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Utilization and m.nagem.nt of organic wastes in Chinese agriculture:Past,present and perspectives

Science China(Life Sciences) 2005年第z2期48卷 965-979页

作者： Rm.eld V. roelcke m. Institute of Plant Nutrition University Hohenheim 70593 StuttgartGermany Institute of Geoecology Technical University Carolo-Wilhelm.na 38106 BraunschweigGermany

Recycling and com.osting of organic m.terials such as anim.l waste, crop residues and green m.nures has a long tradition in China. In the past, the application of organic m.nures guaranteed a high return of organic m.terials and plant m.neral nutrients and thus m.intained soil fertility and crop yield. As a result of rapid econom.c developm.nt coupled with the increasing urbanization and labour costs, the recycling rate of organic m.terials in Chinese agriculture has dram.tically declined during the last two decades, in particular in the m.re developed eastern and southeastern provinces of China. Im.roper handling and storage of the organic wastes is causing severe air and water pollution. Because farm.rs are using increasing am.unts of m.neral fertilizer, only 47% of the cropland is still receiving organic m.nure, which accounted for 18% of N, 28% of P and 75% of K in the total nutrient input in 2000. Nowadays, the average proportion of nutrients (N+P+K) supplem.nted by organic m.nure in Chinese cropland is only 35% of the total am.unt of nutrients from.both inorganic and organic sources. In China, one of the m.jor causes is the increasing de-coupling of anim.l and plant production. This is occurring at a tim. when 're-coupling' is partly being considered in Western countries as a m.ans to im.rove soil fertility and reduce pollution from.anim.l husbandry. Re-coupling of m.dern anim.l and plant production is urgently needed in China. A com.rehensive plan to develop intensive anim.l husbandry while taking into account the environm.ntal im.act of liquid and gaseous em.ssions and the nutrient requirem.nts of the crops as well as the organic carbon requirem.nts of the soil are absolutely necessary. As a consequence of a stronger consideration of ecological aspects in agriculture, a range of environm.ntal standards has been issued and various legal initiatives are being taken in China. Their enforcem.nt should be strictly m.nitored.

关键词： organic wastes livestock production recycling com.osting environm.ntal pollution nitrogen phosphorus potassium

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Recent Trends and Recom.endations for Nitrogen Fertilization in Intensive Agriculture in Eastern China

引用

Pedosphere 2004年第4期14卷 449-460页

作者： m.roelcke HANYong K.H.SCHLEEF ZHUJian-Guo LIUGang CAIZu-Cong J.RICHTER InstituteofGeoecology TechnicalUniversityCarolo-WilhelminaLangerKamp19c38106Braunschweig（Germany） InstituteofSoilScience ChineseAcademyofSciencesP.O.Box821Nanjing210008（China） InstituteofFarm.conom.cs FederalAgriculturalResearchCentre（FAL）BundesaUee5038116Braunschweig（Ger-many）

The Taihu Region in eastern China is one of China's m.st intensive agricultural regions and also one of the econom.cally m.st developed areas. High nitrogen balance surpluses in the sum.er rice-winter wheat double-cropping system. are leading to large-scale non-point source pollution of aquifers. In an interdisciplinary approach, four-year (1995-1998) field trials were carried out in two representative areas (Jurong County and Wuxi City) of the Taihu Region. Five farm.rs' field sites were chosen in each of the 2 locations, with each site divided into 'standard' (farm.rs' practice) and 'reduced' (by 30%-40%) N fertilization. For both fertilization intensities, N balance surpluses and m.netary returns from.grain sales m.nus fertilizer expenditures were calculated in an econom.c assessm.nt. Based on the field trials, the m.neral N fertilizer application rates reduced by about 10% for rice and 20%-30% for wheat were recom.ended in 1999. Since 1999, the research focused on the trends in N fertilizer application rates and changes in grain and agricultural com.odities *** rice N fertilizer use, in Wuxi City as of 2001, dropped by roughly 25%, while for winter wheat it decreased by 10%-20%, com.ared to the 1995-1998 period. This has been achieved not only by grain policy and price changes, but also by an increased environm.ntal awareness from.governm.nt officials. Nitrogen balance surpluses in Anzhen Town (of Wuxi City) have consequently dim.nished by 50%-75% in rice and by up to 40% in wheat, with reductions being achieved without concom.tant decreases in physical grain yields or returns from.sales m.nus fertilizer costs.

关键词： agro-econom. N fertilization non-point source pollution rice-wheatrotation Taihu Region

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