Ammonia-oxidation process directly contribute to soil nitrous oxide (NO) emissions in agricultural soils. However, taxonomy of the key nitrifiers (within ammonia oxidising bacteria (AOB), archaea (AOA) and complete ammonia oxidisers (comammox Nitrospira)) responsible for substantial NO emissions in agricultural soils is unknown, as is their regulation by soil biotic and abiotic factors. In this study, cumulative NO emissions, nitrification rates, abundance and community structure of nitrifiers were investigated in 16 agricultural soils from major crop production regions of China using microcosm experiments with amended nitrogen (N) supplemented or not with a nitrification inhibitor (nitrapyrin).
View Article and Find Full Text PDFThe nitrogen cycle has been radically changed by human activities. China consumes nearly one third of the world's nitrogen fertilizers. The excessive application of fertilizers and increased nitrogen discharge from livestock, domestic and industrial sources have resulted in pervasive water pollution.
View Article and Find Full Text PDFWe combine field observations, microcosm, stoichiometry, and molecular and stable isotope techniques to quantify N2O generation processes in an intensively managed low carbon calcareous fluvo-aquic soil. All the evidence points to ammonia oxidation and linked nitrifier denitrification (ND) being the major processes generating N2O. When NH4(+)-based fertilizers are applied the soil will produce high N2O peaks which are inhibited almost completely by adding nitrification inhibitors.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2013
Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world's population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st century. China's participation is essential to global efforts in reducing N-related greenhouse gas (GHG) emissions because China is the largest producer and consumer of fertilizer N.
View Article and Find Full Text PDFHere, we report on a two-years field experiment aimed at the quantification of the emissions of nitrous oxide (N2O) and methane (CH4) from the dominant wheat-maize double cropping system in North China Plain. The experiment had 6 different fertilization strategies, including a control treatment, recommended fertilization, with and without straw and manure applications, and nitrification inhibitor and slow release urea. Application of N fertilizer slightly decreased CH4 uptake by soil.
View Article and Find Full Text PDFExcessive N fertilization in intensive agricultural areas of China has resulted in serious environmental problems because of atmospheric, soil, and water enrichment with reactive N of agricultural origin. This study examines grain yields and N loss pathways using a synthetic approach in 2 of the most intensive double-cropping systems in China: waterlogged rice/upland wheat in the Taihu region of east China versus irrigated wheat/rainfed maize on the North China Plain. When compared with knowledge-based optimum N fertilization with 30-60% N savings, we found that current agricultural N practices with 550-600 kg of N per hectare fertilizer annually do not significantly increase crop yields but do lead to about 2 times larger N losses to the environment.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
January 2008
With enclosed and static chambers, this paper studied the effects of different fertilization modes, i.e., top-dressing nitrogen (N) fertilizer followed by tillage (SF), drilling N fertilizer followed by covering soil (TF), and top-dressing N fertilizer followed by irrigation (SS), on soil ammonia (NH3) volatilization and nitrous oxide (N2O) emission.
View Article and Find Full Text PDFThe influence of nitrification inhibitor (NI) 3, 4-dimethylpyrazole phosphate (DMPP) on nitrate accumulation in greengrocery (Brassica campestris L. ssp. chinensis) and vegetable soil at surface layer were investigated in field experiments in 2002 and 2003.
View Article and Find Full Text PDF