effects. The concern of long-term agriculture should be the depletion of available phosphate fertilizers, rather than the negligible contamination of the soil by trace metals from fertilizer inputs. This conclusion is confirmed by showing that the claimed correlations between fertilizer input and Cd accumulation in crops are not robust. Alternative scenarios that explain the data are presented. Thus, soil acidulation on fertilizer loading and the effect of Mg, Zn and F ions contained in fertilizers are considered using recent Cd2+, Mg2+ and F- ion-association theories. The protective role of ions like Zn, Se, Fe is emphasized, and the question of Cd toxicity in the presence of other ions is considered. These help to clarify difficulties in the standard point of view. This analysis does not modify the accepted views on Cd contamination by airborne delivery, smoking, and industrial activity, or algal blooms caused by phosphates. [ABSTRACT FROM AUTHOR]

Abstract There are large yield gaps in the mixed smallholder farming systems of Africa, with limited opportunities to sustainably increase productivity and adapt to climate change. In this study, the ex-ante potential of residue retention and fertilization measures to meet this challenge is assessed using a positive mathematical programming (PMP) model. This micro-economic model captures decision making at the farm level for a sample population in Northern Burkina Faso for the 2010 to 2045 simulation period. In contrast to previous studies of mixed farms in this area, we model each individual farm in the sample population, instead of one or a small number of representative farms. We are therefore able identify groups of farms for which each measure is profitable, applied either individually or as a combined package. This approach also enables simulation of the economic impacts from indiscriminate applications of the measures or "smart" applications which are restricted to the farms that profit from the measures. Our findings are aligned with other studies showing that residue retention causes trade-offs between crop and livestock production, while fertilization can synergistically raise returns to both production activities. The annual profit losses from the "middle of the road" RCP6 trajectory of climate change assumed in this study were estimated to reach 15% by 2045. The smart package of measures increased aggregate profit the most, although not by nearly enough to claw back the losses from climate change. The fertilizer measures were the next most profitable, with indiscriminately applied residue retention being the only measure to reduce aggregate profit relative to this climate change baseline. Importantly, the measures that are the most profitable at the aggregate level are not necessarily those that would be the most widely adopted. For example, residue retention is profitable for a larger share of the sample population than fertilization. The advantage of the population scale analysis used in this study is that it prevents measures such as residue retention, which can benefit a significant share of farms, from being disregarded by practitioners because they appear to be unprofitable at the aggregate level or when viewed through the lens of an average representative farm. Finally, amidst the growing emphasis of studies on the benefits of packages compared to individual measures, the findings from this study are more equivocal about this choice, suggesting that extension programs should have the flexibility to apply measures individually or as a package. Highlights • Annual profit losses from climate change (RCP6) reach 15% by 2045. • Most profitable adaptation options at aggregate level unlikely to be most adopted. • Residue retention reduces livestock profits, but improves profits for 51% of farmers. • Packages of adaptation options have no clear advantage over individual options. [ABSTRACT FROM AUTHOR]

Abstract The study area is located in the south of Mali and is the most populous part of the country with intense agricultural activities that use a huge amount of mineral fertilizers and pesticides. Mining is another booming industry within the area which is dominated by the proliferation of traditional gold panning where the use of certain heavy metals is inevitable hence resulting in the degradation of the groundwater quality. Groundwater is becoming increasingly vulnerable to pollution from the gold-panning activities. Assessment of the vulnerability of groundwater has become a useful tool for decision support in monitoring the pollution. This study uses vulnerability mapping as a basic tool for monitoring groundwater resources from pollution. It is based on the DRASTIC model for estimating the vulnerability of groundwater pollution in the Upper Niger and Bani Basins. The use of GIS in the model makes it possible to assess the vulnerability of groundwater by superimposing different spatially referenced hydrogeological parameters that affect groundwater contamination. The study focuses on the hydrogeological, hydrodynamic and physicochemical characteristics of over three thousand boreholes. Thirty samples from mining sites only were analyzed to determine presences of heavy metals in the groundwater. Vulnerability analysis makes it possible to understand the role played by heavy metals and nitrates in monitoring the pollution. The results obtained exhibit that 6.43% of the surface has a very high vulnerability; 52.12% are of high vulnerability; 36.89% are of moderate vulnerability; 4.57% are of low vulnerability, and 0.004% are of very low vulnerability. The large variation of the vulnerability index is observed in the elimination of depth layers (mean variation index = 3.09%), the lower the depth, the greater the vulnerability. The vadose zone with an average index change of 0.52% has the least effect on the overall change in the vulnerability index. Validation of the vulnerability map is done using the nitrate map indicating that maximum concentrations of 92.65 mg/l is observed in the very high vulnerability class. The concentrations of heavy metals such as cyanide, cadmium, arsenic, lead, and chromium is also used in the validation. Levels of lead (0.702 mg/l), chromium (0.0588 mg/l) and arsenic (0.54 mg/l) are above the global standard whereas cadmium (0.0013 mg/l) and cyanide (0.006 mg/l) are below international standards. The presence of these metals in very small amounts in groundwater samples indicates contamination. The use of GIS allows interpolation from the data with Geostatistical methods and extraction of zonal statistics for a better interpretation of the results. Highlights • Groundwater Sensibility Assessment as a decision-making tool in the prevention and protection against pollution. • Heavy metals and nitrates pollution in the Upper Niger and Bani basins. • Agriculture, Gold panning and, Mines pollution. [ABSTRACT FROM AUTHOR]

