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1.
The concentration and components of manure phosphorus (P) are key factors determining potential P bioavailability and runoff. The distribution of P forms in swine, poultry and cattle manures collected from intensive and extensive production systems in several areas of China was investigated with sequential fractionation and a simplified two-step (NaHCO3-NaOH/EDTA) procedures. The mean total P concentration, determined by the sequential fractionation procedure of intensive swine, poultry and cattle manure, expressed as g·kg−1, was 14.9, 13.4 and 5.8 g·kg−1, respectively, and 4.4 g·kg−1 in extensive cattle manure. In intensive swine, poultry and cattle manure about 73%, 74% and 79% of total P, respectively, was bioavailable (i.e., P extracted by H2O and NaHCO3) and 78% in extensive cattle manure. The results indicated the relative environmental risk, from high to low, of swine, poultry and cattle manure. There is considerable regional variation in animal manure P across China, which needs to be considered when developing manure management strategies. 相似文献
2.
Marco ROELCKE Lisa HEIMANN Yong HOU Jianbin GUO Qiaoyun XUE Wei JIA Anne OSTERMANN Roxana Mendoza HUAITALLA Moritz ENGBERS Clemens OLBRICH Roland W. SCHOLZ Joachim CLEMENS Frank SCHUCHARDT Rolf NIEDER Xuejun LIU Fusuo ZHANG 《农业科学与工程前沿(英文版)》2019,6(4):388
The Sino-German research collaboration project, “Recycling of organic residues from agricultural and municipal origin in China” (2008–2012), comprising different interdisciplinary research groups, and also German small and medium-sized enterprises, aimed at developing integrated strategies and solutions for the recycling of organic residues in China. In an intensive crop-livestock agricultural region in the Shunyi District of Beijing, five typical cropping systems were investigated. The research was conducted in the form of analyses of phosphorus (P) in soil, plants, animal feed, animal products, manures, mineral and organic fertilizers and the derivation of the corresponding nutrient balances and P flows. The mean annual P balance surplus was 492 kg·ha−1·yr−1 P for the vegetable production system, significantly higher (P<0.05) than that for orchards (130 kg·ha−1·yr−1P) and cereal crops (83 kg·ha−1·yr−1 P). Plant-available P (Olsen-P) concentrations of topsoils (0–20 cm) had good correlations with the amounts of P applied (from mineral and organic sources). Compared to results from the Second Chinese National Soil Survey of 1981, mean concentrations of available P in soils of 19 plots investigated in Shunyi District increased 10-fold (from 7.3 to 60 mg·kg−1) from 1981 to 2009. On average, the critical limit for Olsen-P concentrations (>30 mg·kg−1) that can lead to increased risk of P loss was exceeded in all five cropping systems. With feed additives, the “natural background value” (Chinese Environmental Quality Standard for Soils) of copper and zinc in topsoils was exceeded at several sites. Screening for several substances in the veterinary antibiotic classes of sulfonamides, tetracyclines, and fluoroquinolones revealed widespread topsoil contamination. Calculated livestock densities were 10.6 livestock units per ha arable land in 2007. Animal husbandry is increasingly conducted in large operations, making traditional ways of reuse difficult to apply. Comparing three management systems for treatment of organic residues from a pig farm via aerobic (composting) or anaerobic (biogas) treatment in a life cycle assessment, the resulting cropland demand for a sustainable land application of biogas effluent varied between 139 and 288 ha·yr−1, well above the cropland area owned by the farm (10 ha). The mismatch problems in the above context between business-as-usual and improving performance are framed and discussed as (1) the mismatch between centralized animal husbandry and smallholder farming, (2) the mismatch between livestock density and cropland, (3) nutrient (including P) recycling and increasing organic matter content versus energy production, (4) subsidies for compost production and biogas, as well as (5) advances in the regulatory framework in China. 相似文献
3.
Wood is an ideal type of support material whose porous structure and surface functional groups are beneficial for deposition of various guest substances for different applications. In this paper, wood is employed as a porous support, combined with two kinds of conductive polymers (i.e., polyaniline (PANI) and polypyrrole (PPy)) using an easy and fast liquid polymerization method. Scanning electron microscope observations indicate that the PANI–PPy complex consists of nanoparticles with a size of ~20 nm. The interactions between oxygen-containing groups of the wood and the nitrogen composition of PANI–PPy were verified by Fourier transform infrared spectroscopy. The self-supported PANI–PPy/wood composite is capable of acting as a free-standing supercapacitor electrode, which delivers a high gravimetric specific capacitance of 360 F·g−1 at 0.2 A·g−1. 相似文献
4.
