Uso de azufre en suelos contaminados con Spongospora subterranea (Wallr.) Lagerh y su incidencia en la roña de la papa (Solanum tuberosum L.), estado Mérida, Venezuela

The excessive and indiscriminate use of agricultural lime has produced an increase of soil’s pH at the Merida Paramo, increasing incidence and distribution of powdery scab of potato (Spongospora subterranea), the fact is that this incidence, triggers 6,8-7 pH. In this work, we evaluated the elementary Sulphur use on soil pH and infection on powdery scab of potato (Solanum tuberosum L.) in soils with this pathogen. A farm experiment was installed in Misinta, Rangel Municipality, Merida state. The treatments were applied: T0: 0 kg S/ha, T1: 490 kg S/ha, T2: 980 kg S/ha, T3: 1460 kg S/ha and T4: 1970 kg S/ha. Granola variety´s potato was seeded and the traditional management of cultivation was made. Additionally, in shade house localized in the IIAP- ULA in Santa Rosa, Merida State, polyethylene bags were filled with 2 kg of Misinta soil and treatments were applicable: T0: 0 kg S/ ha, T1: 250 kg S/ha, T2: 500 kg S/ha, T3: 750 kg S/ha, T4: 1000 kg S/ ha and T5’s kg: 5000 kg S/ha. In both experiments, the pH of the soil was determined periodically from the beginning even the 135 and 180 days, respectively. The soil pH at field, was decreased even in 0.4 units by the sulphur application of 1460 and 1970 kg/ha. In the shade house, 1000 kg S/ha application of elementary sulphur, guarantees a decrease of the studied soil pH, in 0.6 units. There were no statistically significant differences in potato yields and powdery scab infection, however, the application of sulfur in the yield, specially the doses of 980, 1460 and 1970 kg S/ha, decreased the occurrence of powdery scab on potato, which indicates that the use of this amendment favored the production of healthy tubers at the studied soils.