Dispersive soils which occur in many parts of the world are easily erodible and segregate in water pose serious problems of stability of earth and earth retaining structures. The mechanism of dispersivity of soils is reasonably well understood. However there is simple method to identify the dispersivity of the soils and even more difficult to quantify the dispersivity. Visual classification, At...

Enrichment cultures for purple nonsulfur and sulfur photosynthetic bacteria were prepared from soil samples collected in central and northern Minnesota. The purple nonsulfur bacteria were found in most wetland soils sampled but were uncommon in woodland and grassland soils. The pH range of the soils in which these bacteria occurred was 3.8 to 7.8, and the oxidation-reduction potential (E(h)) ra...

Culturing in soils from degraded ecosystems significantly influenced the effectiveness of indigenous arbuscular mycorrhizal fungi (AMF) isolated from disturbed and undisturbed soils. The AMF isolates from degraded or artificially created habitats (acid rain polluted site, power station fly ash deposits, spoil banks, pyrite deposit), were not, in most cases, more effective than those from undist...

PURPOSE The sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) to three different artificial soil mixtures was investigated. Artificial soils serve as model systems for improving understanding of sorption phenomena. MATERIALS AND METHODS The soils consisted of quartz, ferrihydrite, illite, montmorillonite, and charcoal. In a previous study, several selected mixtures...

Disease suppressive soils offer effective protection to plants against infection by soil-borne pathogens, including fungi, oomycetes, bacteria, and nematodes. The specific disease suppression that operates in these soils is, in most cases, microbial in origin. Therefore, suppressive soils are considered as a rich resource for the discovery of beneficial microorganisms with novel antimicrobial a...

The purpose of this study was to investigate the regional Cadmium (Cd) concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD) area; and reveal the transfer characteristics of Cadmium (Cd) from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the tran...

Short-rotation hardwood plantations generally require repeated applications of nitrogen (N) fertilizer to maintain desired growth and are being installed on two previous land uses: agricultural fields and cutover forest lands. Because the soil organic matter chemistry is different between agricultural field and cutover soils, indices of N availability developed for one land use or the other may...

Purpose Ammonia oxidation plays an important role in global nitrogen cycle. However, little information is available on ammonia oxidizers in paddy soils. This study aimed to understand the controlling factors of ammonia oxidizers in the paddy soils. Materials and methods Three types of paddy soils were collected from southwest [Chongqing City (CQ)], central [Honghu City (HH)], and northeast [Pa...

No-tillage cultivation offers significant advantages over con­ ventional tillage in terms of water, energy, and particularly soil conservation (Francis et al., 1987). However, continuous no-tillage farming on sandy Ultisols may lead to high bulk density that has a pronounced effect on soil strength due to traffic compaction and lack of plowing (NeSmith et al., 1987). This increase in soil stren...

Phosphorus (P) is an important biogeochemical element and the environmental fate of P receives increasing attention. Through batch equilibration experiments, the adsorption and desorption of P in the absence and presence of exogeneous rare earth elements (REEs) were investigated in five types of agricultural soil samples collected from China. The results showed that the addition of different do...