In the previous paper of this series, the retention characteristics of 4-methyl sterols were investigated with a view for establishing a systematic relationship between the structure of sterols and their gas chromatographic characteristics. The present report deals an extended study on 6methyl sterols prepared from cholesterol. The retention data for five 6-methyl sterols and for their derivati...

An area near the city of Chihuahua has been traditionally irrigated with wastewater to grow forage crops. It has been hypothesized that metal levels could be found in these soils high enough to cause potential health problems to the population. The objective of this study was to determine heavy metal concentrations in different soils due to irrigation practices. Four soil types were evaluated; ...

Topographically heterogeneous agricultural landscapes can complicate and accelerate agrochemical contamination of streams due to rapid transport of water and chemicals to poorly drained lower-landscape positions and shallow ground water. In the semiarid Palouse region, large parts of these landscapes have been tile drained to enhance crop yield. From 2000-2004 we monitored the discharge of a ti...

Soil temperature (tB) was determined down to 2 m below ground level at 8 locations in the city of Oberhausen, Ruhr area, Germany, between August 2010 and July 2011 to investigate the subsurface urban heat island (SUHI) and its impact on drinking water quality. The soil temperatures obtained in Oberhausen demonstrate typical location-dependent behaviour. At the depth of drinking water pipes (1 t...

The influence of growth stages of rice on soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN) and enzyme activities (amylase, dehydrogenase, alkaline and acid phosphatase) in a sub-tropical rice field has been screened. The above soil parameters were investigated at two soil depth (0-10 and 10-20 cm) and in five growth stages of rice crop, i.e. 30, 60, 90, 120 and 150 day...

Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NC...

A field experiment was conducted to examine the effects of different depths ofnitrogen (N) fertiliser placements on N accumulation, remobilisation and NO3−-Ncontent in soil of rainfed wheat. Nitrogen was applied on the surface (D1) and inthe 10 cm (D2), 20 cm (D3) and 30 cm (D4) soil layers from 2010 to 2012.Compared with D1 and D2, D3 and D4 treatments obtained significant higher Ndistribution...

Turnover of deep organic carbon in cultivated soils: an estimate from a review of isotope data Description of the subject. This study is an estimate of medium-term renewal (decades) of deep carbon in cultivated soils. Objectives. Sequestration of organic carbon in soils is a way to mitigate the global rise in CO2 and warming. Deep horizons (> 30 cm) contain about half of the soil organic carbon...