levels of prevention meaning in English

分级预防

Based on the situation of demand exceeds supply in the market , the author would like to find out the constraints of the water chestnut development by use of pra ( participatory rural appraisal ) in a survey to carry out stakeholder analysis including the water chestnut farmers , government and processing companies . also , the author applied a tool of system theory to analyze the constraints of water chestnut plant production development . the results are as following : the study shows that a main factor that restricts the plant yield ( per unit yield ) and quality ( product quality ) of water chestnut is the low level of prevention and control of water chestnut culms damping - off ; a disease of the water chestnut
针对贺州市荸荠产业发展中的“销大于产”的突出矛盾，笔者通过运用pra (参与式农村评估)方法，对荸荠种植区的农户、政府机构、加工流通企业等进行了调查研究，并运用系统科学的方法对荸荠种植系统的不同组成因子的制约因素进行分析，得出研究结论如下：农户对荸荠秆枯病害的综合防治水平偏低，制约其荸荠种植的产量(单产)和质量(商品质量) 。