Ning WANG Fengxin WANG Clinton C. SHOCK Lei GAO Chaobiao MENG Zejun HUANG Jianyu ZHAO 《农业科学与工程前沿(英文版)》2022,9(4):614
5.
Phosphorus is a key nutrient element involved in energy transfer for cellular metabolism, respiration and photosynthesis and its supply at low levels can affect legume nodulation, N2 fixation, and C assimilation. A two-year field study was conducted in Ethiopia in 2012 and 2013 to evaluate the effects of P supply on growth, symbiotic N2 nutrition, grain yield and water-use efficiency of three groundnut genotypes. Supplying P to the genotypes significantly increased their shoot biomass, symbiotic performance, grain yield, and C accumulation. There was, however, no effect on shoot δ13C values in either year. Compared to the zero-P control, supplying 40 kg·ha−1 P markedly increased shoot biomass by 77% and 66% in 2012 and 2013, respectively. In both years, groundnut grain yields were much higher at 20 and 30 kg·ha−1 P. Phosphorus supply markedly reduced shoot δ15N values and increased the %Ndfa and amount of N-fixed, indicating the direct involvement of P in promoting N2 fixation in nodulated groundnut. The three genotypes differed significantly in δ15N, %Ndfa, N-fixed, grain yield, C concentration, and δ13C. The phosphorus × genotype interaction was also significant for shoot DM, N content, N-fixed and soil N uptake. 相似文献
6.
Jinxi HUO Bing DU Sifan SUN Shaozhen HE Ning ZHAO Qingchang LIU Hong ZHAI 《农业科学与工程前沿(英文版)》2018,5(2):206
High concentrations of Cd can inhibit growth and reduce the activity of the photosynthetic apparatus in plants. In several plant species, aldo-keto reductases (AKRs) have been shown to enhance tolerance to various abiotic stresses by scavenging cytotoxic aldehydes; however, few AKRs have been reported to enhance Cd stress tolerance. In this study, the gene IbAKR was isolated from sweet potato. The relative expression levels of IbAKR increased significantly (approximately 3-fold) after exposure to 200 mmol·L−1 CdCl2 or 10 mmol·L−1 H2O2. A subcellular localization assay showed that IbAKR is predominantly located in the nucleus and cytoplasm. IbAKR-overexpressing tobacco plants showed higher tolerance to Cd stress than wild-type (WT). Transgenic lines showed a significant ability to scavenge malondialdehyde (MDA) and methylglyoxal (MG). In addition, proline content and superoxide dismutase activity were significantly higher and H2O2 levels were significantly lower in the transgenic plants than in the WT. Quantitative real-time PCR analysis showed that the reactive oxygen species (ROS) scavenging genes encoding guaiacol peroxidase (GPX), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and peroxidase (POD) were significantly upregulated in transgenic plants compared to WT under Cd stress. These findings suggest that overexpressing IbAKR enhances tolerance to Cd stress via the scavenging of cytotoxic aldehydes and the activation of the ROS scavenging system. 相似文献
7.
The mammary gland provides a novel method for producing recombinant proteins in milk of transgenic animals. A key component in the technology is the construction of an efficient milk expression vector. Here, we established a simple method to construct a milk expression vector, by a combination of homologous recombination and digestion-ligation. Our methodology is expected to have the advantages of both plasmid and bacterial artificial chromosome (BAC) vectors. The BAC of mouse whey acidic protein gene (mWAP) was modified twice by homologous recombination to produce a universal expression vector, and the human lysozyme gene (hLZ) was then inserted into the vector by a digestion-ligation method. The final vector containing the 8.5 kb mWAP 5′ promoter, 4.8 kb hLZ genomic DNA, and 8.0 kb mWAP 3′ genomic DNA was microinjected into pronuclei of fertilized mouse embryos, to successfully generate two transgenic mouse lines that expressed recombinant human lysozyme (rhLZ) in milk. The highest expression level of rhLZ was 0.45 g·L−1, and rhLZ exhibited the same antibacterial activity as native hLZ. Our results have provided a simple approach to construct a universal milk expression vector, and demonstrated that the resulting vector regulates the expression of hLZ in milk. 相似文献
8.
