一、引言本文所谓豫东南地区指南阳盆地以东、汝河以南的河南东南部地区,包括驻马店地区大部和信阳地区。豫东南地区地跨华北、华中两大区,作为中国北方和南方重要地理分界线的淮河从中部流过。由表一可以看出,豫东南淮河南北地区在地貌、气候等方面都存在一定差异。不过总体说来,该地区处于过渡地带,兼有暖温带和北亚热带的特点。雨量充沛、雨热同季、河流众多,属于湿润气候。生长期长,作物一般一年两熟,是重要的农业区。但由于七八月份集中降水,故洪涝 I. INTRODUCTION The so-called southeastern Henan region refers to the southeastern part of Henan Province that lies to the east of the Nanyang Basin and to the south of the Ru River, including most of the Zhumadian area and the Xinyang area. The southeastern region of Henan Province runs through the two major regions of North China and Central China. The Huai River, an important geographic boundary between northern and southern China, flows through the central region. It can be seen from Table 1 that there are some differences between the north and south of Huaihe River in the topography and climate. Overall, however, the area is in a transitional zone with both temperate and northern subtropics. Rain is abundant, hot and rainy season, many rivers, are humid climate. Long growing season, crops generally two crops a year, is an important agricultural area. However, since July and August concentrated rainfall, it is flooding