Use of cesium-137 methodology in the evaluation of superficial erosive processes

Abstract

Superficial erosion is one of the main soil degradation agents and erosion rates estimations for different edaphicclimate conditions for the conventional models, as USLE and RUSLE, are expensive and time-consuming. The use of cesium -137 antrophogenic radionuclide is a new methodology that has been much studied and its application in the erosion soil evaluation has grown in countries as USA, UK, Australia and others. A brief narration of this methodology is being presented, as the development of the equations utilized for the erosion rates

Concentration of radioactive elements (U, Th and K) derived from phosphatic fertilizers in cultivated soils

“…In relation to the monoammonia and diammonia phosphates, these are obtained combining phosphoric acid and ammonia. Brazilian soils, mostly situated in the tropical zone, are in general poor as a consequence of constant losses by leaching (Andrello et al, 2003) of certain elements such as nitrogen, phosphor and potassium (Santos Júnior et al, 2005), which are essential to the cultures such as soybean, wheat and sugar cane. The present practice of replacing nutrients in the soils and consequently supplying substances in order to reach high productivity is by the application of chemical fertilizers, mostly compounds commercially named NPK.…”

Measurements of the fallout flux of beryllium-7 and its variability in the soil

“…The key advantages of the cesium-137 approach are the potential to obtain retrospective data and the provision of spatially distributed information on the erosion and deposition rates, on the basis of a single site visit, establishing sediment delivered ratios, the medium term average rates of soil redistribution, besides of its applicability to different environments. However, the cesium-137 methodology has some limitations that are the time-integrated nature of soil redistribution rates, which provide an average value for last 45 years and reflect the whole effects of both water and wind erosion and soil redistribution by tillage activity (Govers et al, 1996;Andrello et al, 2003Andrello et al, , 2004a. It is necessary to separate the erosion and tillage components if information on water and wind erosion alone is required.…”

Gamma-ray spectrometry sensor and geochemical prospecting in an area of sugar cane plantation

“…It is impossible to imagine the Brazilian agriculture in the last 20 years without the utilization of large amounts of the fertilizers. This, however interferes with the environment (Guiraud et al, 2004), but the consequences are still poorly known (Andrello et al, 2003). There are several formula and trademarks of the fertilizers in the market, with variable nitrogen, phosphorous and potassium contents.…”