多年来,实践证明:豁干种湿、播后扶脊、铺砂保苗、育苗移栽、秸秆覆盖等措施皆有很好的保苗效果,近年来塑膜覆盖栽培更是一项保全苗有效技术措施。但是,随着塑膜覆盖栽培的迅速发展和大面积推广应用,却又出现了不同程度的高温烫苗,低温冻苗和墒情不足而缺苗情况,因此,全苗保苗问题仍然是塑膜覆盖下急需研究和解决的课题。三年来,我们就全苗的临界土壤水分下限,烫苗和冻苗的临界温度指标进行了研究。一、研究方法和内容(一)全苗临界需水下限研究据对全苗生态因素分析,影响全苗的主要因素是土 Over the years, practice has proved that it is a very effective seedling protection effect for such measures as wet and dry after planting, ridge support after sowing, seedling sapling, seedling transplanting and straw mulching. In recent years, Measures. However, with the rapid development of plastic film covered cultivation and popularization and application of large area, there are different degrees of high temperature hot seedlings, low temperature cold seedlings and lack of moisture and lack of seedling situation, therefore, the whole seedling protection problem is still plastic sheeting The urgent need to study and solve the problem. In the past three years, we have studied the critical moisture index of the whole seedling, the critical temperature of the hot seedling and frozen seedling. First, the research methods and content (A) the whole seedling critical water requirements According to the analysis of the whole plant ecological factors, the main factor affecting the whole plant is soil