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81.
Evolution of C2H4 from soils under anaerobic conditions was stimulated by amendment with cereal straw, but hay had little effect. Temporary restoration of aerobic conditions resulted in large increases in C3 and C4 hydrocarbons, with both straw and hay amendments. Several known products of the fermentative degradation of carbohydrate increased the evolution of hydrocarbons under anaerobic, and to a greater extent, under aerobic conditions. In particular, ethanol and butyric acid promoted the formation of C2H4 and propylene, respectively. The association between degradation products and C2H4 suggests that both may be implicated when root growth is adversely affected by the anaerobic decomposition of plant residues. 相似文献
82.
83.
The relative persistence of 2,4-D, MCPA and 2,4,5-T in some Saskatchewan soils was assessed under laboratory conditions. Under moist conditions, 2,4-D and MCPA showed half-life times of between 14 and 41 days but the MCPA half-life was usually 1 or 2 days longer. 2,4,5-T exhibited a half-life period over twice the length of the other chemicals. The half-life times were directly correlated to microbial plate counts, the larger numbers of soil microorganisms being associated with shorter residence times. Half-lives depended on soil moisture content and the best moisture levels for chemical loss appeared to be just less than field capacity. The use of 14C in 2,4-D incubation studies showed that the initial cleavage of the 2,4-D molecule was associated with the ether linkage and was not a decarboxylation. 相似文献
84.
An experiment was carried out on a grass/white-clover sward at North Wyke to evaluate the use of mixtures of inorganic and organic nutrient sources to simulate the nutrient effect of animal excreta, both with and without overall PK fertilizer. Grazing with sheep and the return of excreta from caged sheep both increased herbage yields, as did artificial return treatments. Artificial return treatments giving 75% of the nutrient level returned by excreta gave yields comparable with grazing. The effect of the simulated return treatments was not influenced by PK application. Grazing gave a very different botanical composition to that from the treatments in wbich natural or simulated excreta were returned to cut swards. Mixtures simulating excreta may replace the nutrient effect of the grazing animal, but not its physical effect, in some forms of grassland experimentation. They are not recommended for fertilizer trials. 相似文献
85.
K. M. Graham 《Euphytica》1965,14(1):113-119
S. bulbocastanum is highly interfertile with S. cardiophyllum. Through the F1 to F5 little breakdown due to sterility or lack of plant vigour occurred. F1 plants of a 5-species hybrid involving S. pinnatisectum, S. trifidum, S. jamesii, S. bulbocastanum, and S. cardiophyllum could also be intercrossed. One-way compatibility was frequently expressed in progenies of these interspecific crosses. It appears to be cytoplasmically controlled, although nuclear factors may be present which interact with cytoplasmic factors. The group of Mexican diploid potatoes represented by these species is potentially interbreeding and shows evidence of introgression throughout its range in central and Western Mexico.Contribution No. 169, Canada Department of Agriculture Research Station, Fredericton, New Brunswick, Canada 相似文献
86.
K. Abetz 《Forstwissenschaftliches Centralblatt》1961,80(5-6):157-166
Ohne Zusammenfassung 相似文献
87.
WRIGHT LD CRESSON EL SKEGGS HR PECK RL WOLF DE WOOD TR VALIANT J FOLKERS K 《Science (New York, N.Y.)》1951,114(2972):635-636
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