农产品及产地环境中微量元素检测研究进展

农产品及产地环境中微量元素高效、准确检测是农产品政府监管、保障消费安全、促进粮油产业高质量发展的重要手段。本文评述了近几年农产品及产地环境中微量元素的检测技术,比较分析了光谱、质谱、色谱和电化学等方法的原理和特点,及其在微量元素检测实际应用中的优缺点,以期为农产品及产地环境中微量元素检测技术研究提供参考,为粮油产业高质量发展与农产品质量安全提供技术支撑。     

The susceptibility of agricultural grasses to pre-emergence damage caused by Fusarium culmorum and its control by fungicidal seed treatment

A total of 104 cultivars of six agricultural grass species were compared under controlled conditions for their relative susceptibility to the common soil-borne fungus Fusarium culmorum (W.G.Sm.) Sacc. A number of the perennial ryegrass ( Lolium perenne ) cultivars showed a high degree of resistance, their emergence being little reduced under the stringent test conditions. The emergence of others was, however, severely affected. Italian ryegrass ( L. multiflorum ) cultivars generally had a high level of resistance, the outstanding exception being cv. Leda Daehnfeldt which proved very sensitive. None of the cultivars of cocksfoot ( Dactylis glomerata ), timothy ( Phleum pratense ), meadow fescue ( Festuca pratensis ) or tall fescue ( F. arundinaceae ) which were tested had more than a moderate level of resistance and most were highly susceptible.
The vigour of ryegrass seedlings was, in most cases, closely correlated with percentage emergence but was less closely correlated in the more susceptible species. These often had a very low emergence but those seedlings which did establish were frequently of a size similar to that of healthy plants.
Treatment of grass seed with a fungicide mixture of benomyl (15% a.i.) plus captan (60% a.i.) provided excellent protection against F. culmorum on even the most susceptible cultivars.
Drazoxolon (40% a.i.) was, however, much less effective.     

农业产业链管理在茶叶产业中的应用

农业产业链管理是供应链管理理论在农业领域的具体应用,是市场农业发展到一定阶段的必然产物。本文以名山茶叶产业为例,尝试把农业产业链管理理论应用于茶叶产业之中,在对名山茶叶产业链运行的现状进行调查和客观分析的基础上,用农业产业链的系统集成思想,对名山茶叶产业的组织链、价值链、物流链和信启、链进行整合,以此增强名山茶叶产业的市场竞争力,拉动当地经济的发展。     

A comparison of initial spray characteristics produced by agricultural nozzles

Pesticides are commonly applied by using hydraulic nozzles to generate droplets. The properties of these spray droplets can influence the effectiveness and risks associated with the use of pesticides. Initial spray characteristics (initial droplet size and velocity, fan angle and spray liquid density) were therefore measured for a range of hydraulic nozzles and spray mixtures. Particle Image Velocimetry (PIV) was used to measure the spray sheet velocity.There was a significant difference between a standard hydraulic nozzle, Turbo TeeJet^® and air induction nozzle for all measured spray characteristics. The standard hydraulic nozzle generated the smallest droplet sizes, the highest velocity and the highest spray liquid density. The air induction nozzle generated the largest droplet size, the slowest velocity and the lowest spray liquid density. The type of air induction nozzle and spray formulation was also found to influence spray characteristics.This work has demonstrated that initial spray characteristics such as droplet size and velocity, liquid density, fan angle and included air can vary depending on nozzle design, operating parameters and spray formulations. Initial droplet velocity was found to be significantly correlated to droplet size (D_v0.5) and spray pressure.     

Studies on structural integrity of polyester-cotton friction spun yarn by cycling extension test

Yarns and fabrics are subjected to a low level of stresses or strains of repetitive nature in processing and actual use which leads to breakage, permanent deformation, bagging and loss of useful life of the product. The ability of the spun yarns and fabrics to withstand such stresses depends upon their structural integrity. A structurally rigid yarn (i.e. yarns in which fibres are tightly bound) would behave more like an elastic solid and consume more energy during deformation as the constituent fibres have to be deformed. Once the strain is released, the recovered energy will also be more. On the other hand if the structural integrity of the same yarn is poor, fibres would easily slip during deformation and would consume much less energy. The recoverable energy also will be much less. The present investigation reports on the structural integrity of friction spun yarns in terms of energy loss or decay by employing cyclic extension test. It has been observed that friction spun yarns in which the core is immediately wrapped by long and strong polyester fibre layer make the structure strongest as polyester is expected to form tight wrappings. The decay in deformation energies during extension cycling depends upon sheath structure i.e. its composition and location of constituent fibres in sheath layers. With increase in core fibre %, the decay has been found to increase. However, the decay values discriminate more between core% differences than between sheath fibre layer arrangements.     