Abstract Fertilizer samples were collected in the city of Rio de Janeiro and were analyzed using HPGe detector. The specific activities of Ra-226 ranged from 1.48 Bq/kg to 597 Bq/kg, of Ra-228 from 2.66 Bq/kg to 832 Bq/kg and of K-40 from 16 Bq/kg to 13941 Bq/kg. The risk to human health was found to be negligible. Highlights • Several fertilizer samples were analyzed by gamma spectroscopy. • Specific concentration of fertilizers were calculated. • Were analyzed the risk to human health and for environmental contamination. [ABSTRACT FROM AUTHOR]

In agriculture honey bees may be exposed to multiple pesticides. In contrast to single applications of plant protection products (PPP), the effects of tank mixtures of two or more PPP on honey bees are not routinely assessed in the risk assessment of plant protection products. However, tank mixes are often common practice by farmers. Mixtures of practically non-toxic substances can lead to synergistic increase of toxic effects on honey bees, observed for the first time in 19921 in combinations of pyrethroids and azole fungicides. 2004 Iwasa et al. already reported that ergosterol-biosynthesis-inhibiting (EBI) fungicides strongly increase the toxicity of neonicotinoids in laboratory for the contact exposure route. Furthermore, in agricultural practice additives, adjuvants and fertilizers may be added to the spray solution. For these additives usually no informations on potential side effects on bees are available when mixed with plant protection products. Therefore, it is considered necessary to investigate possible additive or synergistic impacts and evaluate potentially critical combinations to ensure protection of bees. Here, we investigated the effects on bees of combinations of insecticides, fungicides and fertilizers under controlled laboratory conditions. A spray chamber was used to evaluate effects following contact exposure by typical field application rates. Subsequently, mortality and behaviour of bees were monitored for at least 48 h following the OECD acute contact toxicity test 2143. Dependencies of synergistic effects and the time intervals between the applications of the mixing partners were evaluated. [ABSTRACT FROM AUTHOR]

Purpose: Vegetables are major economic crops in China. Their cultivation usually involves high fertilizer application rates leading to significant losses of N and P to the wider environment, resulting in water contamination and low nutrient use efficiency. Hence, it is a matter of urgency to understand the mechanisms and factors that affect N and P losses in vegetable production systems in order to develop optimum fertilization regimes.Materials and methods: Different fertilization regimes were applied in a long-term chili (Capsicum spp. L.) production soil to study the effects on nitrogen (N) and phosphorus (P) runoff losses, microbial biomass, microbial community, and crop yields. Three fertilization regimes were implemented: control (no fertilizer; CK), farmer’s fertilization practice (FFP), and site-specific nutrient management (SSNM). A fixed collection device was used to quantify the total volume of water output after each precipitation event. All water samples were analyzed for total nitrogen, ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total phosphorus (TP), and available phosphorus (AP). Soil samples were collected for analysis of the physicochemical properties and for DNA extraction after chili harvest. High-throughput sequencing was used to further investigate the relationship between the microbial community and nutrient losses.Results and discussion: The SSNM fertilizer regime resulted in a 23.3% yield increase and enhanced agronomic N use efficiency from 11.87 to 15.67% compared with the FFP treatment. Soil available nutrients (i.e., AN and AP) and ATP content increased significantly after SSNM implementation. Under the SSNM regime, N losses decreased by 25.8% compared with FFP but did not lead to significantly different P losses. High-throughput sequencing results showed that each treatment formed a unique microbial community structure. VPA results revealed that the microbial community structure was mainly (50.56%) affected by the interactions between N and P. Mantel results indicated that the soil properties that significantly affected soil microbial community structure followed the order: AP, AK, and salinity.Conclusions: Our study has demonstrated that SSNM not only generates lower N losses but also provides higher contents of soil available nutrients and plant yield, which were mainly attributed to the multiple top dressings and meeting of the plants’ demand with adequate nutrient supplies. The combined data showed that the microbial community differentiation between the different fertilizer regimes was mainly linked to the interactions between N and P in the soil. [ABSTRACT FROM AUTHOR]

Agroecosystems face double pressures of producing more food to feed growing global population and reducing greenhouse gas (GHG) emissions to mitigate climate change. The Huang-Huai-Hai (HHH) plain produces ∼1/3 wheat and maize of China with very high resource inputs, particularly synthetic nitrogen (N) fertilizers since the 1980 s. Although fertilizer input has substantially increased crop yield and enhanced biomass carbon (C) input to the soil and thus stimulating soil C sequestration, GHG emissions (e.g., nitrous oxide (N 2 O)) relating to the fertilizers have been also dramatically increased. Yet, a systematic regional assessment on the trade-offs between crop yield, soil C sequestration and N 2 O emissions as impacted by management practices and environmental conditions is lacking. Here we calibrated a farming system model to conduct comprehensive assessment on crop yield and GHG emissions (soil CO 2 and N 2 O emissions) during the period 1981–2010 across the HHH plain at the resolution of 10 km. We found that soil in HHH plain was a C sink with an annual C sequestration rate of 1.53 CO 2 -eq ha −1 yr –1 (0–30 cm soil layer) during the period under current typical agricultural practices, but this sink could only offset about 68% of global warming potential from contemporary N 2 O emissions. By reducing the annual N input rate (from current more than 300 to ∼250 kg N ha −1 yr −1 ) and enhancing crop residue retention rate (from current 30% to 100%), the HHH plain could act as a net sink of GHG without sacrificing grain yield. Apart from management, the effects of three key environmental factors, i.e., mean annual rainfall and temperature and initial soil organic carbon stock on dynamics of crop yield, soil CO 2 and N 2 O emissions were also studied. The results will have important implications for the development of management strategies to maintain yield while reducing GHG emissions. [ABSTRACT FROM AUTHOR]

