成都地区土壤硼元素含量及其养分管理建议

STUDY OF BORON CONTENTS IN SOIL AND NUTRIENT MANAGEMENT SUGGESTIONS FROM THE CHENGDU AREA, CHINA

成都地区浅层土壤中全量硼较为丰富,但是部分地区土壤有效硼较为缺乏。土壤中有效硼的含量与土壤有机质含量、pH值呈正相关,与土壤类型也有关系,而与硼全量关系不大。有效硼的缺乏主要是由于有机质缺乏、土壤pH值较低引起。黄壤地区酸性土壤种植油菜会有缺硼症状;水稻土和紫色土有效硼含量达到植物正常生长所需要的临界值,种植油菜就不缺乏硼,但是种植小麦仍然会缺硼。开展硼的区域生态地球化学评价时,不能只用土壤硼全量来评价其丰缺,还应该考虑用有效硼、有机质、pH值、土壤类型以及不同的植物种类等进行综合评价,更有利于指导农业生产土壤养分管理和选择种植适宜的植物。增加土壤有效硼含量的主要措施是施用硼肥,同时施用有机肥,酸性土壤适量施用石灰。

In this paper, we have evaluated the status of boron contents in soils from the Chengdu area and have proposed reasonable suggestions for the management of soil nutrition based on the study of distributed characteristics of the total boron and available boron in soils and boron concentrations in rape and wheat, and the relationship between available boron and organic matter, pH value, and soil types.The main research methods in this paper show are as following: (1)soil and plant samples from different districts with different soils that bear different pH values and total boron contents based on the multi-purpose geochemical mapping at scale 1 ∶250 000 in the Chengdu area; (2)total boron, available boron, pH value, organic matter in the soil were measured, and boron concentrations in haulms and plant seeds were analyzed; (3)the data of the samples were analyzed for relationship between the available boron, total boron, pH value, and organic matter in surface soils, and the distributed plot of available boron in soils from the Chengdu area was mapped.We have reached the following main conclusions: (1) there exist positive correlations between available boron and organic matter, pH value, but no correlations between available boron and total boron; (2) deficiency of available boron is caused by deficiency of organic matter, lower pH value, and types of soil; (3) boron-deficiency symptom will appear when planting rape in yellow-soil area; but no boron-deficiency symptom appeared when planting rape in paddy-soil and purple-soil area where boron-deficiency will still appear when planting wheat; (4) when we evaluated the ecological geochemical environment of boron, we should not only consider the total boron, but also take available boron in to account, pH value, organic matter, agrotype etc. Based on our results, we give the reasonable suggestions: (1)increasing available boron content by employing boron fertilizer and organic fertilizer; (2)adding pH value of soil by employing proper lime in acid soil.