土壤重金属元素的空间分布特征与来源分析——以三江平原某农业耕作区为例

针对三江平原某农业耕作区,运用地统计学和主成分分析法对土壤中Cu、Cd、Se、Cr、Ni、Zn、As、Hg 8种重金属元素的空间分布特征与来源进行研究。结果表明:8种元素含量的变异系数Cv在10.49%~49.23%之间,其空间分布各具特征;且在小范围内存在明显的空间变异性。经过地统计分析得出Cu、Cr、Ni呈现中等程度空间自相关性,其空间变异可能受到自然和人为因素的共同作用;Hg、As、Cd、Se、Zn具有强烈的空间自相关性,主要受到土壤母质等自然因素的影响。结合主成分分析得出,As、Cd、Se、Zn、Hg、Cu除了来源于自然因素外,也受低程度农业施肥等活动的影响;而Ni、Cr主要来源于土壤母质和农业施肥、矿产资源开发利用过程。将主成分分析结果再次进行统计分析得出块金值和基台值之比[C_0/(C_0+C)]为35.70%,大于25%,进一步说明土壤元素已受到耕作施肥、工业生产等人类活动的影响,需要合理安排工农业生产方式以保障生态农业的健康发展。

农业耕作区经济发展难题与对策

本文对传统农业耕作的基层地区的经济发展特点和存在的问题进行了分析,并对促进基层农村经济发展提出相应对策。

遵义农业耕作区土壤质量的模糊评价

以遵义东南部地区农业耕作区的土壤质量为研究对象,对该地区农业土壤中重金属Cd、Pb、Cr、Hg、As含量进行监测分析和模糊评价。结果表明,仅泮水镇土壤质量为Ⅰ级,属于清洁,仅马蹄镇土壤质量为Ⅲ级,属于污染,其余13个乡镇土壤质量均为级尚清洁。主要重金属污染物是Cd。

农田土壤污染与修复技术研究

2018年,习近平总书记在全国生态环境保护大会上提出:要全面落实《土壤污染防治行动计划》,突出重点区域,行业和污染物,强化土壤污染管控和修复,有效防范风险,让老百姓吃得放心,住的安心。农田土壤的污染有原生母质重金属含量超标,发育的土壤相应也会超标;另外则是通过大气沉降、污染水源灌溉、污染水源侧渗,或者其他人为生产活动导致污染。在农田土壤中还有大量的农业土壤处于生产障碍,目前大家为了引起社会的重视,也笼统地归纳为土壤污染范畴。在一些成土母质含有重金属的农业耕作区,土壤的污染将随着母质的风化持续保持,即使修复也很难实现安全,一般建议不作为农业生产耕地使用。

Analysis of Division of Beibei Agro-climatic Zones

[Objective] The aim was to analyze and explore division of agro-climatic zones of Beibei District in Chongqing municipality. [Method] According to major triple-cropping crops in Beibei District, such as wheat （spring and winter）, rice （midmaturation early season rice, later-maturation early rice, later-maturation late rice and middle-season rice）, heat demanded by rapeseed, different cultivation methods and cultivation regions with different crop varieties, the accumulated temperatures in four cultivation regions featured by special cultivation methods and variety-matching are concluded. Based on average and accumulated temperatures in different locations in 30 y and other factors, such as terrain, elevation, rainfall and soil property, Beibei District can be classified into four agro-climatic zones. [Result] Four cultivation regions are as follows： the 1st cultivation region where accumulated temperature in T y is ≥6 530 ℃, the 2nd cultivation region where 6 530 ℃ accumulated temperature in T y≥6 350 ℃, the 3rd cultivation region where 6 530 ℃ accumulated temperature in T y≥5 990 ℃, and the 4th cultivation region where accumulated temperature in T y is ≤5 990 ℃. Beibei District can be classified into four agro-climatic zones, involving lower hill temperate zone, higher hill temperate zone, single-slope lower hills and karst temperate zone, and lower ridge cool zone. [Conclusion] Based on characters of four agro-climatic zones and accumulated temperatures required in four cultivation regions, agro-climatic zones can be classified in Beibei District, providing references for rational arrangement of crops and is of significance for stabilization of agricultural production, improvement of crops and increase of farmers’ income.