The objective of this study was to manufacture of a granular biochar-ammonium phosphate (BAP) as an uncoated-slow release fertilizer by using the reaction among biochar (derived from rice husk), phosphoric acid and ammonia gas for fertilization of sandy soil. In this study we assessed the influence of two types of BAP {1.5 mol NH 3 +(0.76 molH 3 PO 4 +150 g biochar) BAP1and 1.5 mol NH 3 +(0.76 mol H 3 PO 4 +220 g biochar) BAP2} on nitrogen (N) use efficiency (NUE) and N losses in leachate water and compared them to a conventional mineral N fertilizer (ammonium phosphate, AP). Additionally the surface morphology of biochar, BAP1 and BAP2 was examined by scanning electron microscopy (SEM) and Fourier transfer infra-red (FT-IR). SEM and FT-IR confirmed the formation of ammonium phosphate inside the biochar's pores. Release of the available nitrogen (NH +4 -H and NO −3 - H) from both BAP1 and BAP2 fertilizers was detected to be slow and low compared with AP fertilizer. pots treated with either BAP1 or BAP2 demonstrated fundamentally higher (p < 0.05) N content and vegetative improvement compared with AP, however no critical difference (p > 0.05) were found among BAP1 and BAP2 fertilizers. Correspondingly, the synthesis of this new fertilizer using this technology provided a unique organic matter in the manufacture of uncoated-slow release fertilizer. Subsequently, BAP could be used as an uncoated-slow release fertilizer to maximize the functions of the nitrogen fertilizer when added to a sandy soil and minimize its environmental impact. [ABSTRACT FROM AUTHOR]

Accounting for nitrogen (N) release from organic amendments (OA) can reduce the use of synthetic N-fertiliser, sustain crop production, and potentially reduce soil borne greenhouse gases (GHG) emissions. However, it is difficult to assess the GHG mitigation potential for OA as a substitute of N-fertiliser over the long term due to only part of the organic N added to soil is being released in the first year after application. High-resolution nitrous oxide (N 2 O) and carbon dioxide (CO 2 ) emissions monitored from a horticultural crop rotation over 2.5 years from conventional urea application rates were compared to treatments receiving an annual application of raw and composted chicken manure combined with conventional and reduced N-fertiliser rates. The repeated application of composted manure did not increase annual N 2 O emissions while the application of raw manure resulted in N 2 O emissions up to 35.2 times higher than the zero N fertiliser treatment and up to 4.7 times higher than conventional N-fertiliser rate due to an increase in C and N availability following the repeated application of raw OA. The main factor driving N 2 O emissions was the incorporation of organic material accompanied by high soil moisture while the application of synthetic N-fertiliser induced only short-term N 2 O emission pulse. The average annual N 2 O emission factor calculated accounting for the total N applied including OA was equal to 0.27 ± 0.17%, 3.7 times lower than the IPCC default value. Accounting for the estimated N release from OA only enabled a more realistic N 2 O emission factor to be defined for organically amended field that was equal to 0.48 ± 0.3%. This study demonstrated that accounting for the N released from repeated application of composted rather than raw manure can be a viable pathway to reduce N 2 O emissions and maintain soil fertility. [ABSTRACT FROM AUTHOR]

European agriculture is a large importer of nutrients in the form of chemical fertilizers. Additionally, countries with livestock-intensive farming face problems with disposal of nutrients in animal manure. The availability of chemical fertilizers has changed farmers' past dependence on manure. Nowadays, despite its nutrient content, manure is sometimes considered as a waste product. However, if the characteristics of manure and other waste streams could be enhanced through processing, it could be transformed into an alternative bio-based fertilizer recycling the nutrients within the farming sector. This would also create opportunities for nutrient exchange between different European regions. However, a key question is what is needed for farmers to accept these products as replacements for their current chemical fertilizer use? In this paper, key attributes determining the acceptance of alternative bio-based fertilizer products are identified. Based on the identified attributes, a discrete choice experiment was designed to reveal farmers' preferences and Willingness-To-Pay for these attributes. Identical experiments were conducted in seven different European countries. The results indicate that farmers from the different countries have common preferences for concentrated products that have certainty in the nitrogen content and at a lower price than chemical fertilizer. Other attributes such as the presence of organic carbon, hygienization of the product and fast release of nutrients were only statistically significant in some countries. The results imply that a bio-based fertilizer similar to chemical fertilizers could be sold at around 65% of the price of mineral fertilizer. Additionally, we show which attributes industry should take into consideration when estimating the demand for new bio-based fertilizer products. [ABSTRACT FROM AUTHOR]

Nitrogen runoff from agricultural fertilisation causes serious environmental damage to surface waters. Environmental and consumer advocates demand government intervention to mitigate these externalities. The present study examines the effects of nudge-based regulatory strategies. Using an incentivised single-player, multi-period business management game as an experimental device, we study how nudges affect compliance with the minimum-distance-to-water rule in a sample of German farmers. We investigate two different nudge treatments: a nudge with information and pictures showing environmental and health damages that are presumably caused by breaching the minimum-distance-to-water rule, and a nudge with an additional social comparison suggesting that the majority of farmers in the same region comply with the rule. Three core experimental outcomes are observed: first, nudging has a preventive effect and reduces not only the share of non-compliant participants, but also the total area that is illicitly fertilised. Second, against all expectations, the preventive effect of the nudge with an additional social comparison is not stronger than that of the nudge with information and pictures alone. Third, despite the overall positive effects of nudging, the nudge with social comparison even increased the severity of non-complying behaviour in the deviant subpopulation. [ABSTRACT FROM AUTHOR]

