PERFIL SALINO-SODICO DE UN MOLLISOL REGADO CON AGUAS SUBTERRÁNEAS Y RESIDUALES NO DEPURADAS EN LA CUENCA
DEL LAGO DE VALENCIA, VENEZUELA

F. J. MÉNDEZ

UCV. FAGRO. Instituto de Ingeniería agrícola. Maracay. Venezuela.

Abstract

The salts and sodium contents in two experimental plots (MOLLIC USTIFLUVENTICS, FRANCOSA CARBONATICA MIXTA ISOHIPERTERMICA) cultivated with sugar cane were studied. The first plot (T1) was irrigated for more than 10 years with non-treated wastewaters (R1) and the second plot (T2) with groundwater (S1). During the study period (from July 1997 to June 1998) 200 soil samples were taken by means of a systematic soil survey in each experimental plot, corresponding to 4 sampling points and 5 depths. The two irrigation water sources showed average values of ECr of 2,1 dS m-1 and 3,0 dS m-1, and SARº of 10,8 and 6,9, respectively. The soils of the experimental plots showed average values of ECe of 1,0 dS m-1 and 2,0 dS m-1, ESP of 5,9 and 2,3; and SAR of 5,1 and 2,4, respectively. Neither study soil showed risks of salinization and sodification during the research period. Statistical analysis showed significant differences in ECe and SAR between the two treatments (T1 and T2), and the interaction factor treatment x depth was only significant for ECe. Crop yields of the two plots (T1 and T2) were not affected, moreover the yields obtained (175 t ha-1 and 162 t ha-1, respectively) were greater than average yields of the region.

Key words: salinity, sodicity, wastewaters, Valencia Lake, sugar cane.