论水稻土肥力进化与土壤质量——以太湖地区为例

EVOLUTION OF SOIL FERTILITY IN RELATION TO ITS QUALITY IN PADDY FIELD OF THE TAIHU LAKE AREA

太湖地区是我国古老农业区之一。在六七千年之前先民已开始种植水稻 ,随着耕作培肥措施不断加强 ,与土壤肥力进化同步伴随着耕作轮作制的不断演进 ,由轮荒———沤田———水旱轮作———三熟制的变化 ,土壤基础肥力稳步提高 ,稻麦单位面积产量逐年上升。该区水稻土历经数千年的耕肥与平田整地等人为活动 ,在起源土壤背景上发育成五类水稻土 ,这五类水稻土经过培肥改良均达到水旱轮作高产稳产阶段 ,尽管地力上还存在不同程度的差异 ,这不能不说是人为定向培育的成果。在一般情况下 ,土壤质量是由土壤肥力决定的 ,基础肥力高低是农业生产优质高产低耗的关键 ,在评价土壤质量时必需首先予以关注。当然 ,随着工业的发展 ,土壤污染所波及的农产品超标问题 ,也应在评价土壤质量时予以关注 。

The Taihu Lake area is an ancient agricultural zone in China.Ancestors began the rice cultivation in this area as early as about 6 to 7 thousand years ago.With the soil build up practice over centuries,the soil fertility has evolved in combination with the development of crop rotation systems being from fallow system to water logging field,to the alternation of upland and paddy field,and to the triple planting system.The basic soil fertility has been growing steadily,and so the yield of rice and wheat in per unit area.During several thousand years cultivation,fertilization,together with land leveling and many other human activities,the soil in the paddy field has been ameliorated from its original earth into five types of soil.In spite of the various degrees in productivity,these types of soil have been cultivated as an alternation of paddy field and upland farmland with relatively high and stable yields.It,however,has to be mentioned that this has been a result of artificially directed cultivation in this area.The soil quality,on the other hand,is determined by its feritility,and the basic fertility of soil is the key factor influencing the agricultural production.It is thus considered that the assessment of soil quality should be the priority in soil research.With the development of industry,the soil pollution and its consequent effect in agricultural products should however also be considered as an important factor in the integrated evaluation system of soil quality.