Urban and suburban lawns make up a large share of land use in the US. Maintaining lawns to fulfill aesthetic norms has environmental consequences. In this analysis, we examine household decisions to apply nitrogen-containing lawn fertilizer. Using survey data of 298 households in Nashville, Tennessee, we first examine the prevalence of fertilizer use and the rate of annual nitrogen applied. We find that the resulting distribution is skewed, with the top 20% of the sample applying 56% of the total share of nitrogen. In contrast to this subset of “intensive” fertilizers, 93% of households applied at or below levels recommended by landscaping professionals, challenging the assumption that the over-application of fertilizer is widespread. We employed multi-level modeling to examine the relative importance of household- and block-level characteristics on fertilizer use and the intensity of use. Consistent with prior work, we find that the desire for a green lawn is a significant predictor of fertilizer use. However, we also find that living on a wealthy block and living near others who value a green lawn independently predict fertilizer use. In addition, we observe that intensive fertilizing households tend to be less wealthy than others on their block, suggesting the possibility of an aspirational dimension to fertilizer use. Finally, we find evidence that environmental concern is associated with less intensive fertilizer use, suggesting that households may be willing to take some steps to mitigate the impact of their lawn care on the environment. [ABSTRACT FROM AUTHOR]

The degradation of land formerly reclaimed after surface‐coal‐mining (opencast) is a widespread problem in upland Wales (UK). This community‐based project aims to support the voluntary sector in land reclamation by investigating the means of reversing land degradation. It explores ways of encouraging trees to ameliorate the severely compacted, infertile, mine‐soils typical of former opencast sites. This study evaluates the benefits of a single initial application of 2‐year slow release fertilizer (SRF), both with and without additional supplements, through a 10‐year controlled experiment in a mixed planting of common Alder (Alnus glutinosa (L.) Gaertn), Oak (Quercus petraea (Matt.) Liebl., Quercus robur L. and hybrids) supplemented with Scots Pine (Pinus sylvestris, L.); Silver Birch (Betula pendula, Roth); Goat Willow (Salix caprea, L.) and Rowan (Sorbus aucuparia, L.). After 10 years, SRF treatment resulted in a small, marginally significant, decrease in survival (85% vs. 83%) across all species, except Oak, but SRF‐treated trees were significantly larger than those given no‐SRF at planting (421 cm vs. 368 cm). By contrast, in Year 5 data, only SRF‐treated Alders are marginally significantly larger, whereas in Years 1–3 across all six species, significantly more records show greater mean growth in trees with no‐SRF than those given SRF at planting. Probably, this delayed response to SRF treatment resulted from the slow development of the larger soil ecosystem. Treatment with additional supplements (double SRF, remineralization agent and superphosphate) tended to have negative impacts on growth but double SRF and to a lesser degree remineralization had a positive effect on survival. [ABSTRACT FROM AUTHOR]

The need to ensure food safety has been recognized in China and the ‘Green Food’ system is used to restrict the use of chemical fertilizers and pesticides in its certified products. There has been limited study of the environmental impacts associated with the production of green food certified (GFC) products in China. In this study, life cycle assessment was used to evaluate environmental impacts of GFC cucumber cultivated under a greenhouse system in the suburbs of Beijing relative to conventional cultivation (CON), with the aim of identifying the key areas of potential environmental burden in cucumber cultivation. Eight environmental impact categories are considered, including global warming potential, energy depletion (ED), water depletion, acidification potential, aquatic eutrophication (AEU), human toxicity (HT), aquatic eco-toxicity (AET) and soil eco-toxicity (SET). Results showed that the environmental index of the GFC cucumber system was higher than that of the CON cucumber system. SET, EU and ED were identified as the main potential environmental impacts in cucumber systems, largely caused by fertilizer use on the farm. The potentials of HT and AET in GFC cucumber were lower than those in the CON system, mainly due to the reduced use of chemical pesticides. The agricultural input of plastics was the main contributor to energy depletion in both cucumber cultivation systems. Potential approaches to mitigate the environmental impacts of cucumber cultivation include increasing the fertilizer use efficiency, avoiding use of animal manure with high heavy metal content and recycling of plastics under the GFC cultivation system. [ABSTRACT FROM AUTHOR]

Owing to their accessibility, shallow groundwater is an essential source of drinking water in rural areas while usually being used without control by authorities. At the same time, this type of water resource is one of the most vulnerable to pollution, especially in regions with extensive agricultural activity. These factors increase the probability of adverse health effects in the population as a result of the consumption of shallow groundwater. In the present research, shallow groundwater quality in the agricultural areas of Poyang Lake basin was assessed according to world and national standards for drinking water quality. To evaluate non-cancer health risk from drinking groundwater, the hazard quotient from exposure to individual chemicals and hazard index from exposure to multiple chemicals were applied. It was found that, in shallow groundwater, the concentrations of 11 components (NO3−, NH4+, Fe, Mn, As, Al, rare NO2−, Se, Hg, Tl and Pb) exceed the limits referenced in the standards for drinking water. According to the health risk assessment, only five components (NO3−, Fe, As, rare NO2− and Mn) likely provoke non-cancer effects. The attempt to evaluate the spatial distribution of human health risk from exposure to multiple chemicals shows that the most vulnerable area is associated with territory characterised by low altitude where reducing or near-neutral conditions are formed (lower reaches of Xiushui and Ganjiang Rivers). The largest health risk is associated with the immune system and adverse dermal effects. [ABSTRACT FROM AUTHOR]

