The impact of agricultural management on global warming potential (GWP) and greenhouse gas intensity (GHGI) is not well documented. A long-term fertilizer experiment in Chinese double rice-cropping ...systems initiated in 1990 was used in this study to gain an insight into a complete greenhouse gas accounting of GWP and GHGI. The six fertilizer treatments included inorganic fertilizer nitrogen and phosphorus fertilizer (NP), nitrogen and potassium fertilizer (NK), and balanced inorganic fertilizer (NPK), combined inorganic/organic fertilizers at full and reduced rate (FOM and ROM), and no fertilizer application as a control. Methane (CH₄) and nitrous oxide (N₂O) fluxes were measured using static chamber method from November 2006 through October 2009, and the net ecosystem carbon balance was estimated by the changes in topsoil (0-20 cm) organic carbon (SOC) density over the 10-year period 1999-2009. Long-term fertilizer application significantly increased grain yields, except for no difference between the NK and control plots. Annual topsoil SOC sequestration rate was estimated to be 0.96 t C ha⁻¹ yr⁻¹ for the control and 1.01-1.43 t C ha⁻¹ yr⁻¹ for the fertilizer plots. Long-term inorganic fertilizer application tended to increase CH₄ emissions during the flooded rice season and significantly increased N₂O emissions from drained soils during the nonrice season. Annual mean CH₄ emissions ranged from 621 kg CH₄ ha⁻¹ for the control to 1175 kg CH₄ ha⁻¹ for the FOM plots, 63-83% of which derived from the late-rice season. Annual N₂O emission averaged 1.15-4.11 kg N₂O-N ha⁻¹ in the double rice-cropping systems. Compared with the control, inorganic fertilizer application slightly increased the net annual GWPs, while they were remarkably increased by combined inorganic/organic fertilizer application. The GHGI was lowest for the NP and NPK plots and highest for the FOM and ROM plots. The results of this study suggest that agricultural economic viability and GHGs mitigation can be simultaneously achieved by balanced fertilizer application.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Agricultural fields are an important anthropogenic source of atmospheric nitrous oxide (N₂O) and nitric oxide (NO). Although many field studies have tested the effectiveness of possible mitigation ...options on N₂O and NO emissions, the effectiveness of each option varies across sites due to environmental factors and field management. To combine these results and evaluate the overall effectiveness of enhanced-efficiency fertilizers i.e., nitrification inhibitors (NIs), polymer-coated fertilizers (PCFs), and urease inhibitors (UIs) on N₂O and NO emissions, we performed a meta-analysis using field experiment data (113 datasets from 35 studies) published in peer-reviewed journals through 2008. The results indicated that NIs significantly reduced N₂O emissions (mean: -38%, 95% confidential interval: -44% to -31%) compared with those of conventional fertilizers. PCFs also significantly reduced N₂O emissions (-35%, -58% to -14%), whereas UIs were not effective in reducing N₂O. NIs and PCFs also significantly reduced NO (-46%, -65% to -35%; -40%, -76% to -10%, respectively). The effectiveness of NIs was relatively consistent across the various types of inhibitors and land uses. However, the effect of PCFs showed contrasting results across soil and land-use type: they were significantly effective for imperfectly drained Gleysol grassland (-77%, -88% to -58%), but were ineffective for well-drained Andosol upland fields. Because available data for PCFs were dominated by certain regions and soil types, additional data are needed to evaluate their effectiveness more reliably. NIs were effective in reducing N₂O emission from both chemical and organic fertilizers. Moreover, the consistent effect of NIs indicates that they are potent mitigation options for N₂O and NO emissions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this study, a novel slow-release fertilizer (SRF) consisting of kaolinite and Ksub.2SOsub.4 was prepared, employing the process of mechanochemical milling in a planetary ball mill. To obtain the ...optimum milling time and speed, several samples were made at fixed mass ratios of kaolinite: Ksub.2SOsub.4 (3:1). The milling rotational speed ranged from 200 to 700 rpm for 120 min. Different milling times ranging from 60 to 180 min at fixed 600 rpm milling speed were also investigated to evaluate the incorporation of Ksub.2SOsub.4 and to measure the liberation of Ksup.+ and SOsub.4 sup.2− ions into solution. The properties of the studied samples were analyzed by Fourier transformation infrared spectrometry (FTIR), thermal gravimetric analysis (TGA), and ion chromatography (IC). The mechanochemical process is a green chemistry procedure that is successfully applied to incorporate Ksub.2SOsub.4 into the amorphous kaolinite structure. The slow-release performance was evaluated by determining the Ksup.+ and SOsub.4 sup.2− content in the aqueous solution upon leaching. The optimum released amount of Ksup.+ after 24 h was 32 mg Lsup.−1 for the milling conditions of 180 min and 700 rpm, indicating that Ksub.2SOsub.4-kaolinite has good slow-release properties. The novel SRF is cost-effective, environmentally friendly, and improves the fertilizer’s efficiency in many agricultural applications.
