Data/hora: 08/06/2024 09:44:51

Provedor de dados: | 117
País: | Chile
Título: | Glyphosate Mineralization: Effect of Temperature and Soybean and Corn Crop Residues
Autores: | Rampoldi,Ariel; Hang,Susana; Barriuso,Enrique.
Data: | 2008-03-01
Ano: | 2008
Palavras-chave: | Glyphosate; Stubbles; Mineralization; Non-tillage system; Total microbial activity.
Resumo: | Mineralization is the main mechanism of dissipation of glyphosate herbicide (N-[phosphonomethyl] glycine) in soil. However, there is scarce information about the mineralization process in strata formed by stubbles in no-tillage systems. The kinetics and rate of mineralization of herbicide in stubbles of soybean (Glycine max L. Merr.) and corn (Zea mays L.) were investigated. To evaluate the effect of age of crop residues, samples of soybean stubbles were collected immediately after harvest (Soja 1) and four months after harvest (Soja 2). Corn crop residues were collected three months after harvest. Glyphosate evolution and total microbial activity (TMA) were monitored by release of 14C-CO2 and C-CO2 under laboratory conditions with two temperatures, 15 and 28 ºC. Crop residues size was evaluated using grinding (1 mm) and cut (1 to 2 cm) stubbles. Results showed that glyphosate mineralization was affected by the incubation temperature and the origin and age of crop residues. Size of crop residues did not modify glyphosate mineralization. Average glyphosate mineralization after 56 days of incubation at 15 and 28 ºC was of 3.9 and 9.9%, respectively, of the 14C-glyphosate initially applied. In maize crop residues the percentages were 2.0 and 3.0%, respectively, at 15 and 28 ºC. A similar evolution was detected for TMA. The co-metabolic nature of glyphosate mineralization was corroborated. An inverse relation between C/N ratio and glyphosate mineralization was detected. Higher glyphosate mineralization was detected in fresh soybean stubbles, suggesting that applications on aged crop residues could increase the persistence of glyphosate in no-tillage systems
Tipo: | Journal article
Idioma: | Inglês
Identificador: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000100002
Editor: | Instituto de Investigaciones Agropecuarias, INIA
Formato: | text/html
Fonte: | Chilean journal of agricultural research  v.68 n.1 2008