Perennial cropping systems typically exhibit extensive root systems that contribute to important ecosystem services. However, the root systems and the distribution of roots throughout the soil profile in novel perennial grains have yet to be reported. In addition, understanding the full impact of perennial grain cropping systems on belowground processes requires knowledge of how N regimes might influence biomass partitioning and N retention. Here, we quantified root biomass distribution, crop biomass allocation, and whole-crop fertilizer N use efficiency (NUE, defined as the ratio of plant N to total N fertilizer applied) in annual winter wheat (Triticum aestivum L. 'Caledonia') and perennial intermediate wheatgrass [IWG, Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] across three N treatments over a 3-yr period. Nitrogen treatments included Low N (90 kg ha-1 of poultry manure), Mid N (90 kg ha-1 of urea), and High N (135 kg ha-1 of urea). As a perennial plant, IWG had significantly greater root biomass than annual wheat to the 40-cm depth (p < 0.05), but no differences were found between the crops at deeper depths. Nitrogen treatments did not affect root biomass, except for IWG in its fourth year (p < 0.05). Regardless of N level, IWG always had greater whole-crop NUE than annual wheat (p < 0.05). Results demonstrate that IWG roots represent a large pool of N that contributes to enhanced NUE and ultimately greater N retention than in annual wheat roots. [ABSTRACT FROM AUTHOR]

The use of fertilizers in greenhouse-grown crops can pose a threat to groundwater quality and, consequently, to human beings and subterranean ecosystem, where intensive farming produces pollutants leaching. Albenga plain (Liguria, Italy) is an alluvial area of about 45 km 2 historically devoted to farming. Recently the crops have evolved to greenhouses horticulture and floriculture production. In the area high levels of nitrates in groundwater have been detected. Lysimeters with three types of reconstituted soils (loamy sand, sandy clay loam and sandy loam) collected from different areas of Albenga plain were used in this study to evaluate the leaching loss of nitrate (NO 3 − ) over a period of 12 weeks. Leaf lettuce ( Lactuca sativa L.) was selected as a representative green-grown crop. Each of the soil samples was treated with a slow release fertilizer, simulating the real fertilizing strategy of the tillage. In order to estimate the potential risk for aquifers as well as for organisms exposed via pore water, nitrate concentrations in groundwater were evaluated by applying a simplified attenuation model to the experimental data. Results were refined and extended from comparison of single effects and exposure values (Tier I level) up to the evaluation of probabilistic distributions of exposure and related effects (Tier II, III IV levels). HHRA suggested HI >1 and about 20% probability of exceeding RfD for all the greenhouses, regardless of the soil. ERA suggested HQ > 100 for all the greenhouses; 93% probability of PNEC exceedance for greenhouses containing sand clay loam. The probability of exceeding LC50 for 5% of the species was about 40% and the probability corresponding to DBQ of DEC/EC50 > 0.001 was >90% for all the greenhouses. The significantly high risk, related to the detected nitrate leaching loss, can be attributed to excessive and inappropriate fertigation strategies. [ABSTRACT FROM AUTHOR]

Nitrite-oxidizing bacteria (NOB) are key players in the second step of nitrification, which is an important process in the soil nitrogen (N) cycle. However, the ecology of nitrite oxidizers and their response to disturbances such as long-term fertilization practices are scarcely known in agricultural ecosystems. We used samples from a Red soil subject to a long-term chemical and organic fertilization experiment, including control without fertilizer (CK), swine manure (M), chemical fertilization (NPK), and chemical/manure combined fertilization (MNPK) treatment, to explore how agricultural practices impact the community structure, abundance, and potential activity of nitrite oxidizers (PNO). The abundance of Nitrobacter was significantly increased in the M and MNPK plots, whereas the abundance of Nitrospira was significantly reduced in the M and NPK treatment plots and less inhibited in the MNPK treatment. The PNO showed a similar trend to that for Nitrobacter abundance. The diversity of Nitrobacter increased in the M-treated plots, while that of Nitrospira increased in the M and MNPK plots and decreased in the NPK plots. Non-metric multidimensional scaling (NMDS) revealed that the Nitrobacter - and Nitrospira -like NOB community was shift in these four fertilization treatments. Redundancy analysis showed that pH+SOC (soil organic carbon) and pH+TN (total nitrogen) significantly explained the variation in the composition of Nitrobacter and Nitrospira , respectively. In addition, the Nitrospira/Nitrobacter abundance ratio and community structure of Nitrobacter - and Nitrospira -like NOB are responsible for the changes of soil PNO. Collectively, these data suggest that the nitrite-oxidation process in the red soil is possibly controlled by both Nitrospira and Nitrobacter -like NOB, which were shaped by pH+TN and pH+SOC, respectively. [ABSTRACT FROM AUTHOR]

ABSTRACT Day, F.P.; Adams, E.C.; Gibala-Smith, L.A.; Graziani, D.J.; McMillan, B.; Sedghi, N.; Shafer, J., and Smith, M., 2018. Determining change in coastal barrier island dune vegetation following a decade of nitrogen fertilization. Nitrogen deposition from agricultural and industrial sources is a threat to terrestrial biodiversity, and impacts are likely to be greatest in nitrogen-deficient systems. The results of a 10 year fertilization treatment on nitrogen-deficient coastal barrier island dunes and the decade following cessation of fertilizer application are reported here. The study objective was to determine the resilience of the dune plant communities. Would these communities return to their former state in terms of density, species composition, and species diversity after nitrogen additions ended, and if so, how rapid was their recovery? Plant density by species and species diversity were determined over a 20 year period from permanent plots established on three different-aged dunes on a Virginia barrier island. Two dominant species responded differently to nitrogen additions. Ammophila breviligulata abundance was enhanced by the additions, and, in most cases, Spartina patens abundance was repressed. On the older Hog Island dunes, the addition of nitrogen over a 10 year period had a dramatic and rapid negative effect on diversity. However, recovery to diversity values observed in the control plots was rapid, beginning almost immediately after nitrogen additions were stopped. The dune vegetation on a Virginia barrier island appears to be quite resilient, as it rapidly recovered from diversity loss after 10 years of nitrogen additions. [ABSTRACT FROM AUTHOR]

