MULTIPLE DISCRIMINANT ANALYSIS IN SOIL SURVEY

Multiple discriminant analysis can be used to distinguish to best advantage several multivariate, more or less polythetic, classes of soil. The method allows profiles to be allocated consistently and most appropriately to existing groups for which representatives have already been chosen. The method is described in geometric terms and is applied to the allocation of profiles in both well known and little known areas, South Central England and Sabah. For the areas in England good separation between soil classes was demonstrated; in Sabah the classes of the reconnaissance survey were less distinct. Representative profiles were chosen for all existing classes and the remainder of the profiles allocated using discriminant functions. In all cases a better classification resulted in that there was less dispersion within classes and hence better separation between them. Provided conformant data can be collected in routine survey the method promises to allow a good working combination of man and machine: the soil surveyor to decide the classes desired, and the computer to handle large quantities of data and make routine allocation.     

THE RELATION BETWEEN COST AND UTILITY IN SOIL SURVEY

This paper discusses how to compare the utility of soil maps. For three contrasting areas, in Southern England, it compares the utilities of a number of single-property and general purpose (series) soil maps, produced by free and grid survey, at map scales from 1 :20,000–1:70,000. The‘purity’of series mapping units increases with survey effort. Where the soil boundaries had fairly clear external expression free survey was superior to grid survey. On average the purity of maps by grid survey was higher than for maps by free survey at comparable survey effort. The uniformity of soil properties within mapping units was measured by relative variance (RV)= within-unit variance/total variance, (1–RV) indicates the increased precision achieved by the soil map. It increased with survey effort. For series maps by free or grid survey (1–RV) depended on how closely soil properties were associated with profile classes, and on the extent to which soil boundaries could be mapped on their external expression. Free survey was preferred at scales between 1: 100,000 and 1:30,000, when the soil boundaries could be mapped on their external expression, (1–RV) for the profile classes on which the mapping units are defined puts a ceiling to the utility of series maps (grid or free) which is already nearly achieved at map scales near 1:25,000. Except for properties very poorly associated with profile classes, single property maps do not have great advantage over series maps at medium map scales, but they attain higher values of (1–RV) at scales greater than 1: 25,000.     

RECONNAISSANCE FOR SOIL SURVEY

The total length of soil boundary on a map can be measured by counting the number of intercepts between boundaries and a randomly distributed array of sampling lines. It is thus also possible to estimate the length of the same boundaries before survey by means of a similar array of field traverses. The per cent sampling error of estimates of boundary density (boundary per unit area), is approximately the reciprocal of the square root of the number of intercepts.     

CALCULATING THE ECONOMIC BENEFITS OF SOIL SURVEY

A farmer (or other users of land) achieves greatest net return by using each soil for the crop and management which gives maximum return. A soil map indicates the boundaries between soils requiring different management for optimum returns. The benefits from a soil survey increase with the ‘purity’ of the soil units as mapped. The cost of soil survey increases sharply with the ‘purity’ to be achieved. So it is necessary to recognize the stage beyond which the costs of yet more detailed soil survey are unlikely to exceed the benefits to be expected from mapping units of greater ‘purity’. This paper reports a simple algorithm for calculating the probable benefits from further soil survey to produce a map of higher ‘purity’ than so far achieved.     

静态辐照加工产品质量控制

以江苏里下河农科所钴室辐照加工实践为依据 ,对辐照加工产品质量控制等方面进行了研究和探讨     

控制辐照食品安全的HACCP质量管理体系

介绍了食品危害分析与关键控制点体系 (HACCP) ,对脱水蔬菜辐照灭菌过程中的各个环节可能造成的潜在危害进行了分析 ,并探讨了在中国辐照食品加工企业中建立HACCP的方法     

土壤环境质量指导值与标准研究V.镉在土壤-作物系统中的富集规律与农产品质量安全

通过查阅国内现有镉污染农田土壤和作物中镉含量的相关资料,包括近30年来公开发表文献、国家"七五"科技攻关环保项目"土壤环境容量研究"等科研成果,结合本实验室在长江三角洲、珠江三角洲典型地区污染农田调查数据,经筛选后从88组研究中共收集到镉污染农田土壤和作物中镉含量对应数据509对.根据镉盐来源,将收集的数据分为污染农田调查数据和添加镉盐试验数据;根据作物不同,分为水稻、小麦、茎/叶类蔬菜、根菜和果菜地调查数据.采用富集系数和一元回归模型的方法基于土壤镉含量预测作物可食部分镉含量;采用多元回归模型的方法基于土壤镉含量和土壤pH预测作物可食部分镉含量.结果表明,回归模型对作物可食部分镉含量的预测效果明显优于富集系数中位值;回归模型95%预测上限对作物可食部分镉含量的保守预测优于富集系数90分位值.土壤pH显著影响作物对镉的吸收.影响模型回归效果和预测能力的主要因素是数据分布不均和数据量不足.模型对比后选用多元回归模型的95%预测上限推导稻田和茎/叶类蔬菜用地基于农产品质量安全的土壤镉含量环境基准.     