AIMS AND BACKGROUND: Soil fertility quality index is a useful indicator that helps to improve sustainable land use management and achieve economical yield in agriculture production. The objectives of ...this study were to evaluate the changes of soil fertility quality between the 1980s and 2000s in different cropping systems and its significance to crop productivity and sustainability. METHODS: We collected all published data on crop yields and soil parameters from 58 long-term experiments in three typical double-cropping systems in China, including maize-wheat (M-W), rice-rice (R-R) and rice-wheat (R-W) cropping systems, and selected seven fertilizer treatments in each experiment, including inorganic fertilizer nitrogen and phosphorus fertilizer (NP), nitrogen and potassium fertilizer (NK), phosphorus and potassium fertilizer (PK) and balanced mineral fertilizer (NPK), combined NPK with farmyard manure (NPKM) or crop straw (NPKS), and no fertilizer application (served as control). For comparison, an integrated fertility quality index (IFQI) was used to estimate the variations in soil fertility in different cropping systems. Moreover, the mean production variability index (PVI, %) in each cropping system was calculated to evaluate the stability of crop production. RESULTS: Over cropping systems, the averaged relative yields of PK, NK and NP ranged from 38.0 to 97.4 %, while the mean yields can be increased by 2.4–5.1 % in NPKM, compared to NPK. The mean yields were similar between NPK and NPKS for maize and wheat crops, but the yield was increased by 4.3–10.0 % in NPKS. Among the different treatments, the highest variability of cereal productivity was obtained in NK, PK or Control, while the lowest value was mostly recorded in NPKM or NPKS in these three cropping systems. Relative to the control, the IFQIs in fertilization treatments were increased by 9.4–150.0 %, 6.2–41.5 % and 1.3–17.5 % in M-W, R-W and R-R systems, respectively (except for PK treatment in R-R system). However, changes of IFQI in topsoil differed among fertilizer treatments, and greater increases existed in the treatments receiving organic residues (NPKM and NPKS). CONCLUSIONS: The increase in crop yield is exponentially correlated with the increased IFQI over treatments in three cropping systems. Over the treatments and systems, production variability among years is shown to be negatively, linearly related to IFQI (P < 0.001). Therefore, the high grain yield and low production variability can be simultaneously achieved by increasing soil fertility in all three cropping systems.
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BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Improvements in nitrogen use efficiency in crop production are critical for addressing the triple challenges of food security, environmental degradation and climate change. Such improvements are ...conditional not only on technological innovation, but also on socio-economic factors that are at present poorly understood. Here we examine historical patterns of agricultural nitrogen-use efficiency and find a broad range of national approaches to agricultural development and related pollution. We analyse examples of nitrogen use and propose targets, by geographic region and crop type, to meet the 2050 global food demand projected by the Food and Agriculture Organization while also meeting the Sustainable Development Goals pertaining to agriculture recently adopted by the United Nations General Assembly. Furthermore, we discuss socio-economic policies and technological innovations that may help achieve them.