European managed grasslands are amongst the most productive in the world. Besides temperature and the amount and timing of precipitation, grass production is also highly controlled by applications of nitrogen fertilizers and land management to sustain a high productivity. Since management characteristics of pastures vary greatly across Europe, land-use intensity and their projections are critical input variables in earth system modeling when examining and predicting the effects of increasingly intensified agricultural and livestock systems on the environment. In this study, we aim to improve the representation of pastures in the dynamic global vegetation model LPJ-GUESS. This is done by incorporating daily carbon allocation for grasses as a foundation to further implement daily land management routines and land-use intensity data into the model to discriminate between intensively and extensively used regions. We further compare our new simulations with leaf area index observations, reported regional grassland productivity, and simulations conducted with the vegetation model ORCHIDEE-GM. Additionally, we analyze the implications of including pasture fertilization and daily management compared to the standard version of LPJ-GUESS. Our results demonstrate that grassland productivity cannot be adequately captured without including land-use intensity data in form of nitrogen applications. Using this type of information improved spatial patterns of grassland productivity significantly compared to standard LPJ-GUESS. In general, simulations for net primary productivity, net ecosystem carbon balance and nitrogen leaching were considerably increased in the extended version. Finally, the adapted version of LPJ-GUESS, driven with projections of climate and land-use intensity, simulated an increase in potential grassland productivity until 2050 for several agro-climatic regions, most notably for the Mediterranean North, the Mediterranean South, the Atlantic Central and the Atlantic South. [ABSTRACT FROM AUTHOR]

To recycle the phosphorus in P-bearing steelmaking slag and use the slag as phosphate fertilizer, it is necessary to study the distribution of P2O5 between the P-rich phase and matrix phase in P-bearing steelmaking slag. The addition of MgO and MnO into the slag has no effect on the phosphorus form of existence in the slag and has little effect on the %(P2O5)SS. In contrast, Na2O and CaF2 in the slag change the phosphorus form of existence in the slag and increase %(P2O5)SS obviously. Lp’, γ P 2 O 5 ( S S ) ${\gamma _{{{\rm{P}}_2}{{\rm{O}}_5}(SS)}}$ , γ P 2 O 5 ( M ) ${\gamma _{{{\rm{P}}_2}{{\rm{O}}_5}(M)}}$ , CP(M) and CP(SS) were calculated, and it was found that %(CaO), %(T.Fe) and %(P2O5) in the P-rich phase and matrix phase significantly affect Lp’. MnO and MgO in the slag have little effect on the distribution of P2O5 between the P-rich phase and matrix phase, whereas Na2O and CaF2 affect the distribution of P2O5 between the P-rich phase and matrix phase. [ABSTRACT FROM AUTHOR]

Conservation agriculture (CA) based on the principles of minimum soil disturbance, crop residue retention, and crop rotation has been the focus of intensive research in recent years. A study was carried out to determine the effects of tillage and fertilizer on the population densities of plant-parasitic nematodes in maize. Three tillage regimes, (i) basin planting, (ii) rip line seeding, and (iii) conventional tillage, were combined with four fertilizer regimes: (i) no-fertilizer, (ii) low fertilizer rate, (iii) medium fertilizer rate, and (iv) high fertilizer rate. The experiment was arranged as a split plot in randomized complete block design, replicated three times with tillage as the main plot factor and fertilizer as the sub-plot factor. The study was conducted on finetextured Cambisol soils at Chinhoyi University of Technology farm, Zimbabwe, over two cropping seasons between December 2014 and April 2016. Eight plant-parasitic nematode genera were observed belonging to five groups based on their feeding sites: (i) sedentary endoparasites (Meloidogyne and Rotylenchulus), (ii) migratory endoparasites (Pratylenchus), (iii) semi-endoparasites (Scutelonema and Helicotylenchus), (iv) ectoparasites (Xiphinema and Trichodorus), and (v) algal, lichen or moss feeders (Tylenchus). In both cropping seasons, semi-endoparasitic nematodes were double under rip line seeding and triple under basin planting compared to conventional tillage. Basin planting had higher plant-parasitic nematode richness than rip line seeding. Nematode densities did not have a measurable effect on maize grain yield. Maize grain yield was higher in rip line seeding (37%) and planting basins (52%) than conventional tillage during 2014/15 cropping season. On the other hand, during 2015/16 cropping season, maize grain yield was 78% and 113% higher in rip line seeding and basin planting, respectively, compared to conventional tillage. The results show that under the environmental and edaphic conditions of this specific study site, semi-endoparasitic nematodes were higher under rip line seeding and basin planting compared to conventional tillage. The authors conclude that (i) plantparasitic nematode genera exhibited differential responses to different tillage systems but were not affected by fertilizer application, and (ii) in the present study, maize grain yield response under different tillage and fertilizer regimes was overall not related to nematode population density and composition. [ABSTRACT FROM AUTHOR]

Temporal variation of rice growth and nitrogen (N) uptake generally follow a sigmoid curve and may respond positively to the N-fertilizer application at critical growth stages. In this study, it was hypothesized that the amount of N-fertilizer applied at critical growth stages possibly follows a geometric pattern such as line, parabola, and sinusoidal to attain maximum yield and nitrogen use efficiency. To test and identify the best pattern, short-term modeling-field testing-long-term modeling strategy was followed. The patterns with the highest simulated yield and nitrogen use efficiency from short-term modeling were tested in the field. Finally, long-term evaluation of N-fertilization patterns was performed using 25 years of historical weather data, resulting in the line pattern with 14% more yield and 25% less NO3− leaching in comparison to the conventional N-Fertilization pattern. Therefore, line pattern may be adopted to enhance the yield and nitrogen use efficiency in rice. [ABSTRACT FROM AUTHOR]