On-line monitoring of cellulase treatment by differential refractometer

Cellulase treatment of cellulose fibers needs to be monitored to give proper weight loss without significant strength loss. On-line monitoring of cellulase treatment is presented which can monitor the weight loss of cotton fabrics by measuring differential refractive index in real time. On-line monitoring was tried under the condition where the cellulase treatment of scoured 100% cotton knits would give weight loss of about 6.6% during one hour cellulase treatment. For comanalyses processing solutions with treatment time of 5, 10, 20, 30, 45 and 60 minutes were taken out, and subjected to sugar analyses using total organic carbon (TOC), and dinitrosalicylic acid (DNS) method as well as HPLC analyses. HPLC analyses showed that cellobiose and glucose were the major components resulting from cellulase treatment of cotton fabric. TOC and differential refractive index measurement proved to be linear to total sugar concentration while DNS method result was dependent on the type of sugar. Various sugar concentrations of the processing solutions measured by these methods were compared with HPLC measurements and correlated with the actual weight loss of the cotton fabric processed. The on-line monitoring device using differential refractometer gave a real time signal which was independent of the ratio of cellobiose and glucose but dependent on the total sugar concentration. The device was also non-destructive.     

改革稻田耕作制度，提高农业生产效益

针对双峰县稻田生产中存在的问题 ,根据该县特点 ,提出了全县耕作制度改革的基本原则、推广模式和具体对策。     

Slope stability evaluation of an agricultural embankment by statistically derived rainfall patterns

Paddy and Water Environment - Torrential rainfall has a detrimental impact on the stability of soil-based agricultural embankments due to seepage and slope failure. The impact on the stability of...     

Characterizing nitrogen use efficiency in natural and agricultural ecosystems to improve the performance of cereal crops in low-input and organic agricultural systems

Low-input and organic farming systems have notable differences in nitrogen (N) sources, cycling and management strategies compared to conventional systems with high inputs of synthetic N fertilizer. In low-input and organic systems, there is greater reliance on complex rotations including annual and perennial crops, organic N sources, and internal N cycling that more closely mimic natural systems. These differences in farming system practices fundamentally affect N availability and N use efficiency (NUE) and could impact crop traits and breeding strategies required to optimize NUE. We assess genetic and environmental factors that could assist breeders in improving crop performance in low-input and organic farming systems by examining NUE in natural and agricultural ecosystems. Crop plants have often been bred for high N productivity, while plants adapted to low N ecosystems often have lower productivity and higher levels of internal N conservation. Breeders can potentially combine N productivity and N conservation through the use of elite and wild germplasm. Beneficial genetic traits include the ability to maintain photosynthesis and N uptake under N stress and the ability to extract soil N at low concentrations, perhaps through beneficial associations with soil microorganisms. In addition, breeding for specific adaptation to climactic and management practices so that crop uptake patterns match N availability patterns, while minimizing pathways of N loss, will be critical to improving NUE.     

Detection of disease in stored potatoes by volatile monitoring

The feasibility of early disease detection in potato storages by the monitoring of volatiles was investigated usingErwinia carotovora as a model storage pathogen (soft rot) in both laboratory and commercial site tests. Volatiles were collected by cryogenic air liquefaction and concentrrated on Tenax-GC adsorbent. Analyses by gas chromatography and mass spectroscopy identified acetone, ethanol, and 2-butanone being produced in abnormal concentrations during host-soft rot incubations in a controlled environment. Preliminary comparisons between diseased and normal commercial bins at different storage sites (two cultivars) indicated soft rot infection also created abnormally high concentrations of the above three volatiles, with most notable differences in 2-butanone concentrations. The criteria of selection for volatiles for possible use as incipient disease indicators are discussed in terms of the composite rate of pathogenic destruction within a potato pile. Additional volatiles identified from potatoes inoculated withE. carotovora include: acetaldehyde, methyl acetate, ethyl acetate, propanethiol, hydrogen sulfide, methyl sulfide, methyl disulfide, n-propanol, and isobutanol.     

