微量元素是指土壤中含量很低的化学元素,其中,有些是植物正常生长发育或积累产量不可缺少的营养元素。土壤与植物在微量元素营养上的供求关系,主要取决于土壤中微量元素的含量及其对植物的有效性。前者由土壤类型决定,后者受土壤条件影响。在土壤缺乏微量元素、特别是有效态微量元素时,施用相应的微肥具有一定的促进作物增产的效果。本文所述灰钙土是于1985年起才开始灌耕农用的,在土壤有效态微量元素含量和施微肥效益上还未开展工作,有关的资料尚属空白。因此,我们于1989年起进行了这方面的试验研究工作,并取得下述初步结果。一、材料和方法1.概况:兴堡子川在靖远县北部,是于1985～1989年期间形成的新灌区,处在旱地农业与荒漠牧地过渡线附近。土壤系灰钙土,母质为次生黄土。2.土壤有效态微量元素分析:有效硼用沸水浸提、姜黄比色法测定,有效态锌、铜、锰和铁用 Trace elements are chemical elements with very low content in the soil, some of which are essential for the normal growth or accumulation of plants. Soil and plant nutrient supply and demand in trace elements, mainly depends on the content of soil trace elements and their effectiveness on plants. The former is determined by the soil type, the latter by the soil conditions. In the absence of trace elements in the soil, especially the effective trace elements, the application of the corresponding micro-fertilizer has some effect of increasing crop yield. The limestone described in this article started irrigating agriculture only in 1985, and no work has yet been done on the available trace elements and fertilizing benefits of soils. The relevant data are still blank. Therefore, we conducted pilot studies in this field in 1989 and achieved the following initial results. I. Materials and Methods 1. Overview: Xingbaozi River is a new irrigation area formed in 1985 ~ 1989 in the northern part of Jingyuan County, near the transitional line between dry land agriculture and desert pastures. Soil Department of calcareous soil, parent material secondary loess. 2. Soil available trace element analysis: effective boron was extracted with boiling water, turmeric colorimetric determination of available zinc, copper, manganese and iron