%0 Journal Article
%T Acidification evidences of no-tilled soils of the central region of argentina Evidencias de acidificaci車n de suelos de la regi車n central de la argentina bajo siembra directa
%A Laura Antonela Iturri
%A Daniel Eduardo Buschiazzo
%A Mart赤n D赤az-Zorita
%J Ciencia del Suelo
%D 2011
%I Asociaci車n Argentina de la Ciencia del Suelo
%X Empiric evidences indicate that agricultural soils of Argentina tend to acidify. The objective of this study was to determine the pH values of no-tilled and urea-fertilized-agricultural soils of Argentina during several years. Results indicated that both the actual pH (pH A) and the potential pH (pH P) values were lower in humid than in dry environments. The ratio between  mean annual precipitation:mean annual temperature  of the sites explained between 60 and 80% of the variability in pH values. This suggests that climatic conditions were responsible for current soil pH values. The pH A was 1.14 points higher tan pH P in all studied sites (p<0.01), indicating that a generalized natural acidification process existed. In soils of drier environments, differences between both pH A and pH P were, on average, higher than 1.21, indicating a more intense acidification process. However, pH values were not low enough to affect the normal growth of crops and soil organisms. In soils of humid environments, differences between pH A and pH P were higher than 1.10, being pH A values (6.17 and 5.80) acidic enough to affect the microbial activity and the development of pH sensitive crops. Fertilization with urea decreased pH A between 0.18 and 0.32 points compared to non-fertilized treatments (p<0.05), indicating that fertilization contributed to a decrease in pH values in the studied soils. In conclusion, fertilization with urea slightly increased the natural tendency to soil acidification in most of the studied soils. Evidencias emp赤ricas indican que los suelos agr赤colas de la Argentina tienden a la acidificaci車n. El objetivo de este estudio fue determinar valores de pH de suelos agr赤colas de la Argentina bajo siembra directa de larga duraci車n y fertilizaci車n con urea. Los resultados indican que tanto los valores de pH actual (pH A) como de pH potencial (pH P) fueron m芍s bajos en ambientes h迆medos que en los m芍s secos. El cociente entre  precipitaci車n media anual : temperatura media anual  de los sitios explic車 entre un 60 y un 80% de la variabilidad de los valores de pH. Esto sugiere que las condiciones clim芍ticas fueron responsables de los valores de pH presentes en estos suelos. El pH A fue 1,14 puntos mayor que el pH P en todos los sitios estudiados (p < 0,01) indicando que existi車 un proceso natural generalizado de acidificaci車n. En suelos de ambientes m芍s secos, las diferencias entre el pH A y el pH P fueron, en promedio, mayores a 1,21. Esto indicar赤a una acidificaci車n m芍s intensa. Sin embargo, los valores de pH no fueron lo suficientemente bajos como para afe
%K Acidificaci車n de suelos
%K Fertilizantes nitrogenados
%K Degradaci車n de suelos
%K Soil acidification
%K Nitrogen fertilizers
%K Soil degradation
%U http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1850-20672011000100002