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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
01/08/1992 |
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Data da última atualização: |
20/07/2023 |
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Autoria: |
WIEGERT, R. G.; EVANS, F. C. |
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Título: |
Primary production and disappearance of dead vegetation on an old field in southeastern Michigan. |
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Ano de publicação: |
1964 |
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Fonte/Imprenta: |
Ecology, v. 45, n. 1, p. 49-63, Jan. 1964. |
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Idioma: |
Inglês |
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Conteúdo: |
During the period 1949-60 the flora of a long- abandoned field in southeastern Michigan showed little change. The peak standing crop of vegeta- tion remained relatively constant from year to year, but during this period grasses decreased in importance from more than 90% of the standing crop biomass to less than 50%o. Because of the diverse perennial flora of the Old Field, the peak standing crop was not a good indi- cation of annual net production. Instead, the an- nual disappearance of dead material was equated with the net annual growth, exclusive of herbivore consumption. Dead material in place on the field disappeared at rates of from 8.4 to 1.3 mg/g per day on the upland and 13.6 to 1.8 mg/g per day on the swales, depending on time of year. Material placed in mesh bags did not disappear as fast as undisturbed material, even after being on the field 6 months. But the mesh-bag experiments showed that the rate of disappearance did differ with species of plant during the first 2 months after placement, but not thereafter. The rates of disappearance of dead material, combined with data on green and dead standing crops, were used to calculate net production of the aboveground plant parts and its seasonal distribu- tion in 1959 and 1960. In 1959, shoot production on the Old Field was: upland, 1,328 kcal/m2; swale, 4,102 kcal/m2. In 1960 the corresponding values were: upland, 1,392 kcal/m2 and swale, 4,629. The net annual production of root biomass in 1960 was minimally estimated as 631 kcal/m2 on upland and 1,573 kcal/m2 on the swales. Net production of the vegetation in 1960 (ex- clusive of herbivore consumption but including root production) thus was estimated as 2,023 kcal/m2 on upland and 6,202 kcal/m2 on the swales. Because of the greater quantitative importance of root growth as compared to the amount of herbivore consumption, lack of detailed informa- tion about the latter is less an obstacle to the cor- rect estimation of annual net production of vege- tation than is the present ignorance of the dynamic processes associated with the subterranean parts of the plant community MenosDuring the period 1949-60 the flora of a long- abandoned field in southeastern Michigan showed little change. The peak standing crop of vegeta- tion remained relatively constant from year to year, but during this period grasses decreased in importance from more than 90% of the standing crop biomass to less than 50%o. Because of the diverse perennial flora of the Old Field, the peak standing crop was not a good indi- cation of annual net production. Instead, the an- nual disappearance of dead material was equated with the net annual growth, exclusive of herbivore consumption. Dead material in place on the field disappeared at rates of from 8.4 to 1.3 mg/g per day on the upland and 13.6 to 1.8 mg/g per day on the swales, depending on time of year. Material placed in mesh bags did not disappear as fast as undisturbed material, even after being on the field 6 months. But the mesh-bag experiments showed that the rate of disappearance did differ with species of plant during the first 2 months after placement, but not thereafter. The rates of disappearance of dead material, combined with data on green and dead standing crops, were used to calculate net production of the aboveground plant parts and its seasonal distribu- tion in 1959 and 1960. In 1959, shoot production on the Old Field was: upland, 1,328 kcal/m2; swale, 4,102 kcal/m2. In 1960 the corresponding values were: upland, 1,392 kcal/m2 and swale, 4,629. The net annual production of root biomass in 1960 was minimally estimat... Mostrar Tudo |
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Palavras-Chave: |
Degraded pasture; Pastagem degradada; Restolho. |
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Thesagro: |
Decomposição; Pastagem. |
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Thesaurus Nal: |
Pastures; Soil degradation; Stubble. |
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Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
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Marc: |
null
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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