加强福建省耕地土壤质量管理的建议

耕地土壤质量对作物生长具有重要的作用,农耕系统若要持续健康发展,保持较高的耕地土壤质量是其重要途径之一。从耕地资源、耕地土壤肥力和耕地土壤环境三个方面总结了福建省耕地土壤质量的现状,分析了耕地土壤质量存在的主要问题,并提出了加强耕地土壤肥力建设,提高耕地土壤生产力;加强耕地土壤环境保护,确保农业生产安全;建立耕地土壤质量评价体系,完善相应保护机制等建议。     

中国土壤系统分类中土族划分的典型研究

选择我国北亚热带地区归属湿润淋溶的２２个土壤剖面为研究对象,研究了中国土壤系统分类中土族的划分依据和指标,指出,土族的划分应以土壤本身的性质为依据,反映土壤理化性质并影响土壤利用管理的颗粒大小级别,矿物学类型和土壤温度级别是理想的土族分类标准;土族命名要以这些属性名称加在名称连续命名,以准确地反映土壤的性质和分类地位。     

Profile carbon and nutrient levels and management effect on soil quality indicators in the Mardi watershed of Nepal

Abstract

Soil organic carbon (SOC) and nutrient stocks in the soil profile (0–80 cm) in four dominant land uses [forest, upland maize and millet (Bari), irrigated rice (Khet), and grazed systems)] and 0–15 cm depth along elevation gradient 1000 to 3000 m, and aspects in the Mardi watershed were measured. Soil properties at 0–15 cm depth were also measured in undisturbed forest, forest with free grazed system, managed forest, and grassland to compare the soil quality index (SQI) of topsoils. The SOC and nutrient concentration decreased with increasing profile depth. The SOC and N contents in the 0–15 cm depth of forest soils were significantly greater than the corresponding depth in upland maize and millet, irrigated rice, and grazed systems. On the other hand, available P and K concentrations at the same depth were significantly greater in upland maize and millet compared to irrigated rice, grazed system, and forest land uses. The SOC and N stocks (0–15 cm) increased from agricultural land at the valley bottom at about 1000 m above mean sea level (a.s.l.) (24 and 3 Mg ha^?1) compared to undisturbed forest (74 and 5.9 Mg ha^?1) at 2600 m a.s.l, demonstrating the effects of cover and elevation. Both SOC and N stocks decreased sharply in grassland (54 and 4.5 Mg ha^?1) at elevations of 2600 to 2800 m a.s.l. compared with undisturbed forest. Above 2800 m a.s.l. the cover type changed from grass to coniferous forest, and the SOC and N stocks steadily increased at the summit level (3200 m a.s.l.) to 65 and 6.9 Mg ha^?1, respectively. Slope and aspect significantly affected SOC with the northwest aspect having significantly higher concentrations (46 g kg^?1) than other aspects. Similarly, SOC concentration at the lowest slope position (39 g kg^?1) was significantly higher than the middle or upper positions (25 and 13 g kg^?1). Integrated soil quality index (SQI) values varied from 0.17 to 0.69 for different land uses, being highest for undisturbed forest and lowest for irrigated rice. The SQI demonstrated the degradation status of land uses in the following ascending order: irrigated rice?>?grazed system?>?forest with free grazing?>?upland maize and millet?>?managed forest?>?grass land?>?undisturbed forest. The irrigated rice, grazed system, upland maize and millet, and freely grazed forestlands need immediate attention to minimize further deterioration of soil quality in these land uses.     

预处理秸秆在岩石边坡生态护坡中的改土效应

为探明预处理秸秆对岩石边坡生态防护喷播客土稳定性的影响以及在岩石边坡生态防护中的改土效应,该文利用模拟工程试验,研究了预处理秸秆用量与客土孔隙度、侵蚀产沙量、抗剪强度及收缩率之间的关系,并与原始秸秆进行对比。结果表明,使用预处理秸秆,可提高岩石边坡生态防护喷播客土的总孔隙度和毛管孔隙度,同时减少降雨侵蚀、增强喷播客土的抗剪强度、降低客土的收缩率,从而增强喷播客土的稳定性,并且随预处理秸秆用量的增加,改良效果增强;而原始秸秆用量达到3 kg/m2后,会增加客土的降雨侵蚀量及收缩率,同时,客土的抗剪强度降低,不利于客土的稳定。      

中国土壤氮含量、空间格局及其环境控制

Soil holds the largest nitrogen （N） pool in terrestrial ecosystems, but estimates of soil N stock remain controversial. Storage and spatial distribution of soil N in China were estimated and the relationships between soil N density and environmental factors were explored using data from China＇s Second National Soil Survey and field investigation in northwest China and the Tibetan Plateau. China＇s soil N storage at a depth of one meter was estimated at 7.4 Pg, with an average density of 0.84 kg m^-2. Soil N density appeared to be high in southwest and northeast China and low in the middle areas of the country. Soil N density increased from the arid to semi-arid zone in northern China, and decreased from cold-temperate to tropical zone in the eastern part of the country. An analysis of general linear model suggested that climate and vegetation determined the spatial pattern of soil N density for natural vegetation, which explained 75.4% of the total variance.     

模糊c均值聚类方法在黑河下游土壤属性制图中的初步应用研究

运用模糊c均值聚类方法初步研究了我国典型干旱区黑河下游的土壤属性空间分布规律。通过分析该地区的地形参数(坡度,沿剖面曲率和沿等高线曲率),植被指数(NDVI)及地质数据,设计了16个野外典型样本采集点及9个独立样本用于结果验证。应用室内试验,测定土样的3个属性特征(饱和导水率、土壤容重及土壤含水量)。以模糊隶属度作为权重,运用加权平均法计算得到三组土壤属性的空间分布,结果与9个独立采样点进行对比,无显著性差别。表明该方法在极端干旱区黑河下游地形较平缓地区适用性较强,结果能够满足应用需求,为该区域的地表过程研究提供宝贵的数据支持。     

Biological soil amelioration as the basis of sustainable agriculture and forestry

Before the discovery of plant nutrients, soil amelioration and fertilization was by force of circumstance biological, i.e. done with substances taken from nature. After the discovery of plant nutrients, the chemical concept of fertility displaced the biological one. The defects of chemical cultivation — inefficiency, deterioration in product quality, diminishing productivity of soils and negative effects on the environment — have created an urgent need for the study of fertility as a result of the activity of the biocycles of the ecosystem. With the aid of the advances of modern science, we can understand the defects and deficiencies of the chemical concept of fertility and return the biological concept of fertility to its proper place. This in turn is a good starting point for productive research and developmental work towards an ecologically sustainable agriculture and forestry.     

基于土壤剖面测定数据计算中国土壤有机碳贮量

Soil organic carbon (SOC) storage under different types of vegetations in China were estimated using measured data of 2 440 soil profiles to compare SOC density distribution between different estimates, to map the soil organic carbon stocks under different types of vegetation in China, and to analyze the relationships between soil organic carbon stocks and environmental variables using stepwise regression analyses. Soil organic carbon storage in China was estimated at 69.38 Gt (1015 g). There was a big difference in SOC densities for various vegetation types, with SOC distribution closely related to climatic patterns in general. Stepwise regression analyses of SOC against environmental variables showed that SOC generally increased with increasing precipitation and elevation, while it decreased with increasing temperature. Furthermore, the important factor controlling SOC accumulation for forests was elevation, while for temperate steppes mean annual temperature dominated. The more specific the vegetation type used in the regression analysis, the greater was the effect of environmental variables on SOC. However, compared to native vegetation, cultivation activities in the croplands reduced the influence of environmental variables on SOC.