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511.
512.
A. Betz S. Koritnig H. J. Oel A. Schneider E. Ackermann Hans Schaefer 《Die Naturwissenschaften》1955,42(18):518-520
513.
514.
Kolchugina Tatyana P. Vinson Ted S. 《Mitigation and Adaptation Strategies for Global Change》1996,1(2):197-218
Several management practices are available to conserve and sequester C in the agricultural sector of the former Soviet Union (FSU). The highest rate of C accumulation would result from the implementation of a no-till management option which will only continue during the first ten years until new C equilibrium is reached. Agroforestry management options provide a longer period for C accumulation, but at a lower rate. It is possible that the longest period of C conservation may be achieved by increasing the area under perennial grasses in the crop rotation. During the first decade of implementation of the management practices, the amount of C conserved or sequestered would be approximately equal to the current rate of net C sequestration in FSU forest sector. At present, agricultural soils and vegetation of the FSU store approximately 120 Pg C; the accumulation of soil organic matter is 0.032 Pg C yr-1. The annual C loss in the FSU agricultural sector was estimated at 0.21 Pg C yr-1. 相似文献
515.
IntroductionTheuseofchemicals,includingpesticides,hasbecomeanintegralandeconomicallyessentialpartofmodernagriculture.Pesticide?.. 相似文献
516.
Ensegam A.M. Zohny 《环境科学学报(英文版)》2002,14(1):34-38
IntroductionInnatureCooccursintwooxidationstates ,Co2 + andCo3+ ,andformationofthecomplexanionCo(OH) - 3 isalsopossible .DuringweatheringCoisrelativelymobileinoxidizingacidenvironment,butduetoahighsorptionbyFeandMnoxides,aswellasbyclayminerals,thismetaldoesnotm… 相似文献
517.
本文主要研究了肯尼亚姆瓦彻湾(属于浅潮滩红树林湿地)泥沙交换的动力机制.该港湾属于半日潮,大、小潮的潮差分别为.2m和1.4m,大潮高水位的水面面积为17km2. 相似文献
518.
519.
M.H. Wong 《Agriculture, ecosystems & environment》1985,13(2):139-149
The present paper describes heavy metal contamination of soils and crops resulting from auto traffic, sewage sludge, pig manure and chemical fertilizers, in three separate experiments.The first experiment revealed that although the ADDT (average annual daily traffic) value of the Agricultural Area was lower, higher concentrations of Cu, Cd, Zn, Pb and Mn were obtained in soil when compared with the Commercial-Residential Area. Contaminations of trace metals from various source, e.g., chemical fertilizer, animal manure, night soil and pesticides of the nearby agricultural land were suspected.The second experiment compared the effects of adding a commercial fertilizer and digested sludge which contain substantial amounts of various trace metals to a sandy loam for growing Chinese radish. The results indicated that repeated applications of the fertilizer elevated the contents of various trace metals in the roots of Chinese radish. The phenomenon was further aggravated when digested sludge was also incorporated.The third experiment compared the contents of trace metals in the root and leaf tissues of tree seedlings (Acacia confusa) added with a single dose of the trace metalenriched fertilizer, and different portions of pig manure compost. It was revealed that the fertilizer-treated tree seedlings had a higher content of trace metals in the tissues than those amended with manure compost. Although the metal contents of soil increased as more manure compost was added, the contents in plant tissues did not increase correspondingly. 相似文献
520.
After partial hepatectomy the low proliferation rate of hepatocytes increases dramatically. This is based on a feed-back system whose central link is a liver cell proliferation hormon, the so-called hepatopoietin. The hormon originates from the Peyer's patches: after their resection, the liver cell proliferation after partial hepatectomy decreases by about 80%. Hepatopoietin effects organ specific but species nonspecific. 相似文献