Biological attributes of two Quibor soils with addition of organic fertilizer and salt solutions

Abstract

The evaluation of the effect that applying organic fertilizer and salt solutions had on the biological attributes of two soils of Quibor, in the state of Lara, Venezuela, one under conventional management (CM) and another under conservation management (CS), was done using a greenhouse trial. Three doses of organic matter (OM) were used: 0, 15 and 30 Mg ha-1, and four irrigation solutions (IS): control with water (T), calcium sulfate (CS), sodium chloride (CN) and a mixture of calcium sulfate with sodium chloride (ME); three samplings were done at different moments, 32, 75 and 120 days after transplantation (DAT). The biological attributes were determined: basal respiration (C-CO2), microbial biomass carbon (MBC) and metabolic quotient (qCO2). The study showed that in the CM soil C-CO2 was affected independently by OM and IS, significantly increasing when OM was applied (261 μg C-CO2 g-1 soil 10 days-1), and decreasing with CN (214 μg C -CO2 g-1 soil 10 day-1); the qCO2 affected by the interaction of time with the IS was higher with tap water at 32 DAT (421 mg C-CO2 g-1 CBm day-1), while at 120 DAT it was higher with CN (683 mg C-CO2 g-1 CBm day-1). The CBm in the CM soil, and all biological attributes in the CS soil were affected by the interaction of OM dose with IS; this interaction in turn was inf luenced by time. The C-CO2 and the CBm were higher in CS compared with CM.