Development of crop management techniques for higher yield by optimun control of root zone environment

1. 通过根区直接诊断指导旱地作物的管理技术在加拿大，通过认识到了解作物对肥料的物理和化学需求的重要性，对每个农场的营养状况进行了行政上的直接测试。例如，萨斯喀彻温省在萨斯喀彻温大学校园内建立了拥有众多专业人员和现代化实验设备的土壤测试实验室。他们通过直接试验，引导农民对每一块田地进行最优的施肥设计。他们建议的抽样程序如下。氮肥和硫肥的建议是基于从每个田地提交的土壤样品中测量到的硝酸盐氮和硫酸盐硫的水平。测试0-6英寸、6-12英寸和12-24英寸深度的样品，可以比只测试表面土壤更准确地评估土壤的氮和硫状态。实验室有一个网络…更多的土壤取样剂。然而，由于土地利用型耕作方式和广阔的农田面积，它们对农田的热状况没有提供服务。根区热环境评价与冻土层和积雪深度诊断在美国大平原北部地区，作物季节取决于积雪的积累期和冻土层的起伏。大学土壤学系的气候学家对这些问题进行了研究，并利用化学物质开发了一种特殊但简单的冻结层和雪深测量尺度。测量气候和微气象条件，用热平衡法对其进行分析，评价田间根区热环境。作为第一个试验，利用草莓植物固有的生理生态特性，通过对根区生长期间土壤水分、土壤温度等因素的物理控制，分析了根区栽培草莓光合作用、生长和果实品质的最佳物理环境条件。1986年以来4年草莓栽培试验结果，根区环境要素与草莓生长的关系可以概括为：(1)土壤湿度控制在干燥状态下，果实数量增加，土壤湿度控制在湿润状态下，果实重量增加；(2)提高作物总重的最佳土壤含水量约为30.0%;(3)在使用标准施肥作为土壤养分的情况下，保持较高的土壤温度（至28‰左右），并将土壤水分控制在约35.0%的含水量，可获得果实中最佳的糖含量。少

1. Guidance of management technique for upland crops through direct diagnosis of root-zoneIn Canada, direct testing of the nutrient situation of each farm are made administratively by having recognized the importance of knowing fertilizer requirements of the crop physically and chemically. For example, the province of Saskatchewan established Soil Testing Laboratory with many professional staffs and modern experimental equipments in the campus of the Saskatchewan University. They lead farmers the most optimun design of fertilizing method to each field through the direct testing. They recommend sampling procedures as follows.Recommendations for nitrogen and sulphur fertilization are based on the measured levels of nitrate-nitrogen and sulpate-sulpur in the soil samples submitted from each field. Testing samples from the 0-6, 6-12, and 12-24 inch depths results in a more accurate assesment of the N and S status of the soil than testing of the surface, soil only.The Lovoratory has a netwo … More rk of soil sampling agents. About thermal situation of field, however, they have no services, becauseof land using type farming and vast area of fields.2. Assesment of thermal enviroment of root-zone and diagnosis of frozen layer and snow depth of fieldsIn the northern region of the Great Praily in the United States, crop season depend on the period of accumulation of snow and ups and downs of frozen layer. The climatologists of the department of soil science of the University study on these problems and developed a special but a simple measuring scale for frozen layer and snow depth using chemical substances. They measure climatic and micro meteorological conditions, and analyzed them with the heat-balance method to assesment of thermal environment of root-zone in fields.3. As a first experiment, the optimum physicoenvirommental conditions of a root zone are a for the photosynthesis, growth and quality of fruits in cultivation of strawberry were analyzed by physical control of the soil moisture, soil temperature and other factors at the root zone area during the period of growth, while utilizing the physioecological properties intrinsic to the plant, in an experimental greenhouse strawberry field. The results of experimental cultivation of strawberry over four years from 1986 may be summarized in terms of the relation between the environmental elements at the root zone area and the growth of strawberry as (1) the number of fruits increases by controlling the soil moisture to a dry condition and the weight increases by controlling it to a moist condition, (2) the optimum soil moisture for increasing the total crop weight corresponds to a water content of approximately 30.0% and (3) the sugar content in fruits can be best obtained by maintaining the soil temperature at a high level (until about 28ﾟC) and by cotrolling the soil moisture at a water content of approximately 35.0%, when cultivated using standard fertilization as a nutrient in the soil. Less