The North China Plain (NCP) is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP) for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011–2013) field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE) between the simulated and measured biomass was 0.67–1.25 t·hm−2, and that of relative error (RE) was 9.4%–15.4%, the coefficient of determination (R2) ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm; and RE and R2 in the range of 1.07%–1.20% and 0.880–0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m−3. The simulated impact of long-term climate (i.e., 1980–2010) and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured. 相似文献
9.
Poor soil fertility due to low nutrient inputs is a major factor limiting grain production in Kenya. Increasing soil fertility for crop productivity in China has implications for food security in Kenya. The purpose of this study was therefore to investigate the historical patterns of grain production, nutrient inputs, soil fertility and policies in Quzhou, a typical agricultural county on the North China Plain, and to compare grain production in Quzhou County and Kenya to identify a potential approach for increasing grain production in Kenya. Grain yields in Quzhou increased from 1 to 3 t·ha−1 between 1961 and 1987 by increasing manure application accompanied by small amounts of chemical fertilizer after soil desalinization. There was a further increase from 3 to 5 t·ha−1 up to 1996 which can be mainly attributed to chemical fertilizer use and policy support. Hence, a beneficial cycle between soil fertility and plant growth in Quzhou grain production was developed and strengthened. In contrast, there was only a slight increase in grain yields in Kenya over this period, resulting from low soil fertility with limited external nutrient inputs, a consequence of poor socioeconomic development. It is suggested that grain yields in Kenya would likely be boosted by the development of a self-reinforcing cycling between soil fertility and plant growth with manure and chemical fertilizer use if supported by policy and socioeconomic development. 相似文献
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11.
Greenhouse gas emissions due to biological degradation processes of animal wastes are significant sources of air pollution from agricultural areas. The major environmental controls on these microbe-induced gas fluxes are temperature and moisture content. The objective of this study was to model the effects of temperature and moisture content on emissions of CO2 and CH4 during the ambient drying process of dairy manure under controlled conditions. Gas emissions were continuously recorded over 15 d with paired fully automated closed dynamic chambers coupled with a Fourier Transformed Infrared gas analyzer. Water content and temperature were measured and monitored with capacitance sensors. In addition, on days 0, 3, 6, 9, 12 and 15, pH, moisture content, dissolved organic carbon and total carbon (TC) were determined. An empirical model derived from the Arrhenius equation confirmed high dependency of carbon emissions on temperature and moisture content. Results indicate that for the investigated dairy manure, 6.83% of TC was lost in the form of CO2 and 0.047% of TC was emitted as CH4. Neglecting the effect of temperature, the moisture contents associated with maximum gas emissions were estimated as 0.75 and 0.79 g·g−1 for CO2 and CH4, respectively. 相似文献
12.
Qi WANG Zhanxiang SUN Wei BAI Dongsheng ZHANG Yue ZHANG Ruonan WANG Wopke VAN DER WERF Jochem B. EVERS Tjeerd-Jan STOMPH Jianping GUO Lizhen ZHANG 《农业科学与工程前沿(英文版)》2021,8(3):432-446
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14.
Baifeng ZHENG Yaochao YAN Can FU Guangyi HUANG Long ZHAO Qiong CHEN Renyu QU Guangfu YANG 《农业科学与工程前沿(英文版)》2022,9(1):133-145
15.
Qunbiao Zhou Yaxin Sang Li Wang Shuangshang Ji Jing Ye Xianghong Wang 《Frontiers of Agriculture in China》2010,4(4):489-493
An efficient extraction method by ultrasound-assisted extraction (UAE) was developed for the extraction of polychlorinated
biphenyls (PCB 28, 52, 101, 118, 130, 153, 180) from various shellfish. Analytes were determined by gas chromatography-mass
spectrometry in selected ion monitoring (SIM) mode. All the samples were extracted by n-hexane and decontaminated by concentrated
sulfuric acid. The resulting samples were determined by quantitative detection by comparing with external standards. The average
recoveries of seven kinds of PCBs ranged from 80.92% to 93.89%, and the lowest detectable limit was 0.08-0.03 μg·kg−1. The average concentrations of total PCBs were 14.12–30.61 μg·kg−1 in the samples. This method was highly effective in reducing the cost and time for the pretreatment of samples. This method
may be applied for the screening and monitoring of shellfish for organic pollutants in coastal waters. 相似文献
16.