Rapid detection of potato viruses by dot-ELISA

Summary The dot-ELISA, an immunosorbent assay on nitrocellulose (NC) membranes, was applied to potato viruses. The sensitivity of the test, as determined by visual assessment of the colour reactions in serial dilutions, allowed a reliable detection of the potato viruses M, S, X, Y, A and of potato leafroll virus in leaves of non-potato hosts and potato plants. Tuber extracts taken from the rose end resulted in higher dilution end points than those from the heel end. The test can be performed within two to three hours by using stored NC-membranes precoated with specific γ-globulin. The possibility of storing antigen treated NC-membranes for some days allows the assay to be quickly applied to samples taken in the field.     

Experiences of water transfer from the agricultural to the non-agricultural sector in Taiwan

Two type of water transfer have occurred in Taiwan, namely, regular and emergency transfers. According to the prevailing Water Law, water is permitted to transfer among water rights holders whenever they need and agree upon relevant compensation. As for the emergency transfer, in the event of extensive drought, every water user sector will suffer serious water shortages resulting in unavoidable economic losses. The Government should step in to perform emergency water transfer by suspending agricultural water rights a course of action considered to cause smaller losses even when an entire rice crop is abandoned, to minimize overall losses to the national macro economy. This study has examined two typical water transfer cases that were implemented in Taiwan. The first one involved the regular transfer of agricultural water from the Changhwa and Yunlin Irrigation Associations (IAs) to the industrial user Formosa Petrochemical Corporation (FPC). The second one involved the transfer of agricultural water from the Taoyuan, Shimen and Shinchu IAs to domestic and industrial uses during the period from 2002 to 2006 as an emergency transfer. From the perspective of water transfer options, Taiwanese case studies have demonstrated that an officially recognized marketing oriented water transfer mechanism has yet to be established. However, water transfer is still undertaken whenever necessary. In this respect, regardless of the type of water transfer undertaken, water rights can only be suspended but not terminated. In spite of the types of water transfer, it is inevitable to affect the ecological and environmental functions. Therefore, further investigations with related topics should be broadly taken into account. Ecosystem services of paddy fields have attracted increasing recognition in the monsoon Asian countries. Currently, there is a research program collaborating with the International Water Management Institute (IWMI) on the impact and influence induced by water transfer with a major concern on the ecosystem services of paddy fields in Taiwan.     

Analysis of runoff in the Han River basin by SSARR model considering agricultural water

This study begins to address the need for a runoff model that is able to simulate runoffs at control points in a dam’s upper and lower stream during the seasons of high and low water levels. We need to establish a synthetic management plan on water resources considering the runoff at the upper and lower streams to effectively manage the limited water resources in Korea. For this reason, we classified the Han River Basin into 24 sub-basins and arranged a great amount of rainfall data using 151 rainfall observation stations so as to prepare for the spatial distribution of precipitation. We chose several dams as subjects for this study, which includes the Chungju Regulating Reservoir, Soyang, Chungju, Hoengseong, Hwacheon, Chuncheon, Euiam, Cheongpyeong, and Paldang Dams as main controlling points. Also, we made up input data of this model, selecting the Streamflow Synthesis and Reservoir Regulation (SSARR) model as a runoff model in the Han River Basin. We performed a sensitivity analysis of parameters using hydrological data from the year 2002. And as a result, the findings of this study showed that, among many parameters related to the basin runoff, the following have revealed greater sensitivity than any other parameters: soil moisture index-runoff percent, baseflow infiltration index-baseflow percent, and surface-subsurface separation. On the basis of the above sensitivity analysis, we have used hydrological data between 2001 and 2002 when drafts and floods broke out in Korea to verify and calibrate the parameters of the SSARR model. Furthermore, we verified and calibrated the 2000 data using corrected parameters and performed an analysis of annual water balance in the Han River Basin from 1996 to 2005 considering agricultural water.     

Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha^?1. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.     

Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha⁻¹. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.

