Crop production is the single largest cause of human alteration of the global nitrogen cycle. We present a comprehensive assessment of global nitrogen flows in cropland for the year 2000 with a spatial resolution of 5 arc-minutes. We calculated a total nitrogen input (IN) of 136.60 trillion grams (Tg) of N per year, of which almost half is contributed by mineral nitrogen fertilizers, and a tota...

Nitrate is a key component of synthetic fertilizers that can be beneficial to crop production in agro-ecosystems, but can also cause damage to natural ecosystems if it is exported in large amounts. Stable isotopes, both oxygen and nitrogen, have been used to trace the sources and fate of nitrate in various ecosystems. However, the oxygen isotope composition of synthetic and organic nitrates is ...

The effects of organic and mineral nitrogen fertilization on nitrogen leaching and nitrate concentration in percolated water were simulated using the CANDY model. In a long-term IOSDV field experiment carried out from 1983 to the present in Lukavec, Czech Republic, increasing nitrogen rates from 0 kg to 200 kg N*ha in mineral fertilizers were combined with the application of farmyard manure or ...

Nitrogen management continues to be diffi cult due to transformations of nitrogen fertilizers that are possible when applied to soil and the uncertainties of weather (Cabrera et al., 2008). Nitrogen (N) fertilizer in the form of urea is subject to ammonia volatilization through the activity of the urease enzyme found ubiquitously in soil (Kissel et al., 2008). Nitrate fertilizer is subject to l...

The aim of this study was to evaluate the long-term (16-years) nitrogenefficiency after the application of organic and mineral fertilizers at two sitesLukavec (S1) and Suchdol (S2) with different soil and climatic conditions in theCzech Republic (Central Europe) and to determine grain yield and nitrogen contentwith regard to the requirements of protein content for baking quality of wheat.After ...

The effect that application of nitrogen-phosphorus (NP) rates exerts on some parameters of nitrogen metabolism and on yield in aubergine plants (eggplant, Solanummelongena cv. Bonica) was studied. All plants were grown under controlled conditions in an experimental greenhouse. The treatments consisted of the combination of three rates of N in the form of KNO3 (N1: 15 g m-2, N2: 22.5 g m,-2 and ...

the aim of this study was to determine the effects of ensiling and using of fertilizers nitrogen and phosphorus on chemical composition and ruminal dm degradability of safflower plant (carthamustinctorius l.). the safflower plant was cultivated at december 2009, and harvested at june 2010 in flowering stage, chopped to 3-5 cm particles and then ensiled in the laboratory silos for 60 days. the e...

Modern agriculture has promoted the development of high-nitrification systems that are susceptible to major losses of nitrogen through leaching of nitrate and gaseous emissions of nitrogen oxide (NO and N2O), contributing to global warming and depletion of the ozone layer. Leakage of nitrogen from agricultural systems forces increased use of nitrogen fertilizers and causes water pollution and e...