Pre-Columbian Human-Environment Interactions in the Upper Madeira Basin, southwest...
| Grant number: | 04/01230-0 |
| Support type: | Regular Research Grants |
| Duration: | October 01, 2004 - November 30, 2006 |
| Field of knowledge: | Agronomical Sciences - Agronomy |
| Principal Investigator: | Carlos Clemente Cerri |
| Grantee: | Carlos Clemente Cerri |
| Home Institution: | Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil |
Abstract
Favorable conditions of topography and climate make the Cerrado (wooded savanna) one of the world’s most promising agricultural frontiers. The clearing and burning of the natural vegetation, followed by the cultivation of the soil lead to a decrease in the stock of the soil’s organic material (SOM) and increase in the emission of greenhouse effect gases. Conservationist practices, such as the no-till planting system, are efficient strategies for the mitigation of these effects. The general objective of the research will be to evaluate SOM alterations in the process of the conversion of the Cerrado of Amazonia into areas of conventional cultivation and no-till farming. The work will be undertaken at the Fazenda União, in Vilhena (RO), which has been systematically cleared since 1997 for the planting of annual crops, with the current situation being a chronosequence consisting of cerrado, areas with one or two years of conventional cultivation and with one to four years of no-till farming following on from conventional cultivation. We will collect soil and gas samples in a strip of 1 hectare (200m x 50m), subdivided into five plots of 40m x 50m, which will constitute the repetitions. The levels of C and N, associated with the density of the respective layer, will make it possible to calculate the stock, the variation of which through time will indicate an eventual sequestration of C. The flux of the gases will be measured in five static layers in which the samples will be taken at regular intervals (time 0, 5, 10 and 20 minutes) in 20 ml BD syringes and analyzed by gas chromatography. The measurements will be taken twice in a 24-hour period, at the time of minimum and maximum temperature, and at least twice a year, that is, after harrowing in the dry season and during the development of the crop in the wet season. This sequence should provide information on the dynamic of the flux of gases after the preparation of the soil and the fertilization of the crops. The Century model will be applied to simulate the dynamic of C and N in the soil, initially assuming a state of dynamic equilibrium of the soil under native vegetation, followed by simulation of the temporal variations. The results will be compared with the data effectively measured in the field and potential data contained in the literature. (AU)