【摘要】 <正> 农、林业生产二作的标准化,对提高农、林业生产水平和管理水平具有十分重要的作用。但由于作物生长、发育的复杂性,农业生产的标准化工作,特别是栽培方面的标准化,进展缓慢争尚无成熟经验可循。我们于一九八二年冬接受陕西省水保局、陕西省标准局下达的“制定陕西省水土保持林标准”任务后,于一九八三年对陕西省黄土区水土保持林作了广泛调查,并利用数量化理论(Ⅱ)的方法进行了统计分析,现将该项研究结果报告于后。更多还原

【Abstract】 The regions studied in this project cover the loess hilly and gullyas well as Yuan regions.The widely-distributed Pinus Tabulaeformitscarr.Robinia pseudoacacia Linn.and Caragana korskinskii Kom arethe major tree species in local afforestation.The variables wereexplained with seven major factors affecting water and soil conserv-ation,and the field investigation was carried out in accordance withthe intensity of soil as the basic variable.The discriminant equationwas obtained with the method of quantitive theory（Ⅱ）.The extravariables were gradually eliminated in terms of statistical theory.Finally,the discriminant function with four variables was obtainedas well,thus:y=0.12X₀-0.08X₁-0.17X₂-0.03X₃,of which X₀,X₁,X₂,X₃ were thedestroyed conditions of the forest lands,the vegetation cover rate inthe forest,the canopy density and the thickness of litter layer res-pectively.The criterion was y₁₀=-0.2086,y₂₀=-0.047.The fittingrate of the above functions was 93.55%.The discrimination ratio ofthe waiting discrimination sampling field was 80%,which was ofpractical value.Based on the discriminant functions,water and soil conservationforests can be divided into three grades,water and soil conservationforests of Grade Ⅰ and Grade Ⅱ may play an important role in con-serving soil and water.Forest of Grade Ⅲ has no function in conser-ving soil and water so that it can not be registered into water and soilconservation areas.A criterion table for the forests conserving soil andwater has been worked out based on the discriminant functions forthe convenient application.更多还原