Diagnóstico del nivel de acidez y estimación de las necesidades de enmienda agrícola en suelos del municipio Pamplona, Norte de Santander mediante pruebas de incubación en laboratorio.

Abstract

Soil acidity and aluminum toxicity are considered the most limiting conditions affecting crop growth and yield. Acidic soils in Colombia occupy 85% of the surface approximately 96 million hectares. A good part of these are found in areas constituted by acidic parent materials, in rainy climates and undulating relief such as in the Andean region, Orinoquia and Amazonia. The municipality of Pamplona is located on the Eastern Cordillera of the Andes, with characteristics of high rainfall and abundant vegetation that favor the development of acidic soils. In this sense, in this study the acidity level was evaluated and the agricultural amendment requirements were determined in soils of the Pamplona municipality, Norte de Santander through laboratory incubation tests. For this, a completely randomized experimental design with four treatments and five repetitions was carried out. The treatments corresponded to: T0 = Control or control (0 dose of CaCO3 without liming); T1: 100% CaCO3 of the calculated dose (0.15 g of CaCO3 / 200 g of soil); T2: 50% CaCO3 of the calculated dose (0.075g CaCO3 / 200g soil); T3: 50% of the calculated dose distributed in a proportion of 50% CaCO3 + 50% chicken manure, Abimgra (0.075g of CaCO3 / 200g soil and 0.075g of Abimgra / 200g soil). The soils were incubated under laboratory conditions for a period of 15 days. The pH, electrical conductivity and exchangeable aluminum were measured before incubating the soils with the different treatments and after 15 days of incubation. Additionally, the texture of the soils, the percentage of gravimetric humidity, the apparent density, the organic matter and the electrical conductivity were determined. It was found that the soils presented a clay loam textural class with an important predominance of the percentage of clay, the apparent density was low compared to the reference values for soils of the clay loam textural class, the percentage of organic matter was low to sufficient. Soil pH was moderately acidic (5.29) and electrical conductivity was 14.39 µS / cm. The exchangeable aluminum (Al+3) was 2.0 ± 0.75 meq / 100 g a minimum indicating a medium level which is considered moderately toxic for some crops. The application of the different doses of amendments caused a decrease in the concentration of Al+3 in all treatments except the control (T0). However, significant differences were only found in T1 (use of 100% agricultural lime) on the decrease in Al+3. Similarly, the pH of the soils increased at the end of the 15 days of incubation of the soils, being statistically different in T1 where 100% of recommended agricultural lime was used according to the level of exchangeable aluminum. Al+3 values decreased from moderately toxic to slightly toxic (<1.8 meq / 100 g of soil). Electrical conductivity was low, but increased at the end of the incubation period. It is concluded that the best treatment was T1 in which 100% of the agricultural lime was used. The 15-day incubation period is not sufficient to achieve the reduction of Al+3 to less toxic and safer levels for the cultures. It is recommended to evaluate a longer incubation time and to test different classes and mixtures of agricultural amendments.