Effect of Potash Application Patterns on Crop Yields Under Different Cultivation Systems

Three patterns of potash application were used in the corn-wheat and rice-wheat rotation experiments,which were conducted in the upland and wetland of Siyang County, northern Jiangsu Province, and the wetland of Liyang City, southern Jiangsu Province. The results of 5 cropping seasons (2 seasons/year)showed that the direct response of corn to K was larger than that of wheat, but no difference was found between rice and wheat in Siyang when the total annual amount of K was applied only in one cropping season. However, the response of wheat was much greater than that of rice in Liyang. If potash was applied in the preceding season, the residual effect of K on wheat was larger than that on rice both in Siyang and Liyang, but less than that on corn. The total effect (direct and residual effects) of K applied to corn or rice was greater than that to wheat in Siyang, but that to wheat was greater in Liyang. The direct and total effects of K application in the upland were larger than those in the wetland of Siyang; but for the wetland,the effects were larger in Liyang than in Siyang, especially in the wheat season. The results demonstrated that the most profitable practice to be recommended to the local farmers was to apply a limited amount of potash to only rice or corn but not to wheat. Equally applying half of the total annual amount of K to each of the crops may be advisable in order to lessen possible fertilization risks.

Impacts of application patterns and incorporation rates of dredged Yellow River sediment on structure and infiltration of saline-alkali soil

Soil salinization is an issue of global concern.Despite recent evidence indicates that application of sediments into saline-alkali soil in Yellow River Delta as an additive can increase crop yield,its effects on soil structure and infiltration remain uncertain.In this study,the comprehensively analyses were conducted on the soil infiltration and microstructure of the soil treated with three sediment application layers(surface layer at 0-15 cm,lower layer at 15-30 cm,and plough layer at 0-30 cm)and four sediment incorporation rates(0,2%,5%and 10%),using soil column simulation experiment.Results indicated that the dredged Yellow River sediments can improve the infiltration capacity of saline-alkali soil;and the infiltration capacity increased with the rising sediment incorporation rate under the given application pattern.Compared with the control,applying dredged Yellow River sediments at 10%rate at lower layer and plough layer significantly facilitated the soil infiltration of the saline-alkali soil.Soil macro-porosity for T2,T5 and T10 was 26%,52%and 158%more than that for the control,respectively.This phenomenon was attributed to the increased soil macro-porosity,due to the improved soil microstructure with the incorporation of sediment into the saline-alkali soil.Moreover,the cumulative infiltration was fitted better with Kostiakov infiltration model than Horton and Philip models.

The Application of Pattern Recognition to the Formability of Quasicrystal Formation in Al-alloys

Four parameters of chemical bond havebeen used to span a feature space to classifyquasicrystal-forming Al-alloys from thatalloys without quasicrystal formationwith good result. Since the first quasicrystal-formingsystem, Al-Mn system, discovered by She-chtman in 1984[1], a series of quasicrystal-forming binary alloy systems have beenfound. Most of these systems are Al-contain-ing systems. Bancel has indicated thatthere are three factors affecting theformability of quasicrystals [2]: (1) ele-ctrochemical factor (this factor can be

Chao HUANG,Main Factors Affecting the Improving Efficiency of Gypsum for Solonetzic Soil

In order to more efficiently utilize gypsum to improve meadow alkali soil slightly salinized by soda and sulfate chloride, a total of 27 treatments were de- signed from the perspectives of field capacity, alkalinity, alkaline salt content, optimal irrigation, gypsum conversion, gypsum and soil treatment and improvement depth. The ions on the obtained filtrate were analyzed in terms of salts. The improving ef- ficiency of gypsum for meadow alkali soil was analyzed through comparing the con- tents of soluble salts in pre-improvement and post-improvement soil by reasoning and calculation. The results showed that, （1） the dissolved amount and conversion amount of gypsum were increased, and the soil alkalinity was decreased corre- spondingly with the increased irrigation amount. However, after reaching a certain extent, the linear relationships became unobvious gradually. Therefore, the irrigation amount should be arranged reasonably for different treatment. （2） Compared with those at low temperature, the dissolved amount of gypsum at high temperature was increased by 1.47-1.50 times, the release amount of exchangeable sodium was in- creased by 2.98-4.70 times, and the release amount of exchangeable magnesium was increased by 2.07-2.90 times. In overall, the improving efficiency of gypsum in summer was better. However, gypsum had two shortcomings in summer. First, a large amount of gypsum leaked away. Second, a large amount of exchangeable magnesium, along with exchangeable sodium, was substituted by gypsum. （3） Compared with the other two treatments, treatment B （mixing gypsum and top 20- cm soil） showed the best improving efficiency, and it was characterized by stepwise dealkalization from top to down. In addition, mixing gypsum and topsoil is more practical in the production.

Discussion on Subject Knowledge Service Pattern of Agricultural University Libraries

Taking Heilongjiang Bayi Agricultural University as an example, the discipline service practice was explored from the aspects such as free network resources and tool use, subject navigation, subject librarians, information sharing space and information literacy education. The typical cases were provided;the optimization of utilization method of network resources was put forward;the subject theme navigation was developed;and the information sharing space of specific discipline and other working strategies were carried out. The experience and enlightenment of active service for subject construction, priority service for key subjects, subject service by lay and step and seizing of the opportunity of subject service were summarized, which developed ideas and provided reference to the establishment of deep subject services of general libraries of colleges and universities.

Application of wavelet transform in feature extraction and pattern recognition of wideband echoes

A novel approach to extract edge features from wideband echo is proposed. The set of extracted features not only represents the echo waveform in a concise way, but also is sufficient and well suited for classification of non-stationary echo data from objects with different property.The feature extraction is derived from the Discrete Dyadic Wavlet Transform (DDWT) of the echo through the undecimated algorithm. The motivation we use the DDWT is that it is time-shift-invariant which is beneficial for localization of edge, and the wavelet coefficients at larger scale represent the main shape feature of echo, i.e. edge, and the noise and modulated high-frequency components are reduced with scale increased. Some experimental results using real data which contain 144 samples from 4 classes of lake bottoms with different sediments are provided. The results show that our approach is a prospective way to represent wideband echo for reliable recognition of nonstationary echo with great variability.