A greenhouse pot experiment was conducted to study the effects of nitrogen fertilization on Calophy- llum inophyllum seedlings grown with 0, 50, 100, 150, 200, 300, 400 and 600 mg N per seedling according to exponential functions. Seedling height, root collar diameter, leaf area and total biomass increased with increasing fertilization from 0 to 200 mg N per seedling and decreased with further increase in fertilization from 300 to 600 mg N per seedling. The net photosynthetic rate, stomatal conductance, intercellular CO2 concentration and transpiration rate of C. inophyllum seedlings showed a unimodal parabolic trend, with peak values of 7.29 mmol·m−2·s−1, 0.071 mol·m−2·s−1, 220 mmol·mol−1 and 1.34 mmol·m−2·s−1, respectively, when the rate of fertilization was 200 mg N per seedling. Photosynthetic gas exchange parameters were significantly different among nitrogen treatments. Based on the critical values of leaf N and P concentration and N/P ratio, the optimum amount of nitrogen of C. inophyllum seedlings was 200–400 mg per seedling for leaf N and P concentration, and 100–400 mg per seedling for N/P ratio. It was concluded that 200–400 mg N per seedling was the most suitable nitrogen range for C. inophyllum seedlings. 相似文献
17.
Kai WANG Qunfeng ZHOU Tianze YAN Shilong XU Longyi ZHAO Weicheng WANG Zhigang JIN Peng QIN Chenjian FU Liangbi CHEN Yuanzhu YANG 《农业科学与工程前沿(英文版)》2020,7(4):523-529
As a consequence of contamination of soil with heavy metals, cadmium accumulation in grain is of great concern worldwide, but especially in southern China. It is important to evaluate the Cd accumulation potential of grain before or when examining and approving new cultivars. An evaluation method and criteria for verifying Cd accumulation potential in rice are proposed, and the Cd accumulation potential of 56 mid-season indica hybrids collected from the provincial cultivar trials in 2016 were investigated. Genotype, environment and their interactions strongly affected the variation in grain Cd accumulation. Two hybrids were identified as slightly Cd accumulating. Hybrids with slight Cd accumulation potential would be suitable for safe grain production on polluted land (total Cd under 2.0 mg·kg−1) in Hunan Province (China) and should be considered for new cultivar evaluation and approval. This evaluation method and criterion could be applied for certifying Cd accumulation potential of rice cultivars. 相似文献
18.
苹果短枝型品种脱落酸含量与树体生长的研究 总被引:1,自引:0,他引:1
用气相色谱法分析了苹果短枝型品种(系)叶片内源脱落酸(ABA)的含量变化。结果表明,不同年份不同时期苹果短枝型品种(系)叶片ABA含量显著高于非短枝型对照树。4年生短枝型品种新红星在7月25日、9月26日叶片ABA含量分别为0.8543×10-7g·g-1、0.9825×10-7g·g-1;同期对照红星树叶片ABA含量分别为0.3952×10-7g·g-1、0.4340×10-7g·g-1。相关测验结果表明,苹果短枝型品种(系)和对照树叶片ABA含量与9年生树高、新稍长度和节间长度是极显著负相关(P<0.01)。红星苹果芽变枝条测定结果看出,以当地条件同系列非短枝型品种或母体树叶片ABA含量为基准,其含量的二倍值可作为苹果短枝型品种的预选指标。 相似文献
19.
Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil (ECO). Ring-opening polymerization with stannic chloride was used to produce polymerized ECO (PECO), and sodium hydroxide used to give hydrolyzed PECO (HPECO). The HPECO was characterized by Fourier transform infrared, 1H and 13C nuclear magnetic resonance spectroscopies, gel permeation chromatography, and differential scanning calorimetry. The weight-average molecular weight of soluble PECO and HPECO were 5026 and 2274 g·mol-1, respectively. PECO and HPECO exhibited glass transition. Through neutralizing the carboxylic acid of HPECO with different counterions, castor oil-based polymeric surfactants (HPECO-M, where M= Na+, K+ or triethanolamine ion) exhibited high efficiency to reduce the surface tension of water. The critical micelle concentration (CMC) values of HPECO-M ranged from 0.042 to 0.098 g·L-1 and the minimum equilibrium surface tensions at CMC (gcmc) of HPECO-M ranged from 25.6 to 30.0 mN·m-1. The water-hexadecane interfacial energy was calculated from measured surface tension using harmonic and geometric mean methods. Measured values of water-hexadecane interfacial tension agreed well with those calculated using the harmonic and geometric mean methods. 相似文献