Computer Aided Analysis of Forces Applied to Semi-mounted Plough

半悬挂犁工作幅宽大，作业效率高，非常适应大农业生产的要求，为了合理地进行半悬挂犁与拖拉机机组的配套设计和使用，减少耕作过程中的功率消耗，提高机组效率，就必须要对半悬挂犁进行受力和结构参数分析，传统的分析方法是利用图解法。本文从理论上分析了采用图解法进行半悬挂犁受力分析所存在的问题，建立了半悬挂犁受力的矩阵方程组，利用计算机辅助分析，预测了半悬挂犁机组各结构参数变化对机组受力工况的影响，从而为半悬挂犁机组的合理配置、强度计算和优化设计提供了理论依据。     

Evaluating Methods of In‐Field Soil Organic Matter Analysis

Abstract

The actual content of the soil organic carbon (SOC) has to be periodically measured for soil classification and nutrient management purposes. Traditional SOC tests are relatively time consuming and costly. A rapid field test would be valuable to delineate soil map units with similar SOC to simplify the process of land evaluation while increasing precision. The objectives of this study were to develop and evaluate a new field measurement technique for the quick assessment of SOC. The new method measures the emitted CO₂ concentration 3 min after treatment of the soil sample with acidic potassium (K) permanganate solution. The inorganic carbonate content of the soil is measured separately with the addition of sulphuric acid only. Carbon dioxide concentration from both procedures is measured with a portable infrared gas analyzer. The difference between the concentrations measured after the two separate reactions provide an estimate of SOC. Samples from brown forest soils (ca Hapludalf) (0.19–5.53% SOC) were used for the method development. The correlation coefficient between the SOC determined by the new method and laboratory wet combustion method content was 0.76 for the full range of SOC and 0.81 for the soil samples with less than 20% carbonate.     

Water Budget Analysis of Red Soils in Central JiangxiProvince, China

The daily soil water budgets in the red soil areas of central Jiangxi Province, southern China, were investigatedwith a large-scale weighing lysimeter and runoff plots. From 1998 to 2000, peanuts (Arachis hypogaea L.) and rape(Brassica napus L.) were planted in the lysimeter and in 1999, peanuts were planted in the runoff plots. The soil waterbudget components including rainfall, runoff, percolation and evapotranspirat.ion were measured directly or calculated by Richards‘ equation and water balance equation. The results showed that most rainfall, including rainstorms, occurredfrom March to July, and induced the greatest soil water percolation during the year. The evapotranspiration was stilllarge from July to September when rainfall was ininimal. Thus, the lack of synchronization in soil water inputs and losseswas disadvantageous to crops growing in this region. Among the soil water losses, percolation was the largest, followed byevapotranspiration, and then soil runoff. Runoff was very small on farmland with crops. It was significantly different, fromthe uncultivated uplands where large-scale runoff was usually reported. The soil water storage fluctuated sinusoidally,with a large amplitude in the rainy season and a small amplitude in the dry season.     

Analysis of SNP Markers for Blue-shelled Gene in Chicken by PCR-SSCP

决定绿壳蛋鸡壳色的Oocyan(O)基因座位位于一号染色体。绿色蛋壳的色素主要有原卟啉、胆绿素以及胆绿素的锌络合物，将上述色素代谢途径中的酶对应的基因在家鸡基因组序列中进行比对，没有发现与O基因座位相符的位点。基于ALEV1周围微卫星标记较少，在家鸡一号染色体基因组序列上选取距离ALEV1上游3.5 cM的位点设计引物进行PCR-SSCP分析，寻找与绿壳基因座位紧密连锁的SNP标记位点，并且分析标记位点基因型与O位点不同基因型之间的相关性。结果表明,一个标记与绿壳基因位点紧密连锁，该标记上发生2个点突变，分别是家鸡Chr1:61754089T->A与Chr1:61754175A->T上的颠换。在纯合绿壳蛋鸡群体中，81%的个体在2个位点均发生突变，标为AA型，杂合绿壳群体中AB型为89%，粉壳蛋鸡群体中93%的个体与红色原鸡序列一致，标为BB型。在绿壳蛋鸡育种中，建议以AA型作为分子标记提高绿壳蛋鸡育种工作的效率。     

