Data/hora: 03/06/2024 10:52:10

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 20/03/2002
Data da última atualização: | 18/07/2018
Autoria: | McINTYRE, B. L.
Afiliação: | Kansas State University (Manhattam).
Título: | Persistence of Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) as influenced by population densities and corn (Zea mays L.) hybrids.
Ano de publicação: | 1971
Fonte/Imprenta: | Manhattan: Kansas State University, 1971.
Páginas: | 84p.
Idioma: | Inglês
Notas: | Ph.D. Dissertation.
Conteúdo: | A study was conducted during 1968 and 1969 with six corn (Zea mays L.) populations, eight hybridis, and two rates of atrazine (2-chloro-4-(ethylamino-6-(isopropylamino)-s-triazine) to learn how these variables influenced grain and stover yield of corn and the yield and components of yield in soybeans (Glycine max (L.) Merrill) planted on the same area the following season. The six populations used were 19,800, 29,700, 39,500. 49,400, 59,300 and 69,200 plants per/ha in 76-cm rows widths. Atrazine at 3.36 and 6.72 kg/ha was applied preemergent to the corn. Differences in corn grain and stover yields were highly significant and effects of populations were highly significant for the resulting corn grain, stover, and total dry matter yields. Soil samples of O- to 15-cm depths were collected from each plot in the fall after corn harvested and in the spring just after the soybeans were planted. Soybean plant bioassays were performed on them to detect the persistance of atrazine. Soybean were planted between the old corn plot rows from the preceding year by planting the beans in 51-cm rows. Data collected for the soybeans included plants/meter of row, nodes/plant, pods/node, beans/pod, weight/100 beans, and plant height in 1969 and 1970. An additional study consisting og for treatments, atrazine at 3,36 cr 6.72 kg/ha and planting half of the plets to corn, leaving the other half fallow, was imitiated in the summer of 1970. Soil sample were collected at 0- to 15-, 15- to 30-, and 30- to 60-cm depths at intervals of three weeks for fifteen weeks. Extra samples were collected at the 0- to 5-, 5- to 10-, and 10- to 15-cm depths on two dates, one early in the season and one at the conclusion of the experiment. Bioassay were run on all these soil samples and the emergence, epicotyl lenght, hypocotyl above soil lenght, epicotyl lenght above first true leaves, epicotyl fresh weight, hypocotyl fresh weight, epicotyl dry weight, hypocotyl dry weight, and a herbicida injury value were recorded. No phytotoxic disturbance occurred in the field soybeans that followed the corn experiments or in the bioassays of the 1968 fall, 1969 spring, 1969 fall, or 1970 spring soil samples. In the additional study, corn plants increased the rate of strazine dissipation, but by the end of the fifteen week period, the atrazine concentration had been reduced to a non-phytotoxic level. It was concluded that applied at recommended rates will not persist beyond a single growing season in phytotoxic concentration. The herbicide did not leach beyond the 0- to 15-cm soil depth under the conditions that prevailed during this study. Atrazine dissipation was attributed to the combined processes of chemical hydrolysis, plant uptake, and microbial decomposition.
Palavras-Chave: | Corn Plant; Growth; Morfologia; Morphology.
Thesagro: | Agronomia; Cereal; Crescimento; Fisiologia.
Thesaurus Nal: | physiology.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (33999-1) - ADD - TS - PP - TS89.00375 -  - 1989.00375 - DIS