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Effects of Soil Degradation on the migration of Environmental Materials in an Agricultural Field.

土壤退化对农田环境物质迁移的影响。

基本信息

批准号：
09460106
负责人：
MIYAZAKI Tsuyoshi
金额：
$ 8.9万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The purpose of this study were to (1) find the causes why soils are undergoing serious degradation recently in the 380 ha upland fields in Fukaya, Saitama Prefecture, (2) classify the effects of soil degradation on the migration of such environmental materials as water, solutes (including salts, nitrogen, phosphorous, etc.), and gasses (including OィイD22ィエD2,COィイD22ィエD2, NィイD22ィエD2O etc.), and (3) propose the ways of soil restoration by which physical properties and drainage efficiency of the soils are recovered.The main results are as follows.1. The suffering from deterioration of drainage efficiency and excess water in upland fields were due to not only by soil degradation but also configurations of structures such as roads, drainage canals, green houses etc.2. The saturated hydraulic conductivities of soil samples from well drained fields were not necessary higher than those from poorly drained fields. This contradiction was explained by other physical properties of soils.3. The poor efficiency of drainage from upland fields were attributed to the low stability of aggregation, high sensitivity to the application of salts, the tendency of easy-to-form surface crusts, and high consistencies.4. The soil degradation was classified into two types : one is the surface soil degradation where the soils are mechanically disturbed, directly compacted and periodically fertilized, and other is the subsurface soils degradation where the soils are indirectly compacted resulting in the increase of bulk density.5. The deep plowing was effective for the restoration of subsurface soils but plowing with organic matter did not show any advantage for the physical properties of soils.6. Application of polyacrylamid (PAM) may be effective for the soil restoration especially in its permeability. Further investigation of the PAM efficiency is needed.

本研究的目的是：(1)找出近期福谷县380公顷旱地土壤严重退化的原因；(2)分类土壤退化对水、溶质(包括盐、氮、磷等)和气体(包括O-ィイD22-ィエD2、CO-ィイ-D22-ィエ-D2、N-ィイ-D22-ィエ-D2O等)等环境物质迁移的影响；(3)提出恢复土壤物理性质和排水效率的土壤恢复途径。旱地排水效率下降和水分过剩不仅与土壤退化有关，还与道路、排水渠、温室等构筑物的配置有关。排水较好的土壤样品的饱和导水率不一定高于排水较差的土壤样品。这一矛盾可以用土壤的其他物理性质来解释。旱地农田排水效率低的主要原因是团聚体稳定性差、对盐分的敏感性高、易形成表层结皮、浓度高。土壤退化分为两种类型：一种是表层土壤退化，土壤受到机械扰动，直接压实，定期施肥；另一种是亚表层土壤退化，间接压实导致土壤容重增加。深耕对亚表层土壤的恢复是有效的，但有机质耕作对土壤的物理性质没有任何好处。应用聚丙烯酰胺(PAM)可以有效地修复土壤，特别是提高土壤的渗透性。PAM效率有待进一步研究。