Field experiments were carried out in Huantai County from 2006 to 2008 to evaluate the effects of different nitrogen (N) fertilization and irrigation management practices on water leakage and nitrate leaching in the dominant wheat–maize rotation system in the North China Plain (NCP). Two N fertilization (NF1, the traditional one; NF2, fertilization based on soil testing) and two irrigation (IR1...

Subsidence of the Everglades Histosols occurs at a rate of approximately 3 cm/year. The major cause of this loss of soil is the oxidation of the organic matter by the microbial community. One of the products of this microbial activity is inorganic nitrogen. Assuming an annual subsidence rate of 3 cm, approximately 1400 kg/ha of nitrogen is released per year. Much of this nitrogen accumulates in...

Wet soil microcosms were established to determine effects of organic matter and nitrate additions on microbial respiration and redox potentials. Organic matter (1%) and nitrate (100 ppm and 200 ppm) treatments were applied in factorial combination. Soil pH, redox potential, and CO2 emissions were measured. Data were analyzed by ANOVA for repeated measures and separately by sampling day. Additio...

Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N) for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer app...

Mulching and nitrogen are critical drivers of crop production for smallholders of the Loess Plateau in China. The purpose of this study was to investigate the effect of mulching and nitrogen fertilizer on the soil water content, soil nitrate-N content and vertical distribution in maize root-zone. The experiment was conducted over two consecutive years and used randomly assigned field plots with...

The Lower Burdekin Delta (LBD) is located on the dry-tropical coastal strip in North Queensland, Australia. The region is Australia’s largest sugar producing area with approximately 38,000 hectares of land under sugarcane. However, the LBD also borders the Great Barrier Reef World Heritage Area (GBRWHA). Thus industry, community, and federal, regulatory and environmental organisations are inter...

The effect of nitrate, acetate, and hydrogen on native perchlorate-reducing bacteria (PRB) was examined by conducting microcosm tests using vadose soil collected from a perchlorate-contaminated site. The rate of perchlorate reduction was enhanced by hydrogen amendment and inhibited by acetate amendment, compared with unamendment. Nitrate was reduced before perchlorate in all amendments. In hydr...

This study aimed at examining effective sample treatments and spectral processing for an alternate method of soil nitrate determination using the attenuated total reflectance (ATR) of Fourier transform infrared (FTIR) spectroscopy. Prior to FTIR measurements, soil samples were prepared as paste to enhance adhesion between the ATR crystal and sample. The similar nitrate peak heights of soil past...

The negative impact of nitrate (NO3) on groundwater supplies has sparked a great deal of interest and concern in recent years, particularly in areas where coarse-textured soils abound. In light of this concern, the anion exchange chemistry of eight soils from the Middle Atlantic region was studied with particular emphasis on NO3 retention and kinetics. The soils were chosen to encompass a range...

Nitrate uptake kinetics of different phytoplankton communities exhibit great variability over a 1-year period. Classical saturation kinetics accompanied by an induction phase are shown by blooms of Chaetoceros sp. in low nitrate waters. Biphasic kinetics, with transition points between 10 and 50 ìM, are shown by blooms of Skeletonema costatum and flagellates, while unsaturated kinetics (up to 1...