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

1.通过直接诊断根区指导旱地作物管理技术在加拿大，通过认识到了解作物物理和化学需要的重要性，对每个农场的营养状况进行直接测试。例如，萨斯喀彻温省在萨斯喀彻温省大学校园内建立了拥有众多专业工作人员和现代化实验设备的土壤测试实验室。通过直接试验，引导农民对每一块田进行最优的施肥法设计。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本中测得的硝酸盐氮和硫酸盐-硫酸盐的水平。对0-6英寸、6-12英寸和12-24英寸深度的样品进行测试，比只对表层土壤进行测试，可以更准确地评估土壤的N和S状况。Lovoratory有一个网络…更多的土壤采样剂的Rk。而在农田热状况方面，由于土地利用类型和农田面积较大，没有提供任何服务。根区热环境评价及冻结层和田野积雪深度的诊断在美国大草原北部地区，作物季节取决于积雪和冻结层的起伏。该大学土壤科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积雪深度测量标尺。测量气候和微气象条件，并用热平衡法对其进行分析，以评价田间根区的热环境。通过对草莓生长期根区土壤水分、土壤温度等因素的物理调控，利用草莓植株固有的生理生态特性，首次分析了根区对草莓光合作用、生长发育和果实品质的最佳物理环境条件。1986年以来4年多的草莓栽培试验结果表明，根区环境因子与草莓生长的关系如下：(1)控制土壤水分使果实数增加，控制湿润增加重量；(2)增加作物总重的最适土壤水分对应的水分含量约为30.0%；(3)采用标准施肥作为土壤养分栽培时，将土壤温度维持在较高水平(直到约28ﾟC)，并将土壤水分控制在约35.0%，可获得最好的果实含糖量。较少

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