SoilCritZone-2010-05-14 Beijing for US students-zb.ppt

SoilCritZone-2010-05-14 Beijing for US students-zb.ppt

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SoilCritZone-2010-05-14 Beijing for US students-zb

News perspectives for integrative research on SoilCritzone for sustainable agriculture in China Prof. Bin Zhang Institute of Soil Science, CAS Institute of Agricultural Resources and Regional Planning, CAAS bzhang@/bzhang@ What is a soil? Geological to agronomic, ecological and global scientific definitions The thin but precious skin at the Earth’s surface (over unweathered rocks) A living entity composed of an inextricable association of inorganic particles /organic matter, perfused by gases and water The fertile substrates, from which all terrestrial life on this planet springs. A life sustaining pedoshere zone, which is a biologically active, porous and structured media that effectively integrates and dissipates mass fluxes and energy A self-regulating biological entity, analogous to a sponge, regulating and buffering the supply of nutrients and water for the growth of macro and micro flora and fauna, and determining the partitioning of water into rivers and lakes, groundwater Soils are where the organic and the mineral meet… at different scales formation of organo-mineral complexes 30-60% of soil C not separated from minerals SOIL STRUCTUREs… Soil is an interface between: Soil—The Critical Zone Problems of Agriculture of China in relation to soil ssustainability? Food production and demand in China Loss of arable land With a limitation of arable soil resources, to increase food production per unit arable land is the only way to secure food safety. The current strategy includes: High yield varieties, e.g. hybrid rice/corn Multiple cropping within a year / less rotation annually (MCI, 118.9%, max c.a. 200%) Higher inputs (nutrients, water, other chemicals…….) Developing greenhouse agriculture with rational and irrational intensive operations to every small-scale field. High inputs of chemical fertilizers Chemical fertilizer consumption for food production Loss of N from farmland: 1740X103 T/year in total 975X103 T/year in Yangtze, Ye

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