共查询到20条相似文献,搜索用时 46 毫秒
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V. I. Kiryushin 《Eurasian Soil Science》2006,39(11):1157-1163
The acceptance of the biospheric paradigm of nature management anticipated by V.V. Dokuchaev instead of the anthropocentric ideology suggests a solution of problems related to the ecologization of agriculture and its adaptive intensification under the conservation of soil ecological functions. The landscape-ecological principles of human economic activity proposed by Dokuchaev have developed into the modern methodology of agrolandscape design and adaptive-landscape farming. 相似文献
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B Ramaroson-Raonizafinimanana E M Gaydou I Bombarda 《Journal of agricultural and food chemistry》1999,47(8):3202-3205
Analyses of the neutral lipids from Vanilla species before saponification resulted in the identification of a new product family in this genus: long-chain gamma-pyrone compounds with an aliphatic chain containing a cis double bond at the n-9 position. These compounds represent 7-8% of the neutral lipids in mature beans. Using NMR and gas chromatography/mass spectrometry, three gamma-pyrones have been identified, including 2-(10-nonadecenyl)-2, 3-dihydro-6-methyl-4H-pyran-4-one, 2-(12-heneicosenyl)-2, 3-dihydro-6-methyl-4H-pyran-4-one, and 2-(14-tricosenyl)-2, 3-dihydro-6-methyl-4H-pyran-4-one. The major constituent was 2-(14-tricosenyl)-2,3-dihydro-6-methyl-4H-pyran-4-one, which represented 70.3% of the gamma-pyrone fraction. The variability of this compound family has been studied in relation to bean maturity in V. fragrans and V. tahitensis beans. This compound family has not been found either in leaves or in stems or in V. madagascariensis beans. 相似文献
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ROTHAMSTED STUDIES OF SOIL STRUCTURE V. 总被引:1,自引:0,他引:1
R. J. B. WILLIAMS 《European Journal of Soil Science》1979,30(3):453-461
Three pairs of soils were chosen, each with one difficult and one easily manageable soil with similar texture. Mechanical composition and organic matter content greatly affected the measured physical properties some of which related to the field behaviour of each pair. Soils from all horizons were stable to water slaking except some subsoils on the Ragdale, Hanslope, Salop, and Flint series. Dry and total mechanical slaking were less and breaking strengths more for the Denchworth, Evesham, Ragdale and Hanslope series than for the Salop and Flint soils. Water-holding capacity was largest for the Denchworth and Evesham soils, but slow penetration of water into their dense clods could influence regeneration of tilth. 相似文献
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Jensen HD Krogfelt KA Cornett C Hansen SH Christensen SB 《Journal of agricultural and food chemistry》2002,50(23):6871-6874
Analysis of the hydrophilic fraction of cranberry juice by reversed-phase HPLC using an Aqua LUNA column with diode array or MS detection revealed the presence of quinic acid, malic acid, shikimic acid, and citric acid. For the first time, two iridoid glucosides were found in the juice. The two iridoid glucosides were shown to be monotropein and 6,7-dihydromonotropein by MS and NMR spectroscopy. A fast reversed-phase HPLC method for quantification of the hydrophilic carboxylic acids was developed and used for analyses of cranberry, lingonberry, and blueberry juices. The level of hydrophilic carboxylic acids in cranberries was 2.67-3.57% (w/v), in lingonberries 2.27-3.05%, and in blueberries 0.35-0.75%. In lingonberries both iridoid glucosides were present, whereas only monotropein was present in blueberries. 相似文献
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Igor Grebenščikov 《Genetic Resources and Crop Evolution》1961,9(1):45-57
Summary It is shown in biometrical studies performed for two years and concerning the statistical diversity of fruitshape within one plant having two fruits that fruitshape is inherited as a reaction norm, the mother fruit being without influence on the progeny. The shape of the first fruit is extremely modifiable. Realization of the various fruit shapes is influenced at the end of the vegetative period by the position of the fruit on the plant, by weather, by infection and other environmental conditions. Experiments were done with someCucurbita pepo convar.patissonina Greb. inbred lines of the same origin.
PEP 1, , . , - , ( ) — , , . , ( ) , . ( ) . ( ) , , , . . , ; (Grebenikov 1960).相似文献
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Salt balance in simulated soil coulumns was calculated on the basis of a large amount of long term observation data.The results showed that under the climate conditions of semi-arid region of the Huang-Huai-Hai Plain,the soils in the columns were under salt accumulation conditions when the groundwater depth was controlled at less than 2.0m,and under desalinization conditions when at larger than 2.5m.In the soil columns with clay soil and silty loam soil intercalated with a clay layer,the amount of salt accumulated was far less than that in the soil column with silty loam soil throughout the whole profile.Under no irriagtion conditions crop planting may increase groundwater evaporation and hence salt accumulation in soil,making the soil columns under desalinization be under salt accumulation conditions. 相似文献
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水稻土中氧化还原过程的研究 (Ⅴ)还原性物质的测定 总被引:1,自引:0,他引:1
在上一工作[1]中,已强调指出了区分氧化还原状况的强度因素和数量因素的必要性,因为这是两个虽然也相互有关但却意义不同的方面。根据几年来的研究结果,土壤中的氧化还原电位,作为氧化还原状况的强度因素的指标,可以代表土壤的氧化作用或还原作用的强弱程度,因而可以在水稻土的研究中广泛应用。 相似文献
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Rachhpal-Singh & Nye's model of ammonia volatilization is expanded to account for the effects of steady-state water movement by drainage or evaporation when the soil does not dry out to any great extent. The model shows how upward movement of water during evaporation increases volatilization by carrying urea-derived NH4+ and HCO3? ions upward, thereby increasing the concentration of ammonia gas at the surface. Conversely, water drainage reduces volatilization by carrying the dissolved solutes into the soil. The model is used to assess the effects on volatilization of evaporating conditions and of irrigation or rainfall. 相似文献