Coffee‐Tree Floral Analysis as a Mean of Nutritional Diagnosis

Abstract

Plant part analysis for evaluating the nutritional state of the crops is a practice commonly used. The analysis of flowers can allow an earlier diagnosis of nutritional deficiencies, excesses or unbalances, which facilitates its correction before the occurrence of irreversible losses in productivity and quality. The objective of this study were to determine the coffee tree (Coffea arabica L.) flower nutrients sufficiency ranges, to compare and correlate concentrations of nutrients observed in flowers and leaves collected 90 days after bloom, and to correlate the concentrations of nutrients in flowers and leaves with fruit yield. Samples of 26 experimental plots were collected. The plots were set up in nine different orchards five to nine years old and with 3000–5000 plants/ha, in the region of Viçosa, Minas Gerais State, Brazil. Eleven experimental plots were selected with mean yield greater than 7.0 kg/plant of coffee berry for the calculation of the nutrients sufficiency ranges. The concentrations of nitrogen (N), potassium (K), boron (B), iron (Fe), and zinc (Zn) were similar in flowers and leaves, whereas those of phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), and manganese (Mn) differed among the parts. There was correlation among the contents of N, Mg, Fe, Mn, Zn, and Cu in flowers and in leaves. For flowers a model of six variables and for leaves a model of eight variables explained 80% of the variation in the mean yield of the coffee tree plants. It is concluded that, flowers permit earlier diagnosis and greater precision in the diagnosis of the nutritional state of the coffee tree.     

Analysis of Soil Chemical Properties of Sand-Based Turfgrass Rootzone using Fourier Transform–Infrared Spectroscopy

To evaluate diffuse reflectance Fourier transform–infrared (DRIFT) in near-infrared (NIR) and mid-infrared (MIR) regions in conjunction with partial least square regression analysis for sand-based turfgrass soils, soil samples were collected from greens 6 to 9 years old, composed of two rootzone mixtures and from two establishment fertilization regimes, at different depths (surface to 7.6 cm in 12 layers). Mid-infrared and NIR spectroscopy resulted in similar calibration accuracy for total organic carbon, total nitrogen, cation exchange capacity, electric conductivity, and pH with R ² > 0.80. The modeling process for MIR spectrum was repeated on sample subsets, which were grouped from the original samples based on rootzone mixtures, putting green age, and depth to test the robustness of prediction models. Results of this study suggested that DRIFT-NIR and DRIFT-MIR could be used to predict these properties of sand-based turfgrass soils providing the soil samples are from similar depths.     

The 2012 Census of Agriculture: A Capture–Recapture Analysis

The Census of Agriculture is conducted every 5 years, in years ending in 2 and 7. The Census list frame is incomplete, resulting in undercoverage. Not all operations on the list frame respond, and, based on the response, some misclassification occurs. In 2012, a capture–recapture analysis was conducted to adjust for undercoverage, nonresponse, and misclassification. This was the first time capture–recapture methods were used to produce official statistics for an establishment survey. The number of records on the Census Mailing List that were classified as farms was 1,382,099, and the published estimate of the number of farms was 2,109,303, a 34.5% adjustment. The adjustment was greatest for farms with low production levels and for specialty farms, both of which are difficult to identify and add to the list. The methods used are described. Challenges that arose in the implementation process are discussed. Areas for enhancement being targeted for the 2017 Census of Agriculture are highlighted. Supplementary materials accompanying this paper appear online.     