土壤环境质量指导值与标准研究I·国际动态及中国的修订考虑

介绍了国际上土壤质量指导值的研究动态、指导原则及应用功能,提出对中国现行土壤环境质量标准进行修订的若干考虑。基于风险的土壤质量指导值/标准已是国际发展的必然趋势。基于风险的土壤质量指导值/标准的制定,需考虑不同的土地利用方式,设置各种土地利用方式下的一般暴露途径、暴露参数(如暴露周期和暴露频率)和临界风险受体。基于风险的土壤质量指导值/标准多用于污染场地/土壤的风险管理,是潜在污染场地/土壤健康风险初步识别和预测的依据。中国现行土壤环境质量标准的修订,需对标准的功能和宗旨、制定方法论、土地利用方式、土壤污染物迁移对其他环境介质的影响、污染物的种类等方面予以考虑。现行标准修订的最终目的是要建立保护生态和人体健康的“土壤环境和健康质量指导值/标准”,服务于污染场地/土壤的识别及风险管理,同时还需制定保护土壤资源的“土壤自然质量指导值/标准”。     

土壤水分对小麦产量和品质的影响

本文综述了土壤水分对小麦产量和品质的影响。土壤水分既影响小麦产量,也影响其籽粒品质;土壤水分缺少能够影响器官发育,使叶面积减小,叶绿素含量降低,群体叶片光合性能下降。土壤水分缺少还使开花后的光合产物减少,造成灌浆物质不足,原贮存在营养器官中的物质向籽粒的运转速度加快,贮存物质在粒重中的比例提高,在一定程度上弥补了粒重和产量的降低。同时,土壤水分也影响小麦品质,主要表现在蛋白质和淀粉上。     

SOIL AND WATERCONSERVATION IN CHINA

Present Status and Suggestions on Establishing Soil and Water Conservation Sci-Tech Zones of Sichuan；Some Cognition on Establishing a Big Pilot Area of Soil and Water Conservation in Guang‘an；Ecological Effect of Long-Term Fertilizer Applied Soil；Existing Problems in Applying Poplar into Soil and Water Conservation and Countermeasures;Preliminary Approach to Soil and Water Conservation Modes in Various Kinds of Open Economic Zones and Small Reskdential Districts in Dazhou City.     

SOIL CORROSIVENESS IN SOUTH OXFORDSHIRE

The potential corrosiveness of four soil series was studied in south Oxfordshire by measuring soil properties (resistivity, pH, sulphate content, moisture content and redox potential) thought to be closely connected with ferrous metal corrosion. Fifty random points were located in areas of the soil series map units. Paired measurements of resistivity were made at each sampling point. Analysis of variance over all groups (soil map units) showed that, for all properties except redox potential, between group variance exceeded within group variance. The amount of variance contributed from within the pairs of resistivity measurements was small suggesting little short range variation in this property. There was good association between the properties measured and the soil map units. The kinds of soil identified and the delineations on the soil map therefore represents a useful partitioning of the areas studied in terms of corrosion risk.     

IMPACT OF INTEGRATED NUTRIENT MANAGEMENT ON TOMATO YIELD QUALITY AND SOIL ENVIRONMENT

Sustainable agricultural production incorporates the idea that natural resources should be used to generate increased output and incomes, especially for low income groups without depleting the natural resource base. Integrated nutrient management (INM) integrates the use of all natural and man- made sources of plant nutrients, so that productivity and nutrient status of food increases in an efficient and environmentally benefiting manner without sacrificing soil productivity of future generations. Integrated nutrient management relies on a number of factors including appropriate nutrient application and conservation and the transfer of knowledge about INM practices to farmers through extension personal. Tomato is the most popular home garden and the third most consumed crop in the world. It is very much beneficial for health because of its high nutrient status. Integrated nutrient management effects on its yield and quality parameters to a great extent. This review paper therefore, present review on various aspects of INM use to improve soil environment and tomato yield and quality parameters.     

COMPOSTS AS SOIL SUPPLEMENT ENHANCED PLANT GROWTH AND FRUIT QUALITY OF STRAWBERRY

ABSTRACT

Compost significantly enhanced strawberry (Fragaria × ananassa Duch.) plant growth and fruit quality when used as a soil supplement. Adding half strength of Peter nutrient solution (50% fertilizer) to a mixture of 50% soil plus 50% compost was very effective in significantly increasing plant dry weight to approximately double that of controls (without compost), fruit yield by more than 70%, and fruit size by 15% compared to controls in the two strawberry cultivars (“Allstar” and “Honeoye”). Compost and fertilizer also significantly enhanced leaf chlorophyll content. Nitrate reductase activity significantly increased in leaves and roots with the greatest increases when using 50% soil plus 50% compost. Strawberry plants grown with compost had significantly higher levels of nitrogen (N) and potassium (K), but lower levels of manganese (Mn), iron (Fe), molybdenum (Mo), and nickel (Ni) in fruit of both “Allstar” and “Honeoye”. Adding compost to the soil mix did not change zinc (Zn) and cadmium (Cd) levels. Use of compost also significantly increased levels of organic acids (malic and citric acid), sugars (fructose, glucose, and total sugars), soluble solids content, and titratable acidity content in both cultivars. The results indicate that the use of compost can reduce the amount of fertilizer required for optimum strawberry plant growth.