Effect of Crop Residues and Nitrogen Additions on Decomposition of an Ohio Muck Soil

The effect of increased deposition of atmospheric nitrogen on Calluna vulgaris in upland Britain

“…Increased litter fall can lead to a number of effects on soil processes, including changes in microbial processes, decomposition rate and nitrogen mineralization (Stotzky & Mortensen, 1957 ;Berendse, 1990 ;Singh, 1995), leading to further increases in nitrogen availability ; any effects on these processes are likely to be accelerated by the increased tissue nitrogen concentrations in litter from the treated plots (Vinton & Burke, 1995 ;Fisk & Schmidt, 1996). The total litter weight values given here might therefore represent an underestimate of the increase in litter fall due to nitrogen treatment over the full period of the study.…”

Effect of root refuse of liquorice on different characteristics of soil from southern regions of Iran. I. microbial characteristics

“…The amount of evolved CO 2 from powdered liquorice root refuse of Rishmak, Zarghan, and Shirin-Daroo factories, wheat straw and alfalfa were 51.91, 52.27, 51.70, 55.17, and 63.39 mg (20 g) 21 of soil, respectively ( Table 6). Stotzky and Mortensen (12), and Maftoun and Banihashemi (14), confirmed that the lower production of CO 2 in soils amended with wheat straw than with alfalfa was due to the fact that straw had a higher percentage of microbially-resistant compounds such al lignin, and lower N content than alfalfa. Greater decomposition rate of alfalfa as compared with wheat straw and liquorice root refuses apparently substantiates this hypothesis that a lower nitrogen content or a wide C:N ratio is associated with lower decomposition, because the C:N ratios of alfalfa, wheat straw, and liquorice root refuse are 10.32:1, 51.21:1, and (25.65 -28.68):1, respectively (Table 4); yet, it is not the sole determinant, and other factors, e.g., chemical composition, especially abundant of lignin, may also be operative.…”

“…Greater decomposition rate of alfalfa as compared with wheat straw and liquorice root refuses apparently substantiates this hypothesis that a lower nitrogen content or a wide C:N ratio is associated with lower decomposition, because the C:N ratios of alfalfa, wheat straw, and liquorice root refuse are 10.32:1, 51.21:1, and (25.65 -28.68):1, respectively (Table 4); yet, it is not the sole determinant, and other factors, e.g., chemical composition, especially abundant of lignin, may also be operative. Stotzky and Mortensen (12), by presenting the cumulative CO 2 evolution curves for a peat soil treated with various amounts of rye, alfalfa, and straw and incubated for 113 days, indicated that, a stable rate of CO 2 evolution was achieved by the twentieth day. Stotzky and Mortensen (12), and Maftoun and Banihashemi (14), confirmed that the lower production of CO 2 in soils amended with wheat straw than with alfalfa was due to the fact that straw had a higher percentage of microbially-resistant compounds such al lignin, and lower N content than alfalfa.…”

Respiration and microbial growth in a New Zealand grassland soil

“…These observations contrast with those of Jackman (1960), who found that the micro-flora of a highly developed old pasture on a North Island pumice soil did not respond to sucrose when the soil was wetted after being air-dried. The pumice soil contained 12 per cent carbon, however, as against 3.6 per cent for Craigieburn soil; in fact, it has been often found (e.g., see Stotzky and Mortensen 1957) that available carbon is the chief limiting factor to respiration in soils. The extent to which air-drying made carbon available in Craigieburn soil was indicated by plotting data from a variety of experiments, as shown in Table 4.…”