Agricultural nonpoint source pollution has been increasingly serious in China since the 1990s. The main causes were excessive inputs of nitrogen fertilizer and pesticides. A multi-stage filtration system was built to test the purification efficiencies and removal characteristics of nitrogen and phosphorus when treating agricultural runoff. Simulated runoff pollution was prepared by using river water as source water based on the monitoring of local agricultural runoff. Experimental study had been performed from September to November 2013, adopting 12 h for flooding and 12 h for drying. The results showed that the system was made adaptive to variation of inflow quality and quantity, and had good removal for dissolved total nitrogen, total nitrogen, dissolved total phosphorus (DTP), and total phosphorus, and the average removal rate was 27%, 36%, 32%, and 48%, respectively. Except nitrate (NO− 3 −N), other forms of nitrogen and phosphorus all decreased with the increase of stages. Nitrogen was removed mainly in particle form the first stage, and mostly removed in dissolved form the second and third stage. Phosphorus was removed mainly in particulate during the first two stages, but the removal of particulate phosphorus and DTP were almost the same in the last stage. An approximate logarithmic relationship between removal loading and influent loading to nitrogen and phosphorus was noted in the experimental system, and the correlation coefficient was 0.78–0.94. [ABSTRACT FROM AUTHOR]

The combined use of inorganic fertilizers with organic manures has recently attracted increasing interest in China in attempts to mitigate the deleterious environmental impacts of excessive rates of chemical fertilizers in agroecosystems. However, questions remain concerning temporal change and how the soil microbiome responds to different fertilizer inputs in intensively managed crop rotations. Here, we collected soil samples from a wheat–maize system to investigate the response of the soil microbiome to four years of application of inorganic fertilizer only (NPK), NPK plus either cattle manure or straw, NPK plus both manure and straw, or a zero fertilizer control. The soil bacterial and fungal populations and community composition, nitrogen functional genes ( amoA ) and carbon utilization patterns were assessed. Sampling time had a much greater influence on the soil microbiome than did fertilizer regime, and the effect of fertilization was mostly significant at the wheat harvest. Fertilization increased amoA gene copy numbers but only AOB abundance showed differences among fertilizer treatments. In June the community composition of both bacteria and fungi was clearly separated between the organic matter additions and the zero organic matter treatments. Microbial carbon source utilization was significantly affected by fertilization regime and sampling time. By contrast, at the maize harvest neither microbial populations nor microbial community composition were altered. Our results suggest that the entire soil microbiome is more responsive to organic inputs than to chemical fertilizers in the short term. Temporal shifts in microbial community composition in the crop rotation imply that crop species and environmental conditions need to be carefully integrated into nutrient management strategies. [ABSTRACT FROM AUTHOR]

Increased economic costs and environmental concerns have heightened the desire to reduce crop nitrogen (N) input. Improvements in crop N use efficiency (NUE) are urgently needed for sustainable agriculture. It has been shown that sowing date exerts significant effects on N uptake and grain yield in wheat. However, there is little information regarding the influence of sowing date on crop N status assessed by N nutrition index (NNI), NUE, N uptake efficiency (UPE), and N utilization efficiency (UTE) in winter wheat. There have also been few studies on the effects of varying crop N status on NUE, UPE, and UTE in winter wheat. Here, we evaluated four sowing date treatments of 1 October (early sowing), 8 October (normal sowing), 15 October (late sowing), and 22 October (latest sowing) over two wheat growing seasons. We examined the effects of sowing date on the NNI, reserve N (RN) content at anthesis, tillering, floret differentiation, grain yield and components, NUE and components, and soil N budget. The wheat plants sown at the early and normal dates were in conditions of excess N, while those at the late and latest sowing dates were in near-optimum N conditions after N fertilizer application at jointing. In response to delayed sowing, aboveground N uptake (AGN), accumulation RN, UPE, and spikes per unit area decreased; storage RN, UTE, and grain number per spike increased; and grain yield and NUE remained unchanged. The final mineralized N in the 0–100-cm soil layer at harvest (N f-min ), and apparent N loss (N loss ) were higher in the late and latest sowing dates than in the early and normal sowing dates. The NNI was positively correlated with UPE, and negatively correlated with UTE, while no significant correlation between NNI and NUE was observed. Hence, wheat plants with delayed sowing can use N more efficiently by optimizing crop N status. There exists potential for improvement in NUE by combining delayed sowing and reduced N fertilizer rates that meet but do not exceed crop N requirements. [ABSTRACT FROM AUTHOR]

With the growth of the world population, cadmium (Cd) concentration in the environment has increased considerably as a result of human activities such as foundry, battery disposal, mining, application of fertilizers containing toxic elements as impurities, and disposal of metal-containing waste. Higher plants uptake N as ammonium (NH4+), nitrate (NO3−), and many other water-soluble compounds such as urea and amino acids, and nourishing plants with N, providing part of it as NH4+, is an interesting alternative to the supply of this nutrient in the exclusive form of NO3− under Cd toxicity. The objective was to evaluate the influence of NO3−/NH4+ proportions on the development and tolerance of tomato plants grown under the presence of Cd in the culture medium. The experiment was conducted in a completely randomized block design in a 3 × 3 factorial arrangement consisting of three Cd rates (0, 50, and 100 μmol L−1) and three NO3−/NH4+ proportions (100/0, 70/30, and 50/50) in the nutrient solution. To this end, we quantified the responses of the antioxidant enzymatic system and productive and functional changes in Solanum lycopersicum var. esculentum (Calabash Rouge). Shoot biomass production decreased with the maximum Cd rate (100 μmol L−1) tested in the growth medium, whereas the NO3−/NH4+ proportions and other Cd rates did not significantly influence this variable. The lowest SPAD values were observed at the 100/0 NO3−/NH4+ proportion and in plants exposed to Cd. The largest accumulation of the metal occurred in the shoots at the NO3−/NH4+ proportion of 70/30 and at 100 μmol L−1 Cd and in the roots at 100/0 NO3−/NH4+ and with 50 and 100 μmol L−1 Cd. The concentration and accumulation of NO3− were highest at the NO3−/NH4+ proportion of 100/0 in the shoots and at 50/50 NO3−/NH4+ in the roots, whereas for NH4+, values were higher as the proportion of N supplied in the form of NH4+ was increased. The nitrate reductase enzyme activity decreased with the Cd supply in the nutrient solution. The antioxidant system enzymes were activated as we increased the NO3−/NH4+ proportion and/or Cd rates added to the nutrient solution in both shoots and roots of the tomato plant, except for ascorbate peroxidase. Based on the results obtained, if the plant is to be used as a food source as is the case of tomato, the 100/0 NO3−/NH4+ proportion is the better alternative because it resulted in higher Cd accumulation in the root system over the translocation to the shoots and consequently to the fruit. [ABSTRACT FROM AUTHOR]