Analysis of cationic elements in liquid samples by x‐ray

Abstract

Plant analyses methods have expanded immensely to document plant mineral element deficiency and toxicity disorders and to note mineral element interactions. Experiments were conducted to determine the feasibility of using cation exchange papers for the extraction of cationic elements from solutions to be analyzed by x‐ray fluorescence. The cationic elements Al, Fe, Mn, Zn, and Cu were effectively extracted from solutions by one exchange resin paper disk if solutions were passed several times through the exchange resin paper. Calcium and Mg were extracted from solutions if two or three separate exchange papers were used, and K was not extracted from solutions with the use of up to five separate exchange papers. The relatively high concentrations of K in solutions and the relatively low exchange capacity of ion exchange resin papers apparently prevented the effective removal of K from solution. The detectability limits on the exchange resin disks by this technique were <2.8 μg Al, 0.5 μg Fe, 0.10 μg Mn, 0.10 μg Zn, and 0.08 μg Cu. Extraction of cationic elements from solutions for x‐ray analysis appeared practical and relatively rapid for Al, Fe, Mn, Zn, and Cu, less practical for Ca and Mg, and impractical for K.     

Analysis of variation patterns in rice milled quality in the offspring of indica–japonica hybridization

Genetic Resources and Crop Evolution - Asian cultivated rice (Oryza sativa L.) is divided into two subspecies, indica (O. sativa L. subsp. indica) and japonica (O. sativa L. subsp. japonica)....     

Integrated Analysis of Capture–Recapture–Resighting Data and Counts of Unmarked Birds at Stop-Over Sites

The models presented in this paper are motivated by a stop-over study of semipalmated sandpipers, Calidris pusilla. Two sets of data were collected at the stop-over site: a capture–recapture–resighting data set and a vector of counts of unmarked birds. The two data sets are analyzed simultaneously by combining a new model for the capture–recapture–resighting data set with a binomial likelihood for the counts. The aim of the analysis is to estimate the total number of birds that used the site and the average duration of stop-over. The combined analysis is shown to be highly efficient, even when just 1 % of birds are recaptured, and is recommended for similar investigations. This article has supplementary material online.     

A Preliminary Global Analysis of Remotely Sensed Radiation Characteristics of Ground Features:Ⅱ. Result Discussion

Based on the L,B and V statistics of the 106 ground feature groups or the 769 ground feature class units in the world presented in the part I of the paper,the distribution of the world ground features on the axes of L,B and V,in the planes of L-B,L-V and B-V and in the space of L-B-V was discussed.And the typical numerical characteristics of the various ground features were also summarized.     

Cloning and Sequence Analysis of Encoding Genes in Chicken Oesteoprotegerin(chOPG)

OPG是一种分泌型糖蛋白,属于TNF受体超家族成员,可抑制破骨细胞分化的最终阶段以及成熟破骨细胞的活性并诱导其凋亡(Simonet et al.,1997;Yasuda et al.,1998)。目前,国内外尚未见有关鸡OPG克隆的相关研究报道。本实验在体外成功地培养鸡胚额骨成骨细胞的基础上(张胶和侯加法,2     

A Preliminary Global Analysis of Remotely Sensed Radiation Characteristics of Ground Features: Ⅰ. Methodology and Results

A Landsat data transformation method which was proposed by the author was applied to extract useful information from data of 769 ground feature classification units of worldwide scope.Three most important characteristic values--the general radiance level L,the visible-infrared radiation balance B and the band radiance variation vector (direction and speed) V were calculated.Then the 769 class units were sorted into 106 groups based on their natural characteristics.The means and standard deviations of L,B and V values for all the groups were calculated.The distributions of the 106 groups or the 769 units on the number axes of L,B and V,in the planes of L-B,L-V and B-V,and in the space of L-B-V were investigated.Finally,the typical numerical characteristics of the various ground features are discussed in consideration of their worldwide variations in the present paper.     

Analysis of cinnamaldehyde and diallyl disulfide as eco-pesticides in soils of different textures—a laboratory-scale mobility study

Journal of Soils and Sediments - This work presents for the first time the development of a method for the analysis of cinnamaldehyde and diallyl disulfide in soil by ultrasound assisted extraction...     