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IJS, KISLJ, NUK, SBMB, SIK, UL, UM, UPUK
AIMS: Arbuscular mycorrhizal fungi (AMF) play a key role in the functioning of agricultural ecosystems. Therefore, understanding how the application of fertilizers, a common management practice, ...affects AMF communities is of major importance. Here we aimed to: (i) experimentally test whether different amounts and forms of phosphorus (P) fertilizer affect AMF diversity and community composition associated with the roots of apple trees (Malus domestica); (ii) identify differences in tolerance to P fertilization between AMF taxa. METHODS: We used 454-pyrosequencing of the small subunit rRNA gene amplicons to quantify AMF diversity and community composition in root samples obtained from a three year field experiment, with two inorganic, three slow-release P fertilization and one control treatment. RESULTS: The slow-release fertilizer treatments showed significantly higher AMF richness and differed in community composition compared to the inorganic fertilizer treatments. The distribution of AMF OTUs showed a significantly nested pattern. Additionally, AMF communities in the inorganic fertilizer treatments were a subset of the communities in the slow-release fertilizer treatments. CONCLUSIONS: We demonstrate that application of slow-release fertilizers promoted AMF diversity in the roots of cultivated apple trees in comparison to the other treatments. The application of inorganic fertilizers elevated levels of plant-available P in the soil and selected only a small subset of abundant AMF, resulting in a lower AMF diversity. This may result in AMF communities dominated by inferior AMF mutualists.
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BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The impact of long-term fertilizer on ammonia (NH₃) volatilization in a double rice-cropping system is not well documented. A long-term fertilizer experiment in Chinese double rice-cropping systems ...initiated in 1990 was used in this study to evaluate the NH₃ volatilization. Six fertilizer treatments were designed, including inorganic fertilizer nitrogen and phosphorus fertilizer (NP), nitrogen and potassium fertilizer (NK), and balanced mineral fertilizer (NPK), combined inorganic/organic fertilizers at full and reduced rate (FOM and ROM), and no fertilizer application (served as control). Ammonia volatilization fluxes were measured using a continuous airflow enclosure method during double rice growing seasons from 2007 to 2009. Results showed that the cumulative NH₃ volatilizations in the fertilizer plots ranged from 12.8 to 27.3 kg N ha⁻¹ for the early rice season and from 17.3 to 32.7 kg N ha⁻¹ for the late rice season, which accounted for 9.2–33.6 % and 17.8–32.2 % of the applied N, respectively. The NH₄ ⁺ concentration in floodwater is a predominant factor to NH₃ losses in the double rice-cropping systems. Compared with the NPK, the cumulative NH₃ volatilizations during double rice growing seasons were respectively increased by 9.7, 50.6, and 37.6 % for the NP, NK, and FOM plots, respectively, while they were decreased by 24.6 % for the ROM plots. Compared with the NPK, N uptakes by rice were decreased by 7.2–49.7 % with imbalanced fertilizer application (NP and NK), while they were increased by 9.6–41.0 % with combined inorganic/organic fertilizers application (ROM and FOM). Grain yields were comparable among the NPK, ROM, and FOM treatments, but they were declined by the treatments with imbalanced fertilizer application. These results suggested that agricultural economic viability and NH₃ volatilization mitigation can be simultaneously achieved by balanced inorganic and organic fertilizers application.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The extensive research, production and use of microorganisms to improve plant nutrition have resulted in an inconsistent definition of the term “biofertiliser” which, in some cases, is due to the ...different microbial mechanisms involved. The rationale for adopting the term biofertiliser is that it derives from “biological fertiliser”, that, in turn, implies the use of living microorganisms. Here, we propose a definition for this kind of products which is distinguishing them from biostimulants or other inorganic and organic fertilisers. Special emphasis is given to microorganism(s) with multifunctional properties and biofertilisers containing more than one microorganism. This definition could be included in legal provisions regulating registration and marketing requirements. A set of rules is also proposed which could guarantee the quality of biofertilisers present on the market and thus foster their use by farmers.
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CEKLJ, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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