Fertilizers are an important tool to maintain soil fertility and as an enhancement for the efficient crop production. The system of fertilizers application affects the final dose and commonly causes local overdosing or insuficient spatial distribution of fertilizers which are a very important source of nitrous oxide emissions (N2O) from the soil into the atmospher observation of such phenomenon are among the key factors defining environmental impacts of agriculture. A study was conducted to observe the effect of application dose of fertilizer on N2O emission from the soil. CAN (Calcium ammonium nitrate -- consist of 27 % nitrogen) was spread by a fertiliser spreader Kuhn Axera 1102 H-EMC aggregated with a tractor John Deere 6150 M. Incorporation of fertilizer into the soil was done by power harrow Pöttinger Lion 302. The application dose was set at 0, 100, 200 and 300 kg. ha-1 while monitoring points were selected at the base of this application doses in respective places. Measurements were conducted at time intervals 7, 14, 21 and 28 days after fertiliser application and following incorporation. Nitrous oxide emissions were measured by field gas monitor set INNOVA consisting of a photoacoustic gas monitor INNOVA 1412 and a multipoint sampler INNOVA 1309. Statistically significant differences was found among time intervals and among the application dose (p > 0.05). It was observed that the application dose of selected fertilizers has the direct effect on nitrous oxide (N2O) emissions released from soil into the atmosphere. An increase of greenhouse gas emissions was observed in range from 0.83 to 152.33 %. It can be concluded that the local overdose of fertilizers negatively affects environmental impact of agricultural practices at greenhouse gas emissions (GHGs). [ABSTRACT FROM AUTHOR]

US Midwestern farmers are direct actors in managing nitrogen fertilizers and key to remediating water quality problems in agricultural landscapes. As farmers’ relationships with nature offer insights into their decisions and conservation practices, surveys and interviews with farmers in two Illinois watersheds explored their human-nature relationship perspectives and linkages to conservation practices. While domineering “Master” perspectives theorized as a cause of human-induced environmental problems were found, farmers spoke of obligations to the land and closeness to nature, emphasizing ecologically oriented partnership and stewardship ideals as motivating their conservation efforts. However, production-oriented pressures of the agricultural industry and livelihood and humanitarian considerations complicated farmers’ human-nature relationships and limited their efforts to act upon personal perspectives. Multiple, confounded human-nature relationships are influenced by factors beyond local landscapes with implications for natural resource decision-making, conservation practices, and environmental outcomes. [ABSTRACT FROM AUTHOR]

The paper presents general aspects regarding the importance of chemical fertilizers for agriculture and for the development of the economy, their classification and agrochemical aspects. The stages of nitrogen transformation in soil are: fixation, assimilation, ammonification, nitrification and denitrification. Chemistry of agriculture through the uncontrolled and inappropriate use of chemical fertilizers correlates with environmental problems and the soil is subject to a complex impact. [ABSTRACT FROM AUTHOR]

The global phosphorus cycle has been transformed in recent decades through increased use of mineral phosphorus fertilizer in agriculture and losses to water bodies, leading to risks of fossil phosphorus resource depletion and freshwater eutrophication. By moving phosphorus resources across world regions, international trade of agricultural products (food, feed, fiber and fuel) may contribute to these changes in the global phosphorus cycle, including critical nutrient imbalances. However, we lack a comprehensive, quantitative understanding of the role of agricultural trade in the global phosphorus cycle. By combining detailed data on international trade and the phosphorus content of agricultural products, we demonstrate that phosphorus flows through trade increased nearly eight-fold from 0.4 Tg P/yr in 1961 to 3.0 Tg P/yr in 2011, leading to an increase in the fraction of phosphorus taken up by crops that is subsequently exported from 9% in 1961 to 20% in 2011. The P flows in traded agricultural products was equivalent to 27% of the P traded in mineral fertilizers in 2011. Agricultural P flows were mostly driven by trade of cereals, soybeans and feed-cakes, with 28% of global phosphorus traded in human food, 44% in animal feed and 28% in crops for other uses in 2011. We found a strong spatial pattern in traded phosphorus in agricultural products, with most flows originating from the Americas and ending in Western Europe and Asia, with large amounts of phosphorus moving through trade within Western Europe, in strong contrast with the pattern of the mineral P fertilizer trade. We demonstrate that international trade of agricultural products has affected the domestic phosphorus cycle within many countries, making phosphorus exporters susceptible to the volatility of the mineral phosphorus fertilizer market. Overall, these results highlight the importance of trade as key component of the global phosphorus cycle. [ABSTRACT FROM AUTHOR]