Residual Variance–Covariance Modelling in Analysis of Multivariate Data from Variety Selection Trials

Field trials for variety selection often exhibit spatial correlation between plots. When multivariate data are analysed from these field trials, there is the added complication in having to simultaneously account for correlation between the traits at both the residual and genetic levels. This may be temporal correlation in the case of multi-harvest data from perennial crop field trials, or between-trait correlation in multi-trait data sets. Use of parsimonious yet plausible models for the variance–covariance structure of the residuals for such data is a key element to achieving an efficient and inferentially sound analysis. In this paper, a model is developed for the residual variance–covariance structure firstly by considering a multivariate autoregressive model in one spatial direction and then extending this to two spatial directions. Conditions for ensuring that the processes are directionally invariant are presented. Using a canonical decomposition, these directionally invariant processes can be transformed into a set of independent separable processes. This simplifies the estimation process. The new model allows for flexible modelling of the spatial and multivariate interaction and allows for different spatial correlation parameters for each harvest or trait. The methods are illustrated using data from lucerne breeding trials at several environments.     

Irrigation of steppe soils in the south of Russia: Problems and solutions (Analysis of Irrigation Practices in 1950–1990)

Experience in irrigation of chernozems in the steppe zone of Russia for a period from 1950 to 1990 is analyzed. By the end of this period and in the subsequent years, the areas under irrigation reduced considerably, and the soil productivity worsened. This was caused by the improper design of irrigation systems, on the one hand, and by the low tolerance of chernozems toward increased moistening upon irrigation, on the other hand. The analysis of the factors and regimes of soil formation under irrigation conditions shows that irrigation-induced changes in the soil hydrology also lead to changes in the soil physicochemical, biochemical, and other properties. In particular, changes in the composition of exchangeable cations lead to the development of solonetzic process. In many areas, irrigation of chernozems was accompanied by the appearance of solonetzic, vertic, saline, and eroded soils. The development of soil degradation processes is described. In general, the deterioration of irrigated chernozems was related to the absence of adequate experience in irrigation of steppe soils, unskilled personnel, improper regime of irrigation, and excessively high rates of watering. In some cases, the poor quality of irrigation water resulted in the development of soil salinization and alkalization. To improve the situation, the training of personnel is necessary; the strategy of continuous irrigation should be replaced by the strategy of supplementary irrigation in the critical periods of crop development.     

The Impact of Multiple Freeze–Thaw Cycles on the Microstructure of Aggregates from a Soddy-Podzolic Soil: A Microtomographic Analysis

With the help of computed X-ray microtomography with a resolution of 2.75 μm, changes in the microstructure and pore space of aggregates of 3 mm in diameter from the virgin soddy-podzolic soil (Glossic Retisol (Loamic)) in the air-dry, capillary-moistened, and frozen states after five freeze–thaw cycles were studied in a laboratory experiment. The freezing of the samples was performed at their capillary moistening. It was shown that capillary moistening of initially air-dry samples from the humus (AY), eluvial (EL), and illuvial (BT1) horizons at room temperature resulted in the development of the platy, fine vesicular, and angular blocky microstructure, respectively. The total volume of tomographically visible pores >10 μm increased by 1.3, 2.2, and 3.4 times, respectively. After freeze–thaw cycles, frozen aggregates partly preserved the structural arrangement formed during the capillary moistening. At the same time, in the frozen aggregate from the AY horizon, the total tomographic porosity decreased to the initial level of the air-dry soil. In the frozen aggregate from the EL horizon, large vesicular pores were formed, owing to which the total pore volume retained its increased values. The resistance of aggregate shape to the action of freeze–thaw cycles differed. The aggregate from the EL horizon completely lost its original configuration by the end of the experiment. The aggregate from the AY horizon displayed definite features of sagging after five freeze–thaw cycles, whereas the aggregate from the BT1 horizon preserved its original configuration.