     

Analysis of spatial and temporal risk of agricultural loss due to flooding in paddy farms

Evaluating agricultural loss due to flooding is essential for defining an appropriate risk level in flood management projects. This research introduces a method for computing annual damage risk for rice fields with respect to both spatial and temporal pattern of floods, while considering the effect of crop growth stages on the total damage. For finding the spatial pattern of floods, HEC-RAS was employed to derive selected physical parameters of floods of interest and then a physical loss function was used to calculate the unconditional loss over flood prone areas. A time-dependent loss function was introduced for rice to determine the effect of growth on damages derived through the physical loss function. Due to the seasonal nature of agricultural risk, frequency analysis was performed for seasonal discharges for each growth stage of rice. A method was introduced to use the concept of Expected Annual Damage in agricultural fields. A method called “AGEAD” was introduced for evaluating short-term risk for agricultural activities considering their inherent spatial and temporal characteristics. Results showed that damages evaluated by employing AGEAD were completely different from what was obtained by applying a flood of defined return period, i.e. from the results of long-term risk evaluation. While it is common to attribute a unique predicted loss to all flood prone areas, AGEAD application showed that different zones in flooded paddy fields were subjected to different amount of damages from 100 to 0%.     

Properties of starch-palmitic acid complexes prepared by high pressure homogenization

Aqueous mixtures of defatted corn starch and palmitic acid were heated and high pressure homogenized in order to form amylose inclusion complexes. The effects of homogenization pressure (0–120 MPa) and palmitic acid concentration (0.5–8% based on starch content) on starch-palmitic acid complex formation as well as on complex index, X-ray diffraction, thermal properties, viscosity and particle size were investigated. Complex index increased with an increase in the amount of palmitic acid and homogenization pressure, and reached a maximum value (about 60%) when the fatty acid content was 4% and the homogenization pressure was 100 MPa. X-ray diffraction patterns indicated the formation of V-helical complexes between starch and palmitic acid. This technology could prospectively be used in prepared starch-lipid complexes.     

Assessment of agricultural drought vulnerability to climate change at a municipal level in South Korea

This study aimed to analyze the future vulnerability to agricultural drought of the Korean administrative units of cities (Si) and counties (Gun) following the climate change phenomenon. To assess the vulnerability in a quantitative manner and also to deal with different physical and socioeconomic data on the occurrence of agricultural drought, principal component analysis (PCA), a multivariate statistical analysis method, was adopted, and a vulnerability index, regional vulnerability index to agricultural drought (RVI_AD), was suggested. RVI_AD having a range from 0.0 to 1.0 was calculated by rescaling the weighted summation of principal component scores. The analysis was performed with all 21 standardized variables in each administrative unit of Si and Gun: 3 sensitivity variables, 8 exposure variables, and 10 adaptation variables. It resulted in four principal components explaining about 85.7% of the total variance, and the third principal component, comprised of only climate variables, was used for applying future climate data from the RCP 8.5 scenario. The districts of Chungchongnam-Do (M1), Jeollabuk-Do (L1), and Jeollanam-Do (L2) were evaluated as having the highest vulnerability to agricultural drought based on the climate change scenario, not only in the present but also in future. Despite the limitation inherent in the PCA, the approach in this study could reflect different factors other than climate factors on minimizing subjective interruption, and such is expected to contribute to improving the decision-making for diagnosing the drought adaptation capacity in a region and developing measures to mitigate the drought damage.     

The price elasticity of transferring agricultural water to industrial water during non-drought period in Taiwan

In this study, the demand function for the transferring agricultural water to industrial water during non-drought period covering from January 1998 to December 2008 in Taiwan was estimated, and the water usage statistics derived from the short-term water charge agreements, regarding the charging of water management fees and water usage fees from the irrigation associations, were applied to the estimation in the empirical model. The results of the research are presented as follows: (a) the demand for transferring agricultural water into industrial water is non-elastic; the price elasticity is −0.368; (b) the transferred water volume decreases when the water price rises; (c) the transferred water volume also decreases when the wholesale price index of domestic products rises; (d) the buyer’s industry classification was the significant factor influencing the transfer water demand; (e) the different title of transferred water including: “building utilization cost” or that in “costs for enhanced irrigation management” was the significant factor influencing the transfer water demand; (f) type of repository of irrigation association for transferred water was the significant factor influencing the transfer water demand; (g) whether irrigation association enhances irrigation management was the significant factor influencing the transfer water demand; (h) the source of transferred water was the significant factor influencing the transfer water demand; (i) the method for water transfer was the significant factor influencing the transfer water demand; (j) more water transferred by the industry when the total population of Taiwan increases; (k) the transferred water volume rises when the groundwater level of the water transferred area rises; and (l) the areas for water transferred was the significant factor influencing the transfer water demand.