To feed an increasing population, large amounts of chemical nitrogen fertilizer have been used to produce much of our food, feed and fiber thereby increasing nitrogen levels in soils, natural waters, crop residues, li...To feed an increasing population, large amounts of chemical nitrogen fertilizer have been used to produce much of our food, feed and fiber thereby increasing nitrogen levels in soils, natural waters, crop residues, livestock wastes,and municipal and agricultural wastes, with national and international concern about its potential adverse effects on environmental quality and public health. To understand these phenomena and problems, first the nitrogen cycle and the environment are described. Then recent trends for nitrogen cycling through the food and feed system, N2O emissions from fertilized upland and paddy soils, and NO-3 pollution in ground water in Japan are reported. Finally, mitigation strategies in Japan for reducing N2O emission and NO-3 pollution are proposed, including nitrification inhibitors, controlled release fertilizers, utilization of plant species that could suppress nitrification, utilizing the toposequence, government policy, and appropriate agricultural practices. Of all the technologies presented, use of nitrification inhibitors and controlled release fertilizers are deemed the most important with further development of these aspects of technologies being expected. These practices, if employed worldwide, could help reduce the load, or environmental deterioration, on the Earth's biosphere.展开更多
1 Introduction A variety of Pd(Ⅱ)-catalyzed oxidative transformations ot allcenes with oxygen nucleophiles are catalyzed by PdX_(2)(X=OAc,Cl,etc)with CuX_(n)(n=1 or 2)under O_(2).In the so-called Wacker catalyst of s...1 Introduction A variety of Pd(Ⅱ)-catalyzed oxidative transformations ot allcenes with oxygen nucleophiles are catalyzed by PdX_(2)(X=OAc,Cl,etc)with CuX_(n)(n=1 or 2)under O_(2).In the so-called Wacker catalyst of such,Pd(OAc)_(2) is less reactive compared to PdCl_(2).In an attempt to increase the reactivity of Pd(OAc)_(2),we have now found that tuning of Cu site with catechol gives an intriguing reactivity to Pd(OAc)_(2),which is unprecedented in the chemistry of palladium.展开更多
基金Project supported by the Canadian International Development Agency, Canada and the Chinese Academy of Scicences, China (No. KZCX2-413)
文摘To feed an increasing population, large amounts of chemical nitrogen fertilizer have been used to produce much of our food, feed and fiber thereby increasing nitrogen levels in soils, natural waters, crop residues, livestock wastes,and municipal and agricultural wastes, with national and international concern about its potential adverse effects on environmental quality and public health. To understand these phenomena and problems, first the nitrogen cycle and the environment are described. Then recent trends for nitrogen cycling through the food and feed system, N2O emissions from fertilized upland and paddy soils, and NO-3 pollution in ground water in Japan are reported. Finally, mitigation strategies in Japan for reducing N2O emission and NO-3 pollution are proposed, including nitrification inhibitors, controlled release fertilizers, utilization of plant species that could suppress nitrification, utilizing the toposequence, government policy, and appropriate agricultural practices. Of all the technologies presented, use of nitrification inhibitors and controlled release fertilizers are deemed the most important with further development of these aspects of technologies being expected. These practices, if employed worldwide, could help reduce the load, or environmental deterioration, on the Earth's biosphere.
文摘1 Introduction A variety of Pd(Ⅱ)-catalyzed oxidative transformations ot allcenes with oxygen nucleophiles are catalyzed by PdX_(2)(X=OAc,Cl,etc)with CuX_(n)(n=1 or 2)under O_(2).In the so-called Wacker catalyst of such,Pd(OAc)_(2) is less reactive compared to PdCl_(2).In an attempt to increase the reactivity of Pd(OAc)_(2),we have now found that tuning of Cu site with catechol gives an intriguing reactivity to Pd(OAc)_(2),which is unprecedented in